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After having seen humidity fluctuations in my workshop at the weekend, from a high of 72% on Saturday morning to a low of 26% at lunch time Sunday. It's becoming clear that I need to get some control over it. During the week, when I don't have the time to get into the workshop, I store my guitar body in a large plastic bin liner, with a damp sponge on some plastic inside the sound hole. I started doing this after the humidity dropped to 12% while I was in the workshop a few months ago, and I heard a gut wrenching crack coming from the soundbox - produced by a nasty crack in the top, that I've since repaired.

I fear that I'll be saying "if only I'd had some control over humidity when I built my first guitar..." So, I need to find a solution before I start the next one.

So rather than reinvent the wheel, I thought I'd ask here. Does anybody have an inexpensive solution? Or, is this a problem that needs money thrown at it to make it go away? What are you all using?

Paul, what/where is your shop? One way to get ahold of humidity is to make sure it's sealed. You can epoxy floors in garages and that does a lot to help. You can also ad thick plastic (6mil) around the whole thing, walls and ceiling and then drywall over that.
If you are in a basement, you'll have more problems but you can seal things off with epoxy type products. But yes, this is throwing money at the situation.
Be more specific as to what you shop location is.

I have a basement shop, 12 X 22,Ive been down there 2 years now, I run a sears 30 pint dehumidifier year around. In the spring thru fall I get a gallon a day out of the air, in the winter it takes about 3 days. I maintain a steady 45 to 47 RH at 68 to 70 degrees fh.
My walls are bare cement, as is the floor.

Maybe its just my basement, but it seems to be a perfect environment.

Lance

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Lance@LuthiersForum.com

Paul,

I built a 18 x 48 inch drying box under my workbench. I just enclosed the bench and put doors on the front. Not fancy but it works and keeps my wood and current project in the appropriate humidity. I try to keep things in there when I am not working on them. With a small fan and a 75 watt light bulb running 24/7, I have the humidity at 45. That is because it is wet here in Oregon! When it gets dry I will probably just add a small container of water, or a sponge, and turn off the light. That should work I hope.

Not a permanent solution, but a fix until I can one day insulate my garage and control the environment.

Jeff

Sorry, we don't have basements here, so I didn't think to specify.

It's a free standing garage, a little bigger than a single car garage. Made of wooden stud frame, with fibre cement sheeting on the outside, corrugated iron roof - no lining inside yet, concrete floor.

I'm thinking that the obvious starting point will be to line it with something, or at least partition off a section and line that. And even then I'll still need to control humidity in some way. But, in a few years we're going to be pulling this one down and building a new garage that will be attached to the house with a bedroom or two on top. So whatever I come up with, will either have to be inexpensive, or transportable to it's new home.

Humidity control is important . I try and maintain a 40-50%. I have a heating system with humidity control in the shop, Even with that when the weather is very cold it is hard to get it to stay at 40% and can play havov with the wood when it first comes into the shop.
   I never use wood that is less that 90 days in the shop.
John Hall

Paul you are fortunate that your shop is bare. No matter the environment, dry or wet, hot or cold. A workshop is best if it's constant RH and temp. Not everyone has this luxury. But it probably helps with many problems encountered along the way, such as the one you mentioned.

Humidifier when it's dry, dehumidifier when it's wet. Try to keep the temp the same. If you can work in shortsleeves, the temps about right. So all you need past that is a twenty dollar hygrometer on the wall to know which way to go next.

I vote for insulation, six mil plastic all around including ceilings, a central heat and AC unit., the hygrometer, and two units to humidify and dehumidify. Good luck. Australia is mostly desert climes is it not?

When I built the shop in my barn I lined the whole thing with 6 mil plastic. I used plastic sheet on the cement floor between the PT 2x4 sleepers and the plywood. Taped all the seams.

When the nights are cold and I'm running the wood stove I put about 2 gallons of water into the air every day through the humidifier and the kettle on the stove. I run a window air conditioner in the summer, and a dehumidifier when that won't keep up with the R.H. but only need to empty in once n a while. I've been able to keep the whole space (about 800 s.f.) between 40-45% pretty consistently over the past two years.

Having had basement shops and other kinds of spaces, I'd say the single most vital thing is the sealing against infiltration. It will not only help your humidity control, but also save on heating and cooling costs. Cement forms basically no barrier against moisture: Lance must have pretty dry ground, or a very new basement. Get the floor under control first, either with an overlay or moisture barrier paint. Then wrap the walls and ceiling.

[QUOTE=Dickey]
Australia is mostly desert climes is it not?[/QUOTE]

I live in Sydney, on the east coast. The average relative humidity here is 60%, it usually rains most months, but not so much in the winter. We're currently operating under water restrictions 'cause the dams are running dry.

The problem I have encountered, is I think, when we have a change in the weather, which might only amount to a change in direction of the wind. When the breeze is coming off the ocean, which is the usual state of affairs, the humidity is fairly constant. But if the wind swings around and starts coming from the west, it pulls a lot of dry air from the interior desert regions to the coast. The result of this is, as you'd imagine, a sudden drop in humidity. And unless I keep checking the hygrometer I wouldn't notice the change until my guitar starts making loud cracking noises.

I think I'll start looking for second hand humidifier, dehumidifier, heater and AC. 'Cause the guitar building bug has truly bitten.

Paul,

I'm also in the process of developing climate control. I live about 2hrs. north of Lance (mid-Michigan) and am working with some spare space in my pole barn. My plan is along Bruce's suggestion; monitoring w/hygrometer(s),
humidifier, de.....well you read it, basically the works. You didn't say much on concerns in temp., so maybe just plastic on the walls and ceiling, with a sealant on the floor. I'm still testing the waters, congrats on jumping in with both feet!

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DES - Shepherd, MI

We don't have much change in temp, well, compared to some of you. An average winters day is likely to be 5 degrees C over night, to maybe a top temp of 18 degrees C through the day. Summer temp range is a low of about 20 deg C up to the high thirties, with maybe three or four days over 40 deg C each summer (I think the highest this year was 46 deg C). I'll need to insulate to save on cooling costs.

We have two types of weather, Hot and not so hot   

[QUOTE=Alan Carruth] Lance must have pretty dry ground, or a very new basement.   [/QUOTE]
Al, I do -- Both -- My house is only 4 years old, and its build on a bed of pea gravel with drain tiles, the cement has a 1/8" coating of sealer all the way around the out side. Its dry as a cob inside. We've never had moisture problems at all.

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Lance@LuthiersForum.com

Geez, Lance, I've always lived in these old New England Victorians where they dug out the rocks and clay soil and built the soil up around the foundation hole to save having to go so deep. Then they used the rocks to make the foundation, with maybe some brick above grade. The old mortar is all falling out, and there's always at least a trickle when it rains hard. The basements were designed to store veggies over the winter, so they wanted 100% R.H. and temps just above freezing. That's pretty much what you get, too!

   

Yeah, Alan, I lived in one of those houses growing up. I think builders have wised up and realized that the real basement is designed for the woodworker in mind.