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tlkolrod Samba Member
Joined: June 12, 2014 Posts: 40 Location: PA
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Posted: Wed Aug 13, 2014 7:58 pm Post subject: welding a roof patch with less warping |
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Hey good evening guys I need HELP I have a 69 standard with an after market sun roof that is being removed. I need to weld the hole in the roof shut. I have a donor roof but I am worried about migging in a panel on the roof and warping the roof badly. Even if I stich it I am going to warp and it is a big flimsy area. What are your suggestions besides skipping from side to side with my stiches. I will of course do that.
Thx in advance for the help given
Toby in PA |
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Northof49 Samba Member
Joined: July 22, 2013 Posts: 1759 Location: Winnipeg, Manitoba, Canada
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Posted: Wed Aug 13, 2014 8:08 pm Post subject: |
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Body panel adhesive glue, with backing strips. _________________ 1958 Karmann Ghia owner |
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Thrasher22 Samba Member
Joined: October 05, 2010 Posts: 858 Location: Calgary, Canada
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Posted: Thu Aug 14, 2014 9:11 am Post subject: |
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You can try putting a piece of copper behind the weld to help absorb the heat, I've found it helps a little (although can be a PIA to hold in place depending where you're welding).
Taking a hammer/dolly to where you've just welded also helps. Hitting the weld with the dolly behind it will help stretch the metal back out. Maybe practice on some sheet metal first
Otherwise, its the same old go really slow and let the panel cool down to the touch before hitting an area again. _________________ 1975 Westfalia - http://www.thesamba.com/vw/forum/viewtopic.php?t=516701 |
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modok Samba Member
Joined: October 30, 2009 Posts: 26776 Location: Colorado Springs
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Posted: Thu Aug 14, 2014 8:30 pm Post subject: Re: welding a roof patch with less warping |
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tlkolrod wrote: |
What are your suggestions besides skipping from side to side with my stiches. I will of course do that.
Thx in advance for the help given
Toby in PA |
I think you should not do that. That will make waves for sure.
I'd do one "side" of the square at a time. Tack every 2 inches along one side(probably front or back first) and weld all the way across that side one inch at a time. You could try start ahead an inch and weld back, that might help or it might not. take your time. One long weld will make one uniform crease that is easy to straighten out.
cut it for a slight overlap at first and keep straighteneing it out as you go, and trim back as you go for a perfect fit. I think I could get the front and back perfect but then doing the sides I think that will be bad. Can you cut the hole wider so then the ends are near the drip rail where it won't warp so much???
I do not know how you can weld the corners without warpage. 90degree bends are a mess. That's what filler is for
the secret of welding.............joint design!!
If you don't need a perfect repair or not willing to do it again if it goes south, then buy some of those special pliers to form a jog at the edge and make a lap joint, that's be a lot safer, and oh well lots of filler around the weld. |
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Bobnotch Samba Member
Joined: July 06, 2003 Posts: 22407 Location: Kimball, Mi
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Posted: Fri Aug 15, 2014 5:06 am Post subject: |
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On big unsupported areas like you're trying to do, I normally spot tack it all in. What I mean by that, is that I'll put a tack weld on, then move over about 4 inches and put another one in, repeating all the way around, until I'm back where I started. There are 3 keys to doing this, 1 is to use those clamps that Harbour Freight sell for clamping sheet metal in place (you might need 2 sets to hold it in place (about 20 clamps worth), then after getting it tacked in place, splitting the difference between the tack welds you've already got in place, and continueing to do so as you're working your way around the area. You keep doing this until it's completely welded. The 3rd key, is to let it COOL, before hitting it again. If you can touch a freshly tacked spot with your bare hand, then it's cool enough, if not wait. Once it's all welded up, take your time grinding the welds down, as heat from the grinder can and WILL make the panel warp. Ideally you want to limit the heat from welding and from grinding, as this will lessen the chance for warpage. After grinding, you can body hammer and dolly it, and or even use a shrinking disc.
Note; if you find some spots where the tack welds didn't exactly join each other, add a tack there. Basically you're just tack welding on a tack weld (putting 1 right on the edge of each other, making a weld from a series of tack welds).
I'll be the first to tell you this is a long slow process, and it can't be rushed, but it does work for doing sheet metal.
If you're not comfortable doing that (all of the above listed above), then get 1 of those flanging tools, and flange the roof, so you can drop the filler panel in place, and weld it in.
I hope this helps. _________________ Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120
Tram wrote: |
"Friends are God's way of apologizing for relatives." |
Tram wrote: |
People keep confusing "restored" and "restroyed". |
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Northof49 Samba Member
Joined: July 22, 2013 Posts: 1759 Location: Winnipeg, Manitoba, Canada
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Posted: Fri Aug 15, 2014 8:06 am Post subject: |
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I have found the problem with a flanging tool on a curved surface is that it tends to flatten out the curve. You might have to adjust the curve back into it after flanging it. _________________ 1958 Karmann Ghia owner |
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Bobnotch Samba Member
Joined: July 06, 2003 Posts: 22407 Location: Kimball, Mi
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Posted: Sat Aug 16, 2014 8:24 am Post subject: |
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Northof49 wrote: |
I have found the problem with a flanging tool on a curved surface is that it tends to flatten out the curve. You might have to adjust the curve back into it after flanging it. |
You can take some tin snips, and make relief cuts to help get the curve back too. _________________ Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120
Tram wrote: |
"Friends are God's way of apologizing for relatives." |
Tram wrote: |
People keep confusing "restored" and "restroyed". |
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lightice Samba Member
Joined: December 14, 2012 Posts: 599
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Posted: Sat Aug 16, 2014 9:55 am Post subject: |
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The body shop guy here does this:
1) Wet a rag
2) Use magnets to adhere rag to near where the weld is
3) Weld the seams, ensuring rag stays wet. Else stop, wet and reattach.
Seems to work well. |
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