Mixing paint for my airbrush

[missile-monkey]

Hi everyone,

 

I thought I would come to the great and the good for some advice. I was fortunate enough to be given one of them there airbrush thingy ma jigs for Christmas last year. I'm plodding along with it and trying new techniques each tie I use it.

 

One thing which really surprised me was the small amount of paint it uses each time I fill the cup. When I am mixing colours to make a particular shade I sometimes need to make two or three batches and there're not all the same shade. Whilst I have found this has it's advantages sometimes my question is:

 

If I mix a larger batch of paint, say enough to fill three or four cups how long will the paint keep for and can I use it in my airbrush say a few days later?. I use water based acrylics.

 

Any advice as ever will be greatly appreciated.

 

Regards

 

MM

 

[Corsairfoxfouruncle]

When I make a mix I like I have a notebook that I write every recipe down in. That way if I need to make it again I can do an exact shade i need. Ive used acrylics for a number of years but am switching to lacquer’s myself for a number of reasons. 

[Ngantek]

I've not done this for water based acrylics, but suspect they will keep. Personally I tend to mix into 10ml dropper bottles (like vallejo or mig, they're fairly cheap), that way you can ensure it's not just the same recipe but also the same mix. The dropper bottles are nice for adding to the airbrush pot without dribbling down the side.

 

I actually prefer not to thin at this stage for a variety of reasons. First I suspect it will keep better. Second I may want to touch up later with a brush, which isn't great with airbrush thinned paint. And third you get a more useful amount of the mix. Given it's basically the same paint in the same kind of bottle, they should keep well it kept sealed

[Casey]

Welcome to the mixers club

 

First, as people suggested - WRITE DOWN your recipes. You will be able to reproduce them, but to do that reliably, and if you are mixing small amount (and I am talking fraction of mililiter) invest in scales.

 

It is much easier to control than droplets counting and much more precise. Even an super cheap jewelers scale will help you a lot.

Something like that costs around 20$, look for "jewelry scale" on your favourite shop.

 

But if you are fixed on using volume, you could alternatively invest in pipettor, like:

 

 

This device costs around 30-40$ but needs changeable tips (to keep it from getting dirty). You simply 'dial a volume' and use it to get precise volume dosages. Search for "pipettor", the 100-1000uL is a good choice for small volumes (1000uL = 1 ml). The tips also need to be adjusted for paint density, if it is thick - you need wider one. I prefer mass than volume measurements since it is cheaper in the long run (tips cost!)

 

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If you are planning to make a larger model, you may want to invest into some glass containers or dropper bottles and mix larger volume.

 

Dropper bottles are perfect since you can mix them to the 'ready for airbrush' state, which will be similar to pre-mixed paints from known vendors.

 

If you want to store storing mixed paints for longer - consider getting real acrylic medium for airbrush, instead of just water.  It is not only better (contains binder) but has also anti-molding agents, or alcohol if your paint can handle it (most acrylic can get thinned by IPA), or (at worst) use distilled water. Otherwise - it is just paint!

 

I personally like to make non-thinned version as @Ngantek suggested, since it gives me more flexibility for the further paint use.

 

---

 

And here is how I do it:

 

I use pure pigment acrylic artist paints that have maximum pigment concentration, and my usual process goes like that:

 

1) Craft the recipes. Try them out on very tiny volume of paint if needed. I can use math to calculate them myself but it is not for everyone. Alternatively you can use online tools, like https://goldenpaints.com/mixer and experiment. This is the most fun part for me.

2) Measure the pigments for the paint. For small model (1/72) I rarely need more than around 2-3ml of pigments

3) Add proper medium. I use gloss and matte mediums to make paint have desired finish. It easily makes the total volume of 4-6 ml but ratios vary depending on use. You can skip this process if you like heavy pigmented paints, but the finish of a paint will depend on pigments themselves and pigment heavy paints do not stick very well to the surface. Also - heavy pigment does NOT equal opaque - you can be surprised how transparent some pigments really are. If you are varnishing your model (read: gloss/matt 'clears') then natural paint finish does not matter much for you, so you can as well just use pure airbrush medium (definitely not water if you diluting pure pigments)

4) Store in dropper bottle either pre-thinning it with acrylic airbrush thinner or 'as is'. Airbrush thinner can turn those 6ml into 12 and that's a lot of paint. Yes I like thinner paints in my airbrush.

 

I store a small collection of basic sets I made, like "Generic flesh tones", "Blacks", "Earth and stones", "Greenies", "Metal and gunmetal like" and so on. They get useful almost every time.

 

 

Edited May 26, 2022 by Casey

[Ray_W]

Great advice from all. I do the same. Keep notes on the recipe and make up a mix stored in a small bottle. Usually used, clean paint containers. The dropper bottles is a good idea. I must get some. These easily get through a whole build and often last months if not years stored in well sealed clean containers. Makes the inevitable late build touch up and repair easy. I rarely mix in the airbrush cup unless a very small quantity and unlikely to use again.

[Chimpion]

I'm glacially slow at building, but that does mean I get to learn how long mixed paint can keep 🙂. I mixed two Revell aqua colours together with their own thinner and stored it in one of their own glass bottles with a well sealed plastic top. It was still good well over a year later. It did separate out a bit but a good stir sorted it out. While the paint was still perfectly good the mixing was critical to get the shade to match the previous coat. At one point I got this badly wrong and it came out much darker. I also found it needed some more thinner adding after such a long storage time. 

 

[missile-monkey]

Lady, gentlemen,

 

I apologise for the delay in replying to you all. Work commitments I'm afraid..

 

Thank you all for the sage advice. Mixing slightly larger quantities and not thinning until you are ready to use sounds good, as does finding me some dropper botles to mix/keep the paint in. I'm gonna get me some of them.

 

Casey, thank you for the short tutorial and the link, very interesting.

 

Take care all of you.

 

Regards

 

MM  

[dogsbody]

As for storage, I have a couple old Testor paint bottles that I have cleaned out and I keep my mixed paint in those.

 

 

 

I also have a small box of 8 Pollyscale bottles that I bought years ago that can be used for the same purpose.

 

 

 

Chris

[masterKamera]

i had that thought when i got my timber tech brush, its a side feeder and has a nice syphon bottle that holds 22 cubic centimeters,  i could easily get an entire 23ml bottle of tamiya paint in it... with some thinner. 

 

hand brushing tamiya using the thinner, it seems to dry FAST.. my thinking is that if i need to make enough for one go on the yellow of my pt-20, that bottle SHOULD give me enough paint for the whole thing, plus double as storage.

[malpaso]

I mixed up a Tamiya mix for a 1/24 car, thinned it was just over half of an empty Tamiya small glass jar and enough for three coats.  A small amount left in the jar for a week or so was fine for touch ups though needed thorough mixing.

[masterKamera]

with atmospheric changes due to humidity,  do we really need to worry about the age of the paint we mix?  Seriously, the thinnner is what would evaporate, and if the thinner in the paint doesnt dissappear from a closed can of factory fresh tamiya,,,, should i really be worried that much?

[Mike]

at keeping a note of your mixes... I'm incapable of remembering to do that, so if I need a lot of a shade, I'll mix a batch in an empty bottle, either from a used up paint bottle, or from one that I picked up off eBay.  Acrylics will last in a sealed bottle, as long as there's not too much air in there.  A little paint in a bottle won't last more than a few days to weeks, but a full bottle of mixed paint should last ages

 

Forward planning, and such... you guys!