applying polyurethane when cool

[bsheffer]

I recently installed a bunch of tung and groove pine in an area and now want to put oil based poly on it. The directions talk about not applying in temperatures lower than 65 or humidity higher than 80%. Well, today, it is going to be in the mid to high 50's and raining so I imagine the humidity will be higher. I really cannot just close and heat the area as I need fresh air due to the fumes.

The question is....is the only downside to applying poly in these temps the idea that it will take longer to dry?? If so, that is no problem as I have lots of time but I just want to get this project started??thanks-brian

[Howard Acheson]

Yes, one of the major issues is the time required to fully dry and cure. If you are using oil based poly, you can apply it, set up a fan to keep fresh air moving over the surface and staying off it for a week or two.

Oil based finishes dry by the reaction of their components with oxygen. Reasonable temperatures have little effect except for extending the drying/curing time. The fan and fresh air (oxygen) will ultimately cause the finish to cure, but it could be a long time.

[KC]

bsheffer said:

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I recently installed a bunch of tung and groove pine in an area and now want to put oil based poly on it. The directions talk about not applying in temperatures lower than 65 or humidity higher than 80%. Well, today, it is going to be in the mid to high 50's and raining so I imagine the humidity will be higher. I really cannot just close and heat the area as I need fresh air due to the fumes.

The question is....is the only downside to applying poly in these temps the idea that it will take longer to dry?? If so, that is no problem as I have lots of time but I just want to get this project started??thanks-brian

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Do you have a dust issue? If so, the initial 'dry' time would be a concern to me.

[JR1]

One problem that you hit with waterborne finishes is that when they cure at low temperature they become cloudy. I've seen that with oil based finishes as well. I'd suggest taking a test board and trying the finish process on it. Dust can be a problem as well. Also some poly finishes simply do not cure at all in high humidity.

You might consider renting a salamander like the larger of these . How many BTU will depend on the volume that you are heating. Heating the air will lower the RH as well. Around here ACE hardware rents them as well as most of the contractors supply. They rent pretty cheaply. Be careful with them as they need periodic attention due to their ability to start a fire.

[bsheffer]

Thanks for all the responses. I do not have a dust problem. I ended up applying a coat today and it appears to have dried already and it looks great. I ended up heating the garage to the high 60's so possibly, that did the trick.