Preparing a shop for sub-zero temperatures

ThinWoodsman

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I know the how-do-I-heat-my-shop-in-winter topic has been done to death, so I'll try to keep this pretty limited in scope.

Recently, I reached the limitations of the shop in my basement with its benchtop equipment. There is a barn on my property with a concrete pad the size of a single car bay. To make a long story short, I built a shop on that pad, and acquired some full-sized machines (14" lathe, knee mill). The walls and ceiling of the shop are insulated (~R21 on the walls, ~R30 on the ceiliing), but the concrete pad is not. The shop is 12x28 ft, so 336 sq ft.

Winters here (NH) get cold, 2018 being a great example - about three months solid where it didn't get above freezing, with lows somewhere around -10, -15 degrees for a week or two at a time.

Ideally, I would heat the shop 24/7 to 35-40 deg (F), but that seems impractical for reasons others have mentioned. So I'm looking at some sort of as-needed heat: a kerosene/propane heater with the door (into the rest of the unheated, uninsulated barn) open, or an electric heater.

What I would like to know is: what are the drawbacks to leaving the shop unheated in such conditions? Specifically, do oils and solvents and the like need to be removed from the shop during winter? Do sensitive measuring instruments (dial indicators, micrometers, gage blocks/pins, etc) suffer from being stored so far from their operating range? Will repeatedly heating the room from well-below-freezing temperatures cause long-term problems in any of these?
 
With the insulation that you have, I would say a small electric heater might be practical to leave on during the cold weather just to keep the shop above freezing. Maybe 1.5 KW or so. Then when you want to work in there about a 50K BTU propane heater would warm it up quick, maybe one of the radiant types that are designed to operate in a closed space.

We don't have weeks of really cold weather so I don't heat my shop (1200 sqft), and I'm not insulated near as well as your shop is, but when it's cold I fire up my 150K BTU propane torpedo heater and point it directly at the machines from about 10 feet away to get them warmed up before I run them. Maybe give it a couple of hours to warm the machines up until they are warm to the touch. If I'm going to be in the shop for extended periods, then I fire up the wood stove. I leave the computers & DROs on all the time.

Storing measuring tools at low temperatures won't hurt them, but don't try to use them when they are really cold. You could keep the tools in a tool box and bring them into the house. I keep some of my precision tools in the house during cold weather. At the temperatures you are talking about humidity is not going to be a problem.

Petroleum based oils & solvents won't be affected by cold weather, any water based solvents and cutting fluids could freeze or separate if cold enough.

The biggest problem we have here is an extended period of cold & dry, then a quick warm up with high humidity. Everything sweats, so when I know that it is going to warm up like that, I fire up the wood stove to dry out the shop.
 
Yeah, I know all about humidity - left for a week in August and came back to not only rust, but mildew growing on the just-installed walls of the shop. Bought a dehumidifier that's plugged into a timer to run it for an hour in the afternoon and an hour in the early morning. Seems to have solved the humidity problems.

Re: petroleum-based products and measuring tools: that is what I suspected, but I'm hesitant to ruin a gallon jug of way or circulating oil. For the measuring tools I was worried about metal creep due to the repeated warming/cooling (if shop is not heated 24/7), but looking into it more it appears that would be due to the small size of the devices and the relatively low temperature they'd be raised to (~60F).

For the first winter, I think I'll leave some consumable (read: cheap) dial indicators in the shop, along with filled oil cans. The expensive instruments and the gallon jugs of oil can be stored in the house until I can verify, come spring, that nothing got ruined.

Good idea on doubling up the electric and the propane/kero heaters. I may give that a go.
 
Flame heaters that run on hydrocarbon fuels (gasoline, oil, kerosene, propane, natural gas, etc.) react with oxygen in the air when they burn. The result is that large quantities of H2O (WATER) is produced along with with the heat. With an heater that is not externally vented, the shop will be dripping with moisture, especially when it cools down again. Opening a door or similar helps some, but by no means completely, and also lets your precious heat go out the door or window. If there is a way of installing a chimney, you will be much better off when burning fuels in your shop. Electricity works great in a closed room, no fumes, no cold air coming in to burn the fuel, and no energy going up the flue. Depending on costs in your area, the price of electricity can be quite high or pretty reasonable in comparison to burning fuels. Efficiency numbers and cost of installation and fuel must be factored in to figure out what is best for your situation.
 
From personal experience, one may work comfortably in an indoor shop with the temperature near or above 45ºf. Sure, you gotta dress for it, but you don't start chattering. If you could maintain that temperature with an electric heater, You could go to work and turn up the heat for a warmer place after a while. Or, keep it at that temp.
 
Once that concrete floor freezes solid, its dam near impossible to get the shop warm. Been there done that in Minnesota. I suggest radiant heaters, either electric or propane, use them to keep you warm. Works pretty well if you are running the lathe or mill. Not so much if you need to move all around the shop. before I got my heated shop, I also just gave up for about six weeks in mid winter.
 
Been there done that. Second the problem with the block of ice called the concrete floor. If at all possible keep it at 40 to 45 degrees ambient inside the shop all the time. Tried to use the kerosene torpedo heaters and the high end Kero Sun kerosene radiant heaters. Fumes to choke you out and stink. Plus it took forever to get the temps up. The circulating oil in the machines was the consistency of molasses. The machines just stayed cold even when the air temperature in the shop warmed up enough to work comfortably. Rapidly became not worth the effort once it truly got cold. My only regret with going to a fully insulated shop and heat was waiting so long to do it.
 
It is good to cover the entire floor in an insulating material. The 2' X 2' basement tiles that are OSB bonded to styro work very well. place them everywhere, and your heating bill will be lowered by more than the cost of the tiles.

I used to keep my shop heated to 5C (41F) but now I do it to 8C (47ishF). I can work on the machines after only a little heating of the air in the shop, and the condensation has gone waay down...
 
... and even when cold, such a floor will draw a HECK of a lot less heat from your feet!

[edit] - Don't have the problem myself here in Arizona, and we live in a well drained area, so the anticipated heavy rainfall from the remnants of Rosa will not be a problem. But I used to have a garage/shop in Oregon. Covered much of the floor with interlocking foam mats. I can certainly appreciate the value of your solution!
 
From personal experience, one may work comfortably in an indoor shop with the temperature near or above 45ºf. Sure, you gotta dress for it, but you don't start chattering. If you could maintain that temperature with an electric heater, You could go to work and turn up the heat for a warmer place after a while. Or, keep it at that temp.

Latex gloves (thin ones) keep fingers warm by avoiding perspiration evaporation cooling. My assistant friend & I use small ceramic electric heaters to warm our feet when working in one spot while waiting for the furnace or wood stove to catch up depending on which shop we are in.
 
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