View Full Version : Airbrush paint ratios


Model Man
02-17-2010, 02:59 AM
I got myself a new dual-action brush and will be using model master bottle paints for the first time. For regular Testors' enamels thru my single action, I was going with at least a 1:1 ratio with thinner, sometimes 2:1 thinner : paint. Of course, testors enamels are thick. Model Masters however seem quite liquid, relatively speaking.

I do not want to gum up this new ab, so would seek the counsel of those who have used the MM enamels and what kind of ratio used was successful.

I'm also building up my alclad stock. Those look like they'll be fine thru the airbrush as-is, but being a lacquer will require it's own thinner.

In that regard, do you wait long or run your airbrush thru a special rinse before switching between enamel and lacquer -considering they can be mortal enemies on a model surface if applied in the wrong order?

I don't plan on using an acrylics, but advice on those is always appreciated.

How about dull coat varnish for decals? That is probably best hand-brushed on?

And of course, Future, when I get some, can go straight thru the AB w/ no dilution.

What else am I forgetting?

Ah yes... I thank ye, kindly!

djnick66
02-17-2010, 09:01 AM
I thin most of my paints for airbrushing with lacquer thinner. You can use hardware store type, especially for cleaning. Lately I have really been using a lot of Gunze Mr. Color Thinner, Mr. Color Self Levelling Thinner, or Tamiya Lacquer Thinner. The advantage of these products is they are plastic safe. You can soak a plastic kit part or airbrush assembly in them, and they won't hurt the plastic. Self Levelling Thinner has a retarder built in to improve flow and to make faster drying paints (like acrylics) dry slower and not plug up the airbrush so much.

You can thin Testors, Humbrol, etc. enamels with Lacquer Thinner. Lacquer Thinner also will cut Tamiya and Gunze acrylics and of course the Gunze Mr. Color Lacquer paints.

Thinning ratios vary depending on type of airbrush, pressure setting on compressor, size of spray pattern etc. Tamiya's can be thinned up to 50/50. Most enamels I thin 75/25 paint to thinner.

Alclad cleans up easlily with Lacquer Thinner.

Clear Flat top coats can be airbrushed. I like the Testors Clear Flat Lacquer in a tall square bottle. It can be thinned out and airbrushes nicely. Its safe over all finishes as it dries instantly. There is no time for it to soften underlying paints. I do not like most Clear Flat Acrylic finishes, like Testors. The Testors Flat Acryl tends to turn dark colors like black into a grey, and will dry blotchy or with brown spots.

There is no "Future" any more. It is now Pledge (With Future Shine). It is difficult to airbrush and usually I dip or brush paint it on. But for any Future questions or info, its best to look here: http://www.swannysmodels.com/TheCompleteFuture.html

Mark McGovern
02-17-2010, 11:07 AM
MM,

I have always followed the recommendation of FineScale Modeler magazine, that paint for airbrushing should be thinned "to the consistency of milk". You can get an idea of just what the heck that means by looking at an airbrush-ready paint like your Alclad products, then thin your other paints to match. There isn't a hard-and-fast rule of thumb, except that gloss paints usually require more thinner than flats, and that it's best to use the thinner made by the manufacturer for the particular paint you're spraying. I started out by measuring paint and thinner drop by drop to get the prescribed ratios, but these days I just eyeball the mix.

I think too much has been made of the use of lacquers and enamels. Have you ever sprayed Testors Dullcote over any paint? If so, you were applying a lacquer over an oil-based or acrylic finish. No problems there, right? The issue arises if you apply too heavy a coat of lacquer over a particular paint; then the lacquer solvent will attack the underlying paint (or plastic). Light coats and patience are the keys to a good spray paint job.

As djnick mentioned, lacquer thinner is the solvent of choice for cleaning airbrushes - it will even remove dried acrylic paint. I use it to clean the leftover paint out of my airbrush if I'm spraying widely different colors of solvent-based paints. I don't airbrush acrylics unless I have to, just my personal preference. The only exception would be Future, which I spray with no dilution; it can be thinned or cleaned out of your airbrush with an ammonia-based window cleaner. If you need to remove dried Future from your airbrush or your model, straight ammonia does the (stinky) job.

You need to allow your decals to dry thoroughly before overcoating them with Dullcote or any other clear sealer. If you used a setting solution, you may have to remove any visible deposits with a cotton swab dipped in water or a mild solvent like rubbing alcohol (be careful to test for a possible reaction to your paint finish first). When dry, you can shoot away with your clear coat.

Model Man
02-18-2010, 01:04 AM
Good stuff.
I ask as with my first single action airbrush several years ago, I got some so-called enamel thinner from the hardware store... Well, it turned out that this thinner did not like the testors enamel and while it swirled together nicely, minutes later it literally turned the enamel into a chewed-gum consistency substance -inside the airbrush! So, that was that. One dead $25 brush. Thankfully it was only $25.

Since then I've only used testors enamel thinner as rip-off a price as it is. I don't want the same thing to happen again ever. Especially now that I am stepping up in the world.

John P
02-18-2010, 07:36 AM
My usual airbrush paint ratio is one airbrush to one cup of paint.














:wave:

Trek Ace
02-18-2010, 10:24 AM
I just usually use lacquer thinner for all paints, from acrylics to automotive. Then, I don't have to worry about if I've got the correct thinner to match the correct paint formula. The lacquer thinner has the side benefit of keeping the airbrushes very clean while I'm using them, and I think that the paint lays down better as well.

I just eyeball the paint-to-thinner ratio. I've been doing this for so long, that I don't even think about it, anymore. The 'thin as milk' sounds about right for consistency. I would go with that advice.

Mark McGovern
02-18-2010, 04:11 PM
My usual airbrush paint ratio is one airbrush to one cup of paint.You lookin' fer a Dremel Salute, partner - ? ;)

skinnyonce
02-18-2010, 07:58 PM
You lookin' fer a Dremel Salute, partner - ? ;)


I keep reading bout this dremel salute thing..

it sounds painfull,, is there a story that can be told to a new comer without him being afraid of his favorite power tool..

skinny.........

junglelord
02-18-2010, 11:08 PM
Great thread. My uncle is donating a professional gun to me.
My brother has the compressor, just need to buy the thiingy dingy for water in the compressor. Need to buy paints, model man is ahead of me...LOL>
I will have the advantage of having my uncle tutor me, but great thread.
:thumbsup:

djnick66
02-19-2010, 09:16 AM
One thing to remember also is how much you thin a paint depends greatly on your air supply... what pressure you are painting under. More pressure - thicker paint.

Model Man
02-19-2010, 10:57 AM
My compressor runs shy of 30psi, but w/ the airbrush open, it drops to ~17psi. My air tank can be run past the 50psi limit of the hose, but I don't see why I would want to run it greater than 30 psi while open. So I'd say ~20 will be the typical usage.

But this opens up another question: why one would vary the pressure so greatly in the first place? I've heard people run their brushes from 15-35psi. I've been stuck at 17psi for the last couple years so never had the ability to experiment until now'ish.

skinnyonce
02-19-2010, 11:19 PM
I just usually use lacquer thinner for all paints, from acrylics to automotive. Then, I don't have to worry about if I've got the correct thinner to match the correct paint formula. The lacquer thinner has the side benefit of keeping the airbrushes very clean while I'm using them, and I think that the paint lays down better as well.

I just eyeball the paint-to-thinner ratio. I've been doing this for so long, that I don't even think about it, anymore. The 'thin as milk' sounds about right for consistency. I would go with that advice.




could you recommend a name brand that could be found at a local hardware store like ace or menards, lowes.. or is it best to get it from testors or tamiya,, something like that....


thanks skinny

skinnyonce
02-19-2010, 11:27 PM
never mind

machgo
02-20-2010, 04:08 PM
My compressor runs shy of 30psi, but w/ the airbrush open, it drops to ~17psi. My air tank can be run past the 50psi limit of the hose, but I don't see why I would want to run it greater than 30 psi while open. So I'd say ~20 will be the typical usage.

But this opens up another question: why one would vary the pressure so greatly in the first place? I've heard people run their brushes from 15-35psi. I've been stuck at 17psi for the last couple years so never had the ability to experiment until now'ish.

I vary the pressure a lot myself. Lower pressure can spray thinner paint without puddling. Higher pressure can spray thicker paint without clogging or stippling. Then there's stippling (sp?) Nice effects can be achieved with thicker paint and lower pressure, like stains, mud splash, grease splash, etc.

Also lower pressure can let you get up closer to the work without puddling. I do this when I spray subtle stains on small items that will be top coated. Best example I can think of right now of what I mean is painting panels that are stained all round the edges. I coat it with the finish color. Then I get in as close as I can with black around the edges. Then I go over the whole piece with a thin coat of top color. This mutes the stains and gives a nice effect on mechanical items, like Gundams for instance, as if they've been in service and have been serviced.

Also, if the area to be painted is small, you can avoid masking a large area by lowering the pressure and getting in close enough without fear of overspray.

Mostly though I adjust the pressure up and down to suit the paint I've just poured in the bottle. I don't really measure anything, I just go by eye and experience. I test a little spray, and adjust pressure as needed.

Pressure adjustment can be done quite easily with a regulator and pressure gauge inline with your hose. I use a tank, so its: tank, on/off valve, drier unit, regulator, pressure gauge, hose. But I bet you knew that already.

Hope that helps.

Mark McGovern
02-20-2010, 10:32 PM
could you recommend a name brand that could be found at a local hardware store like ace or menards, lowes...Skinny,

I've used whichever brand of lacquer thinner or mineral spirits the store I happened to be in had. Their chemical composition doesn't vary noticeably as far as I've ever been able to tell. These solvents work fine with Testors oil-based paints, which is the brand I use almost exclusively. For airbrush work I use their thinner.

ajmadison
03-01-2010, 04:20 PM
Without trying to be overly anal retentive about, the rule of thumb I heard was, "Thin airbrush paint to the consistency of SKIM milk."

For those who are new at this, hear is a tip on measuring that consistency. Put a stick (grilling skewer, for example) into your airbrush paint. Lift a drop of it and place it on the side of the A/B reservoir, color cup, or mixing cup, what have you. If the drop falls immediately, its thin enough. If it hangs there, or slowly descends, its too thick.

In general, I prefer the lower-pressure/thinner paint method for everything. Perhaps not for the base coat, but even then, its easy to get runs & drips if you're not in practice. The advantages of lower-pressure/thinner paint are:
very less likely to creep under masks, fine control of the application, less likely to cause runs & drips, and details won't be clogged or occluded with a thick layer paint. One disadvantage is that a thin layer may not be opaque or require several shots to get good coverage. For example whites & yellows, especially the gloss versions, will require several applications to get coverage. Still, not having to worry about sealing masks, or rubbing the masking tape until you break the model or ruin the base coat is worth the extra effort.