I intend to stain a piece of smooth timber to use indoors as a mounting board for some coat hooks; something I've never done before. The instructions for the stain I purchased suggest not to use below 10°C, and it's currently 7°C here during the day. I have a garage I can use to sand the wood, apply and dry the stain out of the rain, but it is unheated.
Will I run into problems if I use the stain in sub-optimal temperatures? Advice websites advise against it, but don't go into the specifics. An answer to another question suggests leaving an exterior fence stain until warmer weather in spring:
Didn't stain my new fence this summer: do it while its cold or wait until next year?
Definitely wait. The temperature will be dropping low enough during the stain's curing process that many problems could present themselves.
but I'd like to do this while I have the time and inclination! This answer doesn't elaborate on what these many problems are (stain taking 10% longer to dry? stain not staining at all? wood spontaneously combusting?!) and how problematic they would be.
Best Answer
I haven't seen anyone test 'how do bad conditions affect staining?' Usually what you'll see is someone posts a picture of a bad stain job and they ask 'what did I do wrong?' The answer is typically temperature, humidity, or technique.
Stains work by penetrating into the wood, getting absorbed into the pores of the wood. Anything else that gets into those pores will hinder absorption, and you'll end up with a blotchy inconsistent stain. That's why you want your wood dry.
Low temperature is less important than moisture, with the exception that if there is frozen water in your wood, that'll mess up the stain as well. If the wood is cold but stays dry, you should be ok.
In ideal temps, the stain should dry in 1-2 days. Low temps will slow the drying process, and if snow/rain gets on the wood before it's done drying, you're in trouble.
If you can keep the wood protected from rain while it dries, you should be fine.