4130 can't be OA welded? [Archive]

December 29th 07, 05:27 PM

On Dec 29, 8:09 am, "Anyolmouse" > wrote:
> > wrote in message
>
> ...
> | On Dec 28, 6:28 pm, "Anyolmouse" > wrote:
> |
> | > For many years that was the only approved method. Then along came
> TIG
> | > welding.
> |
> | American Champion has been using MIG for years now. Quicker
> | and easier than TIG. But their tubing tends to be heavier, too, which
> | makes MIG an easy option.
> |
> | Dan
> |
>
> I didn't know that it was approved for aircraft.

It's approved by manufacturer's drawings. The manufacturer
will call for welds as per their own welding specs, and those specs
plus the airframe drawings are approved by the FAA. We sometimes find
industrial hardware or other "uncertified" parts on airplanes, and
they're approved by their presence on the drawings. For example,
American Champion uses a cheap industrial clip nut on their cowling
installations that has no locking feature and it's really soft so it
cross-threads easily. And is forever falling off or sliding out of
place. This is fixed using the minor modification provisions of the
applicable country's aircraft maintenance laws, replacing those stupid
things with real aircraft hardware.

Dan

Anyolmouse

December 29th 07, 08:13 PM

> wrote in message
...
| On Dec 29, 8:09 am, "Anyolmouse" > wrote:
| > > wrote in message
| >
| >
...
| > | On Dec 28, 6:28 pm, "Anyolmouse" >
wrote:
| > |
| > | > For many years that was the only approved method. Then along
came
| > TIG
| > | > welding.
| > |
| > | American Champion has been using MIG for years now.
Quicker
| > | and easier than TIG. But their tubing tends to be heavier, too,
which
| > | makes MIG an easy option.
| > |
| > | Dan
| > |
| >
| > I didn't know that it was approved for aircraft.
|
| It's approved by manufacturer's drawings. The manufacturer
| will call for welds as per their own welding specs, and those specs
| plus the airframe drawings are approved by the FAA. We sometimes find
| industrial hardware or other "uncertified" parts on airplanes, and
| they're approved by their presence on the drawings. For example,
| American Champion uses a cheap industrial clip nut on their cowling
| installations that has no locking feature and it's really soft so it
| cross-threads easily. And is forever falling off or sliding out of
| place. This is fixed using the minor modification provisions of the
| applicable country's aircraft maintenance laws, replacing those stupid
| things with real aircraft hardware.
|
| Dan
|
|

Thanks,

--
Anyolmouse

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Phil

December 31st 07, 05:13 PM

Have been doing A/C welding of 4130 for 30 yrs. both as an EAA Amateur and
for A/C manufacturing company under Mil. Spec. Cert. ,almost all A/C welding
was done with Oxy./Acet. until the 1960's , at that time it was found that
one could speed up production with TIG welding and the supply of skilled
Oxy./Acet. welders was drying up , I understand that the MIG process has
been approved for some time , a real shame that Oxy. has slowly been
eliminated from the A/C manufacturing , won't go into the HAZ , Thermal
Shock and loss of ductility thing as it is like religion and politics , it
always starts a fight , for all around reliability with respect to welding
4130 , I would place Oxy./Acet. at the top of my list and TIG and MIG as
second and last , Spirit Of St. Louis was Gas welded as was all of those old
J3's , T Craft's .
Happy New Year
Phil Lohiser
EAA 1273
"wright1902glider" > wrote in message
...
> While browsing a bit more of that "good 'ole internet wizdom", I ran
> accross this page:
>
> http://www.ihpva.org/com/PracticalInnovations/materials.html
>
> Its a human-powered vehicle website, but on this page, the author
> seems to think that 4130 cro-mo steel can't be welded with an oxy-
> acetylene torch. Does this sound right? It was always my belief that
> we've been OA welding airplanes out of the stuff for decades. Who is
> wrong on this point?
>
> Harry "I'm still stuck in the wood-age" Frey
>

Bill Daniels

December 31st 07, 07:15 PM

I'm 100% confident that I can use O/A to produce a clean, void free weld in
4130 that is stronger than the surrounding metal. I can also do that with
TIG but I'm not as sure that the join is completely stress free. The
extreme heat from TIG is concentrated in a tiny area whereas the O/A torch
has heated the surrounding metal and effectively relieved the stresses.

That said, if I could afford TIG, that's what I would use. If stress
build-up bothered me, I could always stress releive by reheating and slow
cooling the weld with the old O/A torch.

Bill Daniels

"Phil" > wrote in message
...
> Have been doing A/C welding of 4130 for 30 yrs. both as an EAA Amateur and
> for A/C manufacturing company under Mil. Spec. Cert. ,almost all A/C
> welding was done with Oxy./Acet. until the 1960's , at that time it was
> found that one could speed up production with TIG welding and the supply
> of skilled Oxy./Acet. welders was drying up , I understand that the MIG
> process has been approved for some time , a real shame that Oxy. has
> slowly been eliminated from the A/C manufacturing , won't go into the HAZ
> , Thermal Shock and loss of ductility thing as it is like religion and
> politics , it always starts a fight , for all around reliability with
> respect to welding 4130 , I would place Oxy./Acet. at the top of my list
> and TIG and MIG as second and last , Spirit Of St. Louis was Gas welded as
> was all of those old J3's , T Craft's .
> Happy New Year
> Phil Lohiser
> EAA 1273
> "wright1902glider" > wrote in message
> ...
>> While browsing a bit more of that "good 'ole internet wizdom", I ran
>> accross this page:
>>
>> http://www.ihpva.org/com/PracticalInnovations/materials.html
>>
>> Its a human-powered vehicle website, but on this page, the author
>> seems to think that 4130 cro-mo steel can't be welded with an oxy-
>> acetylene torch. Does this sound right? It was always my belief that
>> we've been OA welding airplanes out of the stuff for decades. Who is
>> wrong on this point?
>>
>> Harry "I'm still stuck in the wood-age" Frey
>>
>
>

Stuart & Kathryn Fields

December 31st 07, 11:29 PM

Bill: I recently did an article for our Experimental Helo magazine and did
some research on PWHT and found things like a minimum of 2hrs required @ 300
degrees C to adequately stress relieve a weld. All of the reports that I
read didn't think that the few tens of seconds of OA heating as a post weld
technique for stress relief was very effective. If you Google stress
relief of welded joints you will get a surprise. There has been a large
amount of testing and review of both pre-heat and post weld heat treatment
done on various materials complete with microscopic examination of the
affected areas. Further, Richard Finch, an EAA tech counselor and one time
head of Aerostar aircraft welding department said that 1800 Aerostar engine
mounts were all TIG welded without pre or post heat treatment. Records show
no cracking, while Fairchild Swearingen's Metroliners all had cracking
problems with TIG welded engine mounts that were both pre and post weld
heat treated. He did mention, however that the Metroliner mounts were TIG
welded with the copper coated welding rod common to OA welding. I know what
the "old timers" say about this but there doesn't seem to be much scientific
data to support the "old tried and true" method.

stu fields
Experimental Helo magazine.
"Bill Daniels" <bildan@comcast-dot-net> wrote in message
. ..
> I'm 100% confident that I can use O/A to produce a clean, void free weld
> in 4130 that is stronger than the surrounding metal. I can also do that
> with TIG but I'm not as sure that the join is completely stress free. The
> extreme heat from TIG is concentrated in a tiny area whereas the O/A torch
> has heated the surrounding metal and effectively relieved the stresses.
>
> That said, if I could afford TIG, that's what I would use. If stress
> build-up bothered me, I could always stress releive by reheating and slow
> cooling the weld with the old O/A torch.
>
> Bill Daniels
>
>
> "Phil" > wrote in message
> ...
>> Have been doing A/C welding of 4130 for 30 yrs. both as an EAA Amateur
>> and for A/C manufacturing company under Mil. Spec. Cert. ,almost all A/C
>> welding was done with Oxy./Acet. until the 1960's , at that time it was
>> found that one could speed up production with TIG welding and the supply
>> of skilled Oxy./Acet. welders was drying up , I understand that the MIG
>> process has been approved for some time , a real shame that Oxy. has
>> slowly been eliminated from the A/C manufacturing , won't go into the HAZ
>> , Thermal Shock and loss of ductility thing as it is like religion and
>> politics , it always starts a fight , for all around reliability with
>> respect to welding 4130 , I would place Oxy./Acet. at the top of my list
>> and TIG and MIG as second and last , Spirit Of St. Louis was Gas welded
>> as was all of those old J3's , T Craft's .
>> Happy New Year
>> Phil Lohiser
>> EAA 1273
>> "wright1902glider" > wrote in message
>> ...
>>> While browsing a bit more of that "good 'ole internet wizdom", I ran
>>> accross this page:
>>>
>>> http://www.ihpva.org/com/PracticalInnovations/materials.html
>>>
>>> Its a human-powered vehicle website, but on this page, the author
>>> seems to think that 4130 cro-mo steel can't be welded with an oxy-
>>> acetylene torch. Does this sound right? It was always my belief that
>>> we've been OA welding airplanes out of the stuff for decades. Who is
>>> wrong on this point?
>>>
>>> Harry "I'm still stuck in the wood-age" Frey
>>>
>>
>>
>
>

Rich S.[_1_]

January 1st 08, 12:06 AM

"Stuart & Kathryn Fields" > wrote in message
.. .
> Bill: I recently did an article for our Experimental Helo magazine and
> did some research on PWHT and found things like a minimum of 2hrs required
> @ 300 degrees C to adequately stress relieve a weld.

Back in the early '60s I worked in the pipefitting shop at Todd shipyards.
Along with the repair work, we were building two new DDE's (Destroyer
Escorts). They were powered with steam turbines running 1500# of steam
pressure at 1000 degrees F. (or so).

The steam piping was Chrome-Moly tubing from 1" IPS (1.315" dia.) up to the
big 6-8" stuff. All of it was welded with TIG and then stress-relieved. We
had a dedicated area of the shop set up for that process. The pipes were
wrapped with asbestos sheeting followed by water-cooled electrical cables.
More asbestos was wrapped on top.

The cables were hooked to a large machine which sent alternating current
through them, inductively heating the piping within the coils. I don't
remember the temperatures or time involved, but they were recorded on chart
recorders. The process lasted many hours - even overnight IIRC. They were
heated to an initial, high temperature (700 F?) and then slowly cooled. The
records became a permanent official part of the piping's history and
pedigree - much like the documentation of aircraft components.

It was a job well-suited for the older, disabled steamfitters as it was
light work but demanded experience and meticulousness. There are few things
more scary than a cracked flange weld on a 6" high-pressure steam pipe at
sea. The escaping gas will easily slice a leg off at the thigh, cauterizing
the wound nicely.

Happy New Year!

Rich S.

Stuart & Kathryn Fields

January 1st 08, 01:41 AM

Thanks Rich: That coroborates all the stuf I found thru digging thru
University research papers, certified welding instructors, Metalurgical
studies and a bunch of writings of people like you and the EAA tech
counselor. All that said, I have an IA friend that still insists on the OA
" normalizing" or "stress relieving" after a TIG weld. However, not on my
helicopter.
Stu
"Rich S." > wrote in message
...
> "Stuart & Kathryn Fields" > wrote in message
> .. .
>> Bill: I recently did an article for our Experimental Helo magazine and
>> did some research on PWHT and found things like a minimum of 2hrs
>> required @ 300 degrees C to adequately stress relieve a weld.
>
> Back in the early '60s I worked in the pipefitting shop at Todd shipyards.
> Along with the repair work, we were building two new DDE's (Destroyer
> Escorts). They were powered with steam turbines running 1500# of steam
> pressure at 1000 degrees F. (or so).
>
> The steam piping was Chrome-Moly tubing from 1" IPS (1.315" dia.) up to
> the big 6-8" stuff. All of it was welded with TIG and then
> stress-relieved. We had a dedicated area of the shop set up for that
> process. The pipes were wrapped with asbestos sheeting followed by
> water-cooled electrical cables. More asbestos was wrapped on top.
>
> The cables were hooked to a large machine which sent alternating current
> through them, inductively heating the piping within the coils. I don't
> remember the temperatures or time involved, but they were recorded on
> chart recorders. The process lasted many hours - even overnight IIRC. They
> were heated to an initial, high temperature (700 F?) and then slowly
> cooled. The records became a permanent official part of the piping's
> history and pedigree - much like the documentation of aircraft components.
>
> It was a job well-suited for the older, disabled steamfitters as it was
> light work but demanded experience and meticulousness. There are few
> things more scary than a cracked flange weld on a 6" high-pressure steam
> pipe at sea. The escaping gas will easily slice a leg off at the thigh,
> cauterizing the wound nicely.
>
> Happy New Year!
>
> Rich S.
>

Phil

January 1st 08, 02:33 AM

NASA published an advisory many years ago that was reprinted in Sport
Aviation , I don't have the article at my fingertips , as I remember , NASA
stated that any 4130 weld assembly that was TIG welded and used on Aircraft
should be post heated via Oxy/Acet , anyone who has ever done any welding
and especially ARC welding must know and has experienced the tension that
has built up after the weld has cooled , just a pinch of common sense would
tell you that this tension load will be there for the life of the weldment ,
to raise the temp. of a given cluster up to a point that allows that cluster
to seek it's sweet spot without that locked in tension and possible
premature failure would only make common sense , NASA is far from perfect
but they were on the money with this advisory .
I don't know how many people that write books on welding have actually
worked on the floor with real airplanes and have actually welded on
commercial airplanes , I have seen many lineal inches of Oxy/Acet weld laid
down and never saw a crack or fracture of that weld that occurred on the
floor even before an assembly was painted , I have seen many TIG welded
assemblies that would crack shortly after welding and again before they saw
paint , if you have an engine mount that needs a small amount of machining
and the machinist is damaging high speed steel end mills with hardened 4130
, this has to be very telling , it's been a few years since I worked for a
Jet engine repair station , as I recall , all welded parts were placed in a
oven and slowly raised to about 1020 Deg. F. and held at that temp. for 3
hrs. and then the temp. was dropped at a certain rate for several hours ,
they didn't do this for there own pleasure , this was FAA mandated .
Best
Phil Lohiser
"wright1902glider" > wrote in message
...
> While browsing a bit more of that "good 'ole internet wizdom", I ran
> accross this page:
>
> http://www.ihpva.org/com/PracticalInnovations/materials.html
>
> Its a human-powered vehicle website, but on this page, the author
> seems to think that 4130 cro-mo steel can't be welded with an oxy-
> acetylene torch. Does this sound right? It was always my belief that
> we've been OA welding airplanes out of the stuff for decades. Who is
> wrong on this point?
>
> Harry "I'm still stuck in the wood-age" Frey
>

Morgans[_2_]

January 1st 08, 04:10 AM

"Stuart & Kathryn Fields" > wrote

> Thanks Rich: That coroborates all the stuf I found thru digging thru
> University research papers, certified welding instructors, Metalurgical
> studies and a bunch of writings of people like you and the EAA tech
> counselor. All that said, I have an IA friend that still insists on the
> OA " normalizing" or "stress relieving" after a TIG weld. However, not on
> my helicopter.

So, do you think that the tig welding does not induce the stresses, and
therefore not need the quick OA "stress relieving" or what? I'm interested
in the reasons you came to this conclusion.

I may need to make cromolly engine mount, but the rest of my dreambuilt
airplane will not require any normalizing.

I hear wood airplanes do very poorly with an OA torch held at their
"clusters." ;-)
--
Jim in NC

Stuart & Kathryn Fields

January 1st 08, 05:28 PM

Morgans: According to everything I read in my research for the article I
wrote, the "Quick stress relieving" by the few seconds of OA after a TIG
weld do not effectively relieve the stress and can actually cause a
weakening of the weld joint. There appears to be quite a bit of truly
scientific experimentation to support this view. As a retired engineer, I'm
more prone to accept the scientists report over the anecdotal evidence from
more questionable sources. All that said, I can relate to failures that I
saw as the result of a crash of Chrome Moly airframe. Tube failures near a
cluster showed a separation that occurred just a short distance (1/4") from
the weld that was relatively clean and very even and roughly resembling a
fatigue failure zone. The Richard Finch that I referred to in an earlier
post wrote the book called Performance Welding and cited his experience at
Aerostar. I'm going with him and his belief supported by the research I did
and will not allow an OA torch near my TIG welded joints.
BTW, with the exception of some welds on my SS exhaust, none of my TIG welds
which includes fuel and oil tanks and the SS railing on a 35' Sailboat have
shown any cracking. None of these had OA "Stress Relief".

Stu
"Morgans" > wrote in message
...
>
> "Stuart & Kathryn Fields" > wrote
>
>> Thanks Rich: That coroborates all the stuf I found thru digging thru
>> University research papers, certified welding instructors, Metalurgical
>> studies and a bunch of writings of people like you and the EAA tech
>> counselor. All that said, I have an IA friend that still insists on the
>> OA " normalizing" or "stress relieving" after a TIG weld. However, not
>> on my helicopter.
>
> So, do you think that the tig welding does not induce the stresses, and
> therefore not need the quick OA "stress relieving" or what? I'm
> interested in the reasons you came to this conclusion.
>
> I may need to make cromolly engine mount, but the rest of my dreambuilt
> airplane will not require any normalizing.
>
> I hear wood airplanes do very poorly with an OA torch held at their
> "clusters." ;-)
> --
> Jim in NC
>

Morgans[_2_]

January 1st 08, 07:28 PM

"Stuart & Kathryn Fields" > wrote

> I'm going with him and his belief supported by the research I did and will
> not allow an OA torch near my TIG welded joints.
> BTW, with the exception of some welds on my SS exhaust, none of my TIG
> welds which includes fuel and oil tanks and the SS railing on a 35'
> Sailboat have shown any cracking. None of these had OA "Stress Relief".
That's what I thought you were saying.

I've never heard of these kind of studies before (that doesn't mean much)
but it seems pretty clear.

I'm surprised the heat of a tig weld are not worse on the frame, with the
small concentration of heat provided by that type of welding. The evidence
does make a strong case for that being true, though.
--
Jim in NC

Stuart & Kathryn Fields

January 1st 08, 07:48 PM

Phil: The stress relieving that you described: of slowly raising the
temperature to1020 Deg. F and holding it for 3hrs then dropping at a certain
rate is certainly different than heating to cherry with an OA in less than a
minute and then letting it cool in less than a couple of minutes. The guy
I referenced in an earlier posting was responsible for the TIG welding of
1800 Aerostar engine mounts that did not crack and had no post weld heat
treatment. That, while anecdotal and not a report of a truly scientific
examination of the weld joints using metallurgical techniques, does carry
some weight with me. Not to mention his survey of a group of airframe
manufacturers which included Piper and Mooney that were surprisingly, using
MIG with no pre or post heating. An awful lot of successful experience of
welded joints without OA "Stress Relieving".
BTW my Baby Belle gets trailered to a bunch of events every year and has in
excess of 125,000 trailer miles over roads that have set ELTs off and I have
never found a crack in any of the welded joints and this includes a 17' tail
boom that has a bunch of welded cluster joints and is not supported
anywhere but at the front end by 4-5/16 bolts in double shear. My ship is
one of at least 5 with high trailer miles and I've yet to hear of a cracked
weld joint. This is an accumulation of about 15years experience with these
ships.
I note however that these joints were designed with amateur builders in mind
and the frame and joints are not designed close to the ragged edge but have
a sufficient margin to allow for less than expert welders. E.g. the tail
boom is of 0.049 wall tubing where similar tubing on the Bell 47 is as small
as 0.025. There are a lot of contributing factors to a successful TIG
welded joint.
I know of no metallurgical research or experiments that prove the very quick
and uncontrolled OA "Stress Relieving" is an effective useful tool in
producing a successful TIG welded joint. In fact my limited research into
the metallurgical reports found reports of decreased tensile strength in the
material as the result of Post Weld Heat Treatment. I know that this is an
area of strong opinions and I'm sure that I will be digging into the
metallurgy of welded joint more as I feel like I've just barely got my nose
into an area that is much more complex than I thought.

Stu
"Phil" > wrote in message
...
> NASA published an advisory many years ago that was reprinted in Sport
> Aviation , I don't have the article at my fingertips , as I remember ,
> NASA stated that any 4130 weld assembly that was TIG welded and used on
> Aircraft should be post heated via Oxy/Acet , anyone who has ever done
> any welding and especially ARC welding must know and has experienced the
> tension that has built up after the weld has cooled , just a pinch of
> common sense would tell you that this tension load will be there for the
> life of the weldment , to raise the temp. of a given cluster up to a point
> that allows that cluster to seek it's sweet spot without that locked in
> tension and possible premature failure would only make common sense , NASA
> is far from perfect but they were on the money with this advisory .
> I don't know how many people that write books on welding have actually
> worked on the floor with real airplanes and have actually welded on
> commercial airplanes , I have seen many lineal inches of Oxy/Acet weld
> laid down and never saw a crack or fracture of that weld that occurred on
> the floor even before an assembly was painted , I have seen many TIG
> welded assemblies that would crack shortly after welding and again before
> they saw paint , if you have an engine mount that needs a small amount of
> machining and the machinist is damaging high speed steel end mills with
> hardened 4130 , this has to be very telling , it's been a few years since
> I worked for a Jet engine repair station , as I recall , all welded parts
> were placed in a oven and slowly raised to about 1020 Deg. F. and held at
> that temp. for 3 hrs. and then the temp. was dropped at a certain rate for
> several hours , they didn't do this for there own pleasure , this was FAA
> mandated .
> Best
> Phil Lohiser
> "wright1902glider" > wrote in message
> ...
>> While browsing a bit more of that "good 'ole internet wizdom", I ran
>> accross this page:
>>
>> http://www.ihpva.org/com/PracticalInnovations/materials.html
>>
>> Its a human-powered vehicle website, but on this page, the author
>> seems to think that 4130 cro-mo steel can't be welded with an oxy-
>> acetylene torch. Does this sound right? It was always my belief that
>> we've been OA welding airplanes out of the stuff for decades. Who is
>> wrong on this point?
>>
>> Harry "I'm still stuck in the wood-age" Frey
>>
>
>

Phil

January 1st 08, 11:32 PM

Like I said in my first little post , religion , politics and I guess you
could add motor oil to the list of a million things that are debatable , I
will still stick with the NASA report and a little common sense , the last
engine mount that I TIG welded was brought up to cherry red , both to do a
little alignment adjusting and to help level out some of the built up strain
from the initial TIG welding , my wife has a diamond ring that is very hard
but not very ductile , I really don't like the idea of having an EAA Biplane
engine mount turned into a diamond , not very flexible , even 1020 can
develop hardness after welding , raise the carbon to 30/100 of 1% and things
really get hard , go to 4140 and you are headed back to the diamond ring
state again .
Best To All
Phil Lohiser
"Stuart & Kathryn Fields" > wrote in message
.. .
> Phil: The stress relieving that you described: of slowly raising the
> temperature to1020 Deg. F and holding it for 3hrs then dropping at a
> certain rate is certainly different than heating to cherry with an OA in
> less than a minute and then letting it cool in less than a couple of
> minutes. The guy I referenced in an earlier posting was responsible for
> the TIG welding of 1800 Aerostar engine mounts that did not crack and had
> no post weld heat treatment. That, while anecdotal and not a report of a
> truly scientific examination of the weld joints using metallurgical
> techniques, does carry some weight with me. Not to mention his survey of
> a group of airframe manufacturers which included Piper and Mooney that
> were surprisingly, using MIG with no pre or post heating. An awful lot of
> successful experience of welded joints without OA "Stress Relieving".
> BTW my Baby Belle gets trailered to a bunch of events every year and has
> in excess of 125,000 trailer miles over roads that have set ELTs off and I
> have never found a crack in any of the welded joints and this includes a
> 17' tail boom that has a bunch of welded cluster joints and is not
> supported anywhere but at the front end by 4-5/16 bolts in double shear.
> My ship is one of at least 5 with high trailer miles and I've yet to hear
> of a cracked weld joint. This is an accumulation of about 15years
> experience with these ships.
> I note however that these joints were designed with amateur builders in
> mind and the frame and joints are not designed close to the ragged edge
> but have a sufficient margin to allow for less than expert welders. E.g.
> the tail boom is of 0.049 wall tubing where similar tubing on the Bell 47
> is as small as 0.025. There are a lot of contributing factors to a
> successful TIG welded joint.
> I know of no metallurgical research or experiments that prove the very
> quick and uncontrolled OA "Stress Relieving" is an effective useful tool
> in producing a successful TIG welded joint. In fact my limited research
> into the metallurgical reports found reports of decreased tensile strength
> in the material as the result of Post Weld Heat Treatment. I know that
> this is an area of strong opinions and I'm sure that I will be digging
> into the metallurgy of welded joint more as I feel like I've just barely
> got my nose into an area that is much more complex than I thought.
>
> Stu
> "Phil" > wrote in message
> ...
>> NASA published an advisory many years ago that was reprinted in Sport
>> Aviation , I don't have the article at my fingertips , as I remember ,
>> NASA stated that any 4130 weld assembly that was TIG welded and used on
>> Aircraft should be post heated via Oxy/Acet , anyone who has ever done
>> any welding and especially ARC welding must know and has experienced the
>> tension that has built up after the weld has cooled , just a pinch of
>> common sense would tell you that this tension load will be there for the
>> life of the weldment , to raise the temp. of a given cluster up to a
>> point that allows that cluster to seek it's sweet spot without that
>> locked in tension and possible premature failure would only make common
>> sense , NASA is far from perfect but they were on the money with this
>> advisory .
>> I don't know how many people that write books on welding have actually
>> worked on the floor with real airplanes and have actually welded on
>> commercial airplanes , I have seen many lineal inches of Oxy/Acet weld
>> laid down and never saw a crack or fracture of that weld that occurred on
>> the floor even before an assembly was painted , I have seen many TIG
>> welded assemblies that would crack shortly after welding and again before
>> they saw paint , if you have an engine mount that needs a small amount of
>> machining and the machinist is damaging high speed steel end mills with
>> hardened 4130 , this has to be very telling , it's been a few years since
>> I worked for a Jet engine repair station , as I recall , all welded parts
>> were placed in a oven and slowly raised to about 1020 Deg. F. and held at
>> that temp. for 3 hrs. and then the temp. was dropped at a certain rate
>> for several hours , they didn't do this for there own pleasure , this was
>> FAA mandated .
>> Best
>> Phil Lohiser
>> "wright1902glider" > wrote in message
>> ...
>>> While browsing a bit more of that "good 'ole internet wizdom", I ran
>>> accross this page:
>>>
>>> http://www.ihpva.org/com/PracticalInnovations/materials.html
>>>
>>> Its a human-powered vehicle website, but on this page, the author
>>> seems to think that 4130 cro-mo steel can't be welded with an oxy-
>>> acetylene torch. Does this sound right? It was always my belief that
>>> we've been OA welding airplanes out of the stuff for decades. Who is
>>> wrong on this point?
>>>
>>> Harry "I'm still stuck in the wood-age" Frey
>>>
>>
>>
>
>

clare at snyder.on.ca

January 2nd 08, 12:14 AM

On Tue, 1 Jan 2008 09:28:01 -0800, "Stuart & Kathryn Fields"
> wrote:

>Morgans: According to everything I read in my research for the article I
>wrote, the "Quick stress relieving" by the few seconds of OA after a TIG
>weld do not effectively relieve the stress and can actually cause a
>weakening of the weld joint. There appears to be quite a bit of truly
>scientific experimentation to support this view. As a retired engineer, I'm
>more prone to accept the scientists report over the anecdotal evidence from
>more questionable sources. All that said, I can relate to failures that I
>saw as the result of a crash of Chrome Moly airframe. Tube failures near a
>cluster showed a separation that occurred just a short distance (1/4") from
>the weld that was relatively clean and very even and roughly resembling a
>fatigue failure zone. The Richard Finch that I referred to in an earlier
>post wrote the book called Performance Welding and cited his experience at
>Aerostar. I'm going with him and his belief supported by the research I did
>and will not allow an OA torch near my TIG welded joints.
>BTW, with the exception of some welds on my SS exhaust, none of my TIG welds
>which includes fuel and oil tanks and the SS railing on a 35' Sailboat have
>shown any cracking. None of these had OA "Stress Relief".
>
>Stu
>"Morgans" > wrote in message
...
>>
>> "Stuart & Kathryn Fields" > wrote
>>
>>> Thanks Rich: That coroborates all the stuf I found thru digging thru
>>> University research papers, certified welding instructors, Metalurgical
>>> studies and a bunch of writings of people like you and the EAA tech
>>> counselor. All that said, I have an IA friend that still insists on the
>>> OA " normalizing" or "stress relieving" after a TIG weld. However, not
>>> on my helicopter.
>>
>> So, do you think that the tig welding does not induce the stresses, and
>> therefore not need the quick OA "stress relieving" or what? I'm
>> interested in the reasons you came to this conclusion.
>>
>> I may need to make cromolly engine mount, but the rest of my dreambuilt
>> airplane will not require any normalizing.
>>
>> I hear wood airplanes do very poorly with an OA torch held at their
>> "clusters." ;-)
>> --
>> Jim in NC
>>
>
The commonly accepted knowlege on this subject is to use a low alloy
filler rod when tig-ing 4130, in still air, and no post-heat stress
relief.
The low alloy filler draws some alloy from the base metal (tubing) and
the fillet is thicker than the substrate, so the total strength of the
"low strength" weld is equal to or superior to the base metal. The
base metal is "drawn" - it is less hard, and slightly weaker but less
prone to cracking, so you get a good, solid, reliable joint.
Cracking is extremely rare when the structure is built this way.

--
Posted via a free Usenet account from http://www.teranews.com

[email protected]

January 2nd 08, 03:57 AM

On Jan 1, 4:32 pm, "Phil" > wrote:
> Like I said in my first little post , religion , politics and I guess you
> could add motor oil to the list of a million things that are debatable , I
> will still stick with the NASA report and a little common sense , the last
> engine mount that I TIG welded was brought up to cherry red , both to do a
> little alignment adjusting and to help level out some of the built up strain
> from the initial TIG welding , my wife has a diamond ring that is very hard
> but not very ductile , I really don't like the idea of having an EAA Biplane
> engine mount turned into a diamond , not very flexible , even 1020 can
> develop hardness after welding , raise the carbon to 30/100 of 1% and things
> really get hard , go to 4140 and you are headed back to the diamond ring
> state again.

Steels aren't hardenable under .40% carbon. 4130 is .30%.
Got to be careful with the flame. Getting it too rich in
acetylene makes it a carburizing flame and will raise the carbon
content of the steel.

Dan

Morgans[_2_]

January 2nd 08, 04:30 AM

<clare at snyder.on.ca> wrote

> The low alloy filler draws some alloy from the base metal (tubing) and
> the fillet is thicker than the substrate, so the total strength of the
> "low strength" weld is equal to or superior to the base metal. The
> base metal is "drawn" - it is less hard, and slightly weaker but less
> prone to cracking, so you get a good, solid, reliable joint.
> Cracking is extremely rare when the structure is built this way.

Thanks for that explanation. The bit about the drawing makes good sense.

Damns, now I gotta go out and find a tig welder and start practicing! <g>
--
Jim in NC

Phil

January 2nd 08, 04:33 AM

Dan , take a piece of 4130 and heat it to dull red and quench , it will
definitely take heat treat , some of the older A/C had the entire fuselage
heated and quenched and tempered in order to develop a higher teasel
strength , on the order of 150 K as opposed to the normal 90-100 K for
normalized 4130 ,this process caused a real problem for repairs as the
average shop couldn't repeat the heat treatment process .
Best To You
Phil Lohiser
> wrote in message
...
> On Jan 1, 4:32 pm, "Phil" > wrote:
>> Like I said in my first little post , religion , politics and I guess you
>> could add motor oil to the list of a million things that are debatable ,
>> I
>> will still stick with the NASA report and a little common sense , the
>> last
>> engine mount that I TIG welded was brought up to cherry red , both to do
>> a
>> little alignment adjusting and to help level out some of the built up
>> strain
>> from the initial TIG welding , my wife has a diamond ring that is very
>> hard
>> but not very ductile , I really don't like the idea of having an EAA
>> Biplane
>> engine mount turned into a diamond , not very flexible , even 1020 can
>> develop hardness after welding , raise the carbon to 30/100 of 1% and
>> things
>> really get hard , go to 4140 and you are headed back to the diamond ring
>> state again.
>
> Steels aren't hardenable under .40% carbon. 4130 is .30%.
> Got to be careful with the flame. Getting it too rich in
> acetylene makes it a carburizing flame and will raise the carbon
> content of the steel.
>
> Dan

[email protected]

January 2nd 08, 06:37 AM

On Jan 1, 9:57*pm, wrote:
> On Jan 1, 4:32 pm, "Phil" > wrote:
>
> > >
> * * * * * Steels aren't hardenable under .40% carbon. 4130 is .30%.
>
> * * * * * Dan

> .
I don't think this is quite true. The data from AR-MMPDS-03 for 4130
and 4135 says the following. It plainly gives the tensile strengths
and other data for 4130 and 4135 heat treated to several different
levels of strength, compared to normalized (no heat treat). This is
the guiding technical standard that all metals in the Space Shuttle,
Space Station, and many other high tech NASA projects are governed
by.
4130 is heat treatable to 180 ksi and 4135 to 200 ksi. The un-
heat treated strength is 75 to 90 ksi. It is true that higher carbon
content (to a point) allows for higher treat heat levels, as the
higher level for 4135 vs 4130 shows.

Regards,
Bud

Phil

January 2nd 08, 12:45 PM

Several years ago a EAA member was building a four place experimental with
4130 as the airframe , the gentleman either couldn't or wouldn't learn to do
GAS welding and he ask the FAA if he could braze the structure together ,
FAA said that as it was under the experimental category and they could not
prevent him from brazing his four place bird together but they would like
him to make some samples to proof test his idea , samples proved his concept
and FAA gave him a green light , I think the filler rod was Eutectic FC16 ,
I did get a couple samples of the filler and made my own samples of 5/8 X
..035 4130 , tubing bent and finally broke after great load was applied , no
failure in the filler , only adjacent to it , the problem with this material
is that it uses a Flux coating and some of it is going to get inside the
tube and the stuff will corrode.
Phil
> wrote in message
...
> On Dec 28, 2:57 pm, wright1902glider > wrote:
>> the author
>> seems to think that 4130 cro-mo steel can't be welded with an oxy-
>> acetylene torch.
> --------------------------------------------------------------------------------
>
> Pure bull****. Indeed, for the stresses encountered in bicycles
> (which is what he's talking about) there are any number of BRAZING
> compounds that yield joints stronger than than normalized 4130.
>
> O/A does just fine airframes... and for bike frames.
>

Blueskies

January 2nd 08, 01:22 PM

"Richard Riley" > wrote in message ...
> On Fri, 28 Dec 2007 19:46:57 -0800 (PST), "
> > wrote:
>
>>On Dec 28, 2:57 pm, wright1902glider > wrote:
>>> the author
>>> seems to think that 4130 cro-mo steel can't be welded with an oxy-
>>> acetylene torch.
>>--------------------------------------------------------------------------------
>>
>>Pure bull****. Indeed, for the stresses encountered in bicycles
>>(which is what he's talking about) there are any number of BRAZING
>>compounds that yield joints stronger than than normalized 4130.
>>
>>O/A does just fine airframes... and for bike frames.
>
> If brazing gives stronger joints that normalized 4130, why aren't we
> brazing airframes?
>
> (I'm not saying it's an incorrect statement - I know better than to
> disagree with VD on something like this. I just figure there must be
> a reason, like the brazing compounds are more expensive.)

Won't withstand high temperatures?

[email protected]

January 2nd 08, 02:40 PM

On Jan 1, 9:54 pm, Richard Riley > wrote:

>
> If brazing gives stronger joints that normalized 4130, why aren't we
> brazing airframes?
>
> (I'm not saying it's an incorrect statement - I know better than to
> disagree with VD on something like this. I just figure there must be
> a reason, like the brazing compounds are more expensive.)
-----------------------------------------------------------------------------

Dear Richard,

That's a good question but you're asking the wrong guy.

Also, it isn't just ANY brazing, it is a form of eutectic brazing
developed specifically for alloy steels, initially for use in military
weapon systems as a means of reducing the cost & weight of certain
structures. The components are cut very accurately on CNC equipment
and most of the joins were done in an oven with the parts secured in a
jig.

The only problem I can see with this method is that REPAIRS would be
rather difficult; certainly not as convenient as with an O/A torch and
wire coat hanger :-)

Dig through French's books. If he hasn't written something about it,
he should have.

-R.S.Hoover

[email protected]

January 2nd 08, 02:55 PM

On Jan 1, 11:37 pm, wrote:
> On Jan 1, 9:57 pm, wrote:
>
> > On Jan 1, 4:32 pm, "Phil" > wrote:
>
> > Steels aren't hardenable under .40% carbon. 4130 is .30%.
>
> > Dan
> > .
>
> I don't think this is quite true. The data from AR-MMPDS-03 for 4130
> and 4135 says the following. It plainly gives the tensile strengths
> and other data for 4130 and 4135 heat treated to several different
> levels of strength, compared to normalized (no heat treat). This is
> the guiding technical standard that all metals in the Space Shuttle,
> Space Station, and many other high tech NASA projects are governed
> by.
> 4130 is heat treatable to 180 ksi and 4135 to 200 ksi. The un-
> heat treated strength is 75 to 90 ksi. It is true that higher carbon
> content (to a point) allows for higher treat heat levels, as the
> higher level for 4135 vs 4130 shows.
>
> Regards,
> Bud

Didn't say it wasn't heat-treatable. Said it wasn't hardenable.
Hardness is usually linked to crack tendencies. Tensile strength can
be changed with heat-treat, I know, but cracking on aircraft tube
structures, as I understand it, is more due to the cooling and
shrinking of the local area and consequent rise of tension in that
area.

Dan

cavelamb himself[_4_]

January 2nd 08, 02:59 PM

Blueskies wrote:
> "Richard Riley" > wrote in message ...
>
>>On Fri, 28 Dec 2007 19:46:57 -0800 (PST), "
> wrote:
>>
>>
>>>On Dec 28, 2:57 pm, wright1902glider > wrote:
>>>
>>>>the author
>>>>seems to think that 4130 cro-mo steel can't be welded with an oxy-
>>>>acetylene torch.
>>>
>>>--------------------------------------------------------------------------------
>>>
>>>Pure bull****. Indeed, for the stresses encountered in bicycles
>>>(which is what he's talking about) there are any number of BRAZING
>>>compounds that yield joints stronger than than normalized 4130.
>>>
>>>O/A does just fine airframes... and for bike frames.
>>
>>If brazing gives stronger joints that normalized 4130, why aren't we
>>brazing airframes?
>>
>>(I'm not saying it's an incorrect statement - I know better than to
>>disagree with VD on something like this. I just figure there must be
>>a reason, like the brazing compounds are more expensive.)
>
>
>
> Won't withstand high temperatures?
>
>

Structural brazing works just fine - if done correctly.

But too much heat causes the brass to migrate into the grain
of the 4130 - resulting in cracks.

It HAS to be done right.
And there is no way to tell afterwards if it was or not -
until it breaks.

Richard

Charles Vincent

January 2nd 08, 04:20 PM

wrote:

>
> Didn't say it wasn't heat-treatable. Said it wasn't hardenable.
> Hardness is usually linked to crack tendencies. Tensile strength can
> be changed with heat-treat, I know, but cracking on aircraft tube
> structures, as I understand it, is more due to the cooling and
> shrinking of the local area and consequent rise of tension in that
> area.
>
> Dan

4130 is indeed hardenable by heat treatment or cold working. And 4135
even more so. I have hardened them both using both water and oil
quenches, though if you took the time to read one of the metallurgical
tomes on the subject, you would find they are spec'd as an oil hardening
alloy. Water has worked fine for me on small sections, though my
default quench (i.e. the bucket next to the forge) is water with a layer
of olive oil floating on the top. I used to use used ATF or motor oil as
it was cheap, but burning olive oil is more friendly.

Charles

wright1902glider

January 2nd 08, 05:58 PM

>Pure bull****. *

Yep. That's what I was thinking. Funny how many OA welded steel
aircraft are still flying. I've been up in a few. My only real
question is wether they were built of 4130 in 1942, or something more
mild. Wasn't Mike Horowitz using 4130 and an HF torch on his Dyke
delta?

In any case, I thought that website was really quite humorous. Its
amazing how much wiz-dum there was on a site dedicated to building...
a bicycle. Well, bicycle-thingie.

Convention be damned when I get my OA cylinders (and if the snow ever
melts)! I'll weld it, test it to distruction, beat the hell out of it,
run over it with my truck, pump it full of air, and if it still looks
good, seek the comments and experiences of you folks. And then I'll
probably beat on it some more and report my results.

Boulder, CO is getting boring. The Kenetic sculpture race was
cancelled this year. Time for me to take up the torch (ha) and
reintroduce a little whackiness... oh yea, and practice my welding
for that homebuilt project.

Happy New Year Everyone,
Harry "90% mad scientist" Frey

Blueskies

January 2nd 08, 07:18 PM

"cavelamb himself" > wrote in message ...

> Structural brazing works just fine - if done correctly.
>
> But too much heat causes the brass to migrate into the grain
> of the 4130 - resulting in cracks.
>
> It HAS to be done right.
> And there is no way to tell afterwards if it was or not -
> until it breaks.
>
>
> Richard

I meant while the part was in service. If an engine mount was brazed, and there was an engine fire, would the braze
joint fail (come apart) where a welded one would hold?

[email protected]

January 2nd 08, 07:22 PM

On Jan 2, 9:58 am, wright1902glider > wrote:
> I thought that website was really quite humorous. Its
> amazing how much wiz-dum there was on a site dedicated to building...
> a bicycle. Well, bicycle-thingie.
> ---------------------------------------------------------------------

The website's attitude is fairly common among folks who have just
discovered the practicality of human-power as a mode of
transportation. Even Henry Ford considered the use of automobiles for
'personal transportation' as a deeply flawed philosophy, pointing out
that no society could afford it (circa 1885) which was why his initial
interest was in using internal combustion to power farm machinery
rather than cars.

Bikes are an interesting engineering challenge, especially in the area
of strength-to-weight. The market for light-weight, efficient chain-
driven 'safety' bicycles provided the financing -- and the intellect
-- for the materials developed for the one to be applied to aviation,
as proven by a couple of brothers from Dayton, Ohio. But most modern-
day re-discoverers of pedal power fail to do their home-work,
inflicting those who have with a constant stream of absurdities.

Anyone who has never built a bike probably should. At the very least
it will add years to your life :-)

-R.S.Hoover

[email protected]

January 2nd 08, 07:44 PM

On Jan 2, 9:20 am, Charles Vincent > wrote:
> wrote:
>
> > Didn't say it wasn't heat-treatable. Said it wasn't hardenable.
> > Hardness is usually linked to crack tendencies. Tensile strength can
> > be changed with heat-treat, I know, but cracking on aircraft tube
> > structures, as I understand it, is more due to the cooling and
> > shrinking of the local area and consequent rise of tension in that
> > area.
>
> > Dan
>
> 4130 is indeed hardenable by heat treatment or cold working. And 4135
> even more so. I have hardened them both using both water and oil
> quenches, though if you took the time to read one of the metallurgical
> tomes on the subject, you would find they are spec'd as an oil hardening
> alloy. Water has worked fine for me on small sections, though my
> default quench (i.e. the bucket next to the forge) is water with a layer
> of olive oil floating on the top. I used to use used ATF or motor oil as
> it was cheap, but burning olive oil is more friendly.
>
> Charles

OK. Must be that the chrome or molybdenum adds to the
hardenability. All my resources say that .4% carbon is necessary to
harden steels.

Dan

Phil

January 2nd 08, 08:42 PM

If you have any doubt as to the hardenability of any piece of steel , just
light up your TIG Torch and get it close enough to your steel specimen and
melt a small fly speck spot , turn off the welder and touch that spot with a
file , even on low carbon steel like 1018 you may find that the file will
give up just about as easy as the hardened 1018 will , hardness and loss of
ductility pretty much parallel each other , I have seen 4130 parts that
couldn't be filed or cut with a hacksaw , not good .
Best
Phil
> wrote in message
...
> On Jan 2, 9:20 am, Charles Vincent > wrote:
>> wrote:
>>
>> > Didn't say it wasn't heat-treatable. Said it wasn't hardenable.
>> > Hardness is usually linked to crack tendencies. Tensile strength can
>> > be changed with heat-treat, I know, but cracking on aircraft tube
>> > structures, as I understand it, is more due to the cooling and
>> > shrinking of the local area and consequent rise of tension in that
>> > area.
>>
>> > Dan
>>
>> 4130 is indeed hardenable by heat treatment or cold working. And 4135
>> even more so. I have hardened them both using both water and oil
>> quenches, though if you took the time to read one of the metallurgical
>> tomes on the subject, you would find they are spec'd as an oil hardening
>> alloy. Water has worked fine for me on small sections, though my
>> default quench (i.e. the bucket next to the forge) is water with a layer
>> of olive oil floating on the top. I used to use used ATF or motor oil as
>> it was cheap, but burning olive oil is more friendly.
>>
>> Charles
>
> OK. Must be that the chrome or molybdenum adds to the
> hardenability. All my resources say that .4% carbon is necessary to
> harden steels.
>
> Dan

Morgans[_2_]

January 2nd 08, 09:28 PM

> wrote in message
...
> On Dec 28, 2:57 pm, wright1902glider > wrote:
>> the author
>> seems to think that 4130 cro-mo steel can't be welded with an oxy-
>> acetylene torch.
> --------------------------------------------------------------------------------
>
> Pure bull****. Indeed, for the stresses encountered in bicycles
> (which is what he's talking about) there are any number of BRAZING
> compounds that yield joints stronger than than normalized 4130.
>
> O/A does just fine airframes... and for bike frames.

I'm not sure where this all fits in, but most lightweight bicycle frames
have a reinforcing "lug" around the tubes at the joints. Are you talking
bicycles or motorcycles?
--
Jim in NC

Morgans[_2_]

January 2nd 08, 09:40 PM

"Charles Vincent" <wrote
>
> 4130 is indeed hardenable by heat treatment or cold working. And 4135
> even more so. I have hardened them both using both water and oil
> quenches, though if you took the time to read one of the metallurgical
> tomes on the subject, you would find they are spec'd as an oil hardening
> alloy. Water has worked fine for me on small sections, though my default
> quench (i.e. the bucket next to the forge) is water with a layer of olive
> oil floating on the top. I used to use used ATF or motor oil as it was
> cheap, but burning olive oil is more friendly.

After you harden it by quenching, do you then go though the normalizing, by
heating to "straw" color, and over a period of several minutes, remove the
heat, a distance at a time?

That was what I was taught eons ago, but only in reference to working mild
"God only knows" what type of steel. I'm talking in cars and trailers and
tractors and such.

I hear people talking about heating up the weld and tube to "cherry" and
that is not what I thought was the proper procedure, for normalizing. I was
taught that "straw" was attainable, by barely seeing any color in a
semi-dark area.

Can anyone straighten out my conceptions, and mis-conceptions, here? <g>
--
Jim in NC

cavelamb himself[_4_]

January 2nd 08, 09:52 PM

Blueskies wrote:
> "cavelamb himself" > wrote in message ...
>
>
>>Structural brazing works just fine - if done correctly.
>>
>>But too much heat causes the brass to migrate into the grain
>>of the 4130 - resulting in cracks.
>>
>>It HAS to be done right.
>>And there is no way to tell afterwards if it was or not -
>>until it breaks.
>>
>>
>>Richard
>
>
> I meant while the part was in service. If an engine mount was brazed, and there was an engine fire, would the braze
> joint fail (come apart) where a welded one would hold?
>
>
>

Dunno, Mongo.

I guess it would depend on how hot for how long.

But remember that it takes an acetylene flame to braze in the first
place.

If if gets that hot in the engine room, whether the mount welds hold or
not is probably going to be a secondary issue...

Richard

cavelamb himself[_4_]

January 2nd 08, 09:55 PM

Morgans wrote:

> > wrote in message
> ...
>
>>On Dec 28, 2:57 pm, wright1902glider > wrote:
>>
>>>the author
>>>seems to think that 4130 cro-mo steel can't be welded with an oxy-
>>>acetylene torch.
>>
>>--------------------------------------------------------------------------------
>>
>>Pure bull****. Indeed, for the stresses encountered in bicycles
>>(which is what he's talking about) there are any number of BRAZING
>>compounds that yield joints stronger than than normalized 4130.
>>
>>O/A does just fine airframes... and for bike frames.
>
>
> I'm not sure where this all fits in, but most lightweight bicycle frames
> have a reinforcing "lug" around the tubes at the joints. Are you talking
> bicycles or motorcycles?

Yep.

And the tubes are sometinmes "stretched" to reduce weight,

and the connections are often brazed.

Go figer...

Richard

clare at snyder.on.ca

January 2nd 08, 09:56 PM

On Tue, 01 Jan 2008 21:54:48 -0800, Richard Riley
> wrote:

>On Fri, 28 Dec 2007 19:46:57 -0800 (PST), "
> wrote:
>
>>On Dec 28, 2:57 pm, wright1902glider > wrote:
>>> the author
>>> seems to think that 4130 cro-mo steel can't be welded with an oxy-
>>> acetylene torch.
>>--------------------------------------------------------------------------------
>>
>>Pure bull****. Indeed, for the stresses encountered in bicycles
>>(which is what he's talking about) there are any number of BRAZING
>>compounds that yield joints stronger than than normalized 4130.
>>
>>O/A does just fine airframes... and for bike frames.
>
>If brazing gives stronger joints that normalized 4130, why aren't we
>brazing airframes?
>
>(I'm not saying it's an incorrect statement - I know better than to
>disagree with VD on something like this. I just figure there must be
>a reason, like the brazing compounds are more expensive.)

It is not your standard brazing. It is "fillet brazing", using a much
stronger "spelter" than your standard braze. The process uses a gas
flux (a "Hookah" bubbling the acetelene (I think - might be the O2)
through the liquid flux ). The flux in the flame is EXTREMELY
reactive, so the flame "scrubs" the joint, leaving little if any flux
behind. These brazed joints ARE stronger than the 4130 or 4140 base
metal.

The process was developed for and used extensively by small race car
chassis fabricators in England and the continent. Lotus is a good case
in point.

--
Posted via a free Usenet account from http://www.teranews.com

clare at snyder.on.ca

January 2nd 08, 09:58 PM

On Wed, 02 Jan 2008 13:22:24 GMT, "Blueskies"
> wrote:

>
>"Richard Riley" > wrote in message ...
>> On Fri, 28 Dec 2007 19:46:57 -0800 (PST), "
>> > wrote:
>>
>>>On Dec 28, 2:57 pm, wright1902glider > wrote:
>>>> the author
>>>> seems to think that 4130 cro-mo steel can't be welded with an oxy-
>>>> acetylene torch.
>>>--------------------------------------------------------------------------------
>>>
>>>Pure bull****. Indeed, for the stresses encountered in bicycles
>>>(which is what he's talking about) there are any number of BRAZING
>>>compounds that yield joints stronger than than normalized 4130.
>>>
>>>O/A does just fine airframes... and for bike frames.
>>
>> If brazing gives stronger joints that normalized 4130, why aren't we
>> brazing airframes?
>>
>> (I'm not saying it's an incorrect statement - I know better than to
>> disagree with VD on something like this. I just figure there must be
>> a reason, like the brazing compounds are more expensive.)
>
>
>Won't withstand high temperatures?
>
Will withstand temperatures higher than anything attatched to the
airframe will ever withstand.

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Blueskies

January 2nd 08, 09:59 PM

>>
>> I meant while the part was in service. If an engine mount was brazed, and there was an engine fire, would the braze
>> joint fail (come apart) where a welded one would hold?
>>
>>
>>
>
> Dunno, Mongo.
>
> I guess it would depend on how hot for how long.
>
> But remember that it takes an acetylene flame to braze in the first
> place.
>
> If if gets that hot in the engine room, whether the mount welds hold or
> not is probably going to be a secondary issue...
>
> Richard

Its just gotta last long enough for me to get it on the ground ;-)

Blueskies

January 2nd 08, 10:01 PM

"clare at snyder.on.ca" wrote in message ...
>
> It is not your standard brazing. It is "fillet brazing", using a much
> stronger "spelter" than your standard braze. The process uses a gas
> flux (a "Hookah" bubbling the acetelene (I think - might be the O2)
> through the liquid flux ). The flux in the flame is EXTREMELY
> reactive, so the flame "scrubs" the joint, leaving little if any flux
> behind. These brazed joints ARE stronger than the 4130 or 4140 base
> metal.
>
> The process was developed for and used extensively by small race car
> chassis fabricators in England and the continent. Lotus is a good case
> in point.
>

What is the melting point for the brazing material?

clare at snyder.on.ca

January 2nd 08, 10:05 PM

On Wed, 2 Jan 2008 06:40:47 -0800 (PST), "
> wrote:

>On Jan 1, 9:54 pm, Richard Riley > wrote:
>
>>
>> If brazing gives stronger joints that normalized 4130, why aren't we
>> brazing airframes?
>>
>> (I'm not saying it's an incorrect statement - I know better than to
>> disagree with VD on something like this. I just figure there must be
>> a reason, like the brazing compounds are more expensive.)
>-----------------------------------------------------------------------------
>
>Dear Richard,
>
>That's a good question but you're asking the wrong guy.
>
>Also, it isn't just ANY brazing, it is a form of eutectic brazing
>developed specifically for alloy steels, initially for use in military
>weapon systems as a means of reducing the cost & weight of certain
>structures. The components are cut very accurately on CNC equipment
>and most of the joins were done in an oven with the parts secured in a
>jig.
>
>The only problem I can see with this method is that REPAIRS would be
>rather difficult; certainly not as convenient as with an O/A torch and
>wire coat hanger :-)
>
>Dig through French's books. If he hasn't written something about it,
>he should have.
>
>-R.S.Hoover

You are referring to "furnace brazing" which is different than "fillet
brazing" (also known as braze welding)

see: http://www.henryjames.com/gasf.html
I believe they are generally a nickel silver braze.

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Phil

January 2nd 08, 10:28 PM

Jim , if my memory serves me correctly , the Straw color that you are
referring to is called Tempering , if you would bring a piece of High Carbon
Steel like a chisel or other tool up to red color and quench it in oil , it
would be very hard and have very little ductility , the reheating or
tempering to what I remember was about 450 deg. would make the part more
serviceable and less likely to shatter , the cherry red that we use to
finish out our TIG welds has somewhat the same effect except that it helps
to bring the entire cluster back to the original 90 ksi and removes the
push-pull and strain that is locked in for 1000 yrs. or so.
Phil
"Morgans" > wrote in message
...
>
> "Charles Vincent" <wrote
>>
>> 4130 is indeed hardenable by heat treatment or cold working. And 4135
>> even more so. I have hardened them both using both water and oil
>> quenches, though if you took the time to read one of the metallurgical
>> tomes on the subject, you would find they are spec'd as an oil hardening
>> alloy. Water has worked fine for me on small sections, though my
>> default quench (i.e. the bucket next to the forge) is water with a layer
>> of olive oil floating on the top. I used to use used ATF or motor oil as
>> it was cheap, but burning olive oil is more friendly.
>
> After you harden it by quenching, do you then go though the normalizing,
> by heating to "straw" color, and over a period of several minutes, remove
> the heat, a distance at a time?
>
> That was what I was taught eons ago, but only in reference to working mild
> "God only knows" what type of steel. I'm talking in cars and trailers and
> tractors and such.
>
> I hear people talking about heating up the weld and tube to "cherry" and
> that is not what I thought was the proper procedure, for normalizing. I
> was taught that "straw" was attainable, by barely seeing any color in a
> semi-dark area.
>
> Can anyone straighten out my conceptions, and mis-conceptions, here? <g>
> --
> Jim in NC
>

[email protected]

January 2nd 08, 10:42 PM

> You are referring to "furnace brazing" which is different than "fillet
> brazing" (also known as braze welding)
>
> see:http://www.henryjames.com/gasf.html
> I believe they are generally a nickel silver braze.
>-------------------------------------------------------------

Roger that. The original post had to do with bicycles, several
manufacturers of which use that method for fabricating the frames.

-R.S.Hoover

[email protected]

January 2nd 08, 10:48 PM

On Jan 2, 3:28 pm, "Phil" > wrote:
> Jim , if my memory serves me correctly , the Straw color that you are
> referring to is called Tempering , if you would bring a piece of High Carbon
> Steel like a chisel or other tool up to red color and quench it in oil , it
> would be very hard and have very little ductility , the reheating or
> tempering to what I remember was about 450 deg. would make the part more
> serviceable and less likely to shatter , the cherry red that we use to
> finish out our TIG welds has somewhat the same effect except that it helps
> to bring the entire cluster back to the original 90 ksi and removes the
> push-pull and strain that is locked in for 1000 yrs. or so.

Exactly. A cold chisel also has about 1% carbon in it. It's a
totally different thing than welding low-carbon steels.

Dan

[email protected]

January 2nd 08, 10:52 PM

On Jan 2, 1:42 pm, "Phil" > wrote:
> If you have any doubt as to the hardenability of any piece of steel , just
> light up your TIG Torch and get it close enough to your steel specimen and
> melt a small fly speck spot , turn off the welder and touch that spot with a
> file , even on low carbon steel like 1018 you may find that the file will
> give up just about as easy as the hardened 1018 will , hardness and loss of
> ductility pretty much parallel each other , I have seen 4130 parts that
> couldn't be filed or cut with a hacksaw , not good .

That applies to just about any steel with any arc. It has
something to do with the extremely intense heat and electron flow of
the arc. I spent years welding up broken castings and worn
crankshafts, and to avoid those hard start-spots (which crack easily
and play hob with the milling and turning cutters after welding) we'd
start the arc on a scrap bit of steel held against the part and run
off that onto the work. The only hard places after that were in the
transition zone, especially in cast iron, which has around 4% carbon.
You had to keep that zone as thin as possible, so we used nickel
filler and applied it a low amperage to minimize dilution of the
parent metal.

DAn

[email protected]

January 2nd 08, 10:53 PM

On Jan 2, 1:28 pm, "Morgans" > wrote:
>
> I'm not sure where this all fits in, but most lightweight bicycle frames
> have a reinforcing "lug" around the tubes at the joints. Are you talking
> bicycles or motorcycles?
> --
--------------------------------------------------------------------------

Hadn't really thought of it... but you CAN use O/A on a bicycle
frame. The swaged fittings you mention are available as a kit, by the
way. They are normally secured via brazing. This allows you to use
very thin-walled tubing, resulting in excellent strength-to-weight for
the finished frame. Motorsickles typically require heavier walled
tubing and are almost always welded directly, typically with MIG. But
if you take a close look at low-cost import bicycles you can see they
tend to use heavier-walled tubing & MIG. (Just lift one. Big
difference between a 'Red Dawn' and a custom-built bike (bicycle).)

-R.S.Hoover

Morgans[_2_]

January 3rd 08, 12:44 AM

> wrote
>
> Hadn't really thought of it... but you CAN use O/A on a bicycle
> frame. The swaged fittings you mention are available as a kit, by the
> way. They are normally secured via brazing. This allows you to use
> very thin-walled tubing, resulting in excellent strength-to-weight for
> the finished frame. Motorsickles typically require heavier walled
> tubing and are almost always welded directly, typically with MIG. But
> if you take a close look at low-cost import bicycles you can see they
> tend to use heavier-walled tubing & MIG. (Just lift one. Big
> difference between a 'Red Dawn' and a custom-built bike (bicycle).)
Yep, and they get lighter all the time.

I remember back in about 1973, I bought a Peugeot, UO-8, I think was the
model.

At the time, it was around 27 pounds, and considered to be pretty light.

Now, that's a tank, compared to the new models.
--
Jim in NC

George

January 3rd 08, 01:50 AM

Blueskies wrote:
>>> I meant while the part was in service. If an engine mount was brazed, and there was an engine fire, would the braze
>>> joint fail (come apart) where a welded one would hold?
>>>
>>>
>>>
>> Dunno, Mongo.
>>
>> I guess it would depend on how hot for how long.
>>
>> But remember that it takes an acetylene flame to braze in the first
>> place.
>>
>> If if gets that hot in the engine room, whether the mount welds hold or
>> not is probably going to be a secondary issue...
>>
>> Richard
>
> Its just gotta last long enough for me to get it on the ground ;-)
>
>
>

Getting it on the ground is no problem, gravity will help you with that
task, now doing it in a survivable manner, that is the trick.

George

Blueskies

January 3rd 08, 02:43 AM

"George" > wrote in message . net...
> Blueskies wrote:
>>>> I meant while the part was in service. If an engine mount was brazed, and there was an engine fire, would the braze
>>>> joint fail (come apart) where a welded one would hold?
>>>>
>>>>
>>>>
>>> Dunno, Mongo.
>>>
>>> I guess it would depend on how hot for how long.
>>>
>>> But remember that it takes an acetylene flame to braze in the first
>>> place.
>>>
>>> If if gets that hot in the engine room, whether the mount welds hold or
>>> not is probably going to be a secondary issue...
>>>
>>> Richard
>>
>> Its just gotta last long enough for me to get it on the ground ;-)
>>
>>
>>
>
> Getting it on the ground is no problem, gravity will help you with that task, now doing it in a survivable manner,
> that is the trick.
>
> George

Reminds me of the guy with the souped up O-200 formula racer. The engine was putting out great power at something like
3200 rpm, till it threw a prop blade at something like 2000' agl... Shook real bad and tore the engine off the mount,
but the safety cable kept it from coming loose from the airframe, so he was able to get it back on the ground "in a
survivable manner". If it had broken completely loose the CG would have been way off and that would have been the end of
it...

Same thing with a fire in flight. I would at least want the engine to hang on for a while to give me a fighting
chance...

clare at snyder.on.ca

January 3rd 08, 03:01 AM

On Wed, 2 Jan 2008 17:01:59 -0500, "Blueskies"
> wrote:

>
>"clare at snyder.on.ca" wrote in message ...
>>
>> It is not your standard brazing. It is "fillet brazing", using a much
>> stronger "spelter" than your standard braze. The process uses a gas
>> flux (a "Hookah" bubbling the acetelene (I think - might be the O2)
>> through the liquid flux ). The flux in the flame is EXTREMELY
>> reactive, so the flame "scrubs" the joint, leaving little if any flux
>> behind. These brazed joints ARE stronger than the 4130 or 4140 base
>> metal.
>>
>> The process was developed for and used extensively by small race car
>> chassis fabricators in England and the continent. Lotus is a good case
>> in point.
>>
>
>What is the melting point for the brazing material?
Designation Description UNS A5.8 AWS Spec Tensile Strength
Lifquidus/Solidus
C-04® Nickel Bronze 680 RBCuZn-B 65,000 psi 162O° F / 1590° F
882° C / 866° C
GF-78 Low fuming Bronze 681 RBCuZn-C 63,000 psi 1630° F / 1590° F
888° C / 866° C
GF-72 Nickel Silver 773 RBCuZn-D 80,000 psi 1715° F / 1690° F
935° C / 921° C

>

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Morgans[_2_]

January 3rd 08, 03:05 AM

"Blueskies" > wrote

> Same thing with a fire in flight. I would at least want the engine to hang
> on for a while to give me a fighting chance...

I would bet big that the firewall would be burned or melted off from the
aircraft, (thereby letting the engine loose) long before a braise got hot
enough to let loose.
--
Jim in NC

Maxwell

January 3rd 08, 04:39 AM

"Blueskies" > wrote in message
...
>
> "clare at snyder.on.ca" wrote in message
> ...
>>
>> It is not your standard brazing. It is "fillet brazing", using a much
>> stronger "spelter" than your standard braze. The process uses a gas
>> flux (a "Hookah" bubbling the acetelene (I think - might be the O2)
>> through the liquid flux ). The flux in the flame is EXTREMELY
>> reactive, so the flame "scrubs" the joint, leaving little if any flux
>> behind. These brazed joints ARE stronger than the 4130 or 4140 base
>> metal.
>>
>> The process was developed for and used extensively by small race car
>> chassis fabricators in England and the continent. Lotus is a good case
>> in point.
>>
>
> What is the melting point for the brazing material?
>

Depends of coarse on specific alloys, but in rough numbers you can figure on
about 1700 for brass filler rod as compared to 2600 for the steel. So you
have a valid point. The next question is what kind of temps will a oil or
fuel fire generate, if being accellerated by 70 to 100 mph intake air?

Anyolmouse

January 3rd 08, 04:31 PM

"Blueskies" > wrote in message
et...
|
| "George" > wrote in message
. net...
| > Blueskies wrote:
| >>>> I meant while the part was in service. If an engine mount was
brazed, and there was an engine fire, would the braze
| >>>> joint fail (come apart) where a welded one would hold?
| >>>>
| >>>>
| >>>>
| >>> Dunno, Mongo.
| >>>
| >>> I guess it would depend on how hot for how long.
| >>>
| >>> But remember that it takes an acetylene flame to braze in the
first
| >>> place.
| >>>
| >>> If if gets that hot in the engine room, whether the mount welds
hold or
| >>> not is probably going to be a secondary issue...
| >>>
| >>> Richard
| >>
| >> Its just gotta last long enough for me to get it on the ground
;-)
| >>
| >>
| >>
| >
| > Getting it on the ground is no problem, gravity will help you with
that task, now doing it in a survivable manner,
| > that is the trick.
| >
| > George
|
| Reminds me of the guy with the souped up O-200 formula racer. The
engine was putting out great power at something like
| 3200 rpm, till it threw a prop blade at something like 2000' agl...
Shook real bad and tore the engine off the mount,
| but the safety cable kept it from coming loose from the airframe, so
he was able to get it back on the ground "in a
| survivable manner". If it had broken completely loose the CG would
have been way off and that would have been the end of
| it...
|
| Same thing with a fire in flight. I would at least want the engine to
hang on for a while to give me a fighting
| chance...

An ex Air Force pilot landed with his engine separated from his airplane
over Illinois a good many years back. I think the airplane was a Globe
Swift that had a Continental 65 in it with a wood prop. The whole
incident from throwing a prop blade, physically loosing the engine and
making a safe landing took place in less than a minute. When the
airplane whipped up into a stall, his jet training kicked in, and he
knife edged it. Let the nose fall through and with full down elevator
and plenty of airspeed he was able to do a near vertical dive to a fresh
plowed field. At the last second he rounded out and plowed the field
again with the firewall. The article said the investigators figured the
plowed field kept the airplane from whipping back up into a stall after
initial contact.

--
Anyolmouse

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[email protected]

January 3rd 08, 08:47 PM

I currently have an aircraft welding business that does repairs,
modifications, and fabrication of 4130 steel, 321 stainless, and all
weldable aluminum alloys. To answer the OP's question, yes, you can
weld 4130 with an OA torch. As to the rest of the discussion, yes,
it's alot like politics and religion...lots of opinions, all dearly
held. So, here is mine, based on many years of daily application.
All fixed wing OEM's that I know about MIG weld airframes. It's
faster and cheaper. Also none do any pre or post weld heat treatment,
as far as I know, and neither do I. Same goes for major kitplane
OEM's. I have been doing more MIG welding as time goes by, for the
same reasons. After-market airframes are mostly TIG welded, I think
because they are more esthetically pleasing to a potential buyer and
because MIG welding thin-wall tubing to aircraft standards is much
more challenging and therefore hard to find and keep competent
weldors. TIG is the same as OA in that you have a heat source in one
hand and a filler in the other. With TIG you have much better heat
control and now with the availability of TIG welders is very popular.
I would recommend TIG or OA for the homebuilder using ER70S-2 or ER80S-
D2 filler. I would not recommend MIG for the homebuilder, even tho you
can get a MIG welder for very little money. They are a different
process and much more skill and experience with thin-wall tubing is
required to do consistent airworthy welds. And triple that experience
to get as nice looking welds as TIG.
Good luck and ... practice, practice, practice in combination with
competent instruction.

Stuart & Kathryn Fields

January 4th 08, 03:03 AM

aviweld: In keeping with the religious aspect of this discussion I will
give you a big Amen. BTW where do you practice? We publish a magazine
dedicated to experimental helicopters and occasionally cite some resources
such as an aircraft welding business.
Stu Fields www.experimentalhelo.com
> wrote in message
...
> I currently have an aircraft welding business that does repairs,
> modifications, and fabrication of 4130 steel, 321 stainless, and all
> weldable aluminum alloys. To answer the OP's question, yes, you can
> weld 4130 with an OA torch. As to the rest of the discussion, yes,
> it's alot like politics and religion...lots of opinions, all dearly
> held. So, here is mine, based on many years of daily application.
> All fixed wing OEM's that I know about MIG weld airframes. It's
> faster and cheaper. Also none do any pre or post weld heat treatment,
> as far as I know, and neither do I. Same goes for major kitplane
> OEM's. I have been doing more MIG welding as time goes by, for the
> same reasons. After-market airframes are mostly TIG welded, I think
> because they are more esthetically pleasing to a potential buyer and
> because MIG welding thin-wall tubing to aircraft standards is much
> more challenging and therefore hard to find and keep competent
> weldors. TIG is the same as OA in that you have a heat source in one
> hand and a filler in the other. With TIG you have much better heat
> control and now with the availability of TIG welders is very popular.
> I would recommend TIG or OA for the homebuilder using ER70S-2 or ER80S-
> D2 filler. I would not recommend MIG for the homebuilder, even tho you
> can get a MIG welder for very little money. They are a different
> process and much more skill and experience with thin-wall tubing is
> required to do consistent airworthy welds. And triple that experience
> to get as nice looking welds as TIG.
> Good luck and ... practice, practice, practice in combination with
> competent instruction.
>