View Full Version : Shop - Temporary heat

12-07-2002, 11:26 AM
Looking for suggestions for temporarily heating the garage - erh I mean, "boatshop". It's 20X20 ft, not insulated, but otherwise tight.

Just looking for enough heat for the occasional use of some chemical varnish stripper, wood bleach, and maybe some other solvent related jobs, that I don't want to be doing in the basement this winter.

What works for you?

Don W
12-07-2002, 11:54 AM
Torpedo heater has always worked quite well, but keep it away from the chemical type stuff or we'll be reading about you in the paper.

12-07-2002, 12:21 PM
What Don says, but make sure you get a propane fueled one, the kerosene exhaust/smoke is very irritating in small, enclosed spaces. Propane burns very clean with no perceptable exhaust or odor. Sometimes a cheap 20" box fan can help move the heat around and even things out.

Mike Vogdes
12-07-2002, 12:51 PM
I have a 12'x24' shop at home and use a combonation of a kerosene and electric.

I use both while I'm out there working and when I'm finished for the night I'll leave the electric heater on so the paint, epoxy or whatever stays relativly warm. Seems to work out pretty well...

Bill Perkins
12-07-2002, 02:11 PM
I've been gearing up for Winter too . Assuming proper operation , which gives off the more dangerous exhaust gases ? K1 kero or propane ?

12-07-2002, 03:13 PM
Assuming proper operation, neither. In my experience. The kero (Salamander, torpedo, what cha call it) stinks only when it flames out due to an empty fuel tank. Both you and it needs O2 to fire and you and it emits CO2 so ya need some ventilation.


ken mcclure
12-07-2002, 03:21 PM
I use a propane-fired radiant heater made by Coleman which clamps to the top of a propane tank. It puts out 45,000 btu and heats the space up quickly.

If you don't have insulation, you're going to be using the heater quite a bit. The above heater will use a standard gas grill tank (20lb), but I'd recommend that you get at least a 30lb tank for your use.

Lowell Bernhardt
12-07-2002, 04:10 PM

I don't know how motivated you are or what your money situation is, but for a building that size you could heat it with a blow dryer if youthrew up some insulation onto the ceiling. Hold on now, I mean the silver backed Celotex stuff not the itch you to death "Pink Cactus". For a 20x20 building you'd only need 13 sheets, at about $5-6 a sheet. You're talkin $85.00 max and you'll save that much in K1 or Propane if you spend anytime at all in the shop. If you were to put it on the wall directly behind the heater silver side out it will work as a giant reflector. And I agree a 20" box fan would do wonders. Hang it in the corner next to your heater and got o town.


Gary Bergman
12-07-2002, 11:40 PM
been running a kero nipco forever, can't beat em, except at -20 or so you have to cover the fan intake to start for a few minutes. biggest problem is alla the snow on my steel garage roof letting go of the snow while i'm in there and an avalanche when i come out!

ion barnes
12-08-2002, 03:26 AM
I much prefer the box heater absolutly because of the exposed flame even if it is hidden ina tube. A great deal of dust is inflamable too. But the box heater will be 220volt if its agood one. Got a welding outlet? or tap of your range connection.

12-08-2002, 09:45 AM
Here in Orlando in the winter I change to a 150 watt bulb. Sometimes I have to open the door...

Gary Bergman
12-08-2002, 11:42 AM
issat to let the bugs in to do the sanding?

12-09-2002, 08:32 AM
Well, if you leave the door open here, the dreaded Snow Snakes might find their way in. They are especially attracted to the aroma of hops, varnish, or epoxy. You definitely don't want them critters anywhere near your varnish job.

I agree some insulation will go a long way. One big drawback - I need to explain to SWMBO why I'm insulating the garage and not the 300 year old abode.

12-09-2002, 01:24 PM
This is cheapest you can get. SOLAR HEATED, my frame, over my boat is arched covered with 9 mil clear plastic, the inside is covered in 9 mil also, with about a 2" air space sealed inbetween the frames. When the sun hits it, even on these blustery New England days, it warms up to around 55-60 degrees. To help it even further, I filled the space around the cradle with dark colored concrete pavers I got from a buddy. They help hold in some of the heat during the day, so the feets ain't so cold while working on her when I get home at night.
The heater at night is an old milk-barn heater (forced-air)1500watt @ 120vac heats the space upto 68'. Warm enough for most anything to cure.
Total cost was under $200 bucks for everything.


12-09-2002, 06:01 PM
Propane burner in a 20 x 20 x 8 high space requires ventilation...but how much to be safe?... a 3'x 7'-6" side door to garage left half way open enough?..with the heater next to the open door?

capt jake
12-09-2002, 06:26 PM
Propane burner in a 20 x 20 x 8 high space requires ventilation...but how much to be safe?... a 3'x 7'-6" side door to garage left half way open enough?..with the heater next to the open door? OK, I have a 20x40x8 space. I heat with a catalytic propane heater (the kind that mounts on top of the bottle). I have 2 windows (about 24" high each). I leave both cracked about 3" all of the time.

No problemo!! smile.gif If you only have one place to ventilate, do that but use a fan to ciculate teh 'stuff' around. This way it will help to exhaust the CO. smile.gif

George Roberts
12-09-2002, 08:25 PM
I heat my 26x28' shop with a 1500watt electric heater. works well down to 30 degrees.

12-11-2002, 11:02 PM
As far as I know, Kerosene heaters are illegal in Connecticut. You might want to check up there in Mass. If your shop suddenly goes up in flames, and the insurance guy sees a melted kerosene heater......

12-12-2002, 03:02 AM
Any fuelled heater that isn't vented to the Great Outdoors is consuming the oxygen in your space and dumping water vapor and CO2. All of these are a bad thing.
I would avoid any kind of non-vented heater except if the space was particularly drafty.

My building shop is 12' x 33' , fairly well insulated and tight. I have two 1500 watt electric heaters, on individual branch circuits, two 250W heat lamps over my epoxy bench and lots of incandescent lighting. These seem to do the trick down to maybe 10F. At a WOT operating cost of $.50/hr., sometimes i concede defeat and work on something in the warm shop.

If a vented propane heater is practical, it'd be more effective and cheaper to operate.

Dave Hadfield
12-12-2002, 11:30 AM
I wouldn't breathe the by products of any heater which burns fuel, period, and I don't care what the catalyst is.

However, you can warm up the garage with that heater, then open the big door for a minute to let the air cycle once, then close up and continue with the more expensive electic. You get warm tools and materials, and clean air to breathe.

Alan D. Hyde
12-12-2002, 11:39 AM
Get a little schoolhouse stove. $100 or less around here, and it'll keep your boatshop good and toasty.

Also gives you a use for otherwise useless cut-offs and scraps.


Ron Williamson
12-12-2002, 12:40 PM
500 Watt halogen work lights are also excellent space heaters.

Sam F
12-12-2002, 01:49 PM
I use a double oil drum stove. There are a bunch of brands out there. Mine is an el cheapo called "Sotz".
It consists of one 55 gal oil drum with a steel door and regulator venting to another 55 gal drum sitting on top of the firebox drum. That upper drum vents into a standard 6" stovepipe to the chimney. The chimney is also standard stove pipe hooked to an insulated thimble in the wall.
It's a lousy chimney but cheap and easily replaced.
The Jotul I use at home is particular about its fuel. It must be dry and properly split to work. That’s not so with the drum stove. It will burn anything you can shove through the door. Wet, dry, pallet scraps full of nails, paper, cardboard you name it. And that upper drum is one heck of a heat exchanger. It isn't pretty. Heck, you’d have to improve it some to bring it up to ugly, but it works. Mine is nearly 20 years old and still going strong.

Lowell’s suggestion of insulating is worthwhile as is Alan's point about getting rid of scraps (and mistakes :eek: )
When I have a big woodworking project going I'd soon be buried under the cut offs if I couldn't burn them.

One wild suggestion: I saw an old photo of a shaker stove that was built into a wall. The door and draft control was outside on the porch. The stove body was inside the room with the chimney venting out the top. If you are allowed to (a big if), why not mount an oil drum stove like that. Use a metal plate (or masonry) installed in the wall with the door facing outside. Make sure all flammable stuff is far enough away or well insulated for safety. No warmed room air would be wasted supporting combustion but you’d have to go outside to stoke it. Another advantage is that there’d be very little dust/vapor explosion risk and no woodstove ash or dust inside the building to mess up your finishes either. If I were building a shop from scratch that’s what I’d do.

The stove I have looks something like the bottom picture:

Alan D. Hyde
12-12-2002, 01:50 PM
Donn, a full-size schoolhouse stove is a long, low, narrow stove that holds four-foot logs.

Most of the small, scaled-down, schoolhouse stoves will hold two-foot logs.

They are cast iron, and are not air-tight.


Sam F
12-12-2002, 06:46 PM
That's right Donn. A friend of mine has a monster maul and told me about the Sotz around 1980. They used to advertise in TMEN which is where he learned about it.
The darn thing is crude but it really works.
The only modification I've made is to add a hinged smoke door inside. It swings up when I toss in a log and keeps most of the smoke in the stove.

12-25-2002, 06:28 PM
For the last eighteen years I've heated my shop (ex-garage, 20x24', un-insulated but tight) with a stove like the middle one in Sam F's picture. It's a used stainless 55-gallon drum (it lasts much better than an ordinary steel drum) with a store-bought set of door, legs, and fitting for the flue. The flue is regular 6" stovepipe with a triple casing where it goes throught the roof. I put a simple flue damper in the pipe. Total cost, about $100. The main trouble with such a stove is that it has two speeds: off and too hot. But it's fine if you don't work too close to it. In about 15 minutes after lighting off, it heats the place to 50 degrees F or so when the outside temp is below 0. Nice dry heat and no problem with fumes. Cutoffs plus about a face cord of firewood last all winter.