Below are several key tips to upkeep the shelf life of your Gamblin medium and get the most out of every bottle.
Gamblin painting mediums (Galkyd, Galkyd Lite, & Neo Megilp) are made with alkyd resin– a polymerized soybean oil, and Gamsol- a mild odorless mineral spirits. Once the factory seal is removed from a new bottle, the drying process is initiated. Alkyd resin dries first by solvent evaporation, then by oxidation- so the introduction of air space into a newly opened bottle permits some solvent evaporation and drying- even with the cap tightly secured. As the medium is used over time, the air space in the bottle gets larger causing the remaining medium to dry out more quickly.
There are several things you can do to help maintain alkyd resin mediums once the factory seal is removed:
- Make sure the cap is securely fastened and store the medium bottle UPSIDE DOWN. Our tests have shown that storage upside down creates the best vapor lock limiting air flow in and solvent evaporation out.
- Check the viscosity of your medium BEFORE EVERY USE by tipping the bottle. If the medium appears to have thickened even slightly, add a small amount of Gamsol and shake thoroughly until it is restored to its original consistency. Managing the viscosity of the medium from the moment it is opened will ensure the longest shelf life possible.
- If a larger size bottle of painting medium is drying out before you can use all of it, consider purchasing a smaller size next time.
- When decanting medium into a separate container, pour out only what you will use in a single painting session.
- Wipe the bottle threads clean after every pour.
- Gamblin bottle caps come with a liner- make sure this insert remains in the cap to ensure an airtight fit.
- Store painting mediums in daylight to maintain their lighter color. All drying oils and alkyd resin mediums will deepen in color when stored in the dark.
For more tips and techniques from Gamblin, please visit https://gamblincolors.com/tips-and-techniques/