How long are model paints good for ?

  to the group;

 I second (or third or fouth???) all the advice about thinners and mixing.

  For me a basic rule of thumb is to use the manufacturers thinner  for each paint brand you're using and see how it works. 

Then with the  several different thinners ideas you get, you can give them a try if you wish, see how they compare. Leaving you better able  to decide on the best combination that works for you.

Anytime sturge. Happy to help out.

Thanks Dre, you may very well be right. clogging is exactly the word to describe what was happening. I have both lacquer and enamel thinners and will give them a try.  

Thanks Stikpusher, I really appriciate the time you took to respnnd to the "new guy". I was thinking along the same lines regarding validity of different paints.  

I am a HUGE fan of MM Airbrush Thinner for enamels. It works great with all the different brands of enamels that I have. Acrylics are far more picky and usually require a brand specific thinner for best results. I gotta second (Harrumph! Harrumph!) the airbrush maintenance advice about periodic disassembly & cleaning. Lacquer thinner and some good cleaning brushes help immensely.

The advice that stikpusher gave about stirring the paint versus shaking is sound. I have found that shaking Testor's Model Master acrylics causes them to clump up and dry out for some reason. Maybe it's because the air in the bottle is making more contact with the paint that way.  Anyway, stir those acrylics!

For what it's worth I agree with you stikpusher about the glue; I switched to Tamiya liquid (Reg. & xtra-thin) much better now. As for MM paints I use their enamels and have been pretty happy I only use Tamiya for acrylic. Anyway, from reading what Testors said you should always use the airbrush thinner as opposed to regular stuff; they say it's stronger and designed specifically for that use. May or may not be contributing  to your problem. Anyway glad your back sturgejl to enjoying a wonderful hobby !

I have some paint also that is pushing twenty years old, and is still usable.

As to the clogging airbrush, I've taken to thinning the paint 50-50:  half paint and half thinner.  It means putting on more coats and thinner coats, but it goes on smoother, doesn't clog the airbrush as much, and stretches out the paint to last longer.

I also use lacquer thinner from the hardware store for thinning the paint and cleaning the airbrush.

It's also a good idea to completely disassemble the airbrush from time to time and give it a really good cleaning.  Simply spraying thinner through the airbrush after each painting session is not enough.  Paint will still accumulate inside.  I use a toothpick soaked in thinner to scrape around.  Don't know if this is necessary for all types.  I use a Paasche H model, which is pretty quick to take apart and reassemble.

Still, it seems clogging will almost always appear eventually, so keep a q-tip handy.  Dunk it in thinner, and wipe the nozzle of the airbrush when you notice it beginning to clog.  I also sometimes just submerge the tip of the airbrush during painting; do a quick shot off the model, and resume spraying.

Good luck to you.

I've got some MM paint here that are 10 years old and there just fine, as for clogging your AB make sure there mixed up good so you don't get clumps in your AB. What kind of thinner did you use, I use a good quility mineral sprits for MM and X10 thimmer for Tamyia paint. I have had some probluems with a couple of MM colors as stated earlier posts,so I just replaced them with Tamyia colors probluems solved. And as DRE and STICKER posted make sure there mixed good before using.   ACESES5

When it comes to Testor's/MM, Stikpusher nails it.  

sturgejl, it sounds like you like have a different problem going on in your AB than old paint.   I've started to use lacquer thinner to cut my enamels and I've been really pleased with the results so far- significantly less tip fouling, clogging or clumping.   As a bonus, the paint really seems to adhere to the plastic a lot better with a more durable finish.

In the past few years I have found that Testors seems to be having some quality control issues with their products that vary from batch to batch. I stopped using their liquid cement because the last couple bottles that I had used were about as effective as sugar water. Paints have had had different issues, adhesion, thickness, clumping. I suspect that some formulations have been changed for environmental law reasons. But that is just speculation on my part. All that being said, I do have some old paints (some are 25+ years) of various brands that still work great, and newer ones of the same brands that have had variations of the same issues that I listed above. Even when they are all stored together. With you older paints, you will just have to test each one individualy to see if they are still usable. My only suggetion is that you make sure that your paints are mixed thoroughly by stirring (not shaking) befire using them in your air brush, and of couse that they are stirred again after being thinned for air brushing.

Paints are generally good up to the time after you just left the hobby store and right before you go to use them.

Welcome to the Forum, Sturgejl! We're glad to have you here. I'm sure someone will chime in with some airbrushing advice, but, you may want to post your question over in the airbrushing category, too. That will ensure maximum coverage.

Tim