Appying finish at cooler temperatures

[Lee Schierer]

For years, I've used Deft Clear wood finish on my furniture projects. I know from experience that I can apply it at temperatures near freezing with no problems other than it takes 24 hours to dry.

I have some trim and door jambs that I need to finish with Minwax Quick Drying Polyurethane to match other trim in the same room and I don't want the fumes in the house. I have place where I can apply the finish where the fumes won't be a problem, but the room temp is only 60 degrees. Will Minwax polyurethane have a problem being applied at 60 degrees? There is nothing on the can except to say that drying times are based on 77 degrees.

Has any one done this?

[Jim Becker]

60ºF is likely well below the temperature range that the manufacturer recommends for the finish and cold will definitely affect curing for an oil based finish. Lacquer and shellac, which are evaporative, are a lot more tolerant, although best results certainly are had at warmer temps. Can you get your hands on a portable electric radiant heater or two? These heat objects and may help you accomplish the task.

[Mike Henderson]

One thing I've done - although I don't know how many pieces you have to do - is to take an electric blanket, put plastic over it, and then put the finished pieces on the plastic. Turn the blanket on high. Most blankets have an automatic shut off at 8 hours so if you need more time, you'll have to go back and reset the blanket.

This will easily get the work above 70 degrees.

Mike

[Bennett Ostroff]

While not ideal, I think you will be okay. In lower temps I've had better luck with the full strength minwax poly. The solvent in wipe-on formula will take too long to evaporate and will affect the appearance.

To save on heating I often finish the bottoms of my pieces with poly in temps in the 60s and have never had problems. Then I warm my shop up to do the top. Since your items won't be high use, they'll have plenty of time to cure once in room temp.

[Wayne Lomman]

Applying at 60F/15C is fine. The product data on the website will confirm this. It will just be a bit slower.

77F/25C is quoted on most products because it is the generally accepted laboratory norm for testing coatings. All products have an ideal temperature and an acceptable range. The range is commonly 10 - 40C and the performance only becomes risky beyond these conditions. Always check data sheets to confirm the details though. Cheers

[Lee Schierer]

Applying at 60F/15C is fine. The product data on the website will confirm this. It will just be a bit slower.

77F/25C is quoted on most products because it is the generally accepted laboratory norm for testing coatings. All products have an ideal temperature and an acceptable range. The range is commonly 10 - 40C and the performance only becomes risky beyond these conditions. Always check data sheets to confirm the details though. Cheers

I went to the Minwax website and found the Fast Drying oil based polyurethane (http://www.minwax.com/wood-products/clear-protective-finishes/interior/minwax-fastdrying-polyurethane) product I'm using they make no reference to temperature, not even drying time at their website.

[Lee Schierer]

Well after about 6 hours I went back and checked the pieces I had applied finish to earlier except where I was a little heavy with the first coat the finish was dry to the touch but not hard. I applied a second coat so I will see in the morning how that turns out.

[Art Mann]

I have used the Minwax rattle can polyurethane many times at temperatures around 60 or 65. It dries a little slower at that temperature but not nearly as slowly as the brush on material. I use it for small CNC router carved products that need a really durable finish - like personalized trivet sets for example. If you can afford the rattle cans, I suggest using those.

[Bennett Ostroff]

A while ago I spoke to Minwax customer service and they said the lowest recommended temperature for their oil based polyurethane and oil based stains is 50 degrees.

[Wayne Lomman]

The Minwax page that Lee references says that drying times will be longer at temperatures below 77F/25C. It doesn't specify a lower limit, but this indicates that you are good to go at lower temperatures.

All architectural coatings have to work in a range of conditions. The 77F/25C is the ideal but if you are on a building site for example, you need to be able to use products for the majority of the year and they are designed accordingly. Cheers

[Lee Schierer]

Well, three coats of brush on finish have been applied and dried. I caught a break in the weather as it warmed up to 68 outside yesterday. The finish has dried and I will probably put the trim pieces in place later today. So I know you can apply Minwax at 60 degrees with no problems.