Proper ventilation and adequate air circulation must be provided when using any wood finishing materials. Most oil-based varnishes dry upon exposure to oxygen, which is also known as “oxidative cure.” A lack of cross-ventilation (air exchange) provides less free oxygen, slowing the drying process. Cross-ventilation is the biggest factor affecting dry times.It is not recommended that any solvents or solvent-based materials be used in a non-ventilated area. It is the oxygen molecules in the air that interact with the varnish, creating a chemical reaction and causing the film to dry. Therefore, the better the ventilation (during and after all coats) the quicker the film obtains its final hardness and other properties.
ASHRAE (The American Society of Heating, Refrigerating and Air Conditioning Engineers) states that the typical air exchange in a residence using only mechanical HVAC can be as low as 0.35 air exchanges/hour. In most cases 0.35 air exchanges/hour will not be adequate to dry Waterlox in 24 hours. We therefore strongly suggest achieving a gentle flow of air by cross-ventilation. This can be achieved by the use of a box fan running at low-speed in a window or door exhausting to the outside air as well as an open window in some other part of the room or house to achieve 3 – 4 air exchanges/hour. Not only will this aide the drying process by pulling in fresh air loaded with oxygen, but it will exhaust the solvent odor.
Read the directions on the label completely before using, including information related to the use of a respirator while applying the finish. Lingering odor indicates inadequate ventilation, high humidity or both. If you cannot ventilate the area choose another product.
Be sure to use proper ventilation:
- While applying the coating,
- During the curing process (first 24 hours after each coating is applied), and
- Continue to ventilate area for 7 days after the final coat is applied.
Examples of poor ventilation:
- Ceiling fans do not bring in fresh air from an outside source, even if windows are opened. They circulate stale air around the room. In fact, ceiling fans have a tendency to direct too much air downward on the surface of the freshly applied coating and can potentially “skin” over the fresh coat. This slows down the drying time because the solvent is trapped beneath the skin, causing a longer or improper cure.
- Heating and air conditioning do not provide enough ventilation. Opened windows with air being exchanged, replenishes the room with fresh oxygen and vents the evaporating solvents.
- Closed doors cut off airflow in a room even if a window fan is in place. If the window fan is working properly, solvent odors should be exhausted and will not enter connected rooms.
- Closets are typically the most difficult areas to ventilate – leave closet doors fully open.
