Worried that the reading on your thermostat might interfere with your wood staining project? Most indoor rooms stay within the safe temperature range, but extremes on the hot or cold end can affect how the stain responds. Cold temperatures can slow the process. If your room feels more like a sauna than an igloo, the warm temps can speed up the process too much. Understanding how temperature affects wood stain helps you choose an ideal time and location for your next wood project.
Ideal Temperature Range
Wood stain works in a wide range of temperatures. Staining at temperatures ranging from 50 to 90 degrees Fahrenheit usually works, but the optimal temperature is around the mid-70s, not too hot and not too cold. Check the label of your product to find a specific temperature recommendation, because products can vary.
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It's not just the air temperature that you need to consider. The wood piece you're painting also needs to be at that optimal temperature for the best results. Say it's winter and you're staining a piece of patio furniture that's been outdoors. Even if you bring the piece indoors where it's warm to do the staining, the cold wood may make the staining process difficult. Give the wood time to warm up if it's colder than the room air. It can take several hours for the wood to warm, depending on its starting temperature.
Likewise, you need your stain to be in the ideal temperature range. You shouldn't store your stain in an unheated garage or cold area, but if it is colder than the temperature of the room, you can warm it up by putting the entire can in a tub of hot water for a few minutes. The ideal storage temperature for wood finishing products is between 65 and 75 degrees Fahrenheit.
Effects of Cold Temperatures
If the room air is too cold, it slows the staining process. Water-based stains rely on evaporation to dry and cure properly. In a cold room, that evaporation process is much slower. It usually doesn't start slowing down until the temperature dips below 70 degrees Fahrenheit, but even then, you might not notice the slower drying time. As the temperature gets closer to 50 degrees Fahrenheit, you may start noticing the slowdown more. Cold temperatures sometimes cause a water-based finish to dimple or get cloudy. The colder air makes it difficult for finishes to level and cure. Taking longer to dry also means you have to wait longer between coats.
If you can't wait for warmer temps, you can add accelerator to a water-based product. It helps speed up the evaporation process so the finish dries faster, even in cold temperatures.
Oil-based finishes don't tend to react to cold temperatures as much as water-based products, but they're still slower to cure. If you're trying to warm up your room, avoid using an open flame or combustible heater because the stain is flammable.
Effects of Hot Temperatures
High temperatures seem like they would be beneficial, but you don't want the room too hot. Excessive heat can cause the stain to dry too quickly. The result is uneven staining, blotchiness and overlap marks left on the wood. When the stain dries that fast, it doesn't have time to penetrate the wood fully. Also, it might dry almost instantly, which makes it almost impossible to apply the stain evenly. Direct sunlight can cause the same effect. That's not usually an issue indoors unless your project is near a window.
If you decide to stain wood under hot conditions, you can add an extender to water-based products. It slows down the drying process, so the stain doesn't dry too fast. This gives you more time to apply it.
Humidity is another major factor in how well your stain performs. Ideal humidity is between 50 to 70 percent, and high humidity can slow the drying process. Set up a dehumidifier if your interior room is really humid. Aim for about 50 percent humidity for the best results.
Ventilation can play a role in the staining process. Not only does proper ventilation keep you from inhaling dangerous fumes, but it also helps projects dry faster. If you can't open doors and windows, turn on a ventilation fan in the room to keep the air moving out of it.