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#11
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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 ** |
#12
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Welded Patch Repair question
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 |
#13
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Welded Patch Repair question
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 |
#14
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Welded Patch Repair question
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. |
#15
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Welded Patch Repair question
"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 ) |
#16
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Welded Patch Repair question
"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 |
#17
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Welded Patch Repair question
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 ** |
#18
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Welded Patch Repair question
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 |
#19
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Welded Patch Repair question
"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 ) |
#20
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Welded Patch Repair question
"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 ) |
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