Re: Well, that's . . . odd


Earl T. Hackett <hacketet@...>
 

Many lacquers are formulated with what are called 'drying oils.' These are oils that polymerize on exposure to oxygen. Linseed oil is the most well known, but there are several others. Every time you open the bottle you let some oxygen in and eventually you will cause the oil to polymerize, making the paint into a gel. If you seal the bottle well you can extend the life of the paint significantly. I know one individual who squirts some nitrogen into the bottle just as he's capping it, but even those precautions will not prevent it from gelling eventually.

As for acrylic paints, they are a very different animal. They consist of small droplets of paint suspended in water. There is a careful balance of surfactants in the water to keep the particles from coalescing (sticking together). When you dilute an acrylic, you upset this balance and the particles start to stick when they bump into each other. During a painting session you won't notice any change, but let the paint sit for a couple of days and you'll find all the solids glopped on the bottom of the jar. Most manufacturers sell a thinner for their acrylics that has the proper balance of solvents and surfactants. There's no guarantee, but you will have a much better chance of not messing up a bottle of paint if you use the recommended thinner. Otherwise, just thin what you need and toss the left overs.

--- In STMFC@yahoogroups.com, "Schuyler Larrabee" <schuyler.larrabee@...> wrote:

Does lacquer ever go bad? I've had this stuff a very long time, having bought a gallon of it years
ago.

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