My Shrinking Discs arrived today.. they're stainless discs with a turned lip that you slap on a grinder and heat the contact (high) spots up on whatever banged up panel youv'e got and then spray with soapy water to shrink them down.

They claim you can get it good enough that you don't need bondo at all..

I'll report back if anyone is interested.. I know it's not terribly rally related

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Andrew M
Onterrible
30ish

I've seen video of similar sounding panel shrinkers. Amazing to watch. The dents just went away.

heymagic Wrote:
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> I've seen video of similar sounding panel
> shrinkers. Amazing to watch. The dents just went
> away.


Yes, it's pretty cool and the theory behind it is sound.

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Andrew M
Onterrible
30ish

They definitely work well. I found out about them from a guy in Sturbridge MA named Wray Schelin. Watched the DVD he produces, and the next day used a disc at my friend's restoration shop on a heavily warped under-seat tool tray in a 1928 Buick. I managed to un-do a .75" bow in the bottom of the tool tray in about an hour. The more you use it, the more you'll love it!

But wear gloves, and wear ear protection. It's noisy as hell and if you touch an edge of the disc while it's spinning it doesn't feel very good!

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Opel is a 4-letter word...
http://www.flickr.com/photos/10498579@N07/sets/

Why soapy water? Something to due with the extra slipperyness?

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Welcome to the cult of JVL drink the koolaid or be banned.

Dazed_Driver Wrote:
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> Why soapy water? Something to due with the extra
> slipperyness?

My understanding is the soapy water has more surface tension. So it sticks around where you want it to longer.

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Andrew M
Onterrible
30ish

Two mentions of video and no links?

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Grant Hughes

yeah, vids please.

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Jon Burke - KI6LSW
Blog: http://psgrallywrx.blogspot.com/

quick search:

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rally gods would turn in their graves if they ever knew Lada's were now part of EU rallying!!!

turoc Wrote:
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> quick search:
>
>


Yeah, just do shrinking disc on youtube.. sometimes it's spelled as disk.

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Andrew M
Onterrible
30ish

hudson Wrote:
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> Dazed_Driver Wrote:
> --------------------------------------------------
> -----
> > Why soapy water? Something to due with the
> extra
> > slipperyness?
>
> My understanding is the soapy water has more
> surface tension. So it sticks around where you
> want it to longer.
>

Soapy water has less surface tension that regular water. This allows the water to flow better over hot surfaces rather than bead up and ride around on little steam pockets.

For this application it will increase the speed at which the metal cools which should increase how much and evenly it shrinks each time you heat it up.

Now if you really wanted to cool things down in a hurry check out superquench. http://lametalsmiths.org/news/robb_gunter.htm

turoc Wrote:
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> quick search:
>
>

ok, I get it....heat metal...cool it...it shrinks.

why wouldn't you just use an open flame instead? propane torch or something.

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Jon Burke - KI6LSW
Blog: http://psgrallywrx.blogspot.com/

Jon Burke Wrote:
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> ok, I get it....heat metal...cool it...it
> shrinks.

You got it!

> why wouldn't you just use an open flame instead?
> propane torch or something.

I think that's where the idea came from, as I've seen that technique before and it's more spontaneous in that it doesn't use a specific tool for the job. The problem with using a torch however, is that you can't target the highs.. you heat a spot.

The disc creates heat only on the raised portions.

I'm having amazing luck for someone who's got next to no body experience taking out a million dents in the roof of this one NSU. Not only are the dents coming out slowly but surely, but I've noticed a considerable increase in strength of the roof panel in the areas that have been mostly dedented (think hail storm).

My worry was that the roof skin was oil canning pretty bad (springy).. and simply slapping bondo over the hail dents wasn't going to be satisfactory.

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Andrew M
Onterrible
30ish

At least whenever I use a propane torch on sheet metal I get lots of rust.. apparently it's from too much oxygen.. at any rate once bitten

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Andrew M
Onterrible
30ish

Any photo's of your disc process before, during, after ?

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As always IMHO

SEAN TENNIS KF7JJR
SEATTLE, WASHINGTON
SAAB 99, SAAB 850
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