Extracting Paint from a Spray Can :
There are many reasons to extract paint from a spray can, like paint that is only available in can form and you wish to air brush it on your model for example, and I'll quickly and easily demonstrate how I extract Primer from my Tamiya spray cans.
The following is required to extract the paint from the can :
Also, remember to do this in a well ventilated area and use an adequate mask.
Step 1 :
Shake your can thoroughly so the paint is well mixed before you begin the extraction. Now take the hollow tube (in this case, I have used an old pen barrel that is big enough to entirely cover the nozzle) and attach it to the nozzle as shown in the picture below.
Step 2 :
Now get your jar ready and point the tube that is attached to the nozzle into the jar. Be warned, as soon as you start spraying, gases start escaping so make sure you are in a well ventilated area and have an adequate mask on.
Step 3 :
Spray away. The paint takes a little bit to get flowing, so be patient. Once it does, you will notice bubbling in the paint and that the jar is getting very cold. This is due to the propellants inside the can. Fill it about 1/3 to 1/2 full and stop. Using a stirrer (or the tube on the nozzle), dip it in the paint and gently agitate it. It will start bubbling very violently. This is normal, it's just the propellants trapped in the paint escaping. Once it bubbles up, stop until it calms down. Now repeat again until the bubbling has stopped altogether.
Once the bubbling has ceased, start spraying again and fill it up to 2/3 or 3/4 full and repeat the process as before - stir, bubble, wait.
Step 4 :
Once all of the propellants have been released from the paint, it's ready to use in your air brush. Depending on the type and brand of paint, you may not need to thin it to use in your air brush. I know for sure that Tamiya Grey Type Primer, which I have used here, does not need to be thinned at all and can be used straight away in your air brush.
Just remember to make sure all the propellant is expelled from the paint because pressure can build up inside the jar and can cause problems.