1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

unibody stiffening (seam welding)

Old Dec 27, 2003 | 04:57 PM
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unibody stiffening

What can be done to strengthen the body on a FB? Besides a cage and strut tower braces. I hear people talk about welding teh seams etc, what seams are they referring too? All of them? I've got my GS all in pieces (changing color) and figured now would be a good time to make it as strong as possible. Any ideas would be good. TIA
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Old Dec 27, 2003 | 05:22 PM
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Search the entire forum with "seam welding" . Some good info, mostly in teh tech and performance sections.

Also do an intraweb search. Tha'll yeild alot of great pics, especially some great work done on rally cars. Was just doing this yesterday.

www.nztarga.co.nz/bodyshell.html

You'll notice they use a stich weld. Much better than doing a whole seam.
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Old Dec 28, 2003 | 09:27 AM
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Thanks a bunch carl, I wasn't sure what to search for. Got a bunch of stuff, a lot in the FC forum. Seems like everyone does just about every seam which makes sense I guess. The one thing I don't get is why you don't weld the whole seam, wouldn't you want it to be rock hard or would that put undo stress on other parts of the frame? Also, anyone here ever try that urethane foam that you pour in the frame rails on a FB?
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Old Dec 28, 2003 | 09:54 AM
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Well every seam isint necessary, but unless your a structural engineer and know which you need and which you dont then do em all. Thats what I plan to do. The reason its done this way is for two reasons.
1- welding on sheetmetal tends to distort it (local heating). So you make a short weld, then move to a spot away from there and do a short weld. This allows the first weld area to cool off. If you make them one after another in a row, the metal will distort.
2- leaving gaps ensures that if you develop a crack in one of teh welds, it cant spread though the entire seam which would weaken the whole structure in one area. It'll stop at the end of the short weld and not progress any further. This is escecially important on a racecar/rally car as the stresses are quite high.

Do an intraweb search for ITW foamseal. This is another project for the upcomming streetcar I plan on building this year. Their website has alot of info, as does the SCC article youll find.
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Old Dec 28, 2003 | 02:14 PM
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Originally posted by Rx7carl
Well every seam isint necessary, but unless your a structural engineer and know which you need and which you dont then do em all. Thats what I plan to do. The reason its done this way is for two reasons.
1- welding on sheetmetal tends to distort it (local heating). So you make a short weld, then move to a spot away from there and do a short weld. This allows the first weld area to cool off. If you make them one after another in a row, the metal will distort.
2- leaving gaps ensures that if you develop a crack in one of teh welds, it cant spread though the entire seam which would weaken the whole structure in one area. It'll stop at the end of the short weld and not progress any further. This is escecially important on a racecar/rally car as the stresses are quite high.
I've listened to a rollcage fabber/welder with plenty of experience and that's exactly what he said.

Now, what would make it a LOT easier would be if you could somehow manage to find one of those 3 foot long spot welders to work on your chassis with. Just *clamp, press button, wait till time's up* and the spot's done.
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Old Dec 28, 2003 | 10:31 PM
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Thanks for the info Carl. I'm far from an engineer at anything so I'll just do everything. That makes sense about containing a crack. I'll have to search about that foam, from the little I have read it looks promising. Now I just gotta buy a welder... I guess a Lincoln gas MIG would probalby be my best bet. Anyone got any suggestions?
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Old Dec 28, 2003 | 10:39 PM
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http://www.itwfoamseal.com/automotive.htm

Same here, no enjineer LOOL. As far as getting a MIG, make sure its a gas setup. The solid core flux gasless ones stink. Ive use both and my gas MIG kicks *** over the flux non gas one. I'm not a great welder, but I can weld with teh real MIG I have.

Last edited by Rx7carl; Dec 29, 2003 at 08:32 AM.
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Old Dec 29, 2003 | 06:36 AM
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Hey Carl,

I'm looking to do atleast the faomseal thing myself and possible some seam welding... that is on my street toy.

Toxic
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Old Dec 29, 2003 | 08:33 AM
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Cool, Im looking forward to the results of this process myself. I have a feeling it will be like a totally new car.
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Old Dec 29, 2003 | 03:01 PM
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wow I have been looking for that foam stuff for the last couple of weeks on the net. the site you gave does not seem to be working right now so I can not tell if that the same company I was looking at a year ago. does anyone know of other companies that make the foam stuff?
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Old Dec 29, 2003 | 03:23 PM
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It works for me, try their home page. http://www.itwfoamseal.com/

I've looked high and low, havent found anyone else who makes the stuff.
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