Painting Question

[Tom Todd]

1.  I'm having a problem with painting dark plastic with yellow and orange paint.  Even a few light coats don't cover.  I remember from long ago somewhere in the recesses of my brain that making a first coat of silver will help with the yellow covering better.  Any thoughts on this?

2.  At a store close out I bought 31 bottles of True Color Paint for $0.45 each.  Then I realized that they contain acetone and therefore should not be used on plastics.  Would a primer coat work?

Inquiring minds, at least mine want to know?

Thanks in advance.

Tom

[peteski]

Tom, I have no problem with Tru-Color on plastic. They probably contain so little acetone that they are safe.

As for using light color paints on dark surface, that will always be problematic.  You will need to first apply white primer undercoat before shooting light colors. I like Tamiya fine white primer. It is pricey, but it works well.  I even decant the spray can and shoot the primer through my airbrush.

Silver IMO is not really a good base color for light colors - white works much better. Plus a primer is pretty dense, so it shoudl easily cover the dark surface.

Edit: to put your mind at ease about plastic compatibility, here are couple of excerpts from the Tru-Color website's FAQ section.

Tru-Color Paint is an acrylic solvent based paint that is designed to be airbrushed directly from the bottle without thinning.  Tru-Color Paint can be blended to produce a variety of shades and hues for your specific product needs.  Although Tru-Color Paint contains a small percentage of acetone we DO NOT RECOMMEND that acetone be used to thin (dilute) the Tru-Color Paint.  Adding just acetone to thin Tru-Color Paint may harm the intended gloss or semi-gloss finish our paint is intended to give as it will dry too fast.  Also, too much acetone will cause the solvent system to evaporate too quickly during air brushing causing the painted surface to appear rough and/or it may blush.

As with any other painting project, the plastic model should be thoroughly cleaned with soap and water, rinsed and dried with a lint free towel. Try not to handle the model excessively (keep oils off model). You may apply primer, if desired. Brass models take special preparation. They must be sand blasted or treated in a similar fashion to insure that Tru-Color Paint will adhere properly; particularly important if masking of the painted model is needed for subsequent paint applications.

[Tom Todd]

Thanks Pete

[robert3985]

Since I do a LOT of painting yellow on various cars and engines, I use Scalecoat II, over a gray primer.  A light gray primer. My paints are in a box somewhere right now, but I use a military figure paint in a rattle can for my primer over plastic.  Just for the helluvit, I thought that Vallejo might offer a good primer that won't conceal details, and the result is this: https://overthebrick.com/products/vallejo-primer-grey?variant=36790305292454&currency=USD&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&gclid=Cj0KCQiA6t6ABhDMARIsAONIYyzGojFbQFGKqio-xE5QtUhqgGTPrdaogPf0eH7tcLovpKCPhVUrdh8aArKiEALw_wcB   which looks like a great way to prime!

Cheerio!
Bob Gilmore

[randgust]

Wow, this is just what I was looking for.

OK, so I'm attempting tru-color right over plastic, and was very concerned about the acetone content.   I can see there's enough in there that it gets a grip but not enough to cause real surface trouble.

But the coverage over gray plastic (test shell chunks, not final model) is pretty darn poor, it's not even and second coat didn't help.   Primer?   Which primer?  Does Tamiya work well enough to justify a shipped price of about $15 a can?  Anybody try just testors white primer?   I'll probably give it a test as my test chunks (leftover Atlas short noses from CF7 conversions) are rather expendable.  But this is a real disappointment.   I don't like anything with acetone in it to begin with, and this isn't helping.

Badger can be weird too, but the second coat forgives any sins on the first one, and it's a much harder surface than anything that Floquil ever did, and I rarely use a primer unless I've got a black plastic shell and going light.

[peteski]

Tamiya primer (and all the other products) to me are well worth the prices. After all, why not use the best on your precious custom-built one-of-a-kind model?

Tru-Color also makes their own primer, but it is light gray.  Actually, Tru-Color white paint (and white paints in general) are quite opaque, so a coat of white paint could be used as a "primer" base-coat for light color top coats.  Tru-Color paints are more like inks, so they go on in very thin layers (if applied properly), so even with multiple layers, they will not hide the surface details.


Main reasons for using a primer is to improve adhesion (which with plastic model is not a problem to begin with), and to provide a uniform neutral color substrate for the top coat. This is especially important when the model is constructed from multiple materials, or cobbled up from parts of different color.

[randgust]

What I see is that if you're using a 'brilliant' color; yellows, reds, oranges, that applying them over gray looses the punch and changes the tint noticeably.  I've been using white primer in those situations for years.  But given the acetone content of Tru-Color, I have visions of it punching right through the white primer and creating a disaster.  By itself, a tru-color White is going to require multiple coats just to cover the plastic, where a good very light coat of primer doesn't.   

[peteski]

What I see is that if you're using a 'brilliant' color; yellows, reds, oranges, that applying them over gray looses the punch and changes the tint noticeably.  I've been using white primer in those situations for years.  But given the acetone content of Tru-Color, I have visions of it punching right through the white primer and creating a disaster.  By itself, a tru-color White is going to require multiple coats just to cover the plastic, where a good very light coat of primer doesn't.   

You guys should relax about the acetone in Tru-Color paints. Safe on polystyrene and safe on primer.  I even use Tamiya primer under "hot" automotive paints, and nail polishes.

[Jim Starbuck]

I use a light coat of Tamiya gray surface primer airbrushed under Tru Color Milwaukee orange with good results.
Interesting that they state not to thin Tru Color with acetone. I’ve done just that without any problems.
If not acetone, what should be used to thin it?

[Wutter]

I use a light coat of Tamiya gray surface primer airbrushed under Tru Color Milwaukee orange with good results.
Interesting that they state not to thin Tru Color with acetone. I’ve done just that without any problems.
If not acetone, what should be used to thin it?

I thin my Tru Color with hardware store Lacquer Thinner, I find that it flashes off much slower than acetone, also if you add too much acetone to paint the finish sometimes comes out a little bit ashy or it seems like the paint partially dries before hitting the model. This is especially noticeable on paints with flake inside them like Silver or Metallic Silver as the flake seems to not stick well.

But I've had good results with just Lacquer Thinner and not found any differences compared to using the Tru Color thinner. I suspect the only differences in real Tru Color thinner would be maybe some retarding additives

[Jim Starbuck]

Excellent! Thank you for the information.

[peteski]

I use a light coat of Tamiya gray surface primer airbrushed under Tru Color Milwaukee orange with good results.
Interesting that they state not to thin Tru Color with acetone. I’ve done just that without any problems.
If not acetone, what should be used to thin it?

The dedicated thinner that Tru-Color sells.  It has acetone mixed with other, slower evaporating solvents. I guess how well acetone works depends on how much of it you add. The paint is already airbrush-ready. If you just add a small amount, that will not affect the drying time enough to affect the finish.

Ron @u18b experienced some dismal failures using acetone with Tru-Color  paint until he started using the dedicated thinner. He documented it in one of his build threads.

I use acetone or lacquer thinner for cleaning the airbrush, but for both AccuPaint (my remaining stash), and Tru-Colro paints I use their dedicated thinner. Never had a problem either.