The Unofficial Airfix Modellers' Forum

Every modeller has their own recommendations on the best ways to thin paints for airbrushing. Every paint manufacturer would have you use their thinner but there are often cheaper/better alternatives. I've tried to gather together as much of this knowledge (where there is consensus) into a handy table.

I've concentrated on the thinning of paints but often these solutions are suitable for cleaning airbrushes too. For thorough cleaning, celluslose thinners, windolene (ammonia based) and proprietary airbrush cleaners are recommend.

Please feel free to post comments and additions below.

Painting Thinning
Brand/Type	Own Brand	White Spirit	IPA	Water	Cellulose	Other	Notes
Humbrol Enamel	yes	yes			yes
Humbrol Acrylic	n/a			yes*		Klear	*hit & miss
Humbrol Clear Cotes	yes*				yes		*slow drying with own brand, website says use cellulose
Tamiya Acrylic	yes		yes		yes
Gunze Sangyo Mr Color Lacquer	yes
Gunze Sangyo Acrylic	yes		yes	yes	yes	GS Mr Color
Testors Model Master Acrylic	yes
Testors Model Master Enamel	yes
Testors Model Master Lacquer	yes
LifeColor Acrylic	yes			yes		Tamiya*	*issues with blues
Vallejo Model Color/Air Acrylic	yes
Citadel Acrylic	n/a			yes*		Tamyia**	*use flow enhancer, **IPA too hot
Xtracolor Enamel	yes	yes
Xtracrylic	yes			yes			spray quite thin as they clog
Revell Acrylic	yes		yes	yes
Polly Scale Acrylic				yes
White Ensign Enamel		yes				Humbrol
Mister Kit Acrylic				yes

Additional Notes

IPA - Iso-Propyl Alcohol
Flow Enhancer - Acrylic additive to achieve smoother finish, available from art shops eg. Windsor & Newton

Some thinners are "too hot" and can cause paint to 'curdle', thorough mixing can sometimes bring it back to a usable consistency.
Tamiya thinners seem to be a weaker ("less hot") IPA solution.
Xtracrylic is a different formulation (possibly ketone based) to most acrylics and so generally doesn't thin well with alcohols (*in light of recent comments by PB I need to re-check this)

very useful table!

can i ask why you say dont spray the humbrol acrylics?.....ive been playing around with them recently and found them very hit and miss...sometimes works and sometimes dont ...but nice when they do work

Beowulf Shaeffer wrote:can i ask why you say dont spray the humbrol acrylics?.....ive been playing around with them recently and found them very hit and miss...sometimes works and sometimes dont ...but nice when they do work

I've not tried myself but the consensus seems to be don't bother - as you say hit&miss. This is not to say that they don't perform well in the aerosol cans.

What have you tried thinning them with?

Actually Gunze does have their own thinner for the Aqueous paint, but I use their Mr. Color thinner. Works great and in my opinion makes the finishes more durable.

Jim

Vallejo have their own ModelAir thinner, from my experience of their paints it's pretty much essential for airbrushing. Tamiya and Gunze both thin very well with cellulose. Most Lifecolor paints work with Tamiya thinner but for some reason blues act very oddly with it, and none of them like straight IPA very much. Their own brand thinner is highly recommended.

JamesPerrin wrote:
What have you tried thinning them with?

water worked okish......ipa not so ok..............i found it comes out 'bitty' for want of a better description...dries very quick..............shame cos theres some very nice colours, especially in the train range.......i was trying to do a dodge viper in 'virgin rail red' ...................epic fail

Good idea and interesting.
Can I add though, my own findings when spraying Revell Aqua clearcoat, i thinned with IPA and it went, (Technical term), Claggy just like the Citadel paint does, in fact it was worse than the citadel it clogged the AB constantly and I was unable to spray it at all and had to ditch the mix in the AB.
Thinning with tap water isn't entirely satisfactory either, not tried the Tamiya thinner, have a small bottle so might have a bash, what do you use as a flow enhancer can I ask?

Thanks for the quick feedback guys. I've updated the table with your comments and additional note about flow enhancer.

From experience:

White Ensign Colour Coat (enamel): Humbrol Thinner (maybe others, I do not know)

Mister Kit (acrylics): Water (note I have had very bad clogging experience with lacquer thinners, etc, and this paint range)

Doesn't the Window cleaner have to be the ammonia based formulation?

Is mineral turpentine no good for thinning Humbrol enamel?
I reckon thats what I used to use.

Nigel

Humbrol acrylic will spray perfectly satisfactorily if thinned with Klear, but it needs to be over a primer coat, otherwise there is a possibility that it will peel off like vinyl with any masking tape you might be using. There is no need to ask how I know this...

peebeep

AndrewR wrote:Doesn't the Window cleaner have to be the ammonia based formulation?

I'm looking at this and thinking shouldn't that be screen wash fluid instead of window cleaner in the table? Ammonia based window cleaner is used for airbrush cleaning, and I know some people use screen wash to thin acrylics.

AndrewR wrote:Doesn't the Window cleaner have to be the ammonia based formulation?

I assume it's the ammonia doing the cleaning and window cleaner is just an easy way of obtaining it. I'll add a note.

peebeep wrote:Humbrol acrylic will spray perfectly satisfactorily if thinned with Klear.

... and then you need the window cleaner to remove the Klear from your airbrush

JamesPerrin wrote:... and then you need the window cleaner to remove the Klear from your airbrush

Not necessarily. You can flush the brush with water provided you do it promptly. Window cleaner is ideal because the ingredients seem to work well at cleaning up after acrylic compounds and Klear is acrylic. I use the Turtle Wax stuff intended for car windscreens, it's brilliant for clean up and thinning. The reason I tried thinning Humbrol acrylic with Klear was to try and improve coverage and adhesion. The former worked, but the latter didn't - not on bare plastic.

peebeep