Need advice on clear coats and Tamiya acrylics curing time

[GU-11]

Hi, all!

Just finished painting up some engine parts with Tamiya gun metal, and I'm waiting for the paint to cure before hand-brushing some Future Floor Polish to seal it.

The question is, how long does the paint need to fully cure?

I googled for some tips, but got no definitive answers. All I found were horror stories of Tamiya acrylics cracking under a coat of FFP due to insufficient curing time. Thing is, none of the forum comments tell you just how long it takes before you can safely clear coat the FFP, only that the paint has to be fully cured.

Also, I AB'ed some gloss red onto some plastic parts with a sufficiently glossy finish, but although I waited 2 weeks for it to cure, some parts that I painted especially heavy is still somewhat tacky. Is it safe to clear coat, of do I continue to let it off-gas until it's hard and smooth like the other areas?

[MechTech]

Hey GU-11! If I remember correctly, you have humidity issues right? That will affect things greatly. Do you have a food dehydrator you can slip your parts into? I remember reading about a guy in Florida (it's always humid there) putting his stuff in a dehydrator. Like I said in your airbrushing thread, I had enamels that needed a week to dry. The Tamiya Gunmetal (I love that stuff) should totally cure in a week if you can keep if "dry." I would paint your kit and then paint some spoons to experiment on. Humidity sucks (been there done that). - MT

[GU-11]

Thanks for the info, MT!

The humidity's been crazy these few weeks with the constant rain, sometimes reaching 100%. According to the weather forecast, at least--I don't own a hygrometer.

While the humidity can't be helped during spraying since it's been raining every day, I only spray indoors and when the weather's the least humid. After that, I place the parts in my display room where the AC 's constantly switched on. While it's said that cold air actually slows the paint drying, the dessicants in the air should more than compensate for it. I've seen how my daily mug of coffee starts to evaporate if left for a while in that room, so the AC air is pretty dehydrating.

I've been looking for a food dehydrator, but no such luck. I've heard that some people make their own "paint oven" using a cardboard box and a light bulb--maybe I'll give that a try.

I'll take your advice and try painting some spoons for clear coat tests.

[GU-11]

@ MT : BTW, can I do a chalk/pastel wash or spray Tamiya clear smoke on the engne parts I painted in gun metal even before it's completely cured?

[electric indigo]

Spraying smoke on top should be no problem, but since washes include wiping over the painted surfaces, you should do some testing in unsuspicious areas.

[GU-11]

Thanks for the heads-up, Indigo!

One question about gloss paints: how does the surface of a gloss coat "feel" when fully cured? It's been a month since I sprayed gloss red onto that plastic spoon, and it feels like the surface of a newly washed car. It's smooth but "sticky", and almost "squeaks" when you rub your finger against it.

It shows all the signs of being fully cured; I attacked it with a fingernail, but despite my best efforts, I didn't put so much as a scratch on it.

I'd let the spoon to cure inside a large plastic container (the kind some people use to make DIY spray booths), so the humidity shouldn't have gotten to it. And it's already been a month.

BTW, the gun metal has fully cured is very hard and smooth to the touch--fingernails can't put a single scratch on it. The dark gray, though, still scratches off even after over 2 weeks.

It seems as though the glossier paints dry harder and tougher than flat paints for some reason, although it might be that I haven't thoroughly washed the spoon, though.

[MechTech]

^{Sorry for the delay, I haven't been on this board a bit. It sounds like your paints are fully cured. The glossy paints actually have a coating in them to make the shiney appearance. They will be harder/denser. The downside, they take longer to cure and the finishes are easily marred if not allowed to cure. Keeping with the water based stuff sounds good with the humidity you're experiencing.}

^{The flat colors are different and will show a scratch or marr when scratched. You're actually micro sanding the paint when it gets marred. The solution, rub the whole thing if you screw it up The good news is you can clear coat it and then decal over it when the coating smooths out the surface. The coating also protects it. Another coating over your decal work will seal the whole thing. Hopefully that helps! - MT}

[Valkyrie addict]

can really add more to MechTech great advice except that clear coating before decaling also aids to glide the decal easier to its position before applying microsol to it.

[GU-11]

Thanks MT and Valkyrie addict! Glad you guys explained everything. Google show up nothing despite days of searching.

And thanks for the tips!

I recently checked some flat white and flat dark gray I AB'ed, and was surprised to find that the flat white cured much stronger and tougher than the dark gray. Scraping at the white paint wore off my nails more than the paint. The dark gray, on the other hand....

Both are Tamiya acrylics and AB'ed the same day.

Forgot to ask this the last time: Can I use Tamiya's clear gloss base for clear coating? I know their flat base isn't meant for use like that, but is their gloss base okay to AB as a clear coat?

[EXO]

gloss base is an additive to make flat paint glossy... not for use by itself.

[David Hingtgen]

I've never heard of a gloss base additive that's the opposite of their flat base---Tamiya makes such a thing? And it actually works? (flattening gloss is easy, the opposite is harder)

Anyways---I tend to give Future a large lee-way in either direction----I don't apply it on top of anything that hasn't cured for a long time, and I don't put anything on top of it until it has cured a long time. ESPECIALLY do not apply decals on top of it without curing for days. It may be ok for touching or painting or re-coating, but most decal liquids will attack Future that's not utterly totally rock-hard-dry.

[GU-11]

@EXO: Many thanks for the heads-up!

@David Hingtgen: I've allowed the parts to cure for at least 2 weeks. That should be long enough. Or is it?

Also, how long does it take for FFP to fully cure?

Yet another thing I forgot to ask (really need to type up a list before starting a new thread): I've heard that you can actually hand-brush FFP thansk to its self-leveling properties. Thing is, I also hear that if you add Tamiya's flat base to it to dull the finish, it messes with FFP and you might not get as smooth a finish as when you brush unmixed FFP. Is that true of just a rumor?

My AB setup (Tamiya Spraywork Basic Compressor w/ AB set) isn't sufficient to airbrush FFP, as it's so thin that you need to dial down the air pressure and only do mist coats--and even then, there's a risk of getting runs and spider-webbing. My AB is a single-action one, and the compressor's air pressure stays at a constant 15 psi, and is NOT adjustable.

[derex3592]

This thread is very interesting. I've always been very impatient and want to work with parts right after I finish painting. It's gotten me into trouble before. Sounds like I need to chill and let things cure for an absolute minimum of 24 hrs. Whether it be enamel, acrylic, or coats of FFP or whatever.

[EXO]

I've never heard of a gloss base additive that's the opposite of their flat base---Tamiya makes such a thing? And it actually works? (flattening gloss is easy, the opposite is harder)

never seen the stuff. but I read a lot of people asking about it.

[GU-11]

never seen the stuff. but I read a lot of people asking about it.

It exists. I actually bought a bottle of it, thinking I could use it as a clear coat, until I was told otherwise.

[EXO]

I wish I had a bottle. I hate this flat black paint. But I just finished the whole thing.

[lavinrac]

Ok So this is reviving a dead horse.. But I am experimenting..

- I have airbrushed a kit with Tamiya Acrylics.

- I then Applied Future for gloss coat..

- Then a wash (Citadel Nuln Oil Shade),

Unfortunately when I went to remove the wash i used rubbing alcohol and it ate through the future and the underlying acrylic got wiped away too. So, Now i am thinking I need to use a Lacquer clear coat instead of future.. I don't know exactly what i want to do there though. I dont run lacquers through my airbrush.. because the are a major pain to clean out.

Any recommendations?

I'm concerned a spray lacquer clear will go on too thick/orangepeel

[Duymon]

Rubbing alcohol eats future like no tomorrow in my experience. Future is just am acryl clear coqt so treat it like all other acryls when it comes to which chemical compounds to use

[007-vf1]

I would definitely not use alcohol on anyhting that tamiya has been aplied to. I would just wipe the wash out with water or very light and quick thinner cutips and make sure it doesn't rub too hard into the surface and way after the undercotas have dried. I do use diluted oil paint washes over the tamiya future undercoats. I know it is dangerous but after several years I have not had issues.

Is there any washes brands anyone has succesfully wiped them from the Future coat or just plain tamiya undercoat without gambling on the previous undercoat paint?

[Noyhauser]

Ok So this is reviving a dead horse.. But I am experimenting..

- I have airbrushed a kit with Tamiya Acrylics.

- I then Applied Future for gloss coat..

- Then a wash (Citadel Nuln Oil Shade),

Unfortunately when I went to remove the wash i used rubbing alcohol and it ate through the future and the underlying acrylic got wiped away too. So, Now i am thinking I need to use a Lacquer clear coat instead of future.. I don't know exactly what i want to do there though. I dont run lacquers through my airbrush.. because the are a major pain to clean out.

Any recommendations?

I'm concerned a spray lacquer clear will go on too thick/orangepeel

I think you just need to change your wash. I use acrylics like you: Gunze or Tamiya with future over top. However unlike you I use artists oil paints ( an enamel cleaned up by mineral spirits) as my wash.

The mineral spirits do not react with the future or the paint... which makes it really easy to wipe off or thin if there is too much on the surface. The best part is that it is cheap; two paints and a small bottle of thinner costs about 10~15 dollars and you will never have to buy anymore, ever.

[lavinrac]

Ok thats worth a try. It sounds like don't understand my thinners very well.

I was thinking that mineral spirits would eat through future.. and acrylics, and anything, because they are a 'strong solvent' (in my mind anyhow)

---

- So spray on future. Let dry, Then mix artist oils (from tube) and thinner to runny consistency for a wash, let dry, and rub off with mineral spirits?

---

Correct?

Do you add any detergent to your wash? (i have heard of this)

Thanks!

I think you just need to change your wash. I use acrylics like you: Gunze or Tamiya with future over top. However unlike you I use artists oil paints ( an enamel cleaned up by mineral spirits) as my wash.

The mineral spirits do not react with the future or the paint... which makes it really easy to wipe off or thin if there is too much on the surface. The best part is that it is cheap; two paints and a small bottle of thinner costs about 10~15 dollars and you will never have to buy anymore, ever.

[Noyhauser]

Ok thats worth a try. It sounds like don't understand my thinners very well.

I was thinking that mineral spirits would eat through future.. and acrylics, and anything, because they are a 'strong solvent' (in my mind anyhow)

---

- So spray on future. Let dry, Then mix artist oils (from tube) and thinner to runny consistency for a wash, let dry, and rub off with mineral spirits?

---

Correct?

Do you add any detergent to your wash? (i have heard of this)

Thanks!

I'm pretty sure I understand your thinners well. White Mineral spirits should not eat through acrylics. I've got about 80 or so models to prove that. It can be a problem when you paint an enamel base coat and your future coverage is not sufficient... White mineral spirits will eat through that.

I usually thin the artist' paint with spirits and then apply it... it should be very liquidy. Sometimes I make it very thick... it all depends on the effect. If I just want panel lining thin is best. If I want a grimy dirty aircraft, I might use a thicker paint and leave more on.

Then I wait a few hours (even several days) before removing the excess with a paper towel or something. Sometimes I don't use anymore spirits unless some have dried on and won't come off with some rubbing. Then again I might not want to remove much... This is a CF-18 I recently built:

You can see how I used smuged oil wash to help make streaks on the wing (along with another product, but its not necessary to achieve this effect.) Its also apparent below the vertical stabilizers... like in real life.

This shows just how grimy it can get:

Really what you do should vary based on what you want to accomplish. I'd suggest you look around for photos of an aircraft similar to what you want... then try to replicate the effects as best you can. You can always ask more questions too.

I hope that helps.

[lavinrac]

That's Extremely helpful! Thanks! I will give mineral spirits on future a try on a couple pieces to see how it goes!

As for grime.. It's mecha (macross, gundam, other), in bot mode, so not too grimy just yet. That grimy look will come in handy on the Votoms Scopedog though!