Experience with Shrinking discs?

[Stooge]

i have some upcoming sheet metal work on one of the '37 that im not exactly looking forward to. the metal isnt far gone enough to have to cut it out, but it has its share of wrinkles and slight dents that are going to be hard to get to with a dolly. ive been looking at the Wolfes shrinking discs that attach to either a 4.5" or 9" grinder and create the friction heat to shrink the sheet metal back to form. His youtube videos make it look a little too easy, and before i get too excited about this, anyone have any experience with these? ive usually done the torch and quench with a wet rag and hammer and dolly methods but for the prices im pretty tempted. i think eastwood used to sell them but couldnt find them on their site.

http://www.wolfesmetalfabrication.com/sdisc.html

 

[Kevin54]

i have some upcoming sheet metal work on one of the '37 that im not exactly looking forward to. the metal isnt far gone enough to have to cut it out, but it has its share of wrinkles and slight dents that are going to be hard to get to with a dolly. ive been looking at the Wolfes shrinking discs that attach to either a 4.5" or 9" grinder and create the friction heat to shrink the sheet metal back to form. His youtube videos make it look a little too easy, and before i get too excited about this, anyone have any experience with these? ive usually done the torch and quench with a wet rag and hammer and dolly methods but for the prices im pretty tempted. i think eastwood used to sell them but couldnt find them on their site.

http://www.wolfesmetalfabrication.com/sdisc.html

You may want to check with a couple of the guys in the Fabrication Forum. A few of them regularly go to Metal Meet for seminars. MP&C would be a good one to ask.

 

[MBfreak]

I am by no means a panel beater expert, but at least a decent amateur.
I do my shrinking with a oxy/ace torch, sometimes.

Suss out the part of the bulge you need to shrink. Draw circular pattern over it with diminishing diameters spaced 20 mm apart. Start from the biggest and heat up a small area to cherry read, cool off with a rag and water. Move 20 mm make the next one .... and go on until you have com to the center.

If iy was just a bulge with not to much rust/rustholes the bulge will be gone.
It requires tinning and filing to shape. Treating the backside is mandatory, otherwise it will rust thru, real quick.

It works but is time consuming. Learned shrinking and tinning from a pro in the sixties.

Ola

 

[K13]

Shrinking disks are probably one of the best tools ever for doing body work. They give you WAY more control than a torch does and the real beauty of them is they focus their heat is on the highs because that is the surface that are running against. They are not as fast as a torch but you run way less risk of over shrinking with them.The other thing is that quenching is really starting to fall out of favour with a lot of metal workers as it work hardens the steel and can lead to stress cracks later on down the road.

 

[toolman1967]

I have used a homemade shrinking disc for about 7 years now, I have both a 4 1/2 inch and a 7 inch. They are great tools for that EXTRA bit of smoothness at the end of hammer and dolly work. They do NOT move a lot of metal, you have to do the required hammer and dolly work FIRST. Metalmeet has posts for making your own wheel and there are several GREAT videos on youtube to show you how to use them. I use the smaller one for the motorcycle work and the larger for the streetrods.I LOVE MINE!!!

Tim the Toolman

 

[Stooge]

Ive been doing the torch and quench with a wet rag for awhile and while it "works" it just doesnt have the precision/ control i would like and if doing a larger flat area, can cause some oil canning in metal that was fine previously. It also seems to change the feel of the metal likes its brittle, which could most likely lead to cracking later on when working continues. Looks like wolfe has some package deals on ebay but need to find something to run the 9" disc on since i dont think my makita 9227c meets the suggested spec.

 

[zkling]

I've been doing some slight shrinking recently to un stretch drawers in a tool box. Been pretty successful with a heat gun or propane torch and a slug of ice. I made the ice slug by cutting the top off a soda can, filling with water and then freezing. Peel off the can and you are left with a cylinder of ice that is easy to apply and won't disappear as quickly as a thinner piece.

I have used a homemade shrinking disc for about 7 years now, I have both a 4 1/2 inch and a 7 inch. They are great tools for that EXTRA bit of smoothness at the end of hammer and dolly work. They do NOT move a lot of metal, you have to do the required hammer and dolly work FIRST. Metalmeet has posts for making your own wheel and there are several GREAT videos on youtube to show you how to use them. I use the smaller one for the motorcycle work and the larger for the streetrods.I LOVE MINE!!!

Tim the Toolman

Tim could you post some details or even pics of the one you made for the 4.5" grinder? I tried making one but it didn't work as good as I thought it would in the end. Wondering what I missed.

 

[ChevyEFI]

Stooge, I wouldn't run that Makita.I've been okay with a 9" grinder from HF. Definitely try and get a guard and if you want one that runs balance and smooth, consider something other than the HF.

 

[JeepsAreBuilt]

I got a 5" and put it on my high speed sander, it works slowly... I havent used it enough to get the hang of it. But its cheap enough to buy, I got mine on ebay.

 

[toolman1967]

ZKling, I will try to get out and get a pic of my discs tomorrow. I used 14 stainless sheet and cut my circle a little larger than 4 1/2 inches and used a hammer and dolly to turn the edge up a bit all the way around the outside edge. The hole was drilled with a unibit and I put a disc grinder nut on the center and used the press to push in the recess. Getting the recess in the center was probable the hardest part. I copied mine from Metalmeet, there are several tutorials there on making your own disc. Metalshapers.org also has a few threads on homemade shrinking discs.

Tim the Toolman

 

[Bruce Amacker]

Shrinking disks are probably one of the best tools ever for doing body work. They give you WAY more control than a torch does and the real beauty of them is they focus their heat is on the highs because that is the surface that are running against. They are not as fast as a torch but you run way less risk of over shrinking with them.The other thing is that quenching is really starting to fall out of favour with a lot of metal workers as it work hardens the steel and can lead to stress cracks later on down the road.

I'd ditto all of this. I am an inexperienced bodyman restoring an old car right now and I've had great luck with the SD, more than I expected. It lowers high spots better for me than a torch and with more control. My only disappointment is that with my inexperience I've accidentally shrunk too much at times. It works really well on wide open areas but it did not work so well trying to shrink a bulge in a weldline where I mated two panels.

Definitely worth whatever you pay, I think I got the big and small for $40-50 on Ebay.

Good Luck!