[DeTomaso] Wheels

[Will Kooiman]

I have a campy wheel with an invisible hole like that.

I mounted a wheel, had it aired up, and it was flat by the time I got home.

I added more air using my home compressor, and heard the air coming out.  I
had to feel the air flowing out with my hand, but for the life of me, I
couldn't see the hole.

The repair was terribly simple.  I bought 2 wheels from Hall for $250 each -
all powder coated and purdy.

-----Original Message-----
From: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com] On
Behalf Of JDeRyke at aol.com
Sent: Thursday, January 26, 2012 3:01 PM
To: michaelsavga at gmail.com
Cc: detomaso at realbig.com
Subject: Re: [DeTomaso] Wheels

In a message dated 1/26/12 6:50:31 AM, michaelsavga at gmail.com writes:

> Does that heating process ruin the finish and require repainting?
> 

Yes. The aluminum paint turns tan at 375F so it also need to be re-sprayed. 
FWIW, I got the annealing info decades ago from Lockheed. Their mag 
annealing method involves 375-390F for 2 hours followed by very slow
cooling. You 
can safely do this in your home oven as mag autoignition temps are 3X this 
high. Some powder coat shops will dry their powder painted mag wheels for 2 
hrs, then wrap your freshly painted wheels in blankets (or let you wrap
them) 
for the mandatory slow cooling.   Needed every ten years or so on magnesium 
wheels.
Magnesium, also known as "compressed corrosion" by engineers, age-hardens 
and most mag is gravity cast so the metal crystals are quite large. Perfect 
for age-related stresses to build up until a pore or a crystal generates a 
micro-crack. Then the casting unzips like plastic wrap. The same thing
happens 
in trying to weld-repair a crack in mag that's not stop-drilled; 
temperature expansion propagates the crack faster than the welder can add
metal. Good 
luck- J Deryke
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