Paint Compatibility

[Black n Decker]

Hello Tomcat Fan,

It's a very interesting topic.....

We just had a club-meeting last week-end and we were also discussing about this problem.

I've just finished my yf-16 (Hasegawa 1:72) and I've been using gunze GLOSS acryls for the first time (and certainly for the last time....). The colors I've used were the H327 (red gloss) and H326 (blue gloss) and also tamyia white spray and MM flat black.

Now what happened:

I applied a thick layer of a gloss coat called Lascaux (Water based acrylic) and then the gunze colors started to run and "shrink" (almost as you use decal solvent on decals...) ?!?

Note that the colors on this plane were drying for over 3 weeks !

And, very interesting, only the gunze colors were reacting on the gloss coat. MM and Tamiya-colors worked well.

I've been using this gloss coat together with MM (acryl), MM (metalizer), Lifecolor (acryl) and Tamiya-colors and so far I've never had problems with it.

I've also been using Future together with the above mentionned colors and had no cracking.

Other experiences:

My clubmates told me that they had also "cracking" - problems. This problem appeard as they used Future along with GLOSS or SEMI GLOSS gunze colors.

However, no cracking observed with gunze flat colors.

Conclusion:

So it definitely seems, as Colin K already mentionnned, that the problem IS gunze GLOSS / SEMI GLOSS colors.

If you want to work on with this colors, then maybe try another varnish (polyscale etc...)

Cheers

[trojansamurai]

I've actually experienced Gunze's Flat Hobby Color cracking when applied over Gloss Hobby Color. This obviously wasn't an issue of hot versus cold, but more related to surface tension and drying time for a flat vs. gloss paint.

Also, the top layer of acrylics tend to dry instantly when exposed to air, but the inner layers take longer to dry when they get "trapped" between the bottom surface and the top layer. This means that you have to refrain from putting on thick coats of paint. Even Future, if applied too thick, will be dry on the surface, but gooey inside.

It's also best to use paints of similar sheen when using multiple colors, as this will provide more uniform drying. This might require adding a little flat base to glossier colors or adding clear gloss to flat colors.

[SLAYER]

The problem is both Gunze, Dullcoat, and Future are not compatible. Gunze is a cold paint, a flexible latex-based acrylic, not a true acrylic. Future is a true acrylic, it is like a hot paint, dries very rapidly and is not flexible. Latex and enamels both are cold paints that take time to cure, but are still flexible when cured. Lacquer (Dullcoat) and true acrylics are hot paints, they dry hard very quickly and have a finish that is hard as nails. The new MM Acryls and Polly Scale are true acrylics. Tamiya and Gunze are latex-based acrylics.

Therefore, never used a hot paint over a cold paint, you will get cracking or wrinkles from the unflexible, quick drying hot paint reacting with the flexible cold paint.

Caz

this is the best explanation, I only use Modell Master paints and Testors laquers and never had a problem not even yelowing of paint. Even you have to know what kind of thinner you must use to avoid cracking of paint.

[wdw]

I suggest three problems are at work here.

Firstly, too many Future coats before decaling.

Secondly, not enough time to cure properly. Just because it has dried does not mean it has cured.

Thirdly, I would avoid using a laquer product over an acrylic one.

wdw

[loftycomfort]

Glossy Gunze acrylics take a looooong time to cure. I'm talking at least a week. Try this next time you spray gloss Gunze. Get a small scrap piece of plastic, and spray the same amount of paint on it as the model: 1 pass on the model, 1 pass on the scrap piece. Set both aside to cure. After a couple of days, take the scrap piece and press your thumb hard against it. If there's a finger print, then it's not cured, and neither is your beloved model. Let it cure until you can't press any more fingerprints to the scrap, then you're ready to future it.

[Winnie]

So, having read the thread multiple times now...

I prime my models first (Mr. Surfacer 1000 thinned with laquer thinner)

Now here's the problem, got the colors for the machine, but got the wrong one for the dark area... so now I need to shoot ONE enamel and the rest are Gunze acrylics...

(Unfortunately the enamel is the darker one)

Am I in trouble, or will this work?

The hobby shops were out of the one I need as well, so there is no other option (darn it).

[MAG One]

Funny, I never noticed this thread before. I guess I could not see the forest for the trees.

The issue here in my humble opinion is the difference between aqueous or waterborne paints verses water-based paints. Polys and true acrylics are actually waterborne paints. The resins in the paint are suspended in a solvent mixed with water. They are called waterborne to distinguish them from true solvent based paints. A true water based paint will disolve in water. If the paint uses an alcohol or ammonia base it is waterborne.

The real issue here though is Gunze and almost any other paint. If I start with Gunze I finish with it. Almost any other brand of paint I will switch back and forth between brands with no adverse affects. I have even used Future as a barrier coat before painting with laquer.

Just my 2 cents worth and we all know what 2 cents will buy these days.

Gary

[HWR MKII]

The main problem is the future. Too thick and it remains gummy. It retains some elasticity for up to a week. I use base tamiyas, layer of future. decals , another layer of future and then testors acryl matt coat on my stuff. I noticed if i spray the testors too soon or too thick it will stretch and crack the future. I have gotten in the habit of letting my layers cure for at least a week and also misting on the matt coat in light layers. This keeps the matt coat from pulling the future layers and also gets you a dead matt finish in return.

[Litvyak]

I've got a sizeable stash of Polly Scale paints including the clears, also a smaller array of Floquil, Humbrol and Gunze. I've also got a couple bottles of Tamiya, but these don't seem to like me. Is there a special technique for brushing them? I've tried, but the paint keeps "balling up" into itself (kinda like mercury)...