Practical welding?

A friend lent me an OA rig so I could learn to weld. Lots of good
material in the library and on the NGs. But all that welding is done on
a welding bench, at a comfortable height. Apparently one does not have
to get near an airframe to get a certificate to weld 4130 with OA.

How does a welder learn how to weld on a built and covered fuselage
(say on fabric/steel)? How does he know how much fabric has to be
removed to insure his heating doesn't screw up glue adhesion? How does
he learn how to protect the nitrate from going up in flames from
sparks? How does he learn the tricks to weld all around a splice
without standing on his head or laying on his back?
-
Mike

Normally, when there is such a major repair to an airframe that requires
welding, it probably needs a recovering anyway. Not always true, of course.

The only way to learn how to weld tubing and in clusters is practice
practice practice. There are also jigs that lets you rotate a fuselage
so you can get at the cluster in a comfortable position

You could attend one of the workshops at AirVenture or one of the welding
classes that the EAA has around the country.

--
Cy Galley
EAA Safety Programs Editor
Always looking for ideas and articles for EAA Sport Pilot

"mhorowit" wrote in message
oups.com...
A friend lent me an OA rig so I could learn to weld. Lots of good
material in the library and on the NGs. But all that welding is done on
a welding bench, at a comfortable height. Apparently one does not have
to get near an airframe to get a certificate to weld 4130 with OA.

How does a welder learn how to weld on a built and covered fuselage
(say on fabric/steel)? How does he know how much fabric has to be
removed to insure his heating doesn't screw up glue adhesion? How does
he learn how to protect the nitrate from going up in flames from
sparks? How does he learn the tricks to weld all around a splice
without standing on his head or laying on his back?
-
Mike

"Cy Galley" wrote in message
newsYmNe.45866$084.12269@attbi_s22...
You could attend one of the workshops at AirVenture or one of the welding
classes that the EAA has around the country.

Short of that, are there good book(s) that you could teach yourself?

I seem to recall practicing clusters with short sections, and putting a tire
valve in it, and see if your welds will hold pressure. I think I saw that
in BengalisIs (sp?) books. Is that a common practice to test the welds?

The second part, IIRC, is tearing it apart, to check penetration and
strength of the welds.

Another test is to put it in a vise and beat the crap out of it with a
hammer. If the tubes break before the welds, its a good weld.

John

"John T" wrote in message
...
Another test is to put it in a vise and beat the crap out of it with a
hammer. If the tubes break before the welds, its a good weld.

Right, that is the first part of step 2.

Step one is to see if the welds are airtight, because aircraft welds should
be, so corrosion (rust) does not eat away the tube, with no visible warning.
--
Jim in NC

Part of the tube cluster test after welding involves sawing the tubes
cluster along its center line. This alows a visual inspection of the root
for each side of the entire joint.
From this half cluster you can cut out bend test coupons.
Depending on how the bend test fails you can determine if you have adaquate
fusion on both sides of the joint; and if preheat may be required.

One method used to extend the life of welded aircraft structures was to pour
in a gallon or so of boiled linseed oil after all welding had taken place
and the structure passed a leak test. It is a time consuming task involving
rolling the structure as it is being tilted to ensure full coverage of the
interior of the tubes.

There is a publication out there that goes into great detail of fabricating
weldments for the tubular weld test just don't remember the name off hand.
I do have one reference I was able to find but it is the tentative code for
welding aircraft structures dated 1944.

They proposed the use of a piece of 1/4" x 6" flat bar 6" long. Three tubes
would be notched and coped to slide over the flat bar and form a Y type
connection with the third tube center on the two tubes forming the Y.
After the weld is completed the weldment was cut across the the flat bar
around the 2 1/2" mark exposing the ends of the tubes; allowing inspection
of the interior .

I had posted a pdf file many years back to a web site I forget the name of
but it was titled welding tubular structures or something along those lines.
It may still be out there.


John Noon


"John T" wrote in message
...
Another test is to put it in a vise and beat the crap out of it with a
hammer. If the tubes break before the welds, its a good weld.

John

Yup. Finch's "Welder's Handbook". Well written, easy read.
Also, just visit your library. Although after trying and if
unsatisfied, visit an EAA Chapter.
- Mike


"Morgans" wrote:


"Cy Galley" wrote in message
newsYmNe.45866$084.12269@attbi_s22...
You could attend one of the workshops at AirVenture or one of the welding
classes that the EAA has around the country.

Short of that, are there good book(s) that you could teach yourself?

I seem to recall practicing clusters with short sections, and putting a tire
valve in it, and see if your welds will hold pressure. I think I saw that
in BengalisIs (sp?) books. Is that a common practice to test the welds?

The second part, IIRC, is tearing it apart, to check penetration and
strength of the welds.

Shouldn't be much nitrate anymore unless you have cotton.

Join your local EAA chapter and find out who has or is building a tube and
fabric plane. They should be able to assist you.

--
Cy Galley - Chair,
AirVenture Emergency Aircraft Repair
A Service Project of Chapter 75
EAA Safety Programs Editor - TC
EAA Sport Pilot
"mhorowit" wrote in message
oups.com...
A friend lent me an OA rig so I could learn to weld. Lots of good
material in the library and on the NGs. But all that welding is done on
a welding bench, at a comfortable height. Apparently one does not have
to get near an airframe to get a certificate to weld 4130 with OA.

How does a welder learn how to weld on a built and covered fuselage
(say on fabric/steel)? How does he know how much fabric has to be
removed to insure his heating doesn't screw up glue adhesion? How does
he learn how to protect the nitrate from going up in flames from
sparks? How does he learn the tricks to weld all around a splice
without standing on his head or laying on his back?
-
Mike

"Cy Galley" wrote:

Shouldn't be much nitrate anymore unless you have cotton.

Join your local EAA chapter and find out who has or is building a tube and
fabric plane. They should be able to assist you.

Cy - the point I was making was the welder is faced not with a bare
fuselage on a turning jig, but if he were faced with a covered a/c
with engine and landing gear. How does he handle that? - Mike