RE: Alloy wheels

["Reid, Warren" <Warren.Reid@xxxxxxxxxxxxxxxxxxx>]

G'day Steve (and digest),

So far as alloy wheels are concerned, the most common method of crack
testing is the dye penetrant method. This is typically used in the =
aircraft
industry. Probably 99% of fatigue cracks start at the surface or at =
least
propagate to the closest surface before they start heading elsewhere. =
What
the dye penetrant method relies on is for a dye that's sprayed onto the
surface to be absorbed into the crack. When the dye on the surface gets
washed off, you can then use a number of methods (developer, =
ultraviolet
light - depending on the dye to show where the cracks are ie. the dye
remaining down the crack is drawn out onto the surface. You can =
probably
find these testing services in your yellow pages.

Having said all of that it could cost you a bit of money for all of =
your
wheels to have it done professionally. There is an alternative and that =
is
to do it your self with one of the dye penetrant test kits that you can =
get.
In Australia here the most common one is put out by Castrol and =
consists of
3 spray cans: a cleaner, dye and developer. Just make sure that you =
follow
the instructions carefully and you will end up with a professional job. =
If
cracks are present they will nearly always be hanging around a change =
in
cross section, sharp radius etc, so start looking in those areas first. =
If
you have something that you know is cracked it might be worthwhile
practising on that first to get your technique right. I have no =
problems
getting my hands on cracked components, I run a modified Austin Healey
Sprite (ie its British) and I have a large box full of cracked =
components -
especially stub axles!

Good luck

Warren Reid

> -----Original Message-----
> From:	Steve Smith [SMTP:SteveSmith@domain.elided]
> Sent:	Saturday, 5 December 1998 3:53
> To:	Reid, Warren
> Subject:	Alloy wheels
>=20
> Hi!
> =A0
> =A0=A0=A0=A0 Your posting got me thinking.
> =A0=A0=A0=A0 I've been running Cromodora mag wheels on my car for =
both daily
> driving and time trialing, using semi sticky, modern compound tires =
for
> some time now. I value the car and don't want to stuff the thing =
because
> of a failed wheel! What tests can you suggest to be sure I'm not =
going to
> have a wheel go south?
> =A0=A0=A0=A0 Thanks for taking the time to educate the masses.=20
> =A0
> Steve Smith
> Carlsbad, Ca

------------------------------