Date:         Thu, 6 Jan 2000 08:36:22 -0700
Reply-To:     "Michael A. Radtke" <m.radtke@ELM.AZ05.BULL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         "Michael A. Radtke" <m.radtke@ELM.AZ05.BULL.COM>
Subject:      Vanagon, Paint, and Isocyanates

Hello,

Painting your Vanagon comes up on this list from time to time.  I am in the
middle of a couple of restoration projects, so I have been researching this
subject for 18 months.  I don't have the answer:

1) Lacquer is easy to apply, has no isocyanates, but dumps lots
   of solvents into the air.  Lacquer cures through evaporation
   of its solvents.  I have a 10 year old professional lacquer
   repair on my Vanagon.  The color still matches perfectly, but
   the surface has crazed.

2) Acrylic enamel does not need hardener.  Acrylic enamel initially
   dries by evaporation of the solvents, but then cures over many
   months by oxidation.  It is quite delicate for the first week
   or two.  Baking can be used to speed the oxidation process.

   An isocyanate hardener is almost always added to acrylic
   enamels these days.  The real purpose of the hardener is to
   catalyze the oxidation process so it completes in hours rather
   than months.  That's why it's sometimes called a catalyst.

   A side effect of using a catalyst with acrylic enamel is that
   the rapid curing makes the paint harder.  That's why the catalyst
   is sometimes called a hardener.

   Old non-catalyzed acrylic enamel tends to be just a bit rubbery.
   It can be scratched more easily than catalyzed acrylic enamel.
   But, scratching catalyzed acrylic enamel may result in chipping
   and flaking because of its greater hardness.

3) Polyurethane auto paint is always catalyzed.  It is more rubbery
   like non-catalyzed enamel, but is tougher (not harder).

4) Isocyanates have been linked to about every type of disease.
   The most common problem is some chronic breathing problem such
   as asthma.  Just don't ever use an isocyanate hardener with out
   a positive pressure fresh air breathing apparatus.

5) Polyurethanes can be cured (cross linked) with non-isocyanate
   catalysts.  Some polyurethanes cure with water.  However, no
   one seems to make a polyurethane paint that uses a safe cure
   for automotive applications.  The closest that I've come is
   Polyfiber's Top Gloss (http://www.polyfiber.com).  This is an
   aircraft paint designed specifically for the DIY market.  While
   it appears to be safe enough, their web site claims "dries to a
   high-gloss, wet-look finish."  However when you buy the paint
   the instruction book says that you can't even hand buff it to
   a gloss, but rather must use a power buffer.  Thus, I haven't
   even tried to paint with it.

So, what have I learned?  Do all the prep myself and let the
professional do the painting.

Mike   '84 GL   '60 Vespa   '58 Isetta   ---   Phoenix, AZ