Hi guys, I am repairing the box of my truck and I have some problems when try to straightened the bed sides, after use the hammer the surfsce looks plain, but wavy, I tried it With the torch heating and cooling it to shrink and straighten out ... There is some method to straighten the steel?
I'd stay away from a torch unless you have lots of experience with flat panel shaping. What I'd try is to give the flat areas a very slight crown to keep it in shape. For the hammer marks try googling a 'shrinking disc' that will do very local shrinks to get rid of the stretched hammer marks. The problem that you'll have is the torch has probably shrunk large areas, do deal with that I'd be trying to give the areas a little crown. I had similaer issues with a Model A bed and I used the bead rolls to advantage and gave the 'flat' areas adjacent to the bead roll a slight crown. The factory used some kind of a feature to get the metal to lay 'flat', the Model A had a large bead rolled into it to create a design, figure out what yours has and work the metal to it.
Ahha, pics! that looks like hammer & dolly work with a little shrinking disc thrown in should get you there. Not as bad as I thought.
The shrinking disk is going to help there. With hammer and dolly you need to raise every area that's not even to the spot next to it. That's likely to both stretch the area you are working and just leveling that panel will make it longer and wider. ( read dementionally bigger ) . The results of that will be an oil canned panel but the shrinking disk will help a bunch there. It will be a dance, repeating the steps over and over.
Plan on making many heat shrinks on those panels. Heat one dime size area dull red and immediately cool with compressed air 15 seconds or so. Repeat. Do several shrinks and then flat hammer/flat dolly the area. Shrink more as needed and to eliminate "oil can" which is a sure sign of stretched metal. Check for flatness with a body file or flat substitute.
a technique that an old friend told me ... heat with the torch , the heated zone , rises up , then first it is hammered and flattened the area and then cooled . dont know if is work, I only heat the área and then cooled with water...
I was taught the same method and taught to knock the risen area down lightly then go around it focusing the blows towards the center with the hammer head on a slight angle pulling the metal towards the center. Still practicing and learning. The guy that taught me made it look easy.
Making it look easy IS the hard part. Metal working is like playing an musical instrument, except for the idiot savant, the only way you can do it is to do it. The only way to get better is to practice. And just like music you're gonna suck at first. A big old flat panel that's exposed on both sides would be a big challenger for the seasoned pro. Get that panel smooth in an area, then run the disk to get it flat. Smooth and flat are very different.
I was taught this exact process over 50 years ago by experienced metal men. It does work! You don't want to keep pounding on it after it is heated, just hammer on dolly enough to flatten the raised "blister" Ray
This is the was I've done it for years. On those flat panels every dent is a stretch spot, I never hammer/dolly before the shrinking process. Easier to see how big the stretch is. Do one dent at a time. If you shrink it too much, just hammer on dolly to stretch it back out.
So. Will work a dent by dent at the time and will get a plain steel surface, my error was hammered first the panel and then try to get straightened doing some heated zones with the torch... Guys I appreciate tour help a lot, really help me....
The heat shrink process can be fine tuned to the degree of the stretch and metal thickness. For example in thin metal with slight stretch I use a stud welder to heat small spots and compressed air to cool. On the thick metal of a flat hood of a WWII Dodge that had been walked on I heated spots cherry red with a torch and quenched with ice water.
Well... Metal expands when heated, the heated (upper) side would both get hotter, and react to the heat first before the heat has transfered through the metal. With the upper side expanding more/earlier, it should push the blister up, not down. That's my theory anyway.
Some progres on the panel, I'm using the shrink disc, but not a real disc, I'm using only the nut and water sprayed the zone... With good results... First I sanding the área with a large woody block....
You can also use a larger grinding disc (200 mm ,say) and turn it around the other way. It will work as a shrinking disc by heating the area that is high. Then you can run water or air over it to complete the shrink process. The area you have pictured is looking pretty good!
Great theory. I thought it had to do with tension in the panel. I guess i kind of hoped that if the spot drooped that the area was at zero tension and it was time to stop shrinking.
The Jalopy Journal
