Calling all Body men. Question about hammer/dolly.

On my 59 I was able to remove a dent the way I've always done with my hammer & dolly. But now I have a buldge that rose up as I removed that dent, tried heat shrinking which seemed to kind of chase the high spot even further.. So I put the torch down and tried hammering again. The buldge will not shrink back into place, it's got an oil can too. The metal doesn't seem to want to move at all now.. Any help out there?

 

Try useing a ******* made from an old file and use a dolly that is flatter than the surface your trying to shape it to, otherwise if your useing a dolly with a crown your only stretching it more. I may not be correct but it works for me.

 

can you take some photos? it'd be easier to A see the area, and B someone can explain it better by referencing the photo.

 

Depends on what the bulge looks like IMO

If it's a real high bulge, a few inches wide, the real old way of heat shrinking was to heat 5 or 6 spots around the outer part of the bulge. Do one at a time and as the heat rises the metal, dolly it down.

After all the outer ones are done, then finish with one in the center. No quenching on that style of shrink.

Try it on a junk panel first. Whack it with a hammer from the back to make a stretch, then give it a try.

 

Thats good info, thanks guys. I'll get a pic.

 

Are you holding your dolly too tight to the surface? Hitting it too hard? Every time you wack that spot your actually quishing the metal and making extra surface area. Like a penny squashed on a train track it gets bigger but thinner. Try heating a spot dime size, Tap the area around the hot spot, hitting it with a 'side' swing towards the hot spot versus straight down on it and let the dolly bounce in your hand as you tap 4-5 times. I rapid cool with air from a distance just to speed things up for the next one if needed. Old tin reacts beautifuly compared to todays brittle metals

 

Thanks Ted, that makes sense, except i dont understand one thing..Wouldn't i want to force the metal away from the hot spot, to the surrounding sheetmetal, because it was stretched?

 

I agree with tedley, you probably stretched the spot, or it was stretched when it was damaged.
You could cold shrink it, either by using a steel hammer and a soft dolly (sandbag), or a wood hammer and a steel dolly.
Heat works, but is trickier to get right. I't easy to over or under do it. I heat the area to the size of a quarter, then working in a spiral pattern quickly go round the outside and work your way to the center. Not hitting too hard! Just move the metal, don't smash it!
Maybe a light spray of water when you're done to cool it...NOT hit it red hot and quench it! You usually have to work the shrink spot to "amost there" stage, so as it cools fully, it finished shrinking to where you want it. Takes some practice/experience to judge it correctly.

 

Think of it like pizza dough, if there was a thin spot in the dough, would you hit it there to make it thicker??? NO!

 

if the panel is oil canning....Then look for the point where it is 'hinging'. oil canning is usually a sign that the metal is overshrunk in a particular area. you should always try to use a dolly that is as close to the shape you need to end up with if you can.

Once you've found the spot where it seems to hinge then ...using the correct crowned dolly and a good planishing hammer ....you need to begin to stretch that area back out until the panel becomes tight again.

As an apprentice panel-beater/coachbuilder I was once asked to repair an old tractor guard (dented and rusty) .My boss new it was a job that the finish wasn't crucial.....well he let me bash,heat,shrink that guard-heavy guage steel too) until i had a lump in it like a g****fruit!! ...I shrunk the lump down but by the time I'd finished the panel was SO BUCKLED it was utterly ****t!!!!!

He just wandered over and looked at it and quietly instructed me where I went wrong and why...then just said bin it we'll make a new one
He was the best boss I ever had ,taught me the OLD way...and I learned not to over shrink panels...incidently ...quenching a shrink with a wet rag or blowing cold air on it will most often cause over shrinking in my experience
just my '02 PB

 

oh ...and the metal will keep pulling in until its pretty well stone cold

 

Try a slapping file with a flatter dolly. Hold the dolly looser against the metal so it forces the excess inward. If that doesn't work, then shrink it with heat. Usually old metal is pretty thick and easier to work with than the new tinfoil metal.....good luck.

 

You guys are making me dizzy...
You have gathered too much material in one spot, thats it.
Now, you need to shrink that bulge, right? First question, do you use a shrinking disc, if yes, then keep going..don't get discouraged. If not, then obviously the torch method is your next choice. Remember, whatever heat you throw into a panel, either quenching or cooling by itself...It's Shrinking!

 

Hey,

Ya didn't say, but I'm guessin that this panel is pretty flat or low crowned? Low /no crowned metal can be tough to straighten especially if stretched & overworked! Sounds like you had a stretch in the damaged area, and your ''on-dolly'' repair work created, yet, more stretched area in the damaged panel-that's the original stretch+ the one you added to the panel=alot more surface area i.e. the bulge or high metal now in the panel. Any time you hit metal with a hammer and dolly, that's metal on metal, you're stretching (thinning or creating more surface area) the metal inbetween.

As someone mentioned, you need to find jus where the movement is comming from in the panel. Start outside the damaged area, and press down with your finger in several different areas around the damage. Study how the panel flexes & where. If you find a knot or hard spot in the middle of the damage this is probably stretched metal being held in place by the surrounding areas of the damage. Land a small (never bigger than a dime) hot shrink in the center of this knot, and remember several small shrinks are always easier to control than a few bigger ones ,e****ally on a low crowned panel. As you work the heated shrink, land your hammer blows in a kinda slapping motion towards the center of the heated spot, and go all around the center of the shrink with these kinda blows. Land your final blow dead center of the shrink & on-dolly. A quick swipe with a wet rag, never hit a red hot shrink with a wet rag, will help pull more of the metal up tight and cool down the panel. What the hot shrink does is move thicker metal back into the areas of the panel that were stretched or made thinner by the damaging force of the collision or your overhammering-on-dolly. If this was a crease type of damage, you may wanna land two shrinks, one at each end of the crease, to lock in the damage and keep it from travling into undamaged low crowned metal. Usually more than one shrink is necessary to tighten up a badly stretched ,low crowned panel.

" Life ain't no Disney movie "

 

the rule that you need to allways remember is {heat shrinks} when you heat metal is gets bigger , and when it cools it will shrink 5 to 7 times what it was,and it will do that when it cools quick or slow the same amount.

 

when i first read this , my first impression was someone was doing improper shrinking ie it not working
Tedley has the method down right to shrink, my only difference is that i use cold water to shrink, which is more messey and usually have to turn off torch and relight

 

I once had a really flat panel with a huge oilcan in it... couldnt get any heat on it and slap it for various reasons... I used a 1mm cut off wheel on a grinder and sliced across the oilcan, then tack welded it up...man did that ****er pull flat or what!!!

 

Sometimes its easier to cut out and replace with new steel patch ,Thats what Im gonna do on my pickup truck cab ,Also shrinking disc ,There my 2 advices

 

Yep,
Its not exactly the way to do it, but it does work on thinner sheetmetal...

 

Better reread fleet-master. That crown is shrunk and you need to stretch & that is why when you heat it (shrink) it gets worse. Very hard to tell the difference between a low crown stretch and shrink, most people think if it comes out twards you it is stretched. But if you look at it from the other side and it is going away from you then you'd think it was shrunk ok?

 

I use a unispotter with no stud. Just press it up against the thin spot and pull the trigger for a few seconds. Then quench with wet rag. This shrinks it up fast.

 

If I had an oilcan, I'd never cut it and weld it just to "fix" the oilcan. You are introducing way more variables into the area. How do you know you won't be stretching the area again as you hammer the weld flat?

It's much easier to just keep working the dents and high spots with a hammer/dolly and heat shrinking. Cutting and welding is like starting over when you were already half done.

 

Here are a few pics

 

Today I used my *******(seen in pic 1) that I made while holding the dolly loosely, after about an hour it didn't move much, maybe a tiny bit, it's hard to tell. I don't think that method worked, also tried my file *******. Everytime I use heat I seem to chase the damage farther, so I'm kind of hesitant on that. Anyone in town care to lend me a hand? I'll buy your lunch.

 

Good pics. That's a pretty good high spot Hope to hear from all the metal gurus tonight. I tried some of yesterdays suggestions myself.




I did get a small stretch fixed today. 32 door. I had to heat and dolly when hot. Quenching alone was not helping. And like someone said yesterday, it is hard to know when is enough or too little. So I went a little at a time.

 

Yeah, I have a hard time judging if my hits are accomplishing any metal movement.

 

I'm pretty sure the side shot exaggerates the buldge, or at least how it feels. I bet this would be a piece of cake for anyone of you guys.

 

Where is that, the back of the cab behind the drivers head?


I am wanting to hear from the disc users to see if that would work on that large bump. I'd also like to know if using a disc, besides for heat shrinking, does the disc movement and force also help push the metal?