Welding question #2; rust holes

AC 43.13 para 4-94 says: " WELDED-PATCH REPAIR. Dents
or holes in tubing may be repaired by using a patch of the same
material, one gauge thicker" and then defines punctured tubing:
b. Punctured Tubing. Holes are not longer than tube diameter and
involve not more than 1/4 of tube circumference.

Question: Can I apply the definition of Punctured Tubing to mean a
hole caused by rust? As I'm stripping my tubing I've notice several
out of the way patches and I'm assuming they are covering rust holes.
I've uncovered two 1/8" holes previously unseen and am wondering if a
simple patch is correct. - Mike

"Michael Horowitz" wrote in message
...
AC 43.13 para 4-94 says: " WELDED-PATCH REPAIR. Dents
or holes in tubing may be repaired by using a patch of the same
material, one gauge thicker" and then defines punctured tubing:
b. Punctured Tubing. Holes are not longer than tube diameter and
involve not more than 1/4 of tube circumference.

Question: Can I apply the definition of Punctured Tubing to mean a
hole caused by rust? As I'm stripping my tubing I've notice several
out of the way patches and I'm assuming they are covering rust holes.
I've uncovered two 1/8" holes previously unseen and am wondering if a
simple patch is correct. - Mike

Is it an 1/8" rust hole?

On Sat, 06 Jun 2009 06:08:46 -0400, Michael Horowitz
wrote:

AC 43.13 para 4-94 says: " WELDED-PATCH REPAIR. Dents
or holes in tubing may be repaired by using a patch of the same
material, one gauge thicker" and then defines punctured tubing:
b. Punctured Tubing. Holes are not longer than tube diameter and
involve not more than 1/4 of tube circumference.

Question: Can I apply the definition of Punctured Tubing to mean a
hole caused by rust? As I'm stripping my tubing I've notice several
out of the way patches and I'm assuming they are covering rust holes.
I've uncovered two 1/8" holes previously unseen and am wondering if a
simple patch is correct. - Mike

forget the bloody semantics of the document.
you are repairing a structure that will have flight loads imposed upon
it unrelentingly in flight.

cut the dodgy stuff out and weld in structurally sound replacement
tube.

ask yourself as you work "would I be prepared to do a 60 degree angle
of bank turn at Vne with maximum all up weight with that repair?"

with rust penetrations what is the internal wall of the tube like?

Stealth Pilot

On Sat, 6 Jun 2009 08:54:08 -0500, "Tim" wrote:


"Michael Horowitz" wrote in message
.. .
AC 43.13 para 4-94 says: " WELDED-PATCH REPAIR. Dents
or holes in tubing may be repaired by using a patch of the same
material, one gauge thicker" and then defines punctured tubing:
b. Punctured Tubing. Holes are not longer than tube diameter and
involve not more than 1/4 of tube circumference.

Question: Can I apply the definition of Punctured Tubing to mean a
hole caused by rust? As I'm stripping my tubing I've notice several
out of the way patches and I'm assuming they are covering rust holes.
I've uncovered two 1/8" holes previously unseen and am wondering if a
simple patch is correct. - Mike

Is it an 1/8" rust hole?

Yes - Mike

On Jun 6, 8:45*am, Michael Horowitz wrote:

Is it an 1/8" rust hole?

If it is a rust hole I'd be real concerned about the health of the
rest of the tube. Just how much rust is in there any way?

I learned this trick from a muffler shop guy long time ago and while
it's not strictly "aircraft method" it does work to find tubes that
are in need of replacement. Grab a set of Channel Lock type pliers
and find a piece of tube in known good shape of the same size and
gauge as the tube in question and squeeze until it just starts to
deflect. Take not of the force required. Now go squeeze the tube in
question. A good tube won't be damaged but a rusted tube will -
generally - deform at a noticeably reduced hand pressure. Really
rusted ones, and I've seen some that looked perfectly fine on the
outside, will crush with a noticeable crackling sound.
=====================
Leon McAtee

On Sat, 6 Jun 2009 09:57:05 -0700 (PDT),
wrote:

On Jun 6, 8:45Â*am, Michael Horowitz wrote:

Is it an 1/8" rust hole?

If it is a rust hole I'd be real concerned about the health of the
rest of the tube. Just how much rust is in there any way?

I learned this trick from a muffler shop guy long time ago and while
it's not strictly "aircraft method" it does work to find tubes that
are in need of replacement. Grab a set of Channel Lock type pliers
and find a piece of tube in known good shape of the same size and
gauge as the tube in question and squeeze until it just starts to
deflect. Take not of the force required. Now go squeeze the tube in
question. A good tube won't be damaged but a rusted tube will -
generally - deform at a noticeably reduced hand pressure. Really
rusted ones, and I've seen some that looked perfectly fine on the
outside, will crush with a noticeable crackling sound.
=====================
Leon McAtee


Excellent. Thanks Leon - Mike

On Sat, 06 Jun 2009 14:10:36 GMT, Stealth Pilot
wrote:

On Sat, 06 Jun 2009 06:08:46 -0400, Michael Horowitz
wrote:

AC 43.13 para 4-94 says: " WELDED-PATCH REPAIR. Dents
or holes in tubing may be repaired by using a patch of the same
material, one gauge thicker" and then defines punctured tubing:
b. Punctured Tubing. Holes are not longer than tube diameter and
involve not more than 1/4 of tube circumference.

Question: Can I apply the definition of Punctured Tubing to mean a
hole caused by rust? As I'm stripping my tubing I've notice several
out of the way patches and I'm assuming they are covering rust holes.
I've uncovered two 1/8" holes previously unseen and am wondering if a
simple patch is correct. - Mike

forget the bloody semantics of the document.
you are repairing a structure that will have flight loads imposed upon
it unrelentingly in flight.

cut the dodgy stuff out and weld in structurally sound replacement
tube.

ask yourself as you work "would I be prepared to do a 60 degree angle
of bank turn at Vne with maximum all up weight with that repair?"

with rust penetrations what is the internal wall of the tube like?

Stealth Pilot

Message understood - Mike