View Full Version : metal shrinking question


09-26-2006, 08:12 AM
I'm restoring an older Dodge Dart - I've got one area over the rear quarter that I've got fairly straight and ready for filler. One problem is a "buckling" area that needs help (about8 x 10), very slight impression but, push on one area, the other pops out, push on that high spot and out pops the other, you know the drill. Anyway it appears I may need to attempt to shrink some, can I get this done with propane ? I own a MIG but don't have access to oxy-acetalene (unless I can rent). It's a relatively small job. Thanks - any advise appreciated. Also - I can't really get to the back side of this area.

09-26-2006, 09:18 AM
I did the hood on my 68 Cutlass with propane. Had the spot at bare metal - heated the area for maybe 30 seconds and immediately threw water on it to cool. Repeated twice. Metal doesn't "oil can" anymore.

Phil V
09-26-2006, 09:39 AM
Rebeldart - Do not use a little portable propane torch to try and shrink that metal. Actually for two different reasons. The first reason is that by the sounds of your problem the answer is not a shrinking issue. The other reason is that if it was a shrinking issue the propane torch tip flame can't be dialed down to a sharp point that is needed for shrinking. The right way to heat shrink is to heat a spot about the size of a dime red hot then tap it once or twice with a flat head body hammer then quench it with a wet rag (all in about 10 seconds). The propane torch heats too large of an area, it will cause more problems than it cures.

99% of the time that you are faced with an "oil can" effect problem where the metal pops in then back out if you push on another area is caused by a high spot at some point surrounding the oil canning metal. With the metal popped in - carefully feel with the palm of your hand the area surrounding the oil canning metal. There WILL a ridge or a high spot. Tap tha ridge down with a flat head body hammer and the oil canning with quit popping in and out. Sometimes the high spot causing the oil canning can be a body line or even a door bottom or other metal panel edge. Tap that edge with a hammer like you are forcing the metal towards the metal thats popping in and out. Give this information a try and see if it works (usually does).

09-26-2006, 01:07 PM
Thanks guys - looks like your opinions conflict somewhat ! I'll study the area closer this evening and see if I can't find the area needing attention.

Lost in NJ
09-27-2006, 12:39 PM
Shrinking without being sure of the cause of an oil can can make the problem just move around. Go off to my website to consider some thoughts about your fender.

Some comments on metal working (http://home.comcast.net/~68c/Metalworking.htm)