Shop & Field: Cabinet Heater

If you don’t keep your shop heated all winter long, a heated cabinet for water based paints and chemicals can keep them from freezing.  Here’s mine.

I heat my workshop with a fairly new 80,000 BTU furnace I acquired when

someone converted their home from oil to natural gas.  I fitted it with a 35° thermostat, but I typically only run it when I’m in the building.  The building is pretty well insulated and warms quickly, and even if the shop is idle (furnace off) during a week-long cold snap. the temperature inside rarely gets below 40°.

Nevertheless, I got tired of worrying about ruining my paint inventory in a bad freeze.  Between the latex and acrylic paints, dyes, clear water-based finishes, additives and extenders, specialty air brush paints, glues, caulks and adhesives, you wind up with a lot of money invested in water-based chemicals.  Epoxy is temperature sensitive as well, and ridiculously expensive.  Moving it indoors seasonally is a hassle, and usually leaves you lacking something, and wondering where it might be.

After years of intending to something about it, I did.

I found a small used flammable paint cabinet on OfferUp for $50.  I have a full-sized one already for my oil based stuff, and thought the double walled construction would offer some insulation value.  I don’t think I could have built a simple plywood box for $50.

I picked up a NOS (New Old Stock- no longer brand new, but never used) explosion proof cabinet heater on eBay for $16, including shipping.  It draws 150 watts, and came equipped with a built-in 50° thermostat.  So much better than the lightbulb-in-a-plywood-box that I never got around to building.

I had a 15A inlet connector lying around, and managed to adapt one of the paint cabinet’s barrel bungs to mount it.  I can use a standard extension cord to power the heater.

The cabinet was a dirty red when I picked it up, and covered with stickers and goo.  I gave it a hasty paint job and mounted it on casters,  I have most of my stuff on casters.  It makes it easy to rearrange things as well as to clean underneath them.  Also, I’ve experienced nasty rust damage with metal cabinets sitting directly on concrete in the past, so, casters all around!

If it was cold enough to force the 150 W heater to run 15 minutes for every 15 minutes it was off (12 hrs/day), and your electrictity was 12¢ per kWh, that would translate to 22¢ per day, or about $6.50 per month.  Three steady months of that would cost $19.50.  Protection for an entire winter for less that a decent gallon of paint.  In my experience so far, I rarely catch the heater on.

Return to: Practicalities