Not all of us have the benefit of a temperature-controlled shop. Winter is here and more cold temperatures are on the way, and before we know it summer will arrive, and we will be fighting heat waves instead. There are so many different finishes out there, and each have a different technique that works best for the individual product. I always recommend going to your favorite products website for specific product information or checking the label. Yet, the basics for many of them, whether oil or water-based, is similar.
Here are some tips and general rules to help you be successful when it comes time to finish your project, no matter the weather:
The desired temperature for applying and storing finishes is between 65° and 75°. You really don’t want to go above 80° or below 60°, or you will have problems.
When it’s cold dry time will slow down exponentially, and the viscosity of the finish will get thicker. This will make it harder to spread evenly, and the leveling agents may not activate to give you a smooth surface. The solvents can also get trapped in the finish and this will cause cracking and hazing.
During hot and humid temperatures, you will encounter the opposite problem. The finish will dry much faster, and the leveling agents will not have time to activate before the finish hardens. This can cause an uneven dried finish, bubbles and brush strokes. Direct sunlight can also be harmful during dry time. DO NOT dry in the sun. Many times, the surface hardens faster than the underlying coat causing blistering and blushing as the solvents try to escape.
- Store products in a temperature-controlled storage area. If the product freezes it may be permanently damaged, so it is recommended to store your products indoors during freezing weather.
- Don’t use any heaters with an open flame when using an oil-based product. This is VERY dangerous.
- You can use retarders to help slow dry time, and viscosity reducers and thinners to speed up the process. Just remember this can involve extra steps and rules. Be sure to read your products instructions before adding anything to your finish.
- Thin even coats are usually best. Do not apply another coat if the finish is still tacky, waterborne finishes in particular, (and try not to stick fingers in your finish if you think it’s still drying!) You’d be surprised how many customers make this mistake.
- When cold give extra dry time between coats. As a rule of thumb, I double the suggested dry time.
- Keep air moving in the shop to support drying
- Be aware of humidity and plan accordingly. I recommend an air system that pulls in outside air, rather then one that recirculates. Dehumidifiers or humidifiers can be helpful.
- Store products off the floor.
- A nice perk of waterborne finishes is the lack of harmful chemicals and smell. This means you many times you can finish in your home (brushing, not spraying). I personally will bring my projects inside and work on them in my kitchen, since I mainly do small woodworking projects.
By Kelsey Yongue at The CrystaLac Company