Acrylics and Alcohol

[Hendarion]

Hiho.

Lately I wanted to airbrush some GW/Citadel Acrylics (Dark Angel Green I think) and my typical habbit is to thin them extremely before spraying. In order to get them drying faster, I use Isopropyl (IPA) for thinning down enamels, but...
Well, I filled some drops IPA into my airbrush can, then added the color and started mixing. Suddenly the color instead of getting thinner (I use IPA normally for enamels or to remove acrylics from minis), the color turned into a pulpy mud. I could have experimented a bit, but I wanted to go on with the work and so just flushed it down the basin and went back to normal water-thinning.

Now I'm curious what IPA really did to the color. Anybody knows? Does it clump up? Does it break the pigments into smaller pigments causing high adhersion? What happens if I add more water to it, does it then stretch the color?
I'm asking because even that I mixed IPA:color like 70:30 or even 80:20 with an already quite fluid color, the result turned out to be super-thick and super-pigmented, it wasn't transparent at all like a color usually is when you thin it so massively in such a ratio with water.

So... tell me, maybe you have more experience or some little chemist is inside of you.

PS:
I don't have a problem to stay with using water, but the basic idea of using IPA was to get the color dryed extremely fast on the model and to have some kind of self-clean-effect inside the airbrush (since acrylics often tend to dry on the top of the needle and then require cleaning which is not the typical problem for enamels).

 

[Einion]

Well, I filled some drops IPA into my airbrush can, then added the color and started mixing. Suddenly the color instead of getting thinner (I use IPA normally for enamels or to remove acrylics from minis), the color turned into a pulpy mud.

I've had something similar happen too, even sometimes with a mix of water and a little alcohol.

Now I'm curious what IPA really did to the color. Anybody knows?

What I think is happening is that the alcohol dissolves the acrylic and in water the solution accumulates into a gloopy (er yeah, that's the technical term) mass, like when you drop in any solvent paint to water.

You might like to contact Golden about it - they're very good about answering technical queries and even though you're using a paint of a different type the chemistries are similar enough between acrylics and vinyl paints that their answer, if they have one, should apply here.

I don't have a problem to stay with using water...

FWIW that's what I use mostly.

Einion

 

[Hendarion]

Ah... of course it dissolves it, thats basically the purpose of IPA, but seams it does it more like a chemical reaction than a thinner. Seams logical, but I didn't even think of that, I thought it just cracks up the binding, but seams it rather cracks the molecules (or parts of the components) itself.
So there's basically no need to try to thin that "gloopy mass" to receive again a paintable color, ah? Just curious though.
And who are "Golden"?

 

[doyme]

Golden are a company that make products for acrylic paints. I have a few pots/bottles of their product. They make mediums, thinners, flow aid, retarder, texture adding compounds for acrylic artists. They know what they're talking about basically.

Yeah I think Einion is bang on. I'm betting also that the IPA messes with the surfactants/detergents added to acrylics to help them flow better and have less surface tension, dissolving the non-polar side of the molecule. There are thinners/drying agents produced specifically for acrylics in an airbrush though right?

 

[Hendarion]

Dunno if there are such agents for airbrushing acrylics, the basic idea was to keep the need clean during spraying, since IPA scrapes off dryed acrylics. But its no problem, just curiosity.

 

[Einion]

Sorry, Golden = Golden Paints, one of the premier US makers of acrylic paints (and a whole heap of mediums and additives).

Dunno if there are such agents for airbrushing acrylics, the basic idea was to keep the need clean during spraying, since IPA scrapes off dryed acrylics. But its no problem, just curiosity.

What I do for this is keep a small stiff-bristled brush handy and brush the tip with alcohol or acetone periodically during spraying, then shoot through a little clean water (or solvent if necessary).

Einion

 

[Hendarion]

The needle isn't a big problem, I can easily access and clean it without efford. Takes 10 secs. I'm just a lazy person

 

[DXM]

This might sound silly but Isopropyl Alcohol has an expiry date.
I had trouble spraying one time, clogging the airbrush. Someone told me to check the date and it had an expiry date 6 months old. Bought a new bottle and it worked.

Also try thinning with windshield washer fluid.

 

[CreganTur]

I've been using Tamiya's thinner, which is an alcohol mix of some sort, with my GW paints when thinning for airbrushing. I've never had a problem with it.

 

[Hendarion]

Well, CreganTur, the problem might be specifically IPA, since it's dissolving Acrylics instead of just solving them. So basically I could even turn the carpet in the bathroom to a clump. Some others just crack up the binding like soap does with fat. But basically Tamiya's thinner (X-20A) is based on IPA aswell as far as I know with some some other stuff and water. Dunno what's the difference. Maybe not all colors from GW are affected that badly but just some. I remember having sprayed a Skull White once with just a tiny drop of IPA and a few drops of water - no problem.

 

[Fuzzyguy]

I've been using the Tamiya acrylic airbrush thinner with GW paints, Vallejo, and Reaper with no problem. I don't have the bottle in front of me, but I seem to want to think that Tamiya's thinner has some acetone in it. It works brilliantly though with my compressor and airbrush. I wouldn't go back to using water to thin after using the Tamiya stuff.

 

[Shawn R. L.]

Ah... of course it dissolves it, thats basically the purpose of IPA, but seams it does it more like a chemical reaction than a thinner. Seams logical, but I didn't even think of that, I thought it just cracks up the binding, but seams it rather cracks the molecules (or parts of the components) itself.
So there's basically no need to try to thin that "gloopy mass" to receive again a paintable color, ah? Just curious though.
And who are "Golden"?

Wild guess here but there may be a molecular reaction with the charge of the particles. My dad used to work with fluids and one thing called flockulent (sp?) when put in liquid would make particles come together in clumps due to their respective charges. Maybe instead of an IPA you could use a stout or porter......:beerwave::beerwave: :silly!:

 

[pae]

And here I was thinking this topic was going to be about drinking alcohol while painting with acrylics. :-/

 

[Hendarion]

Well... you CAN do that too, but I really don't recommend drinking Isopropylalcohol!

 

[Drey Foos]

Additional paint thinning

Hi all, a noob to the CMON site but been experimenting lately with airbrushing my mini's and found that the Vallejo Model Air are "the bomb" and using their related paint thinner works really well http://snmstuff.co.uk/VallejoModelAir.aspx is my source for it, you might have a closer/cheaper one.

They mix well together and produce a really smooth result. Water can be used with them too, just not too much or they lose the ability to stick to the model and become like a really thin wash that drips everywhere and still leave you with a basecoat showing. I found a 7:1 (water : paint) ratio is about as thin as you can comfortably go with water.

I played with GW/Citadel and found the vallejo thinner works well with them too but need a lot more airbrush thinner (like almost 5 times as much) because the pigment pulp stuff is just way too coarse for most airbrushes, citadel and vallejo game color/model color for that matter are designed for handbrushing not airbrushing.

I'm looking to try Liquitex Airbrush Medium next which says can mix happily with any acrylic. If anyone already did this I'm all ears on the result.

Like most here I lay on some cleaning solvent while brushing/colour changing (cheap white spirit in my case). Not perfect or ideal I dare say but gets it done without prolonged heavy soaking and you can't really grumble at £4 or so for a 5 litre bottle. Flush it through with water and job's a goodun. REALLY not recommended for thinning the paint though.

Nothing new under the sun or even profound :laugh: just an alternative to IPA sludge and a bit of additional info to help the fellow painter make an educated decision.

 

[The Inquisitor]

Hi there; haven't been on much lately, but thought i'd chime in. Paint has basically 4-5 chief elements- pigment, binder, filler, vehicle (medium, aqueous additives, etc.) . Usually if you have some reaction, its with one of these, and its usually not the pigment.

IPA can be quite hot, and can react with different paints. For instance, I've found it doesn't work well with a lot of vallejos, but I can use rubbing alcohol (70%), without a problem, or other 'thinners' containing different types or concentrations of EtOH.

However, I use IPA to thin down metallics quite often and blow them through a number of my brushes with very good effects. IPA seems to work very well with GW metallics.

Reducing with water is ok, but it can start changing the nature the 'nature' of your paint, and subsequently, how it acts. If I had time, I could talk more about the dynamic of of paint:air:brush and how/why you modifying these things using different mediums; perhaps an article sometime.