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pitting wheel heads

updated fri 31 jan 97

 

Leon Popik on thu 23 jan 97

I have been asked a difficult question by a peer of mine and can't answer
it. Would anyone know why or what makes wheel heads pit ? Both our Shimpos
and Brents pit, Is there something in the clay that causes a reaction with
the aluminum? If anybody has any answers , send me ........

real_name on fri 24 jan 97

Clay can be acidic, which speeds oxidation (corrosion) of the aluminum.
Doesn't seem to be
a practical solution outside of using stainless steel for wheelheads
(Brent, etc. -- po-lease do!)


----------
>
> ----------------------------Original message----------------------------
> I have been asked a difficult question by a peer of mine and can't answer
> it. Would anyone know why or what makes wheel heads pit ? Both our Shimpos
> and Brents pit, Is there something in the clay that causes a reaction with
> the aluminum? If anybody has any answers , send me ........
>

sam wainford on sat 25 jan 97

Leon Popik wrote:
>
> ----------------------------Original message----------------------------
> I have been asked a difficult question by a peer of mine and can't answer
> it. Would anyone know why or what makes wheel heads pit ? Both our Shimpos
> and Brents pit, Is there something in the clay that causes a reaction with
> the aluminum? If anybody has any answers , send me ........
Leon,
I also have a problem with the aluminum barrel of my Bluebird pug mill
pitting. I think the water in clay causes the aluminum to oxidize. I
have had to file off chunks of oxidized material from the inside of my
pug barrel. It is particularly bad where small defects in the casting
already exist. Water can seep into these "spongy" places in the metal
and cause it to deteriorate faster. I'm sure ph also has bearing on the
rate of oxidation. It's too bad that stainless steel isn't used. It
will not corrode, but the cost of casting stainless is much greater due
to it's higher melting point, difficulty in pouring, and hardness which
makes "chasing" and finishing much more difficult and time consuming.
It would probably help to lightly sand off the pits on your wheelhead
since once the oxidation starts, it seems to pick up speed; and to dry
your wheelhead off after each sitting.
Sam