4130 can't be OA welded?

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 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

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

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

"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?

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

"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?

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

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.

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

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