machine "Sweating" condinsation in shop...

Kentucky

Kentucky

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Dec 13, 2008
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We live in a climate with huge temp swings..Most people don't think of Kentucky as cold but here in the mountains it gets biter cold..Last winter down to -25° on several occasions..Like right now it will dip from 28° last night to 78° right now..You know what happens to big hunks of metal when it goes from really cold to warm, it sweats :grumpy: We are getting spray foam insulation in the ceiling and am getting ready to hook up a propane heater in the shop..Short of getting the entire building air tight or keeping it constantly heated does anyone know of any ways to help with condensation? More air circulation? Or are we pretty much stuck with maybe keeping the heat on at night on low to keep the shop temp above the outside temp all the time?
 
You have to keep the temperature of the items above the dew point during temp swings. Which generally means keeping the temp elevated in general due to the thermal mass of steel and cast iron.

Air circulation will prevent it from hanging around as long but won't prevent it.

Best bet for heat is an infrared unit so the tools are heated faster than the air
 
Circulating fans running at night. Point them at the machines that sweat.

Heater set on 50F running at night. Place them near the machines that sweat.

Dehumidifier running all the time. Place it near the equipment that sweats.

Spraying down big machines occasionally with WD-40 will also slow any water/rust problems down.
 
Well, we bought(because we knew this would happen) a 30,000 btu radiant wall mount heater..Which is way big for our space but I knew all that iron would not be easy to heat so we went with overkill..It has a thermostat anyway..Paid for a 125 gal tank that suppose to be here Friday.
Im thinking that heater set on low through the night with a couple fans circulating should mostly do it. What do you all think?
 
Kentucky said:
Well, we bought(because we knew this would happen) a 30,000 btu radiant wall mount heater..Which is way big for our space but I knew all that iron would not be easy to heat so we went with overkill..It has a thermostat anyway..Paid for a 125 gal tank that suppose to be here Friday.
Im thinking that heater set on low through the night with a couple fans circulating should mostly do it. What do you all think?
Click to expand...

Should work fine.
 
I'm not familiar with heating systems used over there, but a quick Google for "30000btu radiant wall heater" seems to show many unvented units. If yours is an unvented one, I suspect it's likely to make things worse: Every pound of Propane burned produces 1.63 pounds of water vapor. Adding that to your shop atmosphere will raise the moisture loading and increase the amount of condensation you get on cold surfaces.

There's a lot to be said for a dessicant-type dehumidifier. It has a heater in it to regenerate the dessicant which produces a similar heat output to a heater on low, so costs the same to run, but it pulls down the moisture level significantly as well.
 
I agree with timgunn1962. Water vapor is a product of combustion. If it is unvented I would suggest using something different.
 
Same climate here but I have no sweating equipment. Big shop, well insulated, wood heat in winter and AC in summer. I wouldn't have it any other way. Have not needed any heat yet this Fall & no AC in a month. This shop keeps a fairly constant temp.
 
timgunn1962 said:
I'm not familiar with heating systems used over there, but a quick Google for "30000btu radiant wall heater" seems to show many unvented units. If yours is an unvented one, I suspect it's likely to make things worse: Every pound of Propane burned produces 1.63 pounds of water vapor. Adding that to your shop atmosphere will raise the moisture loading and increase the amount of condensation you get on cold surfaces.

There's a lot to be said for a dessicant-type dehumidifier. It has a heater in it to regenerate the dessicant which produces a similar heat output to a heater on low, so costs the same to run, but it pulls down the moisture level significantly as well.
Click to expand...

^^^This for sure. If your heater isn't a vented unit, you will be making the problem worse.

Wood heat would be a nice option, if it was possible. It doesn't take much of a fire to keep an insulated shop at 50-60 degrees.
 
We have not had the problem yet but i know I will unless I do something now..mainly insulating the ceiling.....Ive never had too many problems with ventless heaters..Mom and dad have run them for years but always in a well insulated shop and a ceiling fan right above them. I know they put out water but Im hoping to counter that with constant temps and air circulation like they do..I actually wanted a vented heater but after all the expense of the new shop the budget was getting tight..Vented heaters are more than double and nearly triple the unvented heaters around here for some dang reason..Time will tell I guess.
 
I have condensation problems with my machines. I have a few big hunks of cast iron in my shop that like to sweat and flash rust if I go in and heat the shop up from outside ambient temps during the winter.
I have wood heat, but no insulation to speak of. I hoped to get insulated this year, but it looks like that won't happen. Just gotta be diligent about wiping machines down and keeping them oiled... also better forge ventilation sounds like it will help, and that can get addressed fairly soon.
This is a good topic, it's been frustrating for me to deal with for sure.
 
Salem, its aggrevating for sure..Our other shop which is all metal(corrugated heavy tin off a coal tiple to be exact) and when we would fire the wood stove and the ceiling would sweat like a hog. make it rain it would:grumpy:That was with no insulation just bare metal and no air circulation. I did the same thing, bought shop rags by the bundle and WD40 by the gallon :eek: We'er going to try a few different things with this shop..Water proof the ceiling for one, plenty of circulation and more constant heat(if affordable) We'll go from there and change if we need too I guess.
 
had the issue with the old shop with the little jet heater thing and no ins. in the walls heating things up only when i worked. liek Don when the new shop was built i did it right and had at least R19 in all walls and a shop dogz 45,000 BTU vented heater (no AC yet tho). it is set up to run 50 at night and 65 during workign hours. my tools and my joints love me for it
 
I have found over the years that no matter the shop if you bring a big freezing piece of iron up to room temp its going to sweat and it dosnt matter were its at..The only way to stop that is to keep it from getting cold in the first place.
 
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