condensation in the shop

[Marc Donnelly]

Today in Michigan it reached 64 degrees outside.
My shop is insulated but only heated when I turn on my propane heater. So today I got home and everything is soaking wet in the shop.This happens all the time in the spring, and my tools pay the price, RUST.
I have used a spray can rust inhibitor but does not seem to work.
Anyone have a good idea to stop my tools from taking a beating from condensation.
Thanks

[James Zhu]

In cold climate, the shop needs to be heated in the winter season. Not only for the comfort, but also keep the tools from rusting.

James

[Mark Bolton]

Several issues. Is your shop vapor barriered? Walls have vapor barrier? Floor/slab vapor barrier? Regatdless of either of those you need to be pulling moisture out of the space 52 weeks a year. If your propane heater is not vented combustion your dead. Propane (and a lot of natural gas) is 100% humiditity if burned in a non sealed combustion chamber.

[Bob Falk]

I would guess that your tools are cold and when the air heats up it carries more moisture which then condenses on the much colder metal.....and then, rust. I would, at a minimum, cover your tools during this period with plastic and see if that helps keep the moisture off the tools.

[Bill Orbine]

Heat the shop 24-48 hours prior to warm weather. Monitor and get ahead of the warm weather.

[Harvey Miller]

If you're unwilling to heat the space, I would insure that the air is at least circulating. Maybe an exhaust fan & passive inlet vent?

[Bill Dufour]

Dew point? Is the wood getting wet or just metal?
Bil lD

[Bradley Gray]

My big planer and joiner are in an unheated space. I use fans to get rid of condensation.

[sean meltvedt]

The shop doesn’t have to be heated to comfortable temps, it just has to be warmer than the dew point. If the shop is too large for this, then I would consider mobile bases and move the iron to a smaller portioned off and heated area of the shop.

[Philipp Jaindl]

My basement shop also isnt heated, running a dehumidifier fixed all humidity Problems ive had.

[Mike Cutler]

Marc

Long term fix is to insulate those walls, instal a vapor barrier and the some type of air control.

My shop is also not heated/cooled and only has a vapor barrier and sheet rock on the walls. ( It's barn board and batten.)
All of my machines are covered when not in use. The large flat surfaces have a layer of WD impregnated cardboard, with a 3/4" layer of plywood on top of that, and then covered with moving blankets. I bought the type from Harbor Freight, because I honestly don't think there is a natural fiber in them. They never absorb moisture.The machines are always kept waxed and in winter when I don't expect to use them, a layer of LPS6 goes on top of the jointer and planer, before the layers.
Tool boxes and everything else are bagged.
Even with this I get rust from time to time. It's just not gross amounts, and can be easily cleaned off. If I don't do this, I get some serious issues.
It sucks!

[Darcy Warner]

All these other options sound like way more work than just heating it.

[Marc Donnelly]

Thanks everyone for all your suggestions and input. First what I have to is get some ventilation in there. I have everything stuffed with insulation and no vents, I will install two power ridge vents. I have no means of constant heat. So I will get a dehumidifier as well. And cover my big equipment with blankets too.

I will go from there and see how things work out.
Thanks

[Matt Schrum]

A dehumidifier will help-- but as someone mentioned above, if your propane heater isn't vented, this is going to keep happening. Combustion products are CO2 and H2O-- so heating up the shop with an unvented heater is going to increase the moisture content of the air. Once that air cools back down, the moisture drops out and that's your dew problem. If you vent your whole shop, you're also going to let out a lot of your heat-- but if you can find a vented heater, just the exhaust is vented, which results in a lot less heat loss.

[andy bessette]

...I have to is get some ventilation in there...

You figured it out.

[Andrew Seemann]

Keep on mind that you also don't want to power vent in a bunch of warm moist air when your machinery is cold. You want to keep the moisture away from the machines, and if it is more humid outside than inside, venting makes the problem worse rather than better.

[Jon McElwain]

I lived in SE Alaska for 14 years and had a shop there. It is a rain forest - always wet and cold. I ran a dehumidifier most of the year and it seemed to manage the humidity pretty well. I had the occasional rust spot from a spill, but I don't think that I ever had condensation while it was running.

Someone said it above, but the propane combustion is going to release H2O into the air. I would get a different heat source, or get a radiant tube heater fired with propane that is vented outdoors. You'll always fight condensation with that type of heater in there.

[Bill Dufour]

In a metal working shop the classic answer is a light bulb in the machine base and a blanket thrown on top. Of course no big fire hazard with no sawdust. My metal working lathe had a condensation problem because being so heavy it takes a much longer time to warm up above the dew point as temps change in the shop. I ended up putting two goldenrod heaters in the base.
I may just use an electric blanket on my milling machine.

[Ronald Blue]

You don't need much heat. I may not get as cold as you do but where I am is close. A few years ago when propane went out of sight on cost I used a couple electric heaters to maintain a steady temperature. Two 1500 watt heaters will surprise you. My current shop is 24 by 30 and well insulated. I have never had any moisture issues unless they were of my own creation. Even when the temperatures fluctuate greatly the shop changes slowly. I don't have any ventilation in the shop. I keep the thermostat about 50 if I am not using the shop. Humidity is about 50% at this time but overnight will go back up into the 80% range. Just my two cents. Good luck on a solution.