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Cold Shop Tips?

Mark Durrenberger

Mark Durrenberger

Joined
Jun 4, 2021
Messages
23
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311
Location
Hudson, MA
Website
www.instagram.com
I recently moved. My new shop is in an unheated basement. Lately it's been running about 50 - 53 degrees F (10-12C).
The dust makers (lathe, bandsaw) are in a nice, well insulated space and can be brought up to temp quickly with a 1,200 watt heater. But the area where I want to do finishing (not dusty) can't be enclosed. So it's cold all the time. I've discovered that finishing a piece at ~50 degrees is suboptimal. Any recommendations?

I was thinking about building an insulated box with a thermostat controlled heater (not unlike a wood drying cabinet). And keeping the box at about 70F (21C). Will that work? Is a lower temp OK (65?) My preferred finish is wipe on polyurethane. Also, should I keep the finishes in "warm" storage?


Thanks
 
I think a portable propane heater, or even a kerosene heater would work. However I would get the room heated and switch off the heater before applying finish.
 
Hello @Mark Durrenberger. Yes, I have an idea, but it is a full-on, no-holds-barred, damn the torpedoes, money is no object proposition.

Insulation of the entire foundation and the floor joist/rim joist area above the foundation, and modification to the building HVAC system to provide a source of conditioned air into your workshop.

I'd talk to your municipal building inspector to discuss your local energy and building code requirements to cover all your bases. And electrical requirements while you're at it.

And as a side note, machine-specific dust collection is going to be a very serious matter to make sure your HVAC system isn't sucking in your wood dust, contaminating the hot and cold heat exchange surfaces, contaminating open burner systems, and making a mess of ductwork. Covering the return air duct openings from your basement area with their own pleated furnace filters (MERV 10-11 rated filters might do the trick, and they will be oversized for the duct opening) will go far to keep wood dust out of ducts/furnace/air conditioner. Replace the filters monthly.

Sorry, Wyatt, in my state (MN), "Unvented room heaters and unvented decorative appliances shall not be installed in any dwelling or occupancy." (This is a MN code amendment to the International Fuel Gas Code.) It may be legal under certain circumstances in other states, but dead is dead, and it's a bad idea everywhere, legal or not.

Be comfortable, be safe, and enjoy your craft!
 
I used an old fridge with a 25W light bulb to keep my finishes warm when we lived up north. I like your idea of a thermostat controlled heat source and it may be your most affordable option.
 
Mark Durrenberger said:
I was thinking about building an insulated box with a thermostat controlled heater (not unlike a wood drying cabinet). And keeping the box at about 70F (21C). Will that work? Is a lower temp OK (65?) My preferred finish is wipe on polyurethane. Also, should I keep the finishes in "warm" storage?
Click to expand...

I think that would work, as long as there was enough ventilation to let the finishes dry/cure.
There are plenty of temperature controllers on Amazon, for example. I bought two, one for a small fridge to temporarily store peafowl/guinea/chicken eggs at the optimum temperature for hatching. Another to control the temperature of a brooder heater for little chicks. Easy to use - put the temperature probe in the enclosure, set the temperature, plug in the fridge or heater.

JKJ
 
The hvac for the floors above are heat pumps. The water heater is gas. But that’s not subject to dust from my tools since they are in an enclosed space. Yes the basement walls need insulation. But the rim joists are done and the floor above is mostly done (1” of spray foam installed for air sealing and 6” of fiberglass batts coming soon, almost half of the basement concrete wall is above grade so the walls are cold. )
 
Two to four inches of rigid foam insulation on the walls with good air sealing and filling the rim joist cavities with spray foam will make a world of difference. We also have foam under the concrete slab, but it's probably too late for that in the new place! The zoned heat in our basement has never, to my knowledge, turned on with the thermostat set at 64 degrees despite some exposed wall (not as much as you have). No good reason for a basement to get that cold.

My shop is 64-65 during the day in winter, dropping to mid 50's overnight and I haven't had any issues with oil based poly drying. It takes a little longer than when it's warmer but still gets there. Some of the WB finishes call for higher temperatures so I crank the thermostat up a couple degrees when finishing a larger project and keep the heat on overnight. When I needed to speed up a tung oil finish on some small pieces I made a drying box by putting a light bulb in a big cooler with a temperature controller; that let me keep them at 85 for several days. A violin building friend used a big freezer in a similar fashion for curing the varnish on her instruments; they needed an elevated temperature for a week or two between coats because of the kind of varnish she used. An insulated purpose built box would also work fine.
 
Insulation!

Strap the walls, fit foamboard or rockwool between, cover with drywall, osb or similar, paint and enjoy. The thicker the better. Do the same on the floors if you can (not drywall- Adventech or exterior grade plywood)

Unvented heater in a basement is a terrible idea, adds CO and H20 in a poorly ventilated space. For that matter, using solvent based finishes without adequate venting will catch up to you as well.
 
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It looks like I didn't fully understand your question. I thought you were talking about a drafty outbuilding. In the case of your concrete basement, ideally good insulation and proper central heating system is your solution.
 
Portable electric space heaters are an easy and inexpensive solution. Another solution is to use a finish that will cure at the temperature of your shop in winter.
 
I'm fortunate that my shop is an enclosed one car garage in a split foyer home. I keep the vent open and it stays decent in winter, so far. Coldest while living in SE TN was 60 in the shop. I do have a portable electric heater that helps take the chill off. Got up to 70 once.
Edit: I did build an insulated wall over the metal garage door.
 
Steve Tiedman said:
And as a side note, machine-specific dust collection is going to be a very serious matter to make sure your HVAC system isn't sucking in your wood dust, contaminating the hot and cold heat exchange surfaces, contaminating open burner systems, and making a mess of ductwork.
Click to expand...

When I built my shop I had a heat pump installed for central heat and air. Comfortable year around in all rooms. I was concerned about the dust as you mentioned. The inside unit has two filters, one large filter between the shop and the plenum and one internal. They collect almost no dust which might mean the DC is working sufficiently. (Cyclone, pickups at lathe, bandsaw, drum sander, etc.) And I never, ever fill the air with fine sawdust by power sanding at the lathe with rotating disks.

I've had two stand-alone shops and one in 1/2 of a 2-car garage in the house and none were heated. I used a kerosene heater and started it about 1/2 hour before I planned to work. It worked but was an effort. Also ran a dehumidifier for the summer humidity. Putting in central heat and air when I built my forever shop here at the farm was the smartest thing I've ever done. Besides marrying my Lovely Bride 55 years ago, of course.

JKJ
 
Mark, yes you can make an insulated box in which to finish turned pieces. I needed one for epoxy thread finish on fly rods I was making at the time, and it has worked well. A box also reduces the amount of airborne debris that settles on your finish.

I don't believe you need a thermostatically controlled heater. Build your box, put in 1-2 60 watt incandescent bulbs. They give off just the right amount of heat for a small space. Yes they're hard to find. Try your local Habitat for Humanity Resale Store or other thrift shops. I used halogen puck lamps from the Box store, which are sold for cabinet and under-cabinet lighting, as they would provide light over the full length of the box, an aid in applying finish. Halogen also generates heat in the making of light.

When you've got the box made and the bulb holders installed, plug it in with a thermometer inside. It will soon reach equilibrium temp. If the temp is too high, unscrew one bulb or drill a couple small vent holes. If it's too cool, add another bulb. Placing foam insulation on top of the box is another way to retain heat.

Using a discarded refrigerator is an easy way to have a box without woodworking. Put the bulbs at the bottom and the heat will rise nicely.
 
Dean Center said:
1-2 60 watt incandescent bulbs. They give off just the right amount of heat for a small space. Yes they're hard to find.
Click to expand...

I think someone mentioned reptile heat lamp bulbs too. I got one to try for chick brooders but it didn't quite make enough heat. Seems like it might be fine for finishes if the incandescent bulbs are hard to find.

Another thing for gentle heat to reduce the humidity might be the "damp chaser" electric heating rods. These produce a gentle heat, have a regulated heat, some come with a thermostat. I once installed one in a piano when we had an unusual time of several month of daily rain and the piano keys started sticking. The damp chaser fixed the problem in 1/2 a day. I have a very short one in a gun safe, a gentle heater made for gun storage humidity control.

Some years back when the plan was to quit selling incandescent bulbs I bought a supply for just in case. At that time, the LED light temperatures were not too good but they are far better now.

JKJ
 
sounds like you are planning to insulate the the joists in the cellar. You may want to consider insulating walls instead. It’s more energy efficient if you insulate the walls, with the added bonus of keeping cellar warmer in winter and cooler in summer, with no extra energy cost. It also makes house feel more cozy because the floors stay warmer.

I believe that the latest energy codes in Massachusetts requires insulating cellar walls instead of joists. My house is built this way, I really love it. I’m considering spray foam on joists just to stop the noise from the shop going upstairs, but you already have that.
 
Another thing to consider if you’re going to use the cellar is a radon mitigation system. Mine cost about $1,000, but a nice side effect is it does a great job of keeping the dampness down. Works better than a dehumidifier and costs almost nothing to run. Probably paid for itself in energy savings in 3 years vs a dehumidifier.
 
I work in an uninsulated and unheated shop. A nice, padded mat to stand on keeps feet a bit warmer. I wear a warm hat under my helmet. After turning an hour or two, the hands get cold and I take a break and wrap them around a warm drink. Many pieces are turned and put on the shelf to finish when temps are above 50F. Small items and holiday gifts can be finished in the inside office. Fortunately, the climate here is very seldom below freezing but I do tend to turn more during warmer weather.
 
My workshop is also in the basement, and in winter the temperature is 10-15°C. And I faced with exactly the same problem.
To dry finished parts, I use an electric oil heater. It's great because it can be moved anywhere, it's safe, and it can be left on overnight. I clamp the part in the lathe and place the heater underneath. A low power setting is usually enough to dry the finished parts overnight.
 
Mike Novak said:
Another thing to consider if you’re going to use the cellar is a radon mitigation system. Mine cost about $1,000, but a nice side effect is it does a great job of keeping the dampness down. Works better than a dehumidifier and costs almost nothing to run. Probably paid for itself in energy savings in 3 years vs a dehumidifier.
Click to expand...
Radon is thought to be the #2 cause of lung cancer behind smoking. Wood dust, especially from hardwoods is a lung irritant. Although no definitive studies in increased risk of lung cancer of radon combined with dust, there is a casual relationship that IMHO warrants doing your best to eliminate both.
 
While I don't have the lower temps most folk have to contend with. Before moving to the coast, the in land temps could get to single numbers Celsius,the way I got around the problem was simple. I suspended an old fridge grating type shelf over an old room oil heater, popped the piece on top, then placed a cardboard box over the top of the piece. All the heat is captured in the box where the piece is work like a treat.
 
Wyatt Holm said:
I think a portable propane heater, or even a kerosene heater would work. However I would get the room heated and switch off the heater before applying finish.
Click to expand...
I would discourage this idea...propane heaters give off fumes as well as provide an ignition source for a dust collecting in a confined space. Just my two cents. Instead...I would encourage some form of 'radiant' heat which doesn't use an open flame.
 
I am quite particular about my finishing, but even if I were not, I would bite the bullet and make the investment required to insulate and heat the space. If I had to keep the finish warm (but not too warm) and also warm the piece I was finishing (not ideal to put finish on a cold piece) then, after I had put on the finish, handle it to carry it to the kiln to dry/cure, I would be making my life complicated and worry that I was introducing several unstable factors that could compromise the result.

I have great respect for folks who can work in cold shops, but I am not one of them.
 
Gord Cameron said:
I am quite particular about my finishing, but even if I were not, I would bite the bullet and make the investment required to insulate and heat the space. If I had to keep the finish warm (but not too warm) and also warm the piece I was finishing (not ideal to put finish on a cold piece) then, after I had put on the finish, handle it to carry it to the kiln to dry/cure, I would be making my life complicated and worry that I was introducing several unstable factors that could compromise the result.

I have great respect for folks who can work in cold shops, but I am not one of them.
Click to expand...
Me either. 10 below 0 right now, no insulation in my shop.
 
David A Morris said:
Me either. 10 below 0 right now, no insulation in my shop.
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10 below? Yikes. Saw that in PA as a kid but never here in TN until one cold snap decades ago.
My car wouldn't start! How rude. I disconnected and carried the battery inside and let it warm up in some hot water in the bathtub. Started right away then.

This afternoon it was over 60 - I worked outside in a long-sleeve shirt, no hat.
 
My shop has the same oil burning furnace as whats in my house. When I go into the shop I turn it on and in a few minutes it will be up to 60° and I let it go till it reaches 68° or 70°. Then off and it will be warm enough for the whole day. If I have to do anything in the garage I use a torpedo heater and heat it. Have done that for years and still here. It warmed up to 42° here yesterday and my wife came in and showed me out my window that the snow slid off the roof but did not fall and I have a 5 foot drift hanging from the eaves (south side of house). There is about 3 feet of snow on the ground right now. We're supposed to be in the 40s for a few days so some of that will melt.
 
I recently added an oil filled radiator heater to my lathe room for the same reason. The type that look like an old time room radiator. I'm amazed at how well it does. I leave it on all the time because it uses very little power and is safe.

For your situation an upright freezer with a very small fan to move air thru it and just a light bulb for heat would work great. You can find the freezer for free on marketplace. I use one for a kiln to dry bowls and just a light bulb heats it to 100 degrees.
 
Steve Tiedman said:
and modification to the building HVAC system to provide a source of conditioned air into your workshop.
Click to expand...
I spent 32 years in the hvac business. This is not a good idea. Where air is supplied it must be returned, which means any vapors get circulated through the house. The dust could be filtered but trying to keep up with an organic filter to grab the vapors just doesn’t make sense.

As for curing poly, you want it at least 70 F. Your idea of a temp controlled box is spot on. Mine is sort of temp controlled by how much air I let pass through it. I have a 400w heater in the box and can move flaps to control airflow - cheap and dirty, just the way I like it when it works.
 
Doug Freeman said:
I spent 32 years in the hvac business. This is not a good idea. Where air is supplied it must be returned, which means any vapors get circulated through the house. The dust could be filtered but trying to keep up with an organic filter to grab the vapors just doesn’t make sense.
Click to expand...
Yep, Doug, you're dead on, I'll take my crow deep fried. I should have suggested other mechanical system options to provide conditioned air into the space. Something stand-alone, of which there are more options available today than 20 years ago.
 
If you have 220v outlet... For years I have used a shop heater I bought from Northern Tool a dozen years ago. I see them on Amazon for less than $100 on Amazon. Electric Garage Heater 240V, 4,800-watt Fan-Forced Industrial Heater, With Thermostat Control, (that's not the same one I have but it looks identical and I see others with different brand names on it for similar prices With near 17,000 btu it will easily heat my my 525sq ft insulated garage shop even in sub freezing temperatures at a cost of less than $5/day. I bought one for my wife's potting shed about a year ago as well.
 
Dave Hulett said:
If you have 220v outlet... For years I have used a shop heater I bought from Northern Tool a dozen years ago. I see them on Amazon for less than $100 on Amazon. Electric Garage Heater 240V, 4,800-watt Fan-Forced Industrial Heater, With Thermostat Control, (that's not the same one I have but it looks identical and I see others with different brand names on it for similar prices With near 17,000 btu it will easily heat my my 525sq ft insulated garage shop even in sub freezing temperatures at a cost of less than $5/day. I bought one for my wife's potting shed about a year ago as well.
Click to expand...
With current electricity supply charges, heating my shop would be an exercise in throwing money out the window. I guess in the last 10 years its doubled a couple of times, so much about a third of houses here have solar on the roof and many have solar hot water to boot. There are various subsidies provided by State and Federal Govts to help with the cost, unfortunately we dont quite meet the requirements.
 
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