Airbrushing Incompetence Part 2: Acrylic Boogaloo

[Evil Eye]

You may remember me struggling to deal with airbrushing Citadel paints a while ago. Well, I've since given up on trying to thin regular Citadel into something useable through my Eclipse (though the Citadel Air line seems to be just fine, and I'll definitely get more of those) and I've since acquired some Vallejo Air paints- Bloody Red, Magic Blue, Moon Yellow, Black, Dead White and Model Air Insignia White (for a specific project you see). I also already have their Chrome Silver, which we'll get to later.

 

So, problem number one: Mixing paint seems to behave the exact opposite of how it should.

 

I foolishly thought that if I bought the three primary colours + black and white, I could theoretically mix any colour I wanted from those 5 paints. So for an experiment I tried making a purple by mixing in roughly equal parts Bloody Red and Magic Blue.

 

The result? A very dull and desaturated blue.

Rather perplexed by basic colour theory seemingly not working, I attempted to vary the mixture of red and blue, adding a little white, etc. Unfortunately, the results varied from the same as above but even duller to a dark mauve to a very pale salmon. But try as I might, the nice vibrant purple I was aiming for evaded me. The actual consistency of the paint was fine, and it dried on the spoon (and the base of my spray booth) nice and smooth. But the colour was not what I was expecting.

 

Now obviously I can solve this by not being a cheapskate and just buying more colours, but regardless I am interested to know why it didn't work.

 

And now onto problem number two: Yellow is absolutely awful.

 

Maybe it's because I ran it "neat" (without any flow improver or the like) but Moon Yellow is horrendous, for the opposite reasons as vanilla Citadel. Rather than being thick and cloggy, it's instead way too thin out the bottle. It's abhorrently translucent and very runny, regardless of PSI. It's weird too, because I treated it exactly the same as the other colours and they came out just fine. Did I get a dud bottle or is it just another case of Yellow being a pain to work with?

 

And finally, problem number 3: Clear paints, regardless of manufacturer, don't seem to play nice.

 

As an experiment I tried to do a "candy metallic" effect on some plastic spoons. I primed them with my usual Tamiya fine primer, which went fine. Then I sprayed them with Vallejo Chrome Silver, which is gorgeous and again worked just fine. So then I tried Badger Ghost Tint Purple, FW Eidolon Purple, and Tamiya clear red (which was thinned with a bit of Tamiya thinner)...and none of them worked.

 

All three suffered the same problem (to varying degrees); they refused to adhere to the silver coat, and ran and pooled instead of drying properly. This was especially bizarre for the Tamiya clear red, as their paint has always given me excellent results in the past. Now, the one thing I can think is that it was too cold or humid on the day I tried this and this adversely impacted their ability to dry/adhere. Still, very annoying.

 

So, any advice on what I'm doing wrong and what I can do to fix it?

Edited October 21, 2017 by Squigsquasher

[Arkhanist]

You may remember me struggling to deal with airbrushing Citadel paints a while ago. Well, I've since given up on trying to thin regular Citadel into something useable through my Eclipse (though the Citadel Air line seems to be just fine, and I'll definitely get more of those) and I've since acquired some Vallejo Air paints- Bloody Red, Magic Blue, Moon Yellow, Black, Dead White and Model Air Insignia White (for a specific project you see). I also already have their Chrome Silver, which we'll get to later.

 

So, problem number one: Mixing paint seems to behave the exact opposite of how it should.

 

I foolishly thought that if I bought the three primary colours + black and white, I could theoretically mix any colour I wanted from those 5 paints. So for an experiment I tried making a purple by mixing in roughly equal parts Bloody Red and Magic Blue.

 

The result? A very dull and desaturated blue.

 

Rather perplexed by basic colour theory seemingly not working, I attempted to vary the mixture of red and blue, adding a little white, etc. Unfortunately, the results varied from the same as above but even duller to a dark mauve to a very pale salmon. But try as I might, the nice vibrant purple I was aiming for evaded me. The actual consistency of the paint was fine, and it dried on the spoon (and the base of my spray booth) nice and smooth. But the colour was not what I was expecting.

 

Now obviously I can solve this by not being a cheapskate and just buying more colours, but regardless I am interested to know why it didn't work.

 

Colour mixing theory is based upon mixing light. Red light + blue light = purple light. Paint is made up of pigments that absorb some light frequencies and reflect others; they're not 'pure' colours - plus you have some light reflecting from the under-layer. So red pigment and blue pigment in theory will reflect both frequencies, but it's not that simple - a red paint which also reflects some yellow will desaturate purple as they're complements; you need a blue-biased red (and a red biased blue) - or use a different unique pigment altogether as this is a mix of chemistry and physics, after all. Artists have lookup charts for standard pigments to achieve this sort of thing, but not for model paint AFAIK as the work has already been done in pre-mixed bottles - we mostly use colour theory to adjust colours and to pick schemes (to avoid clashing boundaries etc), rather than mix most of our paint. There's nothing stopping you doing the experimentation yourself, of course, but look into artist pigment mixing to give you a head start on paint colour theory!

 

Another technique is glazing; individual colour glazes layered over the top of each other can give you a different effect than mixing them directly.

 

Rich purple used to be really rare and expensive because it was hard to make; check out the history of tyrian purple for example.

 

 

 

And now onto problem number two: Yellow is absolutely awful.

 

Yes it is. It's near universally true that model paint light yellows are semi-translucent; again down to the chemistry (vibrant opaque yellows use cadmium, which is toxic and the safer substitutes are not great). General rule of thumb; start with an ochre or brown yellow for coverage, then thin layers of the lighter yellows to adjust the hue. I don't know that paint in particular to know if it's a bad bottle, but you could add some thicker matte medium to make the consistency easier to work with. Or try a non-air light yellow.

 

 

 

As an experiment I tried to do a "candy metallic" effect on some plastic spoons. I primed them with my usual Tamiya fine primer, which went fine. Then I sprayed them with Vallejo Chrome Silver, which is gorgeous and again worked just fine. So then I tried Badger Ghost Tint Purple, FW Eidolon Purple, and Tamiya clear red (which was thinned with a bit of Tamiya thinner)...and none of them worked.

 

All three suffered the same problem (to varying degrees); they refused to adhere to the silver coat, and ran and pooled instead of drying properly. This was especially bizarre for the Tamiya clear red, as their paint has always given me excellent results in the past. Now, the one thing I can think is that it was too cold or humid on the day I tried this and this adversely impacted their ability to dry/adhere. Still, very annoying.

 

So, any advice on what I'm doing wrong and what I can do to fix it?

 

Fundamentally, sounds like a combination of not enough 'tooth' and too high a psi. (I assume you're using X20A for the tamiya) You can't airbrush candies in one coat; mutiple thin tint layers is mandatory. Lower the PSI and/or increase the distance from the model until it hopefully stops spidering. Also, do light sweeps, i.e. don't go heavy on the trigger or leave it pointed on one spot for long at all. Patience is key. Another option is to add more tooth to allow the paint to grip a little better; a different primer (such as stynylrez) might help, or doing a thin layer of satin or matte varnish over the metal first.

 

If it's not running but just refusing to dry quickly even in ultra-light coats (this is possible due to weather), you could change the thinner; straight IPA will mix with tamiya clears and dry quicker than their normal thinner (which does have IPA in it) and try and avoid drying retarders and flow improvers if you can.

Edited October 21, 2017 by Arkhanist