TIG welders question

[nonhog]

Somewhere on the web I saw a guy welding up a narrowed front bumper on a
59 or 60 Impala . The guy cut the ends, removed the amount not needed and welded them together w/o grinding or removing the old chrome. Or so it seemed . I would have thought the chrome would need removed for a clean
strong weld. I guess I am curious as well as wondering if I tackle something like that with my MIG what about the chrome ? And is it differant because it was TIG ?
School me , thanks !

 

[PAToyota]

TIG has much more localized heat that MIG, so you're going to affect more metal on either side of the weld if you try to do it with MIG.

 

[mag99]

I think it has to be "reverse chromed" first. Stripped. With a MIG, the metal has to be clean to weld, with a TIG, the metal has to be PERFECTLY clean. The heat from the torch will just boil up any impurities, ie the chrome, nickel, copper, etc. Also, any welding that would be hot enough to actually hold the metal together, will be hot enough to turn loose the chrome, not to mention "blue" the chrome for several inches on each side of the weld.

Now, if the bumper in question bolted together, and the seam was hidden behind a bumper gaurd or something, this would be doable. But the chrome has to be ground off where any welding is going on. Then maybe seal the ground edge of the chrome with some sort of clear, so it doesen't continue to peel off?

 

[nonhog]

I should have mentioned it was obvious that the part on the video will be rechromed (wish I could find it) I was just wondering about impurities.
thanks for the replys

 

[voidifused]

I have tried TIG welding some stuff with the chrome still on it, never had much luck. Now i know on aluminum that has been anodized with some tig welders you can weld it and if you do it right the color will come on to the top of the new weld and look the same.
This deals with it, it ends up kind of like chrome, though i have never seen an aluminum bumper on a car.
http://www.millerwelds.com/resources/communities/mboard/showthread.php?t=1066

 

[iajonesy]

Be careful when welding anything that has been plated as it may give off a poisonous gas such as cyanide. It depends on how good a wash the part got after each stage of the process. Use plenty of ventilation to be on the safe side.

Mike