Model Forum / General / Models / September 2009

I can't see any problem if the paint you are overspraying is absolutely
cured - but remember that doesn't just mean touch\handle dry, full cure
could be days.

The best thing to do is a test yourself.

Not sure how widespread this is, but in the UK (and I think Europe) from Jan
2010 the sale of oil-based paints will be banned, presumably in a bid to
save the environment.  We have just had a ban on 100W lightbulbs too!

So it looks like I will have to move from the humbrol enamels that I prefer.
The trouble I have with acrylics is brush painting.  I still haven't moved
to spraying (I have an airbrush but have never mastered it).  Whilst I find
I can brush paint with enamels pretty well I find acrylics (especially
Tamiya ones) really difficult.

Cheers,

Nigel

__________ Information from ESET NOD32 Antivirus, version of virus signature database 4441 (20090919) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com

I tried spraying enamel over acrylic several years ago. It frosted or
checkered the acrylic. I found I could use acrylic over well cured
enamel.  I hesitate to do so, however, since I generally use a lacquer
overcoat- either dullcoat or glosscoat.  It seems to go over enamel ok,
have been afraid to try it over acrylic.

Correct.  They're chemically incompatible.  Results would depend on the brands,
but it could be like mixing oil & water or milk & vinegar.

You can safely apply acrylic on top of or beside enamel if the enamel is fully
cured.

"Fully cured" means letting the paint dry for at least a few days, preferably a
week, maybe longer in humid weather.  It may feel dry in less than an hour, but
it'll continue hardening and shrinking for some time as the remaining solvents
slowly evaporate.

You may be able to spray enamel on top of acrylic if the acrylic is fully cured
AND you spray very light coats so the enamel will dry quickly.  The problem is
that the solvents in enamel are stronger than those in acrylic, and will
dissolve dried acrylic very quickly, causing problems like paint lifting or
cracking.

Some good info here.
http://www.internetmodeler.com/2006/june/features/airbrushing_acrylics.php
Sorry for the earlier post; too much multi-tasking,
Curt
KVPS

    Well, I would not suggest ever mixing paint in an original
   bottle. You can purchase empty bottles easily enough, and mix
   the concoction in the empty bottle. If the concoction fails, you
   are out a bit of paint, not the entire bottle or more of the
   original colors.

    I have to disclose the fact that I do not like enamel paints,
   and a big reason why I don't like them is how long they take to
   dry to the touch, nevermind cure.

    Having said that, there is no reason you can't use acrylics
   and enamels on a model. The caveat is that the proceeding coat
   has to have cured.

    Acrylics cure very quickly, as a rule (sometimes too quickly),
   lacquers also tend to cure quickly. Enamels - not so much, in my
   experience.

    As mentioned above, acrylics cure quickly - too quickly, in
   general. The way to solve that problems is to add some retarder
   to the base color. 10% or so retarder will help a lot when working
   with acrylics, either airbrushing or paint brushing.

    Also, be prepared to accept that what the color is in the
   bottle is not necessarily the color you will get when dry. Use
   the company recommended retarder until you have some experience,
   then you can try alternative retarders on scrap first.

    And, when using water-based acrylics, (as opposed to synthetic
   acrylics), use distilled water as a thinner, not tap water. You
   never know what the minerals and chemicals in tap water will do
   do the paint.

                            Bruce