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A couple days ago I bought a bigger dehumidifier. It's been running for 2 days straight now and the shop is still at 56%. It's 85-100% outside in VA. The only thing I see in my future is a huge electric bill. Anyone have any suggestions? Old school ways to deal with humidity?

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A seperate humidity controlled room with a lot of insulation gotta figure out where all the moisture is coming into your work area , get a accurate hygrometer and check . I use hygroset

Sounds like one of several factors may be working against you:
-Shop not sealed well enough so that too much outside air is leaking in.
-Something in the shop contains excess moisture (concrete slab, lot's of wood, ??). I have a slab in my shop and it is not a problem but it did take a while to get the humidity down to 40% but once I got it down, it's been there now for about 6 years without a lot of effort.

I think I would give it several more days to see if it slowly starts to drop, if it does then you may be dealing with moisture that is in the shop. If the RH stays steady then you may have too much outside air leaking in.

I am assuming that your dehumidifier is sized correctly for the square footage of your shop.

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Steve Smith
"Music is what feelings sound like"

Hey Joey, hope that all is well with ya my friend.

What the others have said is pretty important to have a space that the RH can be controlled. My own shop needs the dehumidifier running maybe 6 weeks a year and a humidifier barely running 5 - 6 months a year. The dehumidifier is the worst though it's loud, expensive, and produces heat which in the summer is not a welcome thing.

In my research the old school way of observing RH concerns and building was likely doing certain tasks at certain times of the year depending on the local climate. Of course this may also mean that folks are SOL when they want to produce a guitar any time of year and in in say a month's time.

My shop is pretty stable though and the supplemental assistance from dehumidification and humidification is always minor but still necessary to keep me in my desired range of 42 - 48%. When I built my shop I sealed it off very well with vapor barriers and R-13 insulation even on interior walls.

I've built instruments in Kentucky, Virginia, and Missouri, all very humid areas. My solution is like Ernie's: a separate, much smaller room that is humidity controlled. Trying to dehumidify an entire shop is difficult and costly as you have discovered, Joey. Humidity level is really only relevant when you are bracing and assembling bodies (sounds ghoulish, no?). There is no reason for me to dehumidify my main machine room or my main work room. A 6' x 6' well-insulated room with a vapor barrier, including the floor, is easy to construct. The only thing you have to watch is heat buildup inside the room since dehumidifiers throw off a fair amount of heat. This is usually not a big problem with efficient dehumidifiers. My main work room is air conditioned with a window unit and sometimes during hot, humid spells in summer I have to open the door to the assembly room for awhile and let the window unit cool the work room as well as the assembly room.

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Stay with the happy people.
--Reynolds Large

I cannot address your problem, but here's my eye-opener:
I got my Bestaire humidity meter yesterday.
It shows my shop at 80%.
I thought it was strange, took it indoors and it reads 75%.
My local weather channel says 75%, so I reckon it must be accurate.
It feels fine in the shop, and now I know I cannot guess the humidity level.
Dan

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wah
Wah-wah-wah-wah
Wah

I've sealed 2 of the problem walls but I think I better seal the other 2 as well. It's an attached garage with no HVAC so I can't imagine it's the air. The two cinder block walls I sealed were really bad with efflourecence and water coming in. No water is coming in but it seems it's still enough for moisture to find its way in without the puddles.

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I dehumidify a smaller space. I lined a closet I store projects in with plastic and put the dehumidifier in it. When I'm actually working on an instrument I do it in a small room which between heating and dehumidifing I can pull the humidity down to acceptable limits in an hour or so.

Dehumidifying a smaller space is a valid option.

Not to argue either way but here is what I'm doing. Since I am able to dehumidify my shop with a reasonable effort, I prefer to do that for several reasons; I am not time limited when working on parts outside of the dehumidified area, I can leave my work anywhere, my machinery and tools do not rust, and the wood I have stored all over the place stabilizes at 40-45% so I can use any of it anytime.

My shop is standard construction brick, above ground level, insulated walls and ceiling with drywall and on a slab. No specific vapor barriers or anything.

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Steve Smith
"Music is what feelings sound like"

Joey, what temperature do you keep your shop at?

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Joe Beaver
Maker of Sawdust

The reason I ask about temperature is because the humidity we all talk about is Relative Humidity.

That means that for a given amount of moisture in the air (measured as dewpoint) the RF varies with the temperature.

In your case, if your room is 65 degrees and has a RF of 56%, just warming the room to 72 degrees without any further water vapor removal will drop the RF to 44%, just like magic. If that is the case a combination of warming and dehumidifying should do it. (Of course you will need to stop drafts and maybe insulate to keep the energy bills down.)

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Joe Beaver
Maker of Sawdust

One major entry route for humidity in a shop (garage) is through the concrete floor. A good coat of epoxy floor paint will fix that. A window unit A/C is also highly recommended. The A/C goes hand in hand with the dehumidifier in controlling the shop environment. I can't imagine not having both in a southern based shop.

The first thing I'd do is perform a wet bulb test to check my gauge. Dan above states his weather station states 75% and inside his house it reads 75%. Now unless his windows are open in Dec, and they might be in Texas, if he's running a heater he probably is much drier than that. A wet bulb test is fast to perform, you only really need one thermometer and a shop vac.
Be very confident of your hygrometer before you make major decisions based on it.
I'm typically on this soap box as I had a hygrometer long ago that continually read dry and I ended up over humidify my work shop until I figured it out. The dry readings were totally believable to me as I live in the mountains of Northern New Mexico. It's not uncommon for it to be 10% or less humidity in the fall and spring.
But on the up side it's snowing today so the ski area's should be happy.

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Jim Watts
http://jameswattsguitars.com

Yep. I usually only get one month in the fall and one in the spring of good bracing weather. Actually more like 2 months at a time, but a lot of it is wasted by warm spikes like yesterday/today/tomorrow that raise the humidity 10-20%, and then waiting to reacclimate afterward. My current pattern is to build a lot of things at once, and get everything done that I can in preparation for the good months. I don't really recommend it unless your climate has more good humidity months.

Old school method #2 is to build a heated box to store your components in, and only pull them out for gluing. That's what I'm planning next, since it's unlikely that I'll be getting my room insulated well enough anytime soon, and dehumidifiers are too expensive anyway. I'm still plotting and planning on the hot box. I think the size will be determined by what can fit a harp guitar soundboard with cam clamps all over it. My current most space-needing task is gluing side braces, since the cam clamp bars stick out a long way, but I just had a brilliant idea to make some special short bar cam clamps for that And if I make enough of them, I'll be able to glue a lot more side braces at once, since I'm currently limited to 2 or 3 before the clamp bars start running into eachother.

Lowes and home depot have a painted oil or water based paint designed for sealing concrete in bsmts from moisture .I/ve used it to keep down the moisture in the bsmt. In st louis I used a vapor barrier with styrofoam insulation 2 by 4 sleepers and 5/8osb on the floor that plus styrofoam over the concrete walls and 1/2in gyprock helped minimize moisture absorption

in winter it varies but right now its about 55 degrees when its cold outside. Yesterday it was 70 so now it's about 65 but that's about the range. All I have is a small space heater (that i rarely use) right now and will need to figure out a cooling method come summer.

Take 1 step at a time to resolve the moisture issue, gud luck

I'm at 48% right now which is acceptable but the dehumidifier is running constantly. I suppose I'l seal the floor and put styrofoam up in front of the garage door. When I was in Alaska I had the opposite problem- 10% humidity. Here it's always around 90%. Sometimes (rarely) I actually miss upstate NY where I had to deal with both problems but it was rarely extremely dry or extremely humid.

I live with a poorly sealed air space as a shop. My solution was to buy a commercial grade dehumidifier. The home versions don't get the job done under extreme situations. The one I bought is a Santa Fe. I have a relatively small shop, about 300 sq ft, so I am able to get by with one of the smaller commercial Santa Fe units. I just have a hose that runs through the wall to move the water out. It keeps my shop easily in the 40% range and does not run all the time, even under high outdoor humidity. I do have a mini-split AC/Heat pump too, and maintain a fairly even temperature range.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Mine is about 400 sq feet with 12' ceilings. How much did commercial that unit run you?

It's a lot more, but it gets the job done. I turned the output so it comes out the top, put the Santa fe on a little roll around cabinet with a couple of shelves in it, and put a 4' section of 8" duct on it with a flex corner on top to vent the dehumidified air above the unit. I had to buy the optional ducting kit, which is just a plastic ring that the duct fits over. It was more than I thought it ought to be, but works quite well. Mine is not permanently attached, but can be.
Here is where I got mine: http://www.sylvane.com/santa-fe-compact ... ifier.html
Price includes shipping.

It does not have a tank for catching water. The legs that screw in are good for leveling.
It does act as an air cleaner as well. Has a washable pre-filter and a pleated high efficiency filter behind that. Filters aren't cheap, but they last several months.
Here's a pic of my set-up.
http://www.sylvane.com/santa-fe-compact ... ifier.html

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Yeah, that's the one I was referring to as "too expensive anyway" I figure anything less won't be able to get much below what air conditioning already does, and thus would be a waste of money, whereas the Santa Fe would be money well spent... but a lot of it. Though for a full time builder, it would pay for itself pretty quick in time saved goofing around with alternative methods.

I was in Boca Raton, Florida last month, and thought it would be a bear trying to control RH with anything less than a serious unit, and a full wallet to keep it running 24/7. I don't know what it's like the rest of the year, but all the time I was outside, I was perspiring pretty good!

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

Thanks Jim!
No heater, no AC running. I'll do the wet bulb test to verify my meter.
It seems perfectly comfortable to me, but inside 75% does seem hard to believe.
Dan

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wah
Wah-wah-wah-wah
Wah

I live in the Houston area so I probably deal with as much humidity as anyone except for the Florida folks. My cheapo dehumidifier that I got for $200 from the depot works fine in my 400 square foot shop. I typically get 3 to 4 years from one of these units but I can buy 6 of them for what the Sante Fe runs. Like I said before, get your floor sealed and deal with any other significant entry points. Then you won't be trying to remove humidity from the outside air. If you have garage doors, get the plastic trim with the rubber gaskets to seal them up.