I heed a couple of good hints on shrinking body sheet metal with heat. After pounding out a dent I have an oil can condition, the metal is too high. I don't want to push it in and fill with bondo. Ago
i am no pro at this and would also like tips from people more experienced. the thing that i have found to be most helpfull when using a torch to shrink is having a setup where you can hang the torch safely and leave it lit.
Is there specific high spots to get out or just and overall area, you mentioned oilcanning so i ***ume you have a high crown? To get that out i'd use a torch over a biggish area, keep the metal cool enough so it dosn't get to 'blue', then quench with wet rag. Do this a few times and it should tighten right up. When ever you hear a 'hsss' when apply the damp rag then you're shrinking, it is easy to overshrink then you'll have a problem having to both stretch and shrink, keep the metal from going 'blue' because it is more focused on that smaller area. To get rid of a high spot then you'd heat the top of the high spot, about the size of a dime, until it is blue and then quench. To get rid of a silverdollar sized highspot, heat to reddish and work it with hammer and dolly twards the middle gathering the excess metal and then beat the hell out of it with a hammer - well, maybe use some finesse.
Hey Ago, What kinda dent did the ''high'' metal start out as? Sometimes if the dent wasn't bumped out correctly you have two problems-the original damage & that created by not unlocking the damage as necessary, when you bumped it out and overstretched the repair area. If you deside to use a torch to shrink with, go with several small shrinks rather than one ot two bigger ones. If you land your first shrinks where the metal is the highest you may pull in additional stretched metal from the surrounding area and save additional work. Shrinking discs work well with alitle pratice. Check out the HAMB search funtion for info on their use and the results produced. A picture of the damage would help for additional info. " Meanwhyle, back aboard The Tainted Pork "
I would advise against water quenching. I spent a number of years fighting with torch shrinking, until an old timer showed me how to do it with out the water. Rapid cooling has no shrinking effect itself. Any shrinking you might get from the process is actually caused by the heat in a confined area. It expands and pushes against the surrounding metal (you can actually see the metal raise up), the surrounding metal pushes back and causes a small amount of shrinkage. Hitting it with a hammer while it is hot forces more metal to be pushed into itself. Quenching just speeds up the cooling and in turn will harden the metal. Some will tell you that mild steel can not be hardened. Bull ****. My $.02 Good luck.
This is very good advice i have actually seen where water quenching warps panels even worse ver very bad idea...i had to straigten out a panel that someone tried to do this on it was warped 3 ways from sunday not to mention that rapid quenching tempers steel....take a piece of 1/8 mild steel and drill it then take a piece u heated up and quenched in water and see how much harder it is to drill out...always head and work with a hammer do this in small areas dime size to quater size and practice on s**** first...i worked out a side of a 32 roadster one time owner asked it to be metal finished had over 300 dime size shrinks on the side(sat next to a driving range and got pelted with golf balls for about 20 years)
there are books and other good tech on this but I sense just a few simple hints is what you are looking for. Small tip on your torch heat a area about the size of a quarter..count of 5-10 say...now tap this raised spot gently with a flat faced hammer. I am talking lightly like you could be hitting your finger and tolerate the pain. Quickly cool with a wet rag. The cooling keeps your heated area to a minimum. You should only have to do this about twice on your spot to make the oil can go away. Hardest part is knowing when to stop shrinking. You are basicly shoving the raised metal into the surrounding metal. Hope this helps ya some Steve
Check into a shrinking disc. Less chance of doing more harm than good. I've had pretty good luck with one.
I like to use my stud gun to shrink. It has a shrinking tip flat plate of copper. Easy to make lots of small shrinks about a dime size.
I've used a stud welding gun, a shrinking disc, and a torch to heat shrink with. They all work very well depending on the situation. Compressed air is good for quenching as is a wet rag again depending on the situation. When the job calls for a wet rag I use a rag balled up to about soft ball size and SOAKED but not dripping with COLD water. Chill the water if neccessary. It's the coldness not the flowing or dripping water that you want to do the quench. Flowing water quenches without control when shrinking small areas with a torch or stud gun. Large amounts of cold water is ok when using a shrink disc to heat the panel however. With practice heat shrinking can be carefully controlled and the result is a high level of satisfaction and the need for little or no filler.
X2. This how Gene Winfield showed me how to do it, and is now how I do it. It works, and does not take much practice to get good at it.
x2 Do a search for shrinking disc. HAMBer John Kelly sold me mine and I LOVE it, but I don't think he's still in business. Sunchaser is another source.
The number one way to ruin a panel is to shrink it with a torch. The main question you have to answer before you start to shrink is why do you have an oil can? Is it because you were hammering a high crown area and locked in a shrink? Is it because you were welding in a patch panel? Remember every weld is a shrink point, no matter how much you think you prevent a shrink. When heat shrinking you can easily over shrink with the bad advice typically given. I know I did that at one time. Just heating a small spot and letting it cool will cause a shrink. Metal starts shrinking right around when you see it turn blue. Never quench as it never really helps. Hammer only when you know you need to do significant shrinking, which on metal repair is extremely rare (from a beginners perspective). Hammering shrinks should be saved for metal forming a new deep draw. When shrinking the biggest mistake from beginners is to not take a lot of time and let the panel equalize in temp. Even a small amount of heat differential will leave you with an apparent problem. You then think you need to shrink more. I like to let the shrink area cool some on its own and then use some water to cool the metal more and then walk away for a while. You need patience. I really highly recommend a shrinking disk. It is hard to mess up a panel with one and it will let you level metal even when you do not fully understand just what the heck your are doing. I strongly recommend renting some videos from smartflix.com. Shrinking magic and Fender arches are two ***les that come to mind right off. Here is a link to Metal working hints.
no one mentioned it, but ive seen a old timer take and put a socket on the back side, and take a pick hammer and peck the center of the socket area to shrink. ive never tried it though
as long as we are throwing it all out there...........a body man I worked next to years ago would put a block of wood behind the panel and then hit the outer with a pick hammer. Certainly not metal finishing but it always did away with the too much metal (oil can) problem. A good strong blow would take the high spot and surround metal down into the wood block and effectively tighten the panel up. Its all about how "nice" you want the repair to be and how much time you want to spend. Steve
http://www.youtube.com/profile?user=GullWingInn#grid/uploads Spend a few hours watching those^^^ put away the torch and get a shrinking disc. Controling the heat while shrinking is much easier with a disk. use water air or just let it cool on its own. If your doing enough heating and quenching that you are hardening the metal you should rethink your entire strategy. You guys with the pick hammers and soft dollies crack me up... here lets fix it by doing more damage.
As long as we are still at it , my 2 cents now go to the library you can learn much there are many ways to do it my old bro was the best at this stuff I learned all I know from him , no one has talled about slap files or shrinkin hammers , will work also read and find out what works best for you , I,m retired from the trades and the kids coming in us to laugh at me when I would use a torch to do hail, just rember the torch can be your friend or cause you nitemares and remberer you can not fill a high spot you need to idenifiy what your workin on an damm take your time rome was not built in a minute slow down you,ll be fine there,s nothing that can not be fixed
While most of the old ways of doing things to metal are still a fucntional thing, its like comparing an appendectomy using a knife versus using a scope. yeah the knife will do the job, but it requires more time to do, heal and to recover and may leave a nasty scar. using a scope leave little or no scarring, heals faster and takes less time. shrinking disc = scope. torches, pick hammers, shrinking hammers/slap files = knife. The only thing that keeps you guys from doing it correctly is practice and trial and error. oh and 40 bucks for the right tool.
Shrinking discs are fine for shrinking if the situation calls for it. Sometimes using a disc is overkill or the disc is just to big to fit the stretch area. Saying they are the best shrinking tool is like saying an upholsterers magnetic tack hammer is the best hammer. Torches, stud welders, files, discs etc. are tools in the tool box so to speak. Pick the best tool for the job. Every shrink job is differant.
To add to this you must first find out were to shrink the area in question.I approach this by identifying the area and while moving the oil can in and out (I put a spot nail in the center)I follow the outside of the oil can with thumb pressure while push/pulling and wait till the oil can gets locked down.This is your first spot to adress and shrink with the disc.This doesnt take much time and will gradually get you to a happy ending.Now with most oil cans you will find that you now still have more ch***ing to do.Simply repeat untill you no longer have this trouble.The light bulb realy goes off for you guys that havnt tried this.Didnt invent it just was shown by someone with greater skills than mine.P*** it on.Dan
Thanks for all the good advice, It really helped. I ended up going with mild heat (blue) and light hammer and dolly. very little quench. Wife held torch. Ago
The Jalopy Journal
