Getting a good gloss finish with airbrushed acrylics.

[Alasdair]

I'm trying my hand at cars. Unlike military subjects, cars have to be nice and shiny, and you can't pass off your mistakes as 'battle damage' ;-).

 

I very much prefer to use acrylics, and although I've been able to get a nice matte or satin finish, I'm completely failing when it comes to gloss.

 

Nice satin finish:

 

(Yes, a couple of minor flaws - I've been basecoating a lot of spoons.)

 

Lousy gloss finish:
 

 

And more examples here.

 

I've tried a number of combinations. I've tried gloss paint (Tamiya and Golden) and matte paint with a gloss clearcoat (Tamiya, Mission Models, Alclad Aqua or Liquitex gloss medium). I've tried them tinned according to instructions, and thinned with additional thinner. I've tried spaying close to the surface with low pressure and further away with high pressure. I've tried laying on multiple gossamer-thin coats, wafted towards the surface by the gentlest breath of air. Sometimes I follow this up with a final wet coat, sometimes I go straight to the wet stage.

 

It honestly doesn't seem to matter what I do. Everything ends up rough and grainy. Even if I overdo the wet coat, it still ends up like this. Even if the final wet coat looks smooth and glossy when it's still wet, once it dries it ends up rough.

 

The only thing that seems to work is sanding down afterwards with increasingly fine grades of paper, followed by some polishing compound. That gives a really nice finish,. and I have a number of spoons that I'm quite proud of. But spoons are nice and smooth, whereas sanding down a model like this one is next to impossible:

 

(I know - I tried. And then had to strip it all off.)

 

Is it actually possible to spray a decent finish using acrylics? And if so how to you do it? What haven't I tried yet?

 

Thanks,

 

Alasdair

[Alasdair]

Should have mentioned - I'm (ab)using an Iwata HP-BCR with, I believe, an 0.5mm tip, and a Sears Craftsman compressor with a filter and moisture trap.

[Greg B]

Aircraft modellers don’t have it easier, we have cockpits, seats, undercarriage and wheels. Armour modellers can just cover it with mud and say done

 

From what I’ve seen, a lot of car modellers would be happy with that finish and rub down between coats.
Have you added a retarder to the acrylic to keep it “wetter”. Mr Colour Levelling Thinners has one added to it. Tamiya do both a retarder and a laquer thinner with retarder. 

 

[Zorglub]

May be something thing can also be try:  a polishing compound. Tamiya, for example, has polishing compound.
The carefully abrasion of the polish will even out the layer and should remove the "orange skin" effect of the spray.

[Mark Harmsworth]

What do you do before painting? The plastic would need to be highly polished before painting to remove every little imperfection. Then I think a light polish between coats.

 

How about asking the question in the 'Vehicle Discussion' forum?

[Alasdair]

7 hours ago, Zorglub said:

May be something thing can also be try:  a polishing compound. Tamiya, for example, has polishing compound.
The carefully abrasion of the polish will even out the layer and should remove the "orange skin" effect of the spray.

Yes, as I said, I've got decent results on a spoon using increasingly fine grades of wet and dry paper, followed by a polishing compound. But spoons are nice and smooth and easy to polish, unlike real models, with all their crevices and moulded details. When I tried that on the model I pictured, the difference between the areas I could sand and the areas I couldn't was just painful.

[Alasdair]

3 hours ago, Mark Harmsworth said:

What do you do before painting? The plastic would need to be highly polished before painting to remove every little imperfection. Then I think a light polish between coats.

 

How about asking the question in the 'Vehicle Discussion' forum?

I showed a sample of the kind of matte finish that I'm glossing over - seems reasonably smooth to me? (And definitely smoother than the gloss coat.)

 

I can try the automotive section too if you think that's a better place.

 

Thanks.

[Alasdair]

8 hours ago, Greg B said:

Aircraft modellers don’t have it easier, we have cockpits, seats, undercarriage and wheels. Armour modellers can just cover it with mud and say done

 

From what I’ve seen, a lot of car modellers would be happy with that finish and rub down between coats.
Have you added a retarder to the acrylic to keep it “wetter”. Mr Colour Levelling Thinners has one added to it. Tamiya do both a retarder and a laquer thinner with retarder. 

 

Mud, mud, glorious mud 😉.

 

I will investigate retarders, thanks.

[Steve Noble]

Change the paints to Mr Color lacquer and you'll have a perfect result straight from the airbrush. If that's not an option and it must be acrylics then do as you're doing and wet flat and polish the finish. It's much harder with acrylics to get a perfect gloss without a little extra work of polishing etc..

[hendie]

5 hours ago, Steve Noble said:

Change the paints to Mr Color lacquer and you'll have a perfect result straight from the airbrush.

 

I agree with the Mr Color.   I've recently switched to Mr Color Aqueous with their leveling thinner and was blown away by the results.  

Alclad always gave a good finish, but I always found it was never durable and after handling it looked terrible.

[Steve Noble]

7 minutes ago, hendie said:

 

I agree with the Mr Color.   I've recently switched to Mr Color Aqueous with their leveling thinner and was blown away by the results.  

Alclad always gave a good finish, but I always found it was never durable and after handling it looked terrible.

That's Gunze aqueous, they are similar in guise to Tamiya acrylics. Mr Color are the lacquer paint version.

[Alasdair]

On 9/9/2020 at 7:50 AM, Alasdair said:

I showed a sample of the kind of matte finish that I'm glossing over - seems reasonably smooth to me? (And definitely smoother than the gloss coat.)

Turns out I was wrong and @Mark Harmsworth was right 😉

 

I tried a dab of various glosses on a primed spoon to see how well they'd dry without the potential effects of bad airbrush technique. On close examination they all came up grainy, and it was the same graininess as the primer coat.

 

I tried again, this time sanding down the primer coat very carefully, and the final gloss finish was a lot better. 
 

 

Will still need some polishing for a mirror-like look, but it's definitely an improvement. Looks like I really need to make sure that every layer is as smooth as possible.

 

Thanks,

 

Alasdair

 

“Do not try and paint the spoon, that’s impossible. Instead, only try to realize the truth… there is no spoon."

[Steve Noble]

You must always get the primer coat very smooth, as any texture will show through into the gloss layers. If you paint with Mr Color straight onto the spoon (no primer) the finish will be like glass. It's the primer that gives the surface texture..

[Alasdair]

On 9/25/2020 at 12:30 PM, Steve Noble said:

You must always get the primer coat very smooth, as any texture will show through into the gloss layers. If you paint with Mr Color straight onto the spoon (no primer) the finish will be like glass. It's the primer that gives the surface texture..

Thanks, I do appreciate the need for a smooth surface. I've been making sure to sand down the primer layer very carefully before trying the gloss layer, going down to 6000 grit micromesh. I think the primer's pretty smooth now.

 

I've still been getting less than perfect results. Lots of orange peel, which, when I looked it up, seemed as though it might be caused by too low a pressure. So, I tried increasing the pressure and spraying from further away.

 

This doesn't look too bad, Tamiya gloss with X20a thinner in a 1:2 ratio, plus some Tamiya retarder.

 

 

Trouble is, that was when it was wet. It's dried to this:

 

 

 

Still orange-peely. Does anyone know what's going in? Why is my paint doing the opposite of levelling when it dries?

 

[Steve Noble]

That's more the paint, not that you're doing anything wrong. It's just soaking into the under layers and the gloss is sucked out of it. When I used to spray full size cars we called it sinkage. Try a light rub down and reapply the gloss. You may have to do it multiple times before the surface stays glossy. 

[louiex2]

Here's on of the best tutorials I've ever come across about getting a gloss finish on a model car from BM's own  @cmatthewbacon

 

Lou in California

 

 

[Alasdair]

9 hours ago, Steve Noble said:

That's more the paint, not that you're doing anything wrong. It's just soaking into the under layers and the gloss is sucked out of it. When I used to spray full size cars we called it sinkage. Try a light rub down and reapply the gloss. You may have to do it multiple times before the surface stays glossy. 

Ah, OK, thanks for the explanation.

 

Would more light coats before the final wet coat help with this?

[Steve Noble]

Yes, plus a little sanding between coats..