Paint;
This product can be aggravating even for pro's. I can remember working for De-Vilbiss and getting reports of Paint Pots exploding because of paint clogs. What is a Paint-Pot?
Just as the name says, A pot into which you pour your MIXED paint and Appropriate Retarders and Hardeners( Today) and put the lid on like a pressure cooker with latches then pressurise and shoot with a Gun out of a 15 or 25 foot hose. Usually 5 U.S.gallons.
Well, They are like pressure cookers in that they are supposed to have an overpressure relief valve. Don't forget to clean before each loading!
Now, getting to the subject. Many times the Pot went Boom because of Lumps. Lumps? Yup! Not from bad mixing, but lumps of Pigment that solidified beyond the mixability of the product. This usually came from age of the paint.
How does that apply to modelers? Think about it for a second. How long has that bottle or can you just purchased spent in a Container, then a Warehouse then a Truck rumbling down the highway on a 100 degree day?
Model paints like Three things, Cool, Dry, and Dark areas. Why? Heat affects not only the viscosity of the product and it's components, it also affects the Color Purity. So you ask okay what is the paint made from. First, in the trade you have a vehicle(The liquid holding everything in suspension) This can be Varnish, Enamel or the liquids used for Acrylics. I don't think the last is water by the way.
Now in that, per batch they add Pigment. This can also be in liquid or powder form. Sometimes 500 Gallons at a time. Mix well-usually for a relaxed hour or so. You don't mix violently when building the product. Why ? Miniscule bubbles and clumps form along the side of the vessel if you do. They do sometime escape into the bottling or canning process.
Okay Mr. Consumer, You have bought your paint at your favorite Hobby Supply store. Now, Yay! You even got the color you wanted! Shake it till your arm is sore, Right ? NO!! Even the old Pactra( Defunct) and other brands recommend Stirring thoroughly! Why? Back to the bubbles and lumps again. Paint will settle into it's separate components if stored way to long. Especially if it is exposed to extreme temperature shifts!
That is when you see layers of liquid in the bottle. This means the Pigment,Carrier and Vehicle have seperated. The stuff on the very bottom is pigment.The thin layer is Carrier and the milky or in the case of enamel, The Light whiskey colored stuff is the vehicle. If your paint is more than five years old. Then usually in that shape you would be wise to considering discarding it. Now if you can stir gently and eventually get to the bottom of the bottle, there's a chance You can still use it!
Notice, I said Chance. That extreme heat and cold will be a factor in salvaging it. Don't think just by adding a little thinner it will be okay! The pigment has clumped.Now you have to break up every bit of the clumps you have broken up from the bottom. Once it's the consistancy close to where you recognise as paint, try this.
Take a brush and get a scrap of plastic and put a brush stroke on it. If it doesn't flow nice and smooth you will know. There will be a patchy brush stroke on the scrap. Now take the bottle and cap. Clean the top well, Better than you ever have! take the lid and clean out the whole thing with lacquer thinner. Okay, now what you have is a clean bottle full of paint with an air gap. That's alright at this stage. Put the lid on as tightly as you can.
Okay ,here's where you get to exercise your arm! Or Make or buy a paint shaker for model sized containers! Shake the Hades out of it for an hour. Then let it rest for 30 minutes. Come back Open up the bottle and do the brush test again. If you get the same results, Discard the paint, clean out the bottle with lacquer thinner and you have a mixing bottle at least.
See my next-After admonishment post!
Enough Already. You got the Message right?