paint compatibility

[b-body fan]

Has anyone ever put up a chart about using different paints. I.e.you can paint enamel over lacquer but not visa-versa? Someone in the know could probably help the rest of us save a paint job some day. Thanks, Mike.

[Snake45]

There are now so many different kinds of paints floating around, it's almost impossible to make blanket statements about what WILL or WON'T work over what. The best thing to do is run your own tests using the EXACT paints that you want to use on YOUR project. The undersides of interior tubs and the topsides of chassis are good places to test paints or combinations of paints. Screw up there and you haven't damaged anything important.

[Krazy Rick]

Your best bet is to play it safe & use the same brand / system, there is no need or logic in playing around & taking chances- I can never understand what purpose this serves & why some guys continue to , play the goofy scientist & then get peeved when things go bad.

Edited June 8, 2015 by Krazy Rick

[b-body fan]

I was thinking more of when I'm in a position where I have for instance, all the enamels for a particular model but first the perfect body color in acrylic. Seems like a shame to buy several colors that I have if I don't need to. I'm not trying to do any science experiments. I was thinking more about why buy something I don't need, or buy what I need rather than ruin a model.

[b-body fan]

Sorry for the double post. When I was in my early teens or so there was pretty much Testors or nothing it seemed. I made things a little simpler. Back then most true automotive finishes would eat plastic. There is sooooo much more available now. At least from my perspective. Thanks again, Mike.

[Ace-Garageguy]

I'm not trying to do any science experiments.

Well, that may be exactly what you need to do. "Science" is testing things, getting repeatable results, and writing those results down so you can use them for reference in the future. That's all science really is.

Experimenting with the materials YOU have, in various combinations, is the only 100% reliable way you're going to come up with what works for YOU every time.

Exactly what Snake says: "There are now so many different kinds of paints floating around, it's almost impossible to make blanket statements about what WILL or WON'T work over what."

[b-body fan]

I hear you. That's pretty much what I do. Just trying to save some time. My worst fear is it will raise its ugly head after awhile. Not all reactions are instant. Thanks again for your help.

[Snake45]

It costs you virtually nothing to test paints you have on hand as I suggested, and if they don't work out, then you can go buy something else.

Another variable: Not all of today's styrene is created equal. Paint that works fine on one kit might well dissolve another kit before your very eyes. Test on the actual plastic that you're interested in painting.

Edited June 8, 2015 by Snake45

[b-body fan]

Good call Snake. Thanks again.

[Art Anderson]

It costs you virtually nothing to test paints you have on hand as I suggested, and if they don't work out, then you can go buy something else.

Another variable: Not all of today's styrene is created equal. Paint that works fine on one kit might well dissolve another kit before your very eyes. Test on the actual plastic that you're interested in painting.

Good call Richard! There are all manner of styrene blends, from pure styrene, to the various blends of polystyrene, to those that have a bit of synthetic rubber added to them.

Those old, hard styrene model car kits of the late 50's-early 60's can be very problematic to paint with lacquers, while I have very little problem using automotive acrylic lacquers on most modern kits (although I've learned to be careful with some Japanese kits). One thing that sprues from any model kit are great for--testing the paint compatibility, even minute reactions to whatever paint one envisions using on a particular model.

Art

[Brett Barrow]

Good advice all around. My experience is that hobby-type paints (Testors, Humbrol, Tamiya, Vallejo, etc.. the stuff you find in hobby shops) tend to play nice with each other whether they are lacquer/acrylic/enamel, etc since they're typically mild versions of those types. But as advised above, test on a sprue or in a hidden area to be sure.

When you get into automotive or hardware-store paints, then you have to be more careful with compatibility.

[Pete J.]

I hate to throw a wrench into the works but some paint "compatibility" also has to do with technique. How long between coats? How heavy or how light a coat? How much thinner? What thinner? All of these come into play when we talk about compatibility. By compatibility we are talking about common problems such as top coat getting spider cracks or pulling up getting an alligator skin look. It can also have to do with the final look of a color.

Here are some basic rules that I use:

1. Always use the same type of paint from the same manufacture. The paint company formulates it's paints to work together. Each company formulates their paints a little differently.

2. Use the thinner from the same company as the paint was made. All thinners are a cocktail of ingredients and slight variation can cause problems.

3. Always use the same type of paint. Don't mix lacquers, acrylics and enamels even if they are from the same company. You are asking for trouble. If you must, lacquers on the bottom, then enamels and the waterborn paints. This is not a guarantee but the thinners in the top coat should not dissolve the paint below.

4. Record your results. Get a notebook and keep track of what you did and be precise. "Thin to the consistency of milk" drives me nuts. I measure everything and it is not hard. Get a mix bottle and lay a ruler down the side and make some marks on the bottle. 5 parts paint, one part thinner isn't hard or tedious to do that way. If it works then do it that way every time.

5. Last, none of these are "the Code". They are guidelines. You can break the rules once you understand them. I use different types of paint all the time and for good reasons. I may want to highlight something and use an alcohol base acrylic over solvent based lacquer to do so, knowing that if I make a mistake a swipe of alcohol will erase the acrylic without touching the lacquer, but you have to know the rules first.

You said you didn't want a science experiment. Sorry, but you are working with a wide variety of chemicals and it is all a science experiment. Even with paint and thinner from the same company things can go wrong and it doesn't always happen right away. I once did a model for a Tamiya advertisement(Toyota 020) and painted it up with their paints. They were very happy with the result and shot the ad. Two weeks later the clear coat cracked. I didn't let the base coats sit long enough and sprayed the clear just a bit too thick. I learned and never had a problem again, but painting is all about what you learn as you go.

There are no mistakes! Only lessons, and the lessons will continue until they are learned!

Edited June 8, 2015 by Pete J.

[b-body fan]

I'm usually good about allowing ample drying time between coats. You brought up solvent popping (indirectly). Another good point. Thanks.

[Ace-Garageguy]

Another variable: Not all of today's styrene is created equal. Paint that works fine on one kit might well dissolve another kit before your very eyes. Test on the actual plastic that you're interested in painting.

This is an excellent point, and one I usually hammer away at myself.

Not too long ago, I'd used a real-aircraft engine-enamel rattlecan gray on a Micky Thompson Challenger (vintage Revell kit, not re-issue) frame that happened to be molded in metallic blue. I shot it wet, with only about 5 minutes flash between the 3 coats. It slicked out great, looked fine.

At roughly the same time, I was working on a save of a previously hacked '70 Chevelle (also Revell, molded in about the same color of metallic blue, but a much newer kit). I shot the paint exactly the same way, and it crazed almost instantly. Badly. Practically ruined the blue-molded chassis, but didn't touch the custom roll-cage I'd built from Plastruct round rod.

The moral of the story is Snake's line above: Test on the actual plastic that you're interested in painting.