I’m making my first attempt at airbrushing. I’m using a Badger Model 200 (bottom feed, single action, internal mix) received as a gift. I am using Polyscale acrylic paint.
I’ve encountered two challenges:
The colour is splotchy. I think this is because I’ve added too much thinner to the paint. The Polyscale bottle advises to thin to 10-15%. Does that mean the final mix is 10-15% paint or 10-15% thinner?
The airbrush frequently stops spraying paint. To restart paint flow I loosen the flow control at the back of the brush, and get a couple strokes of paint. Then just air. I loosen flow control more, get a couple strokes, then just air again. In the end I loosened the flow control quite wide causing very thick paint application. Could this be a function of the starter spray propellant provided with the airbrush kit? I’ve read that these cans frequently ‘freeze up’ - I noted the can did have quite a bit of frost on it surface. Or am I doing something else wrong?
Any help offered will be appreciated.
BTW - has anyone every used a small compressed gas bottle to propel their airbrush? Compressors are expensive and noisy, but bottles and compressed air is plentiful in my workplace. Thoughts?
Having been through this learning curve last year, I can offer the following solutions to your problems. I don’t use the Polyscale thinner myself, I use the Tamiya product - it’s more easily available here in Australia, so I’m afraid I can’t help you with that.
The reason that your airbrush keeps stopping is because your paint is too thick. Ideally, it should be the consistency of water. I find that a 50/50 mix of thinner and paint works - just keep adding thinner/paint until I get the right mix. You’ll know you have too much thinner if the paint comes out semi-transparent and watery.
Using cans should be alright, but you will need to bear in mind that as they run out, the pressure coming from them drops below a usable level. And the freezing on the outside is normal - it’s part of the chemical reaction drawing heat energy from the air around it to react. I can’t answer for the compressed gas bottle, as I haven’t used one myself. Which gas is it?
Thinning too much will give you a thin or almost transparent layer of paint, but it shouldn’t be splotchy. The splotchy problem is related to your second question.
Paint that’s not mixed properly or is lumpy will cause a splotchy coat or cause the airbrush to clog frequently, which it sound like what you’re describing here. To check for lumps, get a second paint bottle and a small piece of cotton fabric, a piece of an old T-shirt will work fine for this. Place the fabric over the mouth of the empty bottle (with a bit of a sag in it) and carefully pour the paint through the fabric into the bottle. As the paint pours through, the lumps will stay in the fabric. If any of these lumps do show up, it’s a sure sign the paint will clog your airbrush. The strained paint should work fine.
For your airbrush compressed air supply, you can get a portable air tank, it’s like the tank that comes with a compressor, but without the compressor. Since your workplace has a supply of compressed air, you can just take the tank to work with you and refill it. You’ll also need a pressure regulator, since airbrushes need anywhere from 10 to 25 PSI to work properly, and you’ll need to charge the tank well above that to paint a loco shell or two between recharges. I used a 5 gallon one for years before I got my compressor.
10-15% thinner 2. Check your needle size. Many airbrushes ship with a fine needle. a fine needle is usually to small for Acrylic paints. There is information on the Badger web site. Spray water with the air brush. If it works as advertised then the paint is to thick.
No chemical reaction involved. When you compress any gas, it gives off heat. When you allow it to expand, it absorbs heat. That is the principle that makes an air conditioner or a refrigerator work.
Pump your air tank up to about 100 pounds and let it sit for a while. Then let the air out as fast as you can. Notice how cold the tank gets.
Are you sure your mixing the paint thoroughly sound like your trying to spray mud. Mix a new patch using 15% thinner. I like mixing by weight. I put my bottle on the scale tear it to get it to zero and then add paint fist then thinner. Some guys like adding a small ball bearing or a few BB’s to the paint bottle so you can agitate the paint. I bought that little battery operated mixer that Micromark sells at a train show and it’s worth ever dime.
WIll add that dpending on your area’s humidity, the paint could also being drying in the tip in between strokes. I keep a wet Q-tip handy to dab the tip if I have to pause spraying, even for a half minute. I thin Polly Scale with 60% water to compensate for Arizona’s single digit humidity
If you do get around to getting a compressor (highly recommend if you plan on doing a lot of airbrushing), sometimes you can pick up decent ones at Target or Walmart that has a tank on it too for under a $100.00. That’s what I did, and it sprays 25 psi just fine (also good for inflating the tires on the vehicles). Also, look around on the web for a small screen strainer that fits on the end of your airbrush siphon tube. Micro Mark might be a good bet. I got one and it helps with lumps and bits of crap that sometimes flies out of the airbrush.
I’m with Allegheny on this. All the posts I’ve read on the subject of mixing paint say the same thing, “Don’t shake up your paint. Paint will dry to the bottom of the lid, and fall of as chunks into your paint when you open it”. I bought the paint mixer from MicroMark, too, and it works great!!
As far as the compressor vs. air tank issue, I had an air tank. I tell you what, the last thing I wanna do is shovel the driveway in the middle of winter go fill the tank. I bought a compressor from the same company that I bought the airbrush from, and I’ve never looked back. It came with an adjustable pressure regulator (which any good compressor will have) and a moisture trap.
Hey guys, thanks for all the great responses. I was afraid to try again, but you’ve given me ideas that make it seem less scary.
My immediate action will be to do a better job thinning the paint and ensuring there are no solids in the mix. I will also use thinner for the paint in use, not just water. For the longer term I will look for a little compressor.
You’ve if you’re interested in a small compressor, be aware that they’re commonly priced new at around $100. Many of the cheapers ones function decently, however, they can burn out in the long term when used frequently.
You’ve probably seen this already, but for $99, this is what I got from the Home Depot. It is very reliable, easy to use, and tough. Settng the air pressure takes just a gentle turn of the knob. There is a valve at the bottom of the tank to release the moisture that builds up. Since I’m metalizing passenger cars, I want to play it safe and plan on purchasing a moisture filter for the airline, yet I haven’t needed it as the air coming out is clean and free of moisture.
Dwayne. I bought a badger compressor eons ago. It is a continous run compressor that I put on a power strip to shut off when not in use. I also went to ACE hardware and bought a moisture trap/pressure controller to get the right psi. It works great but it does not get used anymore because my parents found an old pasche(I think maybe badger) compressor with a tank and moisture trap and pressure regulator. It is whisper quiet and it has 3 ports with shut off valves for my airbrushes. If you are interested I would be willing to talk to you about my other badger compressor. Drop me a line if you have any questiona