Advice Sort - Separated Paints

[WizardSteve]

I've recently returned to the hobby and I'd like some advice with respect to some of my paints.

 

My citadel paints (current range) have all separated into a thick layer of pigment and a layer of milky, white medium. Depending on the individual paint, the pigment layer ranges from extremely viscous to borderline solid. Are these paints recoverable or should I bite the bullet and replace them?

 

If they are recoverable, how should I go about it? I was considering adding a small hex nut to each one to act as an agitator although I've read somewhere that glass beads are better. If it doesn't make a difference, the hex nuts are more easily obtainable. Alternatively, would something like Badger's battery operated paint mixer be a worthwhile investment?

[plastic_slug]

Do not use anything metal. It will rust and contaminate the paint. I even avoid stainless steel. Glass is your best bet. The current Citadel pots will accommodate up to a normal sized glass marble just fine. I had a Badger mixer. I found it spun too fast and made a mess using it in the average paint jar. Then there was the cleanup. Not worth it.

 

In general, once something has gone solid in a paint pot, it's pretty much garbage at that point.

[Arkhanist]

Stainless steel ball bearings are fine; I've been using these 'ammo' paint mixers for a couple of years now, and they haven't rusted at all - it's not like acrylic is particularly corrosive! They're denser than glass beads so mix the paint easier but it's not a huge difference so glass is fine if you prefer. Don't use ordinary steel though, obviously.

 

In this case, any pigment layer that has gone rubbery or harder, bin - once the paint has chemically bonded, it's done for. Paint that's viscous but still liquid-ish is likely recoverable. Add a mixer and shake away!

 

However, you may need to add a little additional medium to help get the consistency right (don't overdo it!) Acrylic airbrush thinner works well for thinning and getting a smooth flow - liquitex airbrush medium is my standard for recalcitrant citadel pots. GW's lahmian medium is also good, but rather pricey per ml. Failing that, liquid artist matt medium (possibly diluted with a bit of purified water) will work; its cheap per ml, but you tend to have to buy it in big bottles! However, it lacks flow aid, so won't help reduce any chalkiness that remains, most likely in lighter colours.

 

Just adding water alone risks messing up the consistency, particularly when you thin later for painting, but you can get away with it if the paint is pretty much normal after vigorous remixing.

[grimsanity]

I used this https://www.amazon.com/Norpro-Cordless-Mini-Mixer-Piece/dp/B000E39LYO/ref=sr_1_7?ie=UTF8&qid=1504583849&sr=8-7&keywords=drink+mixer+electric with alittle water. The metal mixer bit fits in citadel paint pots, the small plastic bit is good for Vallejo and army painter bottles.

[WizardSteve]

Thanks for the advice everyone. Although I originally decided to replace the paints, I've ordered some of the Ammo paint mixers and I'm going to try and recover them first. It turns out I use thirty paints on every mini so a couple of euros spent trying to save them is a good investment rather than throwing eighty at a complete replacement set.

 

And of course I had to throw a couple of weathering powders into my cart to reach the minimum order #silverlining

[Semper Fortis]

If you happen to do any conversions on old metal minis, you have a source of mixing pellets in the pieces you clip off. I have a number of bottles of older GW paint that I'very kept going with the clipped off tabs that fit into the slot bases. Just roll 'em up and drop 'em in. I also have various pieces of heads, arms, etc serving the Emperor by stirring paint. I figure it's a former of conversion to servitor. :D

[White Wolf]

A good way to bring old acrylic paints back to life is the addition of a small amount of iso propyl alcohol (IPA) readily available on eBay.

 

The chemistry of acrylic paints is that the pigment is generally (not always - Tamiya paints for example) suspended in a mixture of water and IPA. Most modelling acrylic paints such as Citadel, Vallejo and Ammo work this way.  

 

It is the IPA evaporating that causes the paint to dry "rapidly" compared to other types of paint such as enamel and oil.

 

IPA is also useful for brush and airbrush cleaning - most airbrush thinners and cleaners are a mixture of water and IPA in various ratios. It's also really good for stripping paint too - it is the active ingredient in Dettol.

 

Hope this helps

 

ATB WW

[Firedrake Cordova]

Stainless steel ball bearings are fine; I've been using these 'ammo' paint mixers for a couple of years now, and they haven't rusted at all - it's not like acrylic is particularly corrosive! 

I'm also looking at getting some shakers at some point (Vallejo paints are a pain to mix).  In my search, I've seen a few people who managed to get stainless steel BB's to rust by leaving them in salt water for a week or so*, to the point where marine-grade SS BB's were recommended (which are expensive).  Good to know the Mig Ammo shakers are good, though! (I was looking at glass, ceramic, or hematite beads...)

 

* obviously, stainless steel shouldn't rust - they might have been lower-grade, or "plated", rather than "real" stainless steel.

 

However, you may need to add a little additional medium to help get the consistency right (don't overdo it!) Acrylic airbrush thinner works well for thinning and getting a smooth flow - liquitex airbrush medium is my standard for recalcitrant citadel pots. 

Yup, this is a very good idea.  Water does mess around with the consistency a bit.

Edited September 9, 2017 by Firedrake Cordova

[Stoic Raptor]

A good way to bring old acrylic paints back to life is the addition of a small amount of iso propyl alcohol (IPA) readily available on eBay.

 

I agree.  I wouldn't recommend using it as a thinner for day-to-day use because it does cut the "binder" and as WW said, dires much faster (and is unkind to your brushes), but I can say first hand that I have a bottle of a Space Wolves Grey/Blue-Grey blend that's still usable after 25 years because I rescued it with IPA.

[Arkhanist]

Citadel is an acrylic polymer emulsion paint. The actual mix of polymers varies by manufacturer but is usually based around PMMA I believe. The emulsion means it's suspended in a solvent (water); the acrylic polymer (plastic) is the binder, and the pigment gives it the colour.

 

The polymer mix binds to itself, the pigment and to the surface which is what forms the plastic layer - the water solvent evaporates.

 

IPA is an alternative solvent to water that dries far quicker, which has its own effects. As far as I know, it's not used in current citadel paints; they conform to ASTM D-4326 which means they have to list any ingredients that are chronically toxic, that can include IPA. They do specifically say their paints are non-toxic.

 

Tamiya clear though has flammable warnings, irritant, and instructions to use in a well-ventilated area, and has the California cancer warning. This does indicate the use of IPA as a solvent - and are well known for needing thinning with IPA or tamiya 20A thinner rather than plain water (which makes it gooey)

 

IPA will quite aggressively break up clumping of the polymer. It should also be used with knowledge and care, particularly for airbrush paints, more so if in strong concentration. Thus my recommendation for pre-made acrylic thinner (which usually includes some anti clumping agent as well as water and more binder) for dilution as its basically safer - it is mostly just dilute acrylic paint without pigment. Water alone doesn't really break up acrylic polymer that has started to clump though, i.e. it won't re-enter suspension, and you can over-dilute the binder mix.

 

90% IPA can be used as acrylic paint stripper - and is about the same flash point as gasoline.

 

So more generally - always read the labels, particularly if you're in the habit of sucking your brushes or spraying it! 

 

(edit: some vallejo game paints have 'do not spray' which from the FAQ indicates the use of cadmium, as far as I can see they only use alcohol (possibly IPA) in their Liquid Gold range and cleaners.)

Edited September 9, 2017 by Arkhanist