Thinking I'll build a drying cabinet for drying the finish on stocks , realize it needs a little heat, but was wondering if I need to provide a little air . I have an old cpap machine that should be perfect as the air would be filtered.

I have found it depends on the type of finish and stage of finishing. If I am doing an oil finish, I will heat the wood then apply the oil, letting the oil dry as the wood cools with air circulation. If I don't and apply heat, oil absorbed into the pores will bubble out during drying and form nasty little dried oil blisters all over the stock. Once the pores are sealed, the stock can be heated a bit to aid drying. This also holds true for initial coats of varnishes like TruOil. I use an old cardboard moving wardrobe. The stock is hung from the cross bar and a small cube heater is placed just inside a cutout at the bottom. It draws outside air through a filter and blows it into the wardrobe. I keep the temp on low and it does a fine job.

I built a drying cabinet many years ago and use it all the time..It has a 25 watt bulb in the bottom and one in the top and a very small fan..

I also use it for rust blue and have a small hot plate and fan inside, but have not rust blued for probably 5 or more years..The best rust blueing is done by folks that do it all the time.

In the summer I use it without heat, and leave a slight crack in the door for air circulation..It keeps a wet finish from gathering lint and airborne crap..In the winter I use the one or maybe both of the bulbs and I have a thermometer insids the box and it has a glass window also.

After overnight or whatever, when dry I may hang it outside if the weather is right, hot with a mild breeze, that really drys wood and actually starts the curing process. Don't over due this in the beginning as you want the bottom coat to interlock with the next receiving coat..I like to start this process with slap on coats and a week or so to cure, then in the later stages 12 to 18 hours is enough between sandings. then in the box on the last coat and several days or weeks, whatever works with the schedule..All this is mas or minus, not critical as to time other than the wet sanding days..

I find it more than useful for a number of things..

Thanks guys for the advice.