In doing research for my airbrushing tutorial I came across this method to decant Tamiya paint for air brush use.
John
Decanting Tamiya Spray
Article written by: Robert Scott Truesdell
Courtesy of: Acme Novelties
Decanting aerosol rattle cans is worthwhile if you want to airbrush the high quality and readily available Tamiya synthetic lacquers such as found in the TS- series of spray cans. The Tamiya paints spray quite well directly out of the can but tend to deliver too much paint for my particular painting style, especially when trying to get into nooks and crannies. By decanting and airbrushing you gain the advantages of airbrushes which include finer control of paint flow and air flow and consistent operation. You free yourself from the variations caused by temperature or manufacturing tolerances inherent in any mass-produced consumer item.
Advantage of Decanting:
1. Readily available supply of quality paint;
2. Absolute control over the delivery of that paint to your subject;
3. Paint covers much more area because of less overspray and more precise delivery.
Disadvantages of Decanting:
1. Not as convenient as simply picking up a can and spraying. Tamiya spray can products spray straight out of the can better than almost any other paint you can buy, so why bother?;
2. Messy to decant;
3. Difficult and messy to handle.
Background: what is in a spray can?
Spray cans contain a mixture of pigments, carrier, solvent, and propellant. The propellant is a liquid that boils at room temperature at normal pressures. The pressure inside the spray can is high and keeps the propellant in liquid form. This propellant is what makes decanted spray paint difficult to handle and why we out-gas after decanting.
Decanting
The easiest and cleanest way to decant spray paints is to fit a tube to the protruding tip of the spray nozzle and spray into a new container. The tapered shape of the pipette tip means you can cut a nice tight-fitting adaptor. There is a minimum of overspray as the spray collects against the slippery walls of the pipette and slides into your bottle.
Do not fill the bottle past 70% full.
Place the bottle with freshly decanted paint down gently and do not touch for at least one hour. Do not put the cap on the bottle.
See the Cleanup section for directions on how to clean the decanting tube.
Out-gassing
The propellant boils at room temperature which creates pressure to spray. It also makes handling the paint outside a pressure can difficult, messy, and even dangerous. Proper out-gassing will reduce the pitfalls of decanted paints to those of normal store-bought bottled paints.
Leave the lid off the jar of freshly decanted paint and let propellant boil off for at least one hour. Don't try to stir the paint or add anything like thinner or ball bearings; the slight temperature rise caused by these activities will cause the paint to boil vigorously, overflowing the bottle onto the floor and sputtering into the air. Just touching the bottle with your fingers and cause an eruption. The heat from your fingers will cause the paint to boil. The friction of your finger along the side of the glass will create enough heat. I speak from bitter experience.
Allow at least one hour at room temperature (above 70% Fahrenheit) for the propellant to boil off. A longer out-gassing period is better. I usually wait overnight. I have forgotten about an open bottle of decanted paint for an entire weekend with no noticeable loss of sprayability.
The paint bottle should not appear frosty or feel cool.
Once the bottle has reached room temperature you may cap it.
Storing
I used to double-bottle lacquers to minimize evaporation losses. I knew I was losing in single bottles because I could smell lacquer thinner even though the bottle was tightly capped. Double-bottling easily quadruples the storage life of lacquers, if not more. For scale reference, the yellow paint is in a 23ml Tamiya bottle (the large one.) The red paint is in these glass scintillation vials with polyseal caps I get from laboratory supply houses. The larger jar was likewise procured from lab supplies.
That said, I rarely bother to double-bottle my paint any more. The little bottles in this picture hold enough for one 1:24 scale car so I just use the paint up then rinse the bottle in lacquer thinner. I have had decanted paints for well over a year and they are still usable.
(note: the two little black dots in the yellow paint are ball bearings from the local hardware store.)
Handling
Good out-gassing goes a long way toward minimizing handling problems. Since I have learned the Zen of overnight out-gassing, I no longer have messy troubles. I have left freshly decanted Tamiya paint in open jars for over 36 hours with no discernible thickening.
Inadequately out-gassed lacquer will boil at room temperature so be careful handling it; open only in an area where it's OK to spill paint everywhere! Including all over yourself! Cover the jar with an absorbent towel and crack the lid open the tiniest amount. You should be able to see bubbles before you hear hissing. Basically, if you hear hissing you've lost and paint is going to be going places other than your model.
Thinning
You do not need to thin decanted Tamiya synthetic lacquers (TS- series) for airbrush use. If you do want to thin, use a high quality lacquer thinner for acrylic lacquers or Gunze Sangyo Mr. Color thinners. There is a Mr. Color Leveling Thinner which is slow-vap and allows final coats to flow out a little better. My everyday thinner for cleanup and normal thinning is KleanStrip available at Home Depot.
Tamiya lacquers are OK to go as they comes from the can, but I sometimes thin the first coat or two to get a good bite into the plastic. I optionally add Leveling thinner for final top coats. I have successfully used Mr. Leveling Thinner with PPG Duracryl Ultra Gloss clear.
Spraying
Draw off a little paint with a pipette, drop it in your airbrush, and have at it.
Cleanup
Tamiya synthetic lacquers can be cleaned up with standard hardware store lacquer thinner. I keep a gallon of KleanStrip in my paint area for general cleanup. Run a cupful through the airbrush and wipe the top of the paint bottle.
I suck up a small pinch of thinner into the pipette and shake it up, then squirt a little on a paper towel to wipe the exterior of the tip. Some colors (reds and blues, commonly) have dyes in them that attach to the pipette and make it look like it's still dirty even though it rinses clean. Don't worry about it. Personally I keep half a dozen pipettes for special purposes: water-based thinners, lacquer thinner, clear top coats, color paint, and metallic paint.
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Topic: how do I decant paint from a "rattle can" into a jar to use in an airbrush? (Read 10115 times)