The Fate of Cleaning Solvent

Since a spray gun needs to be cleaned after every use – sometimes within a half-hour or slightly less, if permanent crosslinking between paint remnants and catalyst will occur within that time, causing an immovable plug that no amount of solvent or soaking will remove – it soon becomes clear to anyone who makes regular use of a spray gun in car painting that a lot of solvent is going to be used in the cleanup process. The amount of solvent needed is increased by the fact that much of the troubleshooting needed for a spray gun involves cleaning different parts.

Since solvent is not free, and is difficult to dispose of properly (while improper disposal, such as dumping it into a stream, is highly illegal and morally inexcusable as well, since someone might drink the solvent at a point further along the watercourse), you may wish to re-use the cleaning solvent to some extent at least. Some paints may render it totally unsalvageable, but others will allow re-use with a little care and imagination.

The correct type of solvent to use depends on the paint you are spraying. Lacquer thinner should be used for lacquer residue, for example, while enamel reducer is used for enamel. Clean-up solvent should be part of most modern paint systems, formulated to handle the company’s specific type of urethane or polyurethane, and products from other companies should not be used, as usual..

When you are cleaning your gun, spray the solvent into a bucket or large plastic bottle, made of a material that will not dissolve in the solvent. You can test its resistance to the solvent, if unknown, by placing a drop on the exterior, letting it sit for several minutes, then wiping it away and checking to see if the material has been etched or marked at all. If the plastic shows any melting or even roughening at the point where the solvent was applied, then the solvent might well eat through the container and flow out onto your floor.

Catch as much of the solvent in this container as you can by spraying into it during cleaning. Then, you can use one of several different methods to clean the solvent for its next use.