Folks:
The GM paint thing was a bit different. All of the manufacturers
were affected, even some Japanese manufacturers.
Current paint technology is a 4 step process: Rust coat, primer,
color coat, clear coat. During the 80s, a new technology was offered by
almost all of the big paint manufacturers that would reduce this to a 3
step process: Primer+rust coat, color coat, clear coat. Needless to say,
the manufacturers were eager to save money by eliminating a step in
their paint process, and instead use a single product that both primed
and rust proofed the metal.
As it turned out, the prime+rust coat was incompatible with the
remaining two layers when exposed to UV in the presence of an acidic
solution (i.e. acid rain). It took 2-4 years for the problem to appear
(after the warranty expired, of course) and the paint started coming off
in big flakes. This always started on the horizontal surfaces of the car
body, where the acidic rain water could rest on the paint without
draining off. The roof of an 80's minivan is often seen today with
absolutely no paint on it, and a layer of rust is all that remains.
Lawsuits ensued, and the rest is history.
The manufacturers went back to the 4 step process and have
stayed there ever since. There may be different chemistries involved,
but I believe most of the manufacturers have gone to water based
chemistries for environmental reasons.
The 4 step paint process yields a rich luster and offers
pigments that have deep saturated colors compared to the enamel paint on
our LBCs. You also get outstanding oxidation resistance, especially with
pigments that are very prone to react under UV, such as saturated reds.
The enamel process can be done in 3 steps instead of 4, and offers a
harder finish than current 4 step water based technology (better scratch
resistance). The downside is the use of solvents, and a lower oxidation
resistance.
Now as to lacquer....
Vance
-----Original Message-----
From: owner-6pack@autox.team.net [mailto:owner-6pack@autox.team.net] On
Behalf Of R. Ashford Little II
Sent: Wednesday, February 04, 2004 12:39 PM
To: TR250Driver@aol.com; jonmac@ndirect.co.uk; 6pack@autox.team.net
Subject: RE: TR6 paint type
Darrell wrote:
Also while were on the subject I always wondered why I have never
seen an original seventies TR7 that did not need a paint job!
Hey Darrell, I'm far from sure as to the reason of this, but if I were
to
take a WAG, I'd say that the formulation of paint had changed at that
point
due to environmental concerns. Almost all of the late 70's - early 80's
American cars, especially GM products, had entire sheets of paint
flaking
off. A good friend of mine who possesses more knowledge than I about
these
things said it was definitely a change in formulation in that case.
Then again, it could have just been PO'd workers.
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