The environment can play a role in the drying and curing processes. Factors such as temperature and humidity are important to note, but also look for direct, intense sun exposure or high winds if finishing outdoors. Also, different Waterlox coatings may respond differently to different conditions.
Temperature plays a role at the drying, curing and storage phases of any project. Very high temperatures can have negative effects on drying, but also, fluctuating temperatures may also cause some potential problems. There will be little to no effect at normal living temperatures (50°F -90°F), although evaporation and the curing reaction will occur at slightly faster rates as temperature increases.
Waterlox products will work at lower temperatures; however, there are some situations to note. As per our Drying, Curing, Ventilation and Circulation guide, all of our products dry through exposure to oxygen. This means that elevated temperatures are not required to properly cure the product. Low temperatures will have the biggest effect on the immediate application and drying of the product. See the Application in Low Temperatures guide for more detailed information, but in general, when both the product and surface are cold, they are less compatible. A cold surface has a low surface energy and may repel the Waterlox product as you try to apply one of our wet applied finishes (ORIGINAL, H2OLOX, URETHANE or MARINE). They may bead up on the surface and not allow for a nice wet coat. This is not a concern for buff-in products (UNIVERSAL Tung Oil Sealer, TRUETONE, and PURE Tung Oil). The act of buffing/rubbing will drive these products into the wood, although when cold, they will be a little thicker and may require a little more effort to spread (although buffing/rubbing will generate its own heat and will negate any low temperature effects). Ideally, all application should occur when the products, surface and environment are above at least 50°F.
Higher temperatures can cause bigger problems than lower temperatures. This can be because the coatings may be drying too quickly. This is still not a problem with the buffer applied coatings, as the warmer temperatures will reduce the product viscosity and help it to penetrate and spread easier. With the wet applied coatings if the immediate surface dries too quickly, it can actually seal in solvents and lock out oxygen. This results in a poor cure of the film and can lead to softer finishes, lingering odors or surface tackiness. See the lingering odors and tacky finishes guide for more information on correcting that issue. An obvious sign of skinning on the surface is wrinkling. When a really thick, wet application is applied the very top can dry before all of the solvent has escaped from the bottom of the wet layer. As most of this solvent slowly escapes, the coating essentially “deflates” and shrinks, forcing the dry surface to wrinkle up on itself. While your particular project may not show any wrinkling, the same issue of trapped solvents can prevent a good cure.
If you are working in a particularly warm environment (>80°F), one may consider taking certain steps to slow down surface drying and improve drying/cure. The easiest is to minimize air flow. This allows the solvents to work themselves out more slowly and evenly. Use gentle exhaust to remove any solvents, but do not blow air directly over the finished surface immediately after application.
During the course of your project, you may experience large temperature fluctuations. This could be due to the time of year or depend on where you’re finishing your projects. In the winter, ventilation may cause temperatures to drop, and then rise again when windows/doors are closed. In the spring/fall, there may be very cool nights and warmer days. This will not cause any problems in the drying/curing, however, it is best to wipe your surfaces down with a little paint thinner or mineral spirits prior to application of your coat (use a rag lightly dampened with water for the H2OLOX products). When temperatures fluctuate, there may be some contaminants or solvents that may still be sitting on the surface. Wiping the surface with the appropriate product will remove those contaminants and essentially prime it to prepare it for the next coating. This is further described in the Application in Low Temperatures guide.
Store Waterlox products in a cool, dry place away from direct sunlight. Products will store best in an area that doesn’t experience wild temperature extremes, so opt for interior, climate controlled areas instead of sheds or detached garages. H2OLOX products are water-based and are susceptible to freezing. All products should be kept out of extremely warm places to avoid potential skinning or gelling of product.
Humidity plays a very minor role in Waterlox products. All Waterlox products, excluding H2OLOX, are oil-based products and are not really affected by humidity. H2OLOX is also minimally affected by humidity as it is still truly an oil-based finish that is simply delivered in water.
At low humidity, solvents and water will evaporate a little easier as the dry air can hold more vapors. Solvents are less affected because they are not competing with any existing moisture in the air like water does, but drier is still better. H2OLOX products may dry extremely quickly in a very dry environment. This may reduce your working time, but shouldn’t create any typical issues.
At high humidity, the air is already close to saturated with water vapor. This leaves less room for additional water vapor (in the case of H2OLOX) or other solvent vapors. This can slightly slow down drying times, but with moderate ventilation, the affect will be minimal. Good airflow once dry will ensure a good cure.
Other Environmental Factors
There are a few considerations about where you finish your project other than just temperature and humidity. The three most common would be avoiding direct, intense sunlight, windy or completely stagnant environments.
Intense Direct Sunlight
Finishing projects outdoors is a great way to keep odors out of the home or shop and may even help to minimize dust/debris from a shop or construction environment. However, applying finishes in direct, intense sunlight should be avoided at all costs. This is only critical in the first few hours and has to do with the same effects of very high temperatures. Direct, intense sunlight will not only heat the surface, but the UV can also speed up the curing reactions at the surface. This can lead to wrinkling and poorly cured finishes as mentioned in the High Temperature section. If you need to finish your piece in an area that will see regular sunlight, try to apply finishes early in the morning or late evening to minimize exposure. Once the coating is dry to the touch, sun exposure will be less of a concern.
Applying wet coatings in high wind environments can cause a variety of problems. Most obvious would be debris or other particulate being blown into and becoming stuck in the finish. However, equally troublesome would be too rapid drying of the surface. Too much wind will speed up solvent and water evaporation at the surface more than the rest of the coating and can again lead to skinning and poor curing as mentioned in other sections.
Completely stagnant environments are the worst option for a finishing environment. Aside from being dangerous to work in, they may never cure properly. The problem with a completely stagnant environment is twofold; the surrounding air/enclosure may become saturated with water/solvent and may essentially prevent the coating from ever truly drying and without a fresh supply of air, there will not be enough oxygen at the surface to cure the coating. Gentle ventilation and exhausting of solvent fumes/vapors is important for safety and proper drying. Once dried, good circulation and fresh oxygen will result in a proper through cure of the film.
Consider the size of your project – good ventilation and circulation are necessary for proper drying and curing for all Waterlox projects. However, based on the size of your project, that may require different things. For example, finishing the entire first floor of your home will need more ventilation and more airflow than finishing a small jewelry box. With larger projects, there is more solvent or water that needs to evaporate, smaller projects will have much less. Given the same amount of air space, a much smaller percentage of solvent/water is evaporated into that air.