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  #31  
Old 07-26-2018, 06:14 PM
orwell84 orwell84 is offline
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Quote:
Originally Posted by crystallographic View Post
Pinpoint shrinks are done with a sharp, hot (oxidizing) flame.
Point the torch flame straight down (90deg to panel) and with the inner cone a nickel's thickness away. Count one-two, and pull flame off and hit the metal with the flat-faced hammer. (Hold the hammer and torch with the same hand - the torch won't mind the bouncy ride, if the pressure is right.)
Back your work with a 2" thick block of wood, about a 4" X 4" face. This avoids stretching, and adds a romantic aroma to the shop.
Remember that the metal keeps shrinking until it is ALL the same ambient temp. I have measured for this, many times.
Hammer until the metal is only warm to the touch - then wipe with a wet rag - no hissing allowed, just steam.
Thank you, I have a great excuse now to get some oxy/acetylene tanks and pull my torches out of storage. So much you can do with them compared to MIG.
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  #32  
Old 07-27-2018, 02:30 PM
crystallographic crystallographic is offline
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Originally Posted by orwell84 View Post
Thank you, I have a great excuse now to get some oxy/acetylene tanks and pull my torches out of storage. So much you can do with them compared to MIG.

True, MIG does one thing pretty well at the low end: stick steel parts together.
But doing auto repairs, I think, requires a good variable-range heat source.
At least for making espresso, cooking sand dabs and warming tortillas, anyway.
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  #33  
Old 07-29-2018, 02:18 PM
orwell84 orwell84 is offline
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Still trying to sort out the patch. It is very hard to work compared to the rest of the panel. I tends to stay a low spot and when I stretch it out it gets lower unless I really stretch it out and pull it out with a stud. Then it is a high spot. I can shrink it back down, but as it gets closer the surrounding area starts to sink too. I have also tried to work the panel around it. Part of the problem is that it is hard to get a dolly behind it. I have considered putting a relief cut in it so I can shape it better to match the rest of the panel. My other option is to weld in a new patch after working the area around it as close to contour around it so the shape of the patch is a better fit to start with. The rest of the panel has been pretty easy and predictable to work.

Thanks for bearing with me.
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  #34  
Old 07-30-2018, 06:53 AM
Oldnek Oldnek is offline
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James!,

Just a thought, Have you tried to strip the whole door, to to see if there is any filler lurking under the paint. Could be possible that there is further repairs done and giving you grief in the target area.
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  #35  
Old 07-30-2018, 11:23 AM
orwell84 orwell84 is offline
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James!,

Just a thought, Have you tried to strip the whole door, to to see if there is any filler lurking under the paint. Could be possible that there is further repairs done and giving you grief in the target area.
Yes. Thank you. There isn’t any. I am in the process of welding in a new patch. I think the panel was not worked out enough when I welded it in “locking” the panel in the flatter shape. The patch may have been too small to stretch enough to raise the panel to the correct shape. The key to getting this panel into shape seems to start with getting the patch into contour first.

This is the last thing I’m going to try. If I’m still not getting anywhere it’s time for another door.
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  #36  
Old 08-04-2018, 01:05 PM
orwell84 orwell84 is offline
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primer door 2.jpgI was able to find a used door in good condition. Sometimes you have to move on and focusing on one thing too long can become an obstacle to making any progress.

I am still working at it from time to time. I put some primer on it to help find highs and lows. Basically the panel was very overshrunk to the point where it was hard to identify the original shape. Welding in a new patch showed me how much weld shrinkage is amplified in changing the shape of a crowned area as well as any type of shrinking on that kind of shape. I have also learned that shrinking is very quick and easy to do, compared to the time and effort it takes to stretch and raise a shrunken area.

So basically I have a lot of stretching left to do. Even some of the high spots in my photo are probably still below the original contour. I am just going to work at this once and awhile and use it as a learning experience. My plan is to raise the panel mostly using a Martin slapper I just bought, smoothing out the highs and lows as I get closer. I will probably end up having to do some very selective heat shrinking at some point, but only after I'm sure the remaining high spots are really high spots.

Thanks for reading
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Last edited by route56wingnut; 08-05-2018 at 09:10 AM.
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