Shop Humidity

[Dave Fritz]

My shop gets really dry in the winter and static build up is a problem, esp buffing out bowls etc.

What do you do to control humidity in your shop or don't you worry about it?

 

[hockenbery]

Wait for winter for less humidity.
You may be worried about 2 dry . We have too damp.
When I read "control humidity" I think how to remove it.

In the main shop we don't worry about it. Ballistol every 2 weeks or before we leave if we'll be gone a month or so keeps the cast iron and steel from rusting.

We have a room we use for drying where we have a dehumidifier set at 50%.
This lets green wood turnings dry.

Al

 

[Bill Boehme]

The only static here is on the AM radio when using a drill or ROS.

You can now get flexible hose for your shop vac and dust collector that uses conductive plastic. It's great stuff for avoiding shocks. While not as humid as Florida where Al lives, our humidity is typically high so static charge is not normally a problem.

 

[john lucas]

I live on a small lake in Tennessee. Man is it humid. We finally got some days with low humidity. man does it feel fantastic. I have had a shop with bad static. I grounded the dust collector hose.

 

[Dean Center]

From here in the arid Rockies--it's annoying but I just ignore it. The worst time is sanding on the belt/disc sander.

 

[Gerald Lawrence]

I have central A/c in shop and keep it at 89 when not ing the shop . So with the 95 plus summer we have had it runs some even when I am not in shop.

 

[Mike Johnson]

Work harder and sweat a little to increase the humidity.

 

[Fred Belknap]

Static electric is a problem when buffing bowls in the winter when the humidity is low . Rubber mats don't work. I found that if I take off a shoe and put my bare foot on the lathe will stop it. That is a problem when I want to walk somewhere in the shop. I found a solution by using a wire connected to the door latch of the PM3520 and the other end tucked under my watch. For safety I just tuck the stripped wire under the watch so it will pull out easily.

 

[Dave Fritz]

Thank you for the comments. Is the static a safety hazard or just an annoyance?

 

[hockenbery]

An arcing electrical charge from static electricity could ignite highly flammable materials like a room full of gas fumes. Basically it is baby lightning.
They don't allow cells phones to be used near gas pumps and metal shovels are not used in grain elevators.
Unlikely to be an issue in your shop.

 

[Bill Boehme]

An arcing electrical charge from static electricity could ignite highly flammable materials like a room full of gas fumes. Basically it is baby lightning.
They don't allow cells phones to be used near gas pumps and metal shovels are not used in grain elevators.
Unlikely to be an issue in your shop.

Actually, you would want metal shovels as well as metal conveyors, hoppers, chutes, etc. in a grain elevator in order to help drain off any accumulation of static charge. Static charges are created when two nonconductors are rubbed against each other (amber rod and cats fur is the classic science experiment mentioned in grade school textbooks although I'm not sure where you find an amber rod ... another m ore familiar one is rubber soled shoes and wool carpet ... those school textbooks were really old).

The shock from a static charge can certainly be an indirect safety hazard. The reflex reaction to a good zap can cause you to fall or whack your noggin or impale yourself with a turning tool or terrify small children when you let loose with an oath.

 

[Odie]

My shop gets really dry in the winter and static build up is a problem, esp buffing out bowls etc.

What do you do to control humidity in your shop or don't you worry about it?

So.....low humidity contributes to static charges?

Only time I've ever noticed any static charges, is on the buffing wheel. Even then, it's infrequent. Currently, I'm registering 41% humidity in my shop, and it rained about an hour ago.......what does this mean?

I've never tried to control humidity in my shop......and, to tell the truth, I don't pay much attention to it.

ko

 

[Bill Boehme]

Water is a weak conductor of electricity and it becomes an even better conductor when combined with other stuff like dust from wheat or corn. When the RH is high static charges can't build up. Static electricity is rarely a problem here except occasionally in the winter if we get a dry cold front. Some places like central Kansas typically have really low RH. When I was in the Army and stationed at Fort Riley, Kansas the RH was incredibly low. Getting zapped by a static charge seemed to be a regular occurrence. I thought that it was funny when the local people would complain about the muggy weather when the RH would get to 20%. If the RH in your shop is 41% then that is about an average value.

 

[Odie]

Water is a weak conductor of electricity and it becomes an even better conductor when combined with other stuff like dust from wheat or corn. When the RH is high static charges can't build up. Static electricity is rarely a problem here except occasionally in the winter if we get a dry cold front. Some places like central Kansas typically have really low RH. When I was in the Army and stationed at Fort Riley, Kansas the RH was incredibly low. Getting zapped by a static charge seemed to be a regular occurrence. I thought that it was funny when the local people would complain about the muggy weather when the RH would get to 20%. If the RH in your shop is 41% then that is about an average value.

Ok.......I see........hmmmmm.......

All depends on how accurate this cheap digital hygrometer is. Bought it online about five years ago, during the time that Michael Mouse was always posting about the benefits of knowing the relative humidity, and how that effects seasoning roughed bowl blanks. I believe yesterday is the first time I even bothered to look at it in a couple years, and I'm assuming it might be a little higher than it normally would be, since it was right after it rained.

During colder days, and wintertime, I'm using propane heaters to bring the shop temperature up to livable conditions......at which point I turn off the propane heaters, and rely on electric space heaters to maintain the temperature. Would the use of these types of heaters contribute to the RH within the shop, and subsequently effect the static zaps that I sometimes experience while Beale buffing.......?

ko

 

[Mike Johnson]

Odie,
Depends on if your propane heaters are vented/exhausted to the outside, or if you have catalytic type heaters that
exhaust into the living space. If your gas heater is vented to the outside you will consume moisture out of the air.
If you have a catalytic type heater you will gain humidity in your living space. An electric heater will maintain your
humidity levels at a constant level depending on other sources to raise or lower humidity.

Use of a catalytic type gas heater is an easy way to control the humidity level in a shop in the winter. Or bring additional
green wood into your space.

 

[hockenbery]

Air drying wood is controlled by the humidity and temperature of the environment.
At 70F 50%RH wood will dry to 9% and not dryer...



The chart below gives you an idea of what you can achieve air drying without any climate control.
Also gives you a hint of what to expect if you ship an air dried bowl from one area to another.
One more thing global warming affects.

 

[Bill Boehme]

As Mike said, it depends somewhat on the design of the heater. On the old style unvented heaters, it would raise the total moisture content a bit, because one of the byproducts of combustion of propane, butane, and natural gas is water vapor (another byproduct of combustion is carbon dioxide ... and when there is incomplete combustion due to insufficient oxygen then there is the deadly gas carbon monoxide).

However, relative humidity is the important thing (as opposed to total humidity) and that is a function of temperature. Warm air is capable of holding a lot more water vapor than cold air before reaching the saturation point. The bottom line is that any moisture added to the air as a result of combustion is small in comparison to the drop in relative humidity as a result of raising the temperature.

 

[Mike Johnson]

When a vented style furnace, heater, boiler, water heater burns gas as a fuel, it needs oxygen to burn the fuel.
The air in your building is your oxygen supply, as the burner draws air into the burner you are also burning the
moisture in the air. When you increase the use of gas appliances you will quickly lower the relative humidity in
the building. If you have a fresh air intake for the building, the air will be replaced by outside air at the humidity
level outside, winter months are usually drier in humidity levels based on the lower temperatures. The lower the
temperatures the drier the air becomes as the moisture is frozen out of the air and falls in the form of snow & ice.

 

[hockenbery]

Relative humidity is important for the room in which turnings are dried.

a moisture meter will give you the MC (moisture content) of a piece within the accuracy of the meter reading.

If you weigh bowls you have know the temperature and relative humidity in order the know what the equilibrium MC is.
The chart below from the forestry service shows the equilibrium moisture content for temperature and RH. As you can see a "weight dry" bowl could have 24% MC or 1% MC depending on the temperature and RH values of drying room.
I want my bowls between 8-10 MC before returning. I run a dehumidifier in the drying room to keep RH below 50%

 

[Mike Johnson]

I did forget to mention the high efficiency furnaces that use an air intake and exhaust vent usually via plastic pipe
will not take moisture from your living space. With these heating systems you usually need fresh air exchanges
and a dehumidifier to manage the quality of air in the living space. A good quality fresh air intake will preheat the
cold air coming in with the warm air going out via a heat exchanger. Without proper air exchanges and dehumdification
you can end up with mold and mildew easily over time.

 

[Jamie Straw]

My shop gets really dry in the winter and static build up is a problem, esp buffing out bowls etc.

What do you do to control humidity in your shop or don't you worry about it?

Heating with one of those propane torpedo heaters might raise the humidity.

 

[robo hippy]

Heaters lower the humidity level. When I visit family over Christmas (St. Joe, MO where the Pony Express began and Jesse James ended, or just north of KC) Dad has a humidifier going. Still get lots of static shocks. Here in western Oregon, humidity levels can be 90% for days on end, and almost never any static electric charges from walking across the rug. I some times use a cheap humidifier because I heat with a wood stove, and that dries every thing out in the house. More difficult to do in the wood shop with a small electric heater.

robo hippy

 

[Jamie Straw]

Heaters lower the humidity level.

My understanding has been that if the combustion isn't vented (e.g., torpedo heater, typical kerosene heater), humidity is increased. If the heater is vented outside, then humidity would be decreased. That's why I don't use our kerosene heater, even though it would come in handle on these slightly chilly, but not cold, days. When I use the pellet stove, it does dry out the air -- thankfully!

 

[Bill Boehme]

The amount of moisture added isn't significant. Much more significant is the amount of additional moisture that warmer air can hold before it is saturated. The important factor to keep in mind is that we are talking about relative humidity. The word relative refers to the amount of water vapor present at a given temperature.compared to how much water vapor the air can hold at that temperature before it is saturated. Here is a link that helps to explain it: http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/relhum.html

Of greater concern in using an unvented heater is the decrease in oxygen and increase in carbon monoxide.

 

[robo hippy]

If you take a cold shop and take a humidity reading, then heat the shop and take another reading, the relative humidity should go down because hot/warm air will hold more water than colder air where it will condense. Amount of water in the air stays the same.

robo hippy

 

[Bill Boehme]

I don't know about you folks "up nawth", but it is still hot here in Texas. I have the air conditioner running in the shop 24/7 ... the humidity and mosquitoes are keeping me indoors. Once upon a time, mosquito bites were just a nuisance, but now they can be serious.

 

[Jamie Straw]

Of greater concern in using an unvented heater is the decrease in oxygen and increase in carbon monoxide.

Substitute dioxide for monoxide and we get what I was suffering from with my old respirator. To the point, my shop is so drafty right now that using a kerosene heater wouldn't make me pass out, or even get a headache. Once we get the attic ladder installed in the ceiling, and plug up a few other spaces, it'll be better, but never air-tight.

 

[Bill Boehme]

Which respirator was that? Sounds like it might have been a Triton.

 

[Jamie Straw]

Which respirator was that? Sounds like it might have been a Triton.

Actually, my Triton power respirator is great. Naw, this was a North CFR "particulate respirator" - half-face mask with replaceable filters. It was awful, in terms of exhausting air and moisture. I now have a 3M 6200 model, selected with help from this forum. I love it. I only wear the Triton when I'm turning dry bowls.