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Old 07-12-2018, 07:21 AM
orwell84 orwell84 is offline
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Default Help with an oil canning panel

I have been chasing an oil can across a VW bus door for the last few evenings. The problem started with welding up a couple smalll holes in the door where aftermarket van mirrors had been installed decades ago (circles). The holes had been previous filled with bondo. The panel had an oil can which I tried to fix by shrinking at the square spot which only displaced the oil can and flattened the panel at a crowned spot. Trying again, I stretched the shrink back out out including at the holes I welded shut which I should have done at the beginning. I brought the panel up close to its original contour but still had oil canning at the square spot so I tried to shrink it again less aggressively, but got even more oil canning at the oval spots at the right. The panel is close to its original contour when I support the oil can from behind. The circle to the right can't be worked out enough because it is a snarl of weld material and hardened metal from stud gun pins. I get that I should have addressed the distortion caused by the heavy mirror and the shrinking caused by welding up the wallowed out holes and not shrunk the original oil canned area that was undamaged. I am considering cutting out the the hard spot at the right hand circle and welding in a patch so I can bring it out to contour. If I could stiffen the oil canning areas, the panel would be close enough for filler but I think it would just flatten out again and move the oil can somewhere else. I'm really stuck and have been at this for a couple of days. I did most shrinking with a mig welding attachment and some with a carbon arc torch.

oil canning.jpg



I know it's hard to give advice without seeing the panel but any help would be appreciated. Many thanks for reading.
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Last edited by Steve Hamilton; 07-12-2018 at 08:57 AM.
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  #2  
Old 07-12-2018, 09:14 AM
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Steve Hamilton Steve Hamilton is offline
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Oil can repairs are tricky!

I like to use a steel rule to help find the problem areas.

Lay it flat on the panel and check to see where the high and low spots are . Press the ends of the rule down until they touch, and look for gaps between the rule the panel.
Go carefully and check each move of shrink/ stretch.

From the photo I think you you need to do mostly stretching, to bring up the lows. Many hits on dolly starting at the outer edge of the low and work in as the low comes up.

Steve
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Old 07-12-2018, 09:31 AM
Peter Tommasini Peter Tommasini is offline
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James try to put up a picture up of the whole door so I can look at the edges.... it's possible (if the conture is right? ) to use a flat dolly and a polished flipper and stretch the turned edges of the skin close to the damage area , then simply move some of the stretched area to the edge in order to take the oil can out

This is how it's done.............................................
with the flipper and dolly stretch the turned edge close to the damage (do not use a hammer) just a flat flipper (slapper)- do not do this only once... stretch the edge a bit and move the metal over to the edge little at the time, simply by doing your blows side ways towards the edge and hold the dolly under the edge while you do your side ways blows, do this a few times that should tighten the spot in question
Peter
PS.... FIRST!.... make sure that you have not shrunk the panel too much.... this can also give you the impression that the panel is oil can........ it could be simply too tight

Keep in mind that my suggestion is only by seeing a picture of the problem.... it could need a total different approach, As Steve mention it could only be a matter of bringing some low spots up?? Or swap them around meaning...... high spot in to low spot
Next time........ as a suggestion.... solder the hole up with a copper soldering iron and 50/50 solder rather then weld them
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Last edited by Peter Tommasini; 07-12-2018 at 09:49 AM.
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Old 07-12-2018, 10:31 AM
orwell84 orwell84 is offline
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Thank you for your responses. Here is a more complete photo of the door. Are you saying I should stretch the edges around the oil canned ares and move them inward? Or stretching the oil canned areas and moving them toward the edges of the panel? I am still considering removing the welded up hole toward the front of the door as it is such a hard dense point that I cannot stretch or pull out. Thanks again. I will let you know how it goes. It has been a real bear.

door.jpg
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Last edited by orwell84; 07-12-2018 at 10:53 AM.
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Old 07-12-2018, 01:08 PM
orwell84 orwell84 is offline
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Ok. I have read your explanation over and over and I think I understand now. Stretch the metal below the crease that runs along the top of that panel with a slapper while working the stretch toward the welded low spot at the front of the door to bring it up. I am assuming that cutting out the welded spot would only make things worse. Thanks again.
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Old 07-12-2018, 05:46 PM
Peter Tommasini Peter Tommasini is offline
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Quote:
Originally Posted by orwell84 View Post
Ok. I have read your explanation over and over and I think I understand now. Stretch the metal below the crease that runs along the top of that panel with a slapper while working the stretch toward the welded low spot at the front of the door to bring it up. I am assuming that cutting out the welded spot would only make things worse. Thanks again.
The stretching that I am talking about is on the door edge (like if you putting a door skin on) but it is stretch from the out side with a slapper and dolly, then probably to help the tightening (going by the pic) use a hammer and bolster and drive the top swage line upwards very lightly (not inwards) that will help tightening the area
Peter
PS do not put any unnecessary heat on the panel it will make things worse!
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Last edited by Peter Tommasini; 07-12-2018 at 05:49 PM.
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Old 07-13-2018, 11:12 AM
orwell84 orwell84 is offline
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I have been working on raising the lows through stretching as the panel was definitely overshrunk. The panel has come closer to contour with the oil canning softer and retaining their shape when pushed out (though it can be pushed back in). The circled spot toward the front of the door is now its own hard, small oil can, high when pushed out, low when pushed in. I have tried to tap it down, lower it off dolly without heat but it remains either high or low.

Peter, I wasn’t completely understanding your directions. I was stretching along the upper sewage line but pushing the slapper toward the center of the door rather than toward the top edge. I assume that slapping in this direction gathers the metal from the oil can and the stretching along the sewage line gives it somewhere to go.

Thanks for bearing with me. I have been reading a lot about oil canning and learned that there is so much more to it than just shrinking the oil canning area.
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Old 07-14-2018, 10:16 PM
Oldnek Oldnek is offline
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Just as a side line to what has been mentioned, Which is great advice.
make sure your welded area is the same thickness as your parent metal, or you are chasing your tail.
The area behind the panel needs to be flat and smooth as well as the surface. Even if its 0020" thicker it will have a dramatic effect on causing issues.
Good luck with it as there a bugger to chase out.
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Old 07-18-2018, 08:43 PM
orwell84 orwell84 is offline
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I am still fighting with this door. I managed to get the large oil can out at the front of the door but am still fighting with some panel flexing in the center. I was able to remove the large oil can by stretching as close to contour as I could and using a MIG welding attachment to heat shrink little by little evenly around the oil canning are to firm up the panel.

The panel flexes between the center of the panel and the repaired area at the front. It flexes around an untouched area of metal with a brace behind it. The untouched area is obviously firmer and consistently stronger the the worked areas on either side.

It's pretty clear that especially in a low crowned panel having the correct shape gives it its strength, but it seems having the metal a consistent thickness is also part of it.

How do you even out the thickness of a worked area when it is close to the correct shape when you have stretched areas and shrunk areas? I have learned a lot working on this panel but I have considering replacing the whole doorskin. It would be a shame as repro doorskins are not great and I have a feeling I'm not that far off.

I have also consider shimming between the skin and the brace. The factory used foam, but only like one blob toward the bottom of the door.

Thanks again for the help.
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Old 07-19-2018, 04:16 AM
Peter Tommasini Peter Tommasini is offline
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Quote:
Originally Posted by orwell84 View Post
I am still fighting with this door. I managed to get the large oil can out at the front of the door but am still fighting with some panel flexing in the center. I was able to remove the large oil can by stretching as close to contour as I could and using a MIG welding attachment to heat shrink little by little evenly around the oil canning are to firm up the panel.

The panel flexes between the center of the panel and the repaired area at the front. It flexes around an untouched area of metal with a brace behind it. The untouched area is obviously firmer and consistently stronger the the worked areas on either side.

It's pretty clear that especially in a low crowned panel having the correct shape gives it its strength, but it seems having the metal a consistent thickness is also part of it.

How do you even out the thickness of a worked area when it is close to the correct shape when you have stretched areas and shrunk areas? I have learned a lot working on this panel but I have considering replacing the whole doorskin. It would be a shame as repro doorskins are not great and I have a feeling I'm not that far off.

I have also consider shimming between the skin and the brace. The factory used foam, but only like one blob toward the bottom of the door.

Thanks again for the help.
James I would really like to help you out on this one, but unfortunally we are too far away ....... and over the NET it's hard to know the real problem.... or to show you how to fix it
Peter
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