Welding thin metal

[Boris]

Just now, happily burning 'ventilation holes' in my 0.8mm test sheet, I had an idea. I can easily weld a seam in the middle of the plate, but not on the edge. My 0.8mm butt joints are also 'coming along slowly' - very slowly!

My idea is, when welding to thin bodywork:

mark out the area to patch
weld a seam around the area (or at least the vulnerable part)
cut out to the seam
insert thicker (1mm?) patch and seam weld happily ever after.

I'm very new to this metal-vapourising lark and I have not tried this on the actual car, but it seemed to work ok on test pieces. It is more work, for sure and the experts won't need to do it, but it just might get someone out of trouble!

 

[Paul.]

Hi Boris
Not just extra work, but extra heat input into the job, your likely to create problems for yourself with distortion, depending on the type of repair you may be able to overlap your patch and thus create a lap welded joint, if a flush finish is required create a joggle this will also stiffen the patch, if you must butt weld, a good joint fit is essential, on such thin material you don't want to be filling gaps, get some copper bar to use as a heat sink and put it behind the joint, aluminum or brass can also be used but will increase the risk of weld contamination.