If you have old cans of Waterlox products sitting around, there is a good chance that it is still perfectly usable product, regardless of how old it is. The Waterlox products dry and cure through exposure to oxygen and they are fully reacted together to form one uniform liquid, so they will not slowly separate or have additives fall out of solution over time (with some minor exceptions). Check the Storage of Waterlox guide for more information on proper storage to ensure a longer shelf-life for your finishes.
If It’s Still Liquid, It’s Still Good
The general rule of thumb is, if the product is still a liquid, it will still dry and cure properly. The one major exception to this is the gloss level of the Satin Finishes. In order to make a product a low gloss finish, flattening agents are added that cause the product to dry with a lower gloss. After many years, this slowly settles to the bottom. If not stirred back in, the liquid will still dry and cure, however it will be a higher gloss. You should be able to stir the product back in to make a milky golden liquid.
Regardless of which product you have, if it has been sitting for a while, it is recommended to strain your product through a paint strainer or cheese cloth to remove any clumps, gels or dried bits of finish. Even if the can was never opened, it may be wise to strain the material.
When to Stir and DO NOT SHAKE
Some products will need to be gently stirred before they are used to ensure the proper gloss is achieved. All H2OLOX finishes should be gently stirred (gently rock the bottle side to side) to ensure all additives and ingredients are evenly distributed. DO NOT SHAKE as this may cause excessive bubbles in your finish. All solvent-based finishes (ORIGINAL, MARINE, URETHANE, TRUETONE stains, TRUETONE Buff-In Tung Oil Finish, UNIVERSAL Tung Oil Sealer) will follow the rule that if they are in a round can then they should be stirred gently to mix in any flattening agents or colors. The only exception is our URETHANE Gloss, but a gentle stirring wouldn’t hurt. The ORIGINAL, MARINE, UNIVERSAL Tung Oil Sealer, and TRUETONE Buff-In Tung Oil Finish DO NOT need any stirring or shaking before use.
DO NOT SHAKE ANY WATERLOX PRODUCTS!!!! Shaking will cause excessive bubbles in the finish that will either end up on your project or cause product to gel/dry in the can. Shaking distributes air bubbles into the finish meaning that more of the finish may come into contact with the oxygen that will cause it to dry/cure.
Skin vs. Gels in the Can
If your partially filled containers are left on the shelf for a long period of time, a thin skin may form on the surface. This is dried product and it typically protects and seals off the remaining product from the air space in the can. You can typically puncture the skin and retrieve the liquid underneath. Straining/Filtering is highly recommended if you have a skin on the surface.
If your partially filled container has started to gel or become very thick, typically it is not ideal to use it. Gels are usually formed when the can is shook and product starts to dry and cure around bubbles or all the way through the can. Because the tung oil and resin are cross-linking during the curing process, you cannot break these bonds and have them form correctly again. Therefore, you cannot simply dissolve or thin the clumps and expect the same properties. If the product is starting to gel, you can add some paint thinner or mineral spirits to loosen up any uncured material and filter or strain it into a new container.
