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-   -   warpage (http://www.hotrodders.com/forum/warpage-222922.html)

tinman1 08-15-2012 12:20 PM

warpage
 
HI wondering how to avoid warpage when welding in new panels/pieces on bodies of cars, i try to do just a small tack, and skip around from place to place, i also use this jigging putty from eastwood around the weld area, or this gel i have, when i grind the welds down i use to use a 9" grinder but have switched to a small 3-4" 1/4" thick disc and try to keep the heat down sometimes blowing with compressed air-- what am i doing wrong??!?!?!?:mad:

Mach1460 08-15-2012 03:35 PM

Ive had the same issues. The first time i did a patch panel it was a buttweld with a small but tight gap maybe 1/32 and the weld "sunk" on me about 1/4". I was real worried about using too much filler so I picked up a lead/tin body sauder kit and used that to bring up the worst spots then used a light coat of filler to finish. It was a patch panel about 1'x1' and It took me 4 hours to weld. First tack'd it in, let them cool 15 min, split those gaps and so on every 10-15 minutes id do another set of tacks till it was complete. I also used a damp rag to cool the weld, from what I read now is not reccomended.

Just last week i did two large wheelwell patch panels on my bronco. I decided to get one of those pnumatic flanger tools and flanged the top side of the patch and buttwelded the sides. I also cooled this one with my air hose as I went along. Anyway, my sides turned out great but the top (where the flange is) sunk again. made me want to cry. I thought since it was much thicker it wouldnt sink. I thought wrong. From everything ive been doing to figure out why this happens to me, BE SURE to let the welds cool on there own. And make sure to use a gap the size of the sheetmetal. This is very arguable but in my expierence it seems the tighter the gap or no gap the harder it pulls on the metal around it. It depends on the welder I suppose. I have yet to master this craft of patch panels but I think my heat settings and tack welds are hotter than need be.

oldBodyman 08-15-2012 05:35 PM

" what am i doing wrong??!?!?!?"

"try to keep the heat down sometimes blowing with compressed air--"

heating things up and cooling them down with compressed air is called 'shrinking' and will warp the panel.

the new panel should just lay in place, if you need to clamp it down into place it will warp.

practice your welder settings on identical metal and try for enough penetration, not too much build up and the smallest 'heat ring' you can make, then use the 'tack and move' method, letting everything cool naturally.

The time you waste waiting is more than saved on finishing.

tech69 08-15-2012 08:22 PM

I agree with the forced air over the welds. If I do use it I let it naturally cool for a couple minutes than trigger the air so it doesn't shock the metal and warp it. Naturally cooling it is best hands down. Also knowing whether or not the area is prone to warping helps.

deadbodyman 08-16-2012 07:00 AM

You guys are being way to critical on yourselves..the only way to get good at not warping a panel is to actually warp one,just like painting without runs,, you have to get runs first. this isnt something you can just read about and do ,sure theres a lot of good advice here but it takes practice lots of it ,I warped quite a few panels in my day and so has everyone else,just keep plugging away and doing it and you'll get good ,hopefully it wont take as long to learn as those of us that started before the internet was around... If you got the panel welded on at all your doing better than most its a lot of work just getting to that point.and just the fact that you want to do better the next time shows us you got what it takes to get good.Thats what being a craftsman type is all about.enjoy your mistakes thats how you learn to be better...Practice,practice,practice

tinman1 08-16-2012 08:24 AM

Thank you for the replys! is there a way to get this sunk in panel out a bit? perhaps with heat? sometimes i found if i dolly out the warp the weld will crack.

deadbodyman 08-16-2012 08:33 AM

what I do is hammer & dolly as I go, one spot weld at a time but grind the weld first and I use a stone not a grinding disc,I've seen a lot of warpage done just with the grinding.
A shrinking disc can be very helpful from what I hear...I never used one

tinman1 08-16-2012 08:53 AM

thank you, can you post a picture of the "stone" you use, what shape is it? thank you

deadbodyman 08-19-2012 07:53 AM

1 Attachment(s)
Quote:

Originally Posted by tinman1 (Post 1583276)
thank you, can you post a picture of the "stone" you use, what shape is it? thank you

theres two, my favorate is on the far right and theres a much bigger one that goes in my 4" side grinder ,they are about a 1/4 " thick they work much better than grinding disc...

timothale 08-19-2012 09:23 AM

dhammer weld.
 
In the old days it was called hammer welding, done with Oxy-acety torch with a small tip. the weld spot is hot and expanded. Bill Hinds still uses a torch to do most of his work. the metal cools and shrinks causing distortion, To expand the metal back you Hammer on Dolly, weld, cool, hammer, weld, cool, hammer, Sometimes I have had someone else hold the dolly where my arm wouldn't reach. get some body shop dumpster panels and practice. heat shrinking , welding, hammer expansion, An english wheel domes a piece of sheetmetal by compressing it as you roll over that spot. you make that spot a microscope measure thinner, the metal is pushed outward and expands.


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