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Metal Shrinking

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bevoracing Officially Full-On Dubber

327 posts · joined Jan 2009 ·

#838913
The trouble with Country Buggy panels is that they were (almost) flat, and flat is a very hard thing to get them back to. Any kind of dent at all represents a “stretch” of the metal. Country Buggies are utilitarian so they’ve all been climbed on and had materials thrown in them. Mine, KO813 only has a few straight pieces of metal, and most of them have holes that need welding up.
This weekend I’ve been experimenting with the alchemy of metal shrinking. I followed the instructions from here:- http://www.carrepair-1950.com/shrinking-sheet-metal.htm
It works great. After beating the dents out you will always end up with a bulge, and using this technique it can be disappeared. I used an Oxy torch but I expect a carbon arc attachment on a welder would do, anything that will make it red hot.
Now, this bloke talks about getting it so straight you don’t have to use any filler. These panel beater blokes know some secret squirrel trick that I don’t know, that’s for sure. Anyway, hope it helps someone out.
Cheers
Tony
Country Buggy King & Link Pin Overhauls, Type 1 & 2 King Pins, General Machining.
http://forums.aussieveedubbers.com/viewtopic.php?tid=74138
My car is KO813

HappyDaze Superannuated

2,887 posts · joined Jun 2009 ·

#838927
May I just add that using a wet rag to cool the hot metal down, after the 'shrink' is completed, will help. It will also speed up the process. Oxy is best to heat the 'spot', using a small tip.
I'd rather wear a Beetle out by racing it than by polishing it!

helbus Administrator Mad fabricator, paint and body

7,386 posts · joined Sep 2002 ·

#838932
There is no secret. It requires skill and patience. I have been doing it for 20 years, and I consider myself very skilled in metal shrinking, and still it can take many hours to get a flat panel 'tight'. Eventually you can get a flat panle perfect requiring no filler, however the customer often does not want 20 hours labour cost repairing something that can be made in 10 hours.
EJ22 into Bay Microbus - Finished project build thread- click on this spot here for info

Flintstones Custom Title Time!

1,077 posts · joined Aug 2002 ·

#838981
another technique I found works great is to use a shrinking disk.
You can cover a lot of area very quickly where as with an oxy torch, you can only work one spot (usually the size of a 5 or 10 cent coin) at a time.
Do a search on you tube and you'll find some examples.

Cheers
D

helbus Administrator Mad fabricator, paint and body

7,386 posts · joined Sep 2002 ·

#838984
You will see on the you tube that the shrinking disc is all on panels with a round curve shape.

A flat flat panel has to be shrunk using oxy torch. Very tricky and takes a lot of time.

If you have lots of shaping, shrinking and welding to do, the oxy is the primary welding/ heating tool. You just need to get a bit of experience, and you will find you can make anything. The prototype 1 of a kind cars I work on are all made from flat sheet using oxy.
EJ22 into Bay Microbus - Finished project build thread- click on this spot here for info

bevoracing Officially Full-On Dubber

327 posts · joined Jan 2009 ·

#839055
Ahh, there’s the secret, 20 years of experience. I’ll keep at it Helbus, one day perhaps.

You are quite right Mr Daze, I was using a wet rag. There was another article on the internet somewhere by a very experienced panel beater but I can’t find it now. He mentioned all your points exactly.

There is quite a lot of conflicting info on the net, as with all subjects. Some like shrinking discs but say they are hard to find, some talk about using a worn out sanding disc, sounds a bit scary. Others don’t like any discs, just Oxy etc. Some like letting it cool on it’s own, some use compressed air, some like water. Some say it makes no difference, some say it does. Interesting subject.
Country Buggy King & Link Pin Overhauls, Type 1 & 2 King Pins, General Machining.
http://forums.aussieveedubbers.com/viewtopic.php?tid=74138
My car is KO813