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Maintenance of Alkyd Resin Mediums

Gamblin painting mediums (Galkyd, Galkyd Lite, Galkyd Slow Dry, Galkyd Gel & Neo Megilp) are made with alkyd resin- a highly polymerized soy oil, and Gamsol- a mild, slow-evaporating odorless mineral spirit. Alkyd resin dries by solvent evaporation, so the introduction of any air space into a newly opened bottle (or other container used for decanting) allows for solvent evaporation and drying- even with the cap tightly secured.

If your painting medium has thickened but is still fluid, add in a small amount of Gamsol and shake thoroughly. Continue adding more Gamsol and shaking until the medium is close to its original consistency. If a fluid alkyd painting medium has thickened to a gelled consistency, it will no longer help to add solvent. We recommend replacing it with a fresh bottle.

There are several things you can do to help maintain alkyd resin mediums once the factory seal is removed:
1. Gamblin bottle caps come with a paper liner- make sure this insert remains in the cap to ensure an airtight fit once the foil seal is removed from a new bottle.

2. Add a little Gamsol back in immediately after the first use and shake it well. Thereafter, add a small amount of Gamsol into the bottle whenever necessary to offset solvent evaporation and maintain the desired thickness of the medium.

3. When using Gamblin painting mediums, we recommend decanting only what you need for one or two painting sessions. If a larger size bottle of painting medium is drying out before you can use all of it, consider purchasing a smaller size the next time around.

4. Finally, if you know you will not be using an opened bottle of painting medium for several days or weeks, add a little more Gamsol than usual, securely tighten the cap and shake vigorously.

Store all oil painting mediums in daylight to maintain their lighter colour. Dark storage will result in an oil medium becoming darker in colour.