Finishing in cooler temperatures.

[NCGrimbo]

I'm going to be applying some stain and poly on a project soon and I'm a little concerned about the temperature in my workshop. If I run my heaters for about 2 hours, I can get the temp in the 60's in the shop when the outside temps are in the 50's or cooler. (My shop/garage's exterior walls are uninsulated.) The stain and poly mention longer drying times when it's cooler, which I can live with. But I'm wondering if there's anything else I should be aware of when applying stain the sub-70 degree temps.

Thanks,
NCGrimbo

 

[Gofor]

You should be fine with the stain, (above 50) if you wipe off the excess.

The poly will definitely dry slower (65 is recommended, but it will dry at 55 if not too humid). However, the poly will have a lot longer flash time (period evaporating the solvent), and longer tack time, so it will be much more prone to run and sag at lower temps. After you apply it, you will need to check for runs and sags up to 1/2 hour after you get done with applying it. The brush on/wipe off method (poly thinned about 30%) will give thinner coats, but less chance of it running, and easier to control if it does start. If spraying the poly, use light coats and give it plenty of chance to set before coming back with a second coat.

If it drops below 50 in your shop at night, you may have to give an extra day between coats for it to be hard enough to sand.

The above applies to oil-based "poly"/stain. If using water based, I defer to those that use it as I never have.

Above only based on my experiences in an unheated garage.

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