Topic: Welding Sheet Metal

[midlife]

I learned MIG welding at a local VoTech school from a teacher who was more into stick welding than MIG.  I learned basically by trial and error.  One thing I learned is that there are days when welding seems intuitive and easy; other days when you can do no good and you need to just walk away.  Another thing i learned is if you are going to butt weld, make the kerf (the gap between the patch panel and the mating panel) as small as practical: usually just the thickness of your welding wire.  This takes a lot of work grinding on the patch panel to make it fit correctly, but when it does, it makes the whole job much easier. 

Practice, practice, practice.  My abilities are so-so in welding, but I am a great grinder!  With a proper patch panel sizing and using magnets to hold it in place, you can tack it in and then stitch weld all of the gaps.  This takes time (primarily to allow the metal to cool).  Grind the weld down and see if there are remaining holes.  Weld those up and repeat.  When done, and done correctly, you will need only the minimal amount (if at all) of filler.

A good book to understand body work and how to remove dents is contained in this 1953 book called "The Key to Metal Bumping" by Frank T. Sargent.  There are a lot of old-time tips and tricks there.
http://www.amazon.com/Bumping-Instructive-Manual-Fender-Practices/dp/B000O3R1OQ/ref=sr_1_1?s=books&ie=UTF8&qid=1451267663&sr=1-1&keywords=the+key+to+metal+bumping

[Angela]

Thanks Midlife! I actually have that book and agree it's pretty informative. It doesn't address oil-canning, but it does discuss heat shrinking. I think (yet am not sure) oil-canning is removed through a process similar to heat-shrinking, except the location of heat application and the squelching and hammering occur (or don't) at different locations and time in the sequence. I wish I could find a book, video or article that specifically address oil-canning.

Someone asked for additional pictures of the areas I need to weld. Here's another picture of one of the floor pan patches. I intentionally choose to save as much of the original metal as possible, thereby using a patch panel instead of a one-piece off-shore pan. Right or wrong, that was my preference... which of course has the consequence of many, many hours of "extra" welding and metal finishing.

I suspect I am going to have to fully weld the patch panel seam shown here, VS filling the seam with a filler such as "ALL METAL". I'd grade myself as a C+ welder, so completing these welds is going to consume months of spare time. Ugh.

[WT8095]

Use "auto body oil canning" as a Google search term. A couple of the videos that come up:






Ron Covell is a master metalworker. Here's a few quick tips from him:
http://www.hotrod.com/how-to/additional-how-to/1504-fixing-oil-can-dents-in-a-vintage-truck-door/

If you want to see him at work, check out his YouTube channel: https://www.youtube.com/user/covellron

Oil canning is caused by an area that has "too much" metal - i.e. it is stretched, but it can't move in plane with the surrounding metal, so it pops up (or down). The stretched metal must be shrunk to pull it back in.