Many customers have found it difficult to locate compatible solvents for our MSA varnishes. Because of that we have recently tested a limited range of widely available, commercial brands of solvents in order to provide some guidance. While Stoddard Solvent, the product we use to make MSA, or an equally full-strength mineral spirit, continues to be our best recommendation, initial results have shown some specific brands of commercial paint thinner, low-odor, and even odorless mineral spirits did perform adequately for thinning within certain ranges. We summarize those findings below:

Test Parameters: All ratios were calculated by weight using 10 gm of varnish as the base material. Mixing was done in a glass jar at ambient room temperatures of 60-72° F (15.5-22.2° C) and varnish applied over a pre-made commercial canvas board that had been painted black.

	Brand of Solvent	3:1 Varnish: Solvent Ratio	1:1 Varnish: Solvent Ratio	1:2 Varnish:Solvent Ratio
BEST	GOLDEN Stoddard Solvent	Clear. Clean, even application	Clear. Clean, even application	Clear. Clean, even application
BETTER	Klean Strip Paint Thinner	Clear. Clean, even application	Clear. Clean, even application	Clear. Clean, even application
GOOD (up to 1:1 dilutions)	Klean Strip Odorless Mineral Spirits	Clear. Clean, even application	Clear. Clean, even application	Cloudy. Application streaky and uneven.
Not Recommended**	Klean Strip Low- Odor Mineral Spirits	Clear. Clean, even application	Waxy kick-out that went into solution with additional stirring. Clean application.	Cloudy. Application dried clear.
	Ace Odorless Mineral Spirits	Clear. Clean, even application	Waxy kick-out that went into solution with additional stirring. Clean application.	White and cloudy. Application dried clear.
	Crown Odorless	Clear. Clean, even application	Became white and cloudy. General application failure.	Became gelatinous. General application failure.
	Crown Low-Odor	Thickened.	Thickened.	Thickened and cloudy.
	Weber Turpenoid	Thickened.	Thickened.	Thickened.
	Gamblin Gamsol	Thickened.	Thickened.	Thickened.

Do not use at this dilution.

** Although a few samples passed at 3:1 dilution, ultimately all showed signs of incompatibility.

Please Note: While not listed in the above table, turpentine that is specifically labeled as distilled or rectified is a compatible choice. However, as a more aggressive, ‘hotter’ solvent it presents additional health concerns and a greater chance of reactivating previously applied layers of varnish. Because of these reasons we tend to not make this one of our top recommendations.

Lastly, these results are only being provided as an aid. It is important to keep in mind that formulations for these products can vary geographically and over time so the above tests do not guarantee future results and one should still test for compatibility before use. In addition, the issue of diluting the varnish is separate from the issue of whether these solvents are equally good for varnish removal and cleaning up of tools or brushes. We hope to conduct future testing around these concerns and encourage you, in the meantime, to do your own trials whenever possible.

Solvent Compatibility Testing Procedure

While the above results provide some initial guidance we would encourage you to always test these or other brands prior to use. The test is a relatively simple process. First, make sure the temperature of your workspace and all materials are above 60° F (15.5° C) Using a glass container to facilitate examination, mix an equal amount (1:1) of varnish and solvent, stirring with a palette knife. If compatible the varnish will quickly and easily go into solution and have excellent clarity. If the solvent is too weak or otherwise incompatible, you will usually see one of the following:

The varnish becomes gooey or thickens
The mixture develops a cloudy or milky appearance. Even if additional stirring can make this disappear it can be a point of concern as it points to the presence of waxes or other impurities that can possibly effect the final sheen and performance of the varnish.
Transparent and threadlike or gelatinous structures that can be discerned when looking at the mixture held up to a light. Usually a sign the varnish has failed to go completely into solution.

Troubleshooting

If the mixture fails on any of these points first double-check that the temperature of the room as well as all the materials are above 60° F (15.5° C). Some solvents we tested showed signs of failure when used at lower temperatures and were resolved by allowing the materials to reach the recommended levels. If problems still persist, adding a small amount of Xylene can usually solve the issue. In our own testing, as little as 1% addition was enough to correct most problems in even those mixtures that had clearly failed; however it is always possible one could need more depending on the brands used and the ratio of solvent to varnish. Please Note: Use of Xylene posses additional health and safety concerns. Please follow all health and safety warnings as provided by the solvent manufacturer.

Disclaimer
The above information is based on research and testing done by Golden Artist Colors, Inc., and is provided as a basis for understanding the potential uses of the products mentioned. Due to the numerous variables in methods, materials and conditions of producing art, Golden Artist Colors, Inc. cannot be sure the product will be right for you. Therefore, we urge product users to test each application to ensure all individual project requirements are met. While we believe the above information is accurate, WE MAKE NO EXPRESS OR IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, and we shall in no event be liable for any damages (indirect, consequential, or otherwise) that may occur as a result of a product application.