Welded Patch Repair question

On Sun, 20 Jul 2008 21:22:42 +0800, Stealth Pilot
wrote:

On Sat, 19 Jul 2008 11:08:36 -0400, Michael Horowitz
wrote:

I'm working with 4130.
I have a piece of tubing with a series of rust holes which do not
cover an area greater than 1/2 ", so it appears a welded patch repair
would be appropriate.
Reading 43.13,, Figure 4-36, it appears the patch tube will have to be
expanded in diameter in order to fit over the injured tube (can't slip
the patch over the injured tubefrom an end).
Will there be any problem if I heat the patch so I can open open it
and slip it over the injured tubing? - Mike

take a piece of flat 4130 of about the width needed for the job but a
little longer.
(think of toilet paper on the roll. width to match but longer)

tack weld one edge along the tube. it will hang out like b
now heat the flat sheet to red heat with an oxyacetylene torch and
while it is soft bend or gently hammer it down onto and around the
tube.when about half way through the bending trim to shape as
necessary. complete the bend then complete the edge weld all around
the piece.

I have a very neat repair on the auster done just this way.

Stealth Pilot
Or simply split a tube (several inches longer than the damaged
portion) the right size to slide over the existing tube, cut with a
"fishmouth" on both ends to distribute the forces, place it over the
weak area, and weld both seams and both ends.
** Posted from http://www.teranews.com **

On Sun, 20 Jul 2008 13:10:01 -0700 (PDT), mhorowit
wrote:

On Jul 20, 9:22*am, Stealth Pilot
wrote:
On Sat, 19 Jul 2008 11:08:36 -0400, Michael Horowitz

wrote:
I'm working with 4130.
I have a piece of tubing with a *series of rust holes which do not
cover an area greater than 1/2 ", so it appears a welded patch repair
would be appropriate.
Reading 43.13,, Figure 4-36, it appears the patch tube will have to be
expanded in diameter in order to fit over the injured tube (can't slip
the patch over the injured tubefrom an end).
Will there be any problem if I *heat the patch so I can open open it
and slip it over the injured tubing? - Mike

take a piece of flat 4130 of about the width needed for the job but a
little longer.
(think of toilet paper on the roll. width to match but longer)

tack weld one edge along the tube. it will hang out like * * b
now heat the flat sheet to red heat with an oxyacetylene torch and
while it is soft bend or gently hammer it down onto and around the
tube.when about half way through the bending trim to shape as
necessary. complete the bend then complete the edge weld all around
the piece.

I have a very neat repair on the auster done just this way.

Stealth Pilot

Stealth - so you placed a rectangle patch over the injury as opposed
to a diamond shape, or is that what you ment when you said "trim to
shape"? - Mike

it ended up looking like a rectangle with tapered in ends.
if you morphed a rectangle and a diamond you'd have the shape.
I'll email you a photo.

Stealth Pilot

On Sun, 20 Jul 2008 22:27:43 -0400, clare at snyder dot ontario dot
canada wrote:

On Sun, 20 Jul 2008 21:22:42 +0800, Stealth Pilot
wrote:

On Sat, 19 Jul 2008 11:08:36 -0400, Michael Horowitz
wrote:

I'm working with 4130.
I have a piece of tubing with a series of rust holes which do not
cover an area greater than 1/2 ", so it appears a welded patch repair
would be appropriate.
Reading 43.13,, Figure 4-36, it appears the patch tube will have to be
expanded in diameter in order to fit over the injured tube (can't slip
the patch over the injured tubefrom an end).
Will there be any problem if I heat the patch so I can open open it
and slip it over the injured tubing? - Mike

take a piece of flat 4130 of about the width needed for the job but a
little longer.
(think of toilet paper on the roll. width to match but longer)

tack weld one edge along the tube. it will hang out like b
now heat the flat sheet to red heat with an oxyacetylene torch and
while it is soft bend or gently hammer it down onto and around the
tube.when about half way through the bending trim to shape as
necessary. complete the bend then complete the edge weld all around
the piece.

I have a very neat repair on the auster done just this way.

Stealth Pilot
Or simply split a tube (several inches longer than the damaged
portion) the right size to slide over the existing tube, cut with a
"fishmouth" on both ends to distribute the forces, place it over the
weak area, and weld both seams and both ends.
** Posted from http://www.teranews.com **

that also works.

remember in weld repairs to tubes you need to heed the thirds rule.
if the repair is within one third of the tube in from the end it can
be repaired with a patch. if the repair is in the centre third of the
tube it needs to be cut out and replaced.
this is to prevent fatigue failures from vibration.

Stealth Pilot

I know you said you got it, but I figured out how to make some changes
in the program and wonder it it shows up now:
-------------
You should use the next diameter of tube to get easy conformation the
the shape of the tube you are repairing. But, if you have no choice but
to use a patch from
the same diameter tube, there is no problem with heating the patch to
make it plastic enough to conform to the outside contour of the tube
being repaired. If it
doesn't lay down smoothly you can tack welt the patch where it makes
contact with the tube, then heat the patch with the torch and gently tap
it into place, till it lies
down tightly with the tube, with a small hammer. You can tap and tack as
you go until the patch is a tight fit, the weld it.

If you want to make a slip over repair using a whole piece of tube, you
will have to use the next diameter tube as it would be virtually
impossible to expand the
diameter of a tube uniformly and continuously around its circumference.

"Michael Horowitz" wrote in message
...


Bruce - can't open it. Recommendation? - MIke




On Sat, 19 Jul 2008 19:14:38 GMT, "Bruce A. Frank"
wrote:




No problem. Use the next size larger tubing. Run it through the bandsaw
lengthwise. Fix it over the damaged tube and weld everything back together.

Highflyer
Highflight Aviation Services
Pinckneyville Airport ( PJY )

"Highflyer" wrote

No problem. Use the next size larger tubing. Run it through the bandsaw
lengthwise. Fix it over the damaged tube and weld everything back
together.

How about cutting a taper (like points on opposite sides from each other) on
the new tube to avoid creating a stress riser that would occur where the new
tube suddenly stopped, all of the way around?
--
Jim in NC

On Sun, 27 Jul 2008 23:04:01 -0400, "Morgans"
wrote:


"Highflyer" wrote

No problem. Use the next size larger tubing. Run it through the bandsaw
lengthwise. Fix it over the damaged tube and weld everything back
together.

How about cutting a taper (like points on opposite sides from each other) on
the new tube to avoid creating a stress riser that would occur where the new
tube suddenly stopped, all of the way around?

As posted before, required.
** Posted from http://www.teranews.com **

clare at snyder dot ontario dot canada wrote

As posted before, required.

I musta missed that.

Highflyer left that part out, and I wanted to make sure that was understood.
--
Jim in NC

"Bruce A. Frank" wrote in message ...
You should use the next diameter of tube to get easy conformation the the shape of the tube you are repairing. But, if you have no choice but to use a patch from the same diameter tube, there is no problem with heating the patch to make it plastic enough to conform to the outside contour of the tube being repaired. If it doesn't lay down smoothly you can tack welt the patch where it makes contact with the tube, then heat the patch with the torch and gently tap it into place, till it lies down tightly with the tube, with a small hammer. You can tap and tack as you go until the patch is a tight fit, the weld it.
If you want to make a slip over repair using a whole piece of tube, you will have to use the next diameter tube as it would be virtually impossible to expand the diameter of a tube uniformly and continuously around its circumference.



What he said Mike. I generally use the next size tubing for the sleeve.

If I cant slip it over the end, and you usually can't when you are repairing on a fuselage truss, I fishmouth the tube and then slice it lengthwise on my handy metalcutting bandsaw. :-) Then place the two halves of the sleeve over the area to be repaired and weld everything together. See the pictures in AC43-13 and proceed accordingly.

Do cut the fabric well back. A little hot slag on doped fabric makes for an exciting event and can well spoil you entire day! Especially if it was covered with the Ceconite process, that starts with nitrate dope. I did that once, it in approximately ten seconds the fuselage was totally bare except for a few festoons of molten polyester hanging in awkward places! :-)

Highflyer

Highflight Aviation Services

Pinckneyville Airport ( PJY )

"Stealth Pilot" wrote in message
news
On Sun, 20 Jul 2008 22:27:43 -0400, clare at snyder dot ontario dot
canada wrote:

On Sun, 20 Jul 2008 21:22:42 +0800, Stealth Pilot
wrote:

On Sat, 19 Jul 2008 11:08:36 -0400, Michael Horowitz
wrote:

I'm working with 4130.
I have a piece of tubing with a series of rust holes which do not
cover an area greater than 1/2 ", so it appears a welded patch repair
would be appropriate.
Reading 43.13,, Figure 4-36, it appears the patch tube will have to be
expanded in diameter in order to fit over the injured tube (can't slip
the patch over the injured tubefrom an end).
Will there be any problem if I heat the patch so I can open open it
and slip it over the injured tubing? - Mike

take a piece of flat 4130 of about the width needed for the job but a
little longer.
(think of toilet paper on the roll. width to match but longer)

tack weld one edge along the tube. it will hang out like b
now heat the flat sheet to red heat with an oxyacetylene torch and
while it is soft bend or gently hammer it down onto and around the
tube.when about half way through the bending trim to shape as
necessary. complete the bend then complete the edge weld all around
the piece.

I have a very neat repair on the auster done just this way.

Stealth Pilot
Or simply split a tube (several inches longer than the damaged
portion) the right size to slide over the existing tube, cut with a
"fishmouth" on both ends to distribute the forces, place it over the
weak area, and weld both seams and both ends.
** Posted from http://www.teranews.com **

that also works.

remember in weld repairs to tubes you need to heed the thirds rule.
if the repair is within one third of the tube in from the end it can
be repaired with a patch. if the repair is in the centre third of the
tube it needs to be cut out and replaced.
this is to prevent fatigue failures from vibration.

Stealth Pilot

I have often used Stealth Pilot's flat 4130 sheet stock repair when
the repair has to conform to strange shapes, like a gusset to repair
into or near a cluster joint or around any tubing joint. Weld on one
edge of the appropriately shaped patch and then heat and hammer
( gently with a small hammer ) to bring the patch metal into snug
conformity with the metal underneath. Weld up all the edges as you
go and then cool the whole thing down slowly so it doesn't quench
on you and harden up and get brittle.

On an old airplane like the Auster, which was probably built with
1020 tubing and not with 4130 tubing, you don't even have to use
4130 for the patch. :-)

Highflyer
Highflight Aviation Services
Pinckneyville Airport ( PJY )