Advice on humidity management

[kinspeed]

I live in Utah where the humidity can fluctuate greatly from 90%+ this time of the year to 20%- during the summer months. The humidity in my work area right now is 45% according to my very cheap gauge. What can I do to help, inexpensively monitor and control this in my shop? Thanks!

[Dan Bombliss]

I used to use several cheap gauges. I believe at one point I had 7 (or so) cheap $3 analog gauges that I used in the shop. They didn't necessarily have to be accurate to be helpful tools. I started by putting all of them right in the same corner for a week and made notes of any variances between them (to be mindful in the future if any were +-5% or more). Then I just scattered them around the shop. Finished guitars are extremely useful gauges in the dry months as well, as spruce tops start to get a corduroy pattern when it starts to dry and shrink.

-Dan

[jamoat52]

In spite of the fact that I'm a trained and experienced meteorologist, I too have tried cheap hygrometers and thermometers. They are "iffy" at best. In my guitar shop I opted for a certified German wall mount unit bought from LMI. (ABBEON Cal., model HTAB 1698) It cost about $200 as I remember, but if you live and work in an area with wide fluxes of temperature and humidity, as most do, it is well worth the expense in damaged wood or worse.
George

[MaineGeezer]

Last Spring I bought a dehumidifier for the basement to keep that space around 50% humidity in the summer This winter it's dropped down to around 24%. I just bought a humidifier for the upstairs part of the house, and I should probably get a humidifier for the basement. In addition to making guitar construction a lot more predictable, I decided it would be easier to humidify the house than to maintain humidifiers in five guitar cases.

I've got a couple of inexpensive Acu-Rite gauges. They agree fairly closely with each other (with a couple percent) and they are fairly close to the laboratory-grade gauge my luthier friend has in his shop. I ought to re-check them, because I can't remember whether they read high or low. The main thing is, they seem to be consistent and predictable, even though their readings are somewhat off. As long as I know they need to read 55% (or maybe it's 45%) to have 50% humidity they're fine.

[Diane Kauffmds]

I have a very similar problem. The humidity here in WV can vary from 90% to the teens, with the switch only taking a day or two. We actually got down to 9% outside last winter.

I have Caliber IV hygrometers. which can be calibrated. My husband is retired from HVAC, so I use his psychrometer to calibrate the hygrometers. I've had them for 3 years now, and I finally tweaked the calibration again this year. When I compare them to the psychrometer, they're consistently +/- 1. Since they're whole numbers and are therefore rounded, I would say that they're +/- 2% accurate, which is fine for woodwork.

What kind of area are you trying to control?

I've built a workshop in half of my basement, which is hooked into the household furnace/air conditioning system and whole house humidifier. The house humidifier wasn't enough.

I ended up getting a dehumidifier, with a built in dehumidistat as well as a humidifier.

I was lucky, lucky, lucky! I frequent the local Habitat for Humanity Restore. I found a Hunter humidifier with a built in humidistat. It holds ~ 2.5 gallons of water and is filtered. I picked it up for $10.

Both are on at the same time (although not running together). Right now, it's consistently between 46-49% and averages 47% in the workroom. I check them daily, but I've not had to adjust them much after the first month. The GE dehumidifier isn't as accurate as the Hunter humidifier. The dehumidifier is set at 55% and the humidifier is set at 45%. This is the combo that's working right now.

If you want control, you need both.

You can pick up fairly cheap units, which you can be controlled using a couple of methods. The easiest is to use a plug in control. The control plugs into a standard outlet, and the unit plugs into it. You set your desired humidity level on the control, which will toggle your unit on or off. You can find them at Amazon, as well as other places.

Be aware that you would have to buy a separate dehumidifier and humidifier control. One unit doesn't control both.

Or you can get autonomous units like I have, which I find gives me more freedom. If you're going to do a lot of woodwork, then I suggest the 2 unit approach.

My workroom is actually 2 rooms with an open doorway. I have the units fairly close together (~ 4 feet apart) in an area that sits by the doorway.. This way they're sensing the same level of humidity. I have 2 Caliber IV's, each as far away as I can get from the units, in each room. They never vary more than 1 degree from each other, so my strategy is working, so far anyway.

If you're trying to control an open workspace, rather than a room, it'll be more difficult to really control.

[kinspeed]

Thank you all for the replies. I talked to a local luthier and got some additional info as well. He echoed much of what has been said.

Diane, thank you especially for the additional detail. I am doing much the same as you and setting up shop in half of the basement. It's not a very big area. What controllers do you use and do you find them to be as effective as you'd like?

Thank you again everyone!

[tippie53]

the only think I will add is this
if you have concrete and I bet you do seal it if you can. Drylox does well for the walls and cement blocks. There are a number of concrete floor sealers.
You would be amazed at how much moisture can migrate up through the floors.
Also if you have gas heat it will put a good bit of water in the air.

[kinspeed]

the only think I will add is this
if you have concrete and I bet you do seal it if you can. Drylox does well for the walls and cement blocks. There are a number of concrete floor sealers.
You would be amazed at how much moisture can migrate up through the floors.
Also if you have gas heat it will put a good bit of water in the air.

I have both of those John. Thanks!

I was able to acquire an Abbeon Hygrometer, the same model LMI offers, in excellent condition for $55.

[tippie53]

that will be a handy device. I rely on mine a great deal

[Diane Kauffmds]

Thank you all for the replies. I talked to a local luthier and got some additional info as well. He echoed much of what has been said.

Diane, thank you especially for the additional detail. I am doing much the same as you and setting up shop in half of the basement. It's not a very big area. What controllers do you use and do you find them to be as effective as you'd like?

Thank you again everyone!

I have 2, self-contained units. Each have built in controls and hygrometers.

My shop area is ~ 425 square feet now. I'm very happy with the tight control that I've achieved. The workshop is ALWAYS 46-50% RH, but 80% of the time it's 47%. It took a few days of playing with the controls on each unit to gain this control, so that both units weren't running at once.

I started with an "area " shared with my husband, of around 50 Sq feet. I outgrew it in 3 weeks. hahaha!

BTW, all of the concrete in my basement is sealed, as advised by others in this thread.

However, when we moved to WV from OH, I was shocked to find a moat around the perimeter of my basement. Most older houses have this configuration here, because water builds up in the basement walls and needs to be drained from numerous areas. We drilled and installed several pvc pipes, which have drained the block walls. All lead into main pvc pipes, which take the water to the main drain. The pipes are now in the "moat", which we filled with concrete.

Man, drying this 100 year old basement was FUN.