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Tue Mar 13, 2012 10:10 pm

i am working on a 77 vw convertible and behind the door on the 1/4 panel there was some stretched metal i shrunk back with a torch. well now that i am doing the body work i see that there is still an area that is high. i tried to hit it in with the sandbag and a pic but now it is oil canning again. i got it to stop popping in and staying in by heating with a heat gun and cooling with duster in a can but the spot is still a little high. im not sure if i am being too critical or if i need to find a way to shrink this spot and get it low so i can fill it. i dont have access to the oxy/ace torch or a stud gun at this time. any ideas? ill try and get a few pics up soon.

Wed Mar 14, 2012 12:42 am

Grab a small propane torch from home depot or something to you can slowly heat the area and just small areas. Where with an oxy the area can get pretty large. get the spot hot almost red and take a couple paper towels bundled up and soaked in cold water and quench the area you just heated. It will tighten up the area and should shrink down and stop oil caning. You may have to do this in a couple areas to "tighten" up the metal around the area too.

Post up pictures and I'll see if I can help you out a little more.

Wed Mar 14, 2012 7:27 am

i thought about using a small torch but the guy at the local auto paint supply place that is a great bodyman painter said i need a cutting torch. ill get one and try it thank you

Wed Mar 14, 2012 8:14 am

The small hand held propane torch will get it red hot no problem!

Wed Mar 14, 2012 1:40 pm

i will give it a shot. thank you

Wed Mar 14, 2012 2:51 pm

Don't use a cutting torch to shrink metal, unless you want to melt great big holes in the quarter and warp it beyond repair.
Use a proper small brazing tip - it's much easier to control where you put the heat.
Or, try a shrinking disc... it's the cat's ass for sheet metal work. :)

Wed Mar 14, 2012 6:16 pm

If someone at a paint supply store told you you need a cutting torch to cherry out some sheet metal NEVER BUY FROM THEM AGAIN. Horrible, awful, WRONG advice. Unless he meant a torch... That's a totally different tip.

Wed Mar 14, 2012 8:32 pm

well i didnt use the cutting part. i used the oxy/ace with barely and oxy and didnt pull the cutting trigger. just heated the metal up to dime sized red hot areas and quenched.

Wed Mar 14, 2012 8:41 pm

..yeah dude...small dime size circle.

i've used propane torch and even mapp gas and had good results.

///a real nice shrinking hammer with a dolly on the back side and a file works great too.

Wed Mar 14, 2012 9:31 pm

i used the map torch and it worked just fine. thanks

Thu Mar 15, 2012 9:10 am

This is all I use. Home made shrink disk.

Fri Mar 16, 2012 9:00 am

metalchomper wrote: This is all I use. Home made shrink disk.

do like! any more pictures?

Fri Mar 16, 2012 9:55 am

Flavourless wrote: metalchomper wrote: This is all I use. Home made shrink disk.

do like! any more pictures?

I'll take some more this weekend if my shorted out memory will remember. I made a die from MDF and formed the edge with a hammer. I don't remember the grade of SS but I would guess it's ~304. It was very hard to form. You can buy them off of ebay, but I couldn't find one to fit my 7.5" crapsman grinder.

Fri Mar 16, 2012 8:54 pm

You have thinned out the metal too much. By heating it up you shrinking it up in that one spot, then by using the hammer and dolly, you are stretched it outward. When you are heating it up, are you cooling it right after heating it? This will help in shrink it back. By heating the metal the metal gets thinker in that one spot. By rapidly cooling it, it stops the heat from warping around the area and make it thinker in that one spot. Then you can work it easier.
Or using a waffle hammer with or without a dolly, to stretch it outwards. Just hitting it and sliding it, to stretching it outwards or straight down on the dolly to shrink it in the one spot. Just like using a shrimper or stretching tools in the pro shops.

Just my 2 cents.

Sat Mar 17, 2012 7:28 am

they work better than a torch , more control

Thu Mar 22, 2012 12:36 pm

best tool i've used for oil canning spots like described is my stud gun with the solid pointless tip and an airgun. they sell the heatshrink tips with most of the stud guns like at harbor freight and paint shops etc that sell autobody type equipment. i've always been alittle leary on using a torch for heatshinking

Thu Mar 22, 2012 12:48 pm

russell wrote: best tool i've used for oil canning spots like described is my stud gun with the solid pointless tip and an airgun. they sell the heatshrink tips with most of the stud guns like at harbor freight and paint shops etc that sell autobody type equipment. i've always been alittle leary on using a torch for heatshinking

Thu Mar 22, 2012 12:55 pm

aw come on, was that really necessary?

Thu Mar 22, 2012 1:05 pm

russell wrote: aw come on, was that really necessary?

Sorry Russell. I couldn't resist.

Sat Mar 24, 2012 12:50 pm

Ouch. Did somebody find that under the carpet in their new project? Or is that what someone was calling "patina" at the time?