Thursday, December 1, 2016

Decanting Paint from Spray Cans

What's up plamo nerds? I hope you haven't blown your holiday bonuses on kits that will sit on your backlog shelf for at least 2 years! Remember that you don't just need kits, you'll need other modeling supplies too. Paint in particular is a fast-moving consumable in this hobby, and you can easily go through several jars on a single project. Good thing there are cheap alternatives to hobby-grade paints - the most accessible of which is the humble rattle can. Available at almost every hardware and DIY store, these cans are the typical weapon of choice for a modeler's first foray into painting. Eventually though, many of us graduate to airbrushing, and a bunch of half-empty cans end up collecting dust under our work tables. You can still make the most of those old cans by decanting the paint instead!

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You'll need the following:

1. Plastic tubing. A bendable straw or section of air hose will do.
2. A glue gun, loaded.
3. An empty jar, preferably glass
4. A barbecue stick, or some other thin wood stick
5. Old newspaper, so you don't make a mess

Remember to work in an well ventilated area - outdoors is best. Lay down lots of newspaper where you intend to work. Fair warning here, as this can get real messy, real fast. Start by giving the rattle can a good shake and make sure it isn't clogged by spraying it with the can upside down. Next, attach the plastic tube to the nozzle securely with some hot glue. Be careful not to cover the nozzle itself with glue, and don't put too much that it obstructs the trigger's movement. Let the glue harden, then check if it is securely attached to the nozzle with no gaps.

Insert the other end of the tube into your paint jar. Do a test by shooting a very short burst. The paint should collect in the tube and trickle down into the jar, with some gas escaping out the top. If there are no leaks and the tube is holding firmly, you can proceed to spraying the rest of the paint out into the jar.

Notice how there seems to be condensation forming on the tube and on the surface of the jar? That's because this process makes the tube and jar very cold. DO NOT AGITATE THE JAR WHILE YOU ARE SPRAYING THE PAINT INTO IT. I cannot emphasize this enough. DO NOT COVER THE JAR. Do not even touch the jar or let the tip of the tube dip into the paint. Remember that volcano project you did in 1st grade with some baking soda and vinegar? That's not even close to the eruption of paint you will experience if you stir the freshly squeezed paint at this point. Just fill the jar half way and leave it alone for an hour or so to allow all the propellant to evaporate. Here's a gif showing just how "bubbly" the paint is with all that propellant still in it after about 15 minutes of resting...

After about 30 minutes you can try to speed up the aeration process by gently inserting a wooden stick into the jar and stirring the paint slowly. You'll notice it gets bubbly again as you handle the jar, so leave it for another 10-15 minutes, stirring carefully every 2 minutes or so. When the jar feels like it is back up to room temperature, the paint is ready.

Decanted paint is usually okay to use without further thinning, but you can thin it down with the appropriate thinner to your desired viscosity. The acrylic paint I decanted in this demo seemed pretty thin out of the can, so I just loaded up the airbrush and did some spoon tests. The paint sprayed easily at about 20 psi, and went on nice and smooth. I suggest airbrushing freshly decanted paint with the cup's cap off, just in case there's still enough propellant left in there to create pressure.

Store the decanted paint with the lid off for another day or two before putting a lid on it. It's easier to thin it down again later if it starts to thicken up, rather than have to clean up a paint explosion on your work bench.

Until next time, keep building plamo!


  1. what to use in cleaning AB from spray can paints? also for thinning it? thanks

    1. I've been using industrial grade acrylic thinner to clean the airbrush, here's a tutorial: . As for thinning, I don't thin decanted paint I just use it straight from the can so I'm not sure, but probably depends on the type of paint you decant ie. lacquer spray can, lacquer thinner. Don't use industrial grade thinners for paint on plastic kits.