I'm always game to learn better ways of doing stuff. Someone mentioned shrinking steel in the Jesse Lopez thread & I'm always curious how different shapers approach this. I've got my own method that works but I'm not in love with it. Basically cherry red spot, tap down with hammer, use wet rag in a circle around that working from the outside in towards the hot spot. It shrinks the steel but leaves it looking like 8 miles of bad road. Hammer & dolly/planish that followed by shrinking disc. It still looks more worked over than I'd like. So, what do you do? Is there anything I can change in my method that would give a better product? We all seek a filler-less repair, but they can be elusive!
If it's stretched and oil canned a shrinking tip on a stud welder/unspotted works really good. Just use it for a second on a couple spots around the damaged area. don't try to get it out all in one spot by holding the trigger down for a long period of time otherwise your going to create lots of other problems! Another method that works good for me is a shrinking hammer but you HAVE to have the area your working down to bare metal. Hope this helps Posted from the TJJ App for iPhone & iPad
I recommend you not use water..it tends to harden the material. Depending on the amount of gathering you need to do, adjust the amount of heat. A "disc" warms up a panel compared to a torch...try less heat and a slapper instead of a hammer, and "coax" the material into the hot spot (working around into the center)...no need for water, the weight (dolly) and the slapper or hammer are heat sinking as you go. Good luck!
I've use the stud gun method at work but for the thin stuff today but the good old fashion torch and hammer and dolly works best on the real metal of old It's just more workable. . Tap around the center and towards the hot spot and cool with air. Never use a wet rag, it hardens the steel and makes it brittle.
Hey Randy, First order of business is to be sure that what you have is stretched metal, and not displaced metal a.k.a. a false stretch! These are sometimes caused by damage in other areas of the panel that have not been properly bumped out, or areas of old damage that contain filler under old paint Once you've straightened all the surrounding metal, and your sure that a stretched or thin metal is what you have, then, and only then, would I go with a stretch! Shrinking metal that's only displaced, and not really stretched, can create major work by robbing metal from semi & low crowned areas that result in waves, buckles and low spots I still go with a torch, dolly slapper/hammer and wet rag on badly stretched areas for reasons of speed, but seldom heat the metal to a deep cherry red, and NEVER hit a red spot with water. A worn out 60 grit closed coat disc can be used as a shrinking disc inna pinch. It doesn't take much to generate heat for a shrink, especially in a panel that's been worked or ground thin before. " Humpty Dumpty was pushed "
Like pimpin paint said work the area first the shrink if you must. I torch shrink in small amounts. I find the worst area and heat with the torch a dime sized area just til the metal turns color, but no where near cherry red. Then working quickly I tap the area I heated down with a medium crown hammer then plan ish it with the proper dolly and a slapper. Then I cool the surrounding area with a damn rag. Just work it little at a time checking your panel tension after your heat shrink has cooled and don't try to shrink to much at once. Posted from the TJJ App for iPhone & iPad
Got it. I have an old manual that said to do the cherry red- tap down method. I kinda wondered about the water too. I really don't like putting water on bare steel...just seems wrong. Usually I planish out all the deep dents and get everything in line as close as possible. When I feel like everything is worked out and not holding excess tension, I heat shrink the stretched area. I'll try the suggested methods and see what works best for me. I'd love to get away from water all together. Many thanks!
Whats wrong with wet rag (water?), i don't have it soaked but it is the water that absorbes the heat and i don't think the metal knows what the hell we are using anyway.
This would be my favorite way. https://www.youtube.com/watch?v=K8_FP6A_mvg&feature=youtube_gdata_player Apparently this was used be the Vikings to repair armor after battle.
Compressed air works well instead of water and it's very easy to control in a specific area. I like to use my welding torch to shrink when I can so the affected area is much smaller. With this if you've read the panel wrong it's only a small change and less to fix. I do normally heat to a faint red or just before but it depends on the exact case. As Pimpin Paint said a lot times the panel is hiding some other stress and if you go too fast you end up with more work.
When I first started I went for the heat and beat and then cool off with a wet rag, and it will shrink good, but if you do it to much you start work hardening it seems like. Here and there shrinks, like you guys say , after everything else is straight, I can some times do with the slapper file and my crown dolly and sometimes the flat side dolly if the panel is almost where I want it. Sometimes with the heat , you end up chasing the part you want to stetch, and never quite get it. The slap file kinda tells you were to go next, and it does it slower, so if you are in the wrong spot , the file marks tell you. You have to learn to slap file and read whats happening with the file marks on the metal. I rarely get out the heat to shrink anymore. I would like to use a shrinking disc someday, just haven't done it yet.
Hey Randy, if " accents '' are what you're after jus come to Los Angeles In the city I live in we have at last count 67 different languages being spoken My money says not many of um would know how to shrink a stretch On another note, on a badly stretched area like a door skin where you've gota deep gouge running several inches across the panel I've found it's usually best to land a shrink at each end of the gouge, and shrink towards the center of the damage. If you don't , and shrink from one end to the other, the stretch can run on ya, and travel into a loose,low crowned area of the panel and create more work " The ice cream truck in his neighborhood plays Helter-Skelter "
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