Just installed a 23" x 29" driver's side rear floor pan. The piece is "oil canning". New to sheet metal fab. How can I fix it? I added bead rolls in the stock locations. I remember a body man using a slapper bar to fix a quarter panel on my 55 Chevy. Any help would be greatly appreciated. Here is a definition of oil can: "when the sheet metal can pop in and out like the side of an oil can".
I had the same problem on a 12 x 12 piece with beads rolled in 16 gauge. The piece oil canned before I welded it in the car. I was told to use heat and flatten out the piece prior to welding. I did that and it worked. I don't know why but the heat shrank the metal. Maybe you could use some heat to shrink the spot where it is oil canning.
My floor pan is fabricated out of 18ga. Where do I apply the heat? How do I apply the heat? When do I know enough heat has been applied to rememdy the problem? I already welded in the pan, that is when I noticed the oil can effect.
Heat the area with a torch about the size of a soda can and then cool it quickly with water or a wet towel. It will draw the metal up(shrink it). It's oil canning because there is pressure on the metal somewhere.
How did you install the floor pan, weld? Are you done welding or did you tack it and will continue welding? If you are done welding and having to deal with oil can problem - it sounds like a low crown and heat should get you there. With the heel of one hand find the spot where it oil cans the easiest, with your thumb or screwdriver handle move pressure around the floor until you find the spot that reacts to the oil can. Heat that spot to cherry red, dime size. Quench with water soak rag - do the search thing as there is volumes written on how to heat shrink and everybody has a different little trick. Getting rid of an oil canning is difficult.
Hey Joe, It kinda sounds like you've got a " double whammy " goin there- first the beading operation probably took material from the low crowned areas of the panel to have enough to stretch to the depth of the beads-this left the panel stretched and under tension. Next, the welding process, which usually causes sheetmetal to contract when welded, especially flat or low crowned metal, has left some of the areas shrunken. How the panel was welded in maybe key to correcting the problem/s. If butt welded in, you might try on-dolly hammering of the weld beads to stretch those areas and releave tension in the panel. If a good part of the movement in the panel is around the beads you may well have to shrink around those beads in the areas with the most movement. As oj mentioned, you may wanna sheck the search deal, as many have weighted in on this problem in the past. " Life ain't no Disney movie "
sure not a pro approch. my 40 pontiac had that problem after they were installed. a couple of s shaped passes with my mig solved the problem and it didn't show under the carpet
Thanks everyone for the tips. I also searched YouTube and found some great video on different metal shrinking methods.
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