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Ideal shop humdity?
http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10101&t=15533		 Page 1 of 1
Author:  jsimpson [ Fri Jan 25, 2008 3:33 pm ]
Post subject:  Ideal shop humdity?
Hey gang -
Is there an ideal working range for your shop's humidity? Or is that based on your locale? Basement shop here, in the dead of winter with the furnace running frequently. My Walmart ($11) digital temp/humidity meter says anywhere between 32% and 42% humidity, and a not-so-balmy 62 degrees.

Is that okay, or should I buy a humidifier for the basement? Two are going on the main floor of the house already, with no closed doors between main floor and workshop.

Excellent job on the site, Lance/Brock! The speed has quadrupled at least, here on my end anyway.
Author:  SStallings [ Fri Jan 25, 2008 3:54 pm ]
Post subject:  Re: Ideal shop humdity?
I just bought the same thing from Walmart. I'm 62 degrees and between 48% and 52% RH. Don't know if that is acceptable or not.
Author:  WaddyThomson [ Fri Jan 25, 2008 3:56 pm ]
Post subject:  Re: Ideal shop humdity?
Ideal would be between 42% RH and 48% RH. You need to check your gauge. My Walmart Temp/Humidity guage is consistently off by 10 points on humidity. It stays pretty close on temp. Those things, particularly the less expensive ones, are notoriously inaccurate. You need a Sling Psychrometer to check your humidity accurately, and see how accurate your unit is. Basically a wet bulb and dry bulb thermometer which you draw air across and get the difference between them, then figure the humidity on a chart.
Author:  John Elshaw [ Fri Jan 25, 2008 6:01 pm ]
Post subject:  Re: Ideal shop humdity?
I keep the house around 45% humidity, but the big question I have is how in the heck do you keep all your windows from fogging up all winter long? The humidity is fine but I'm worried there might be long term water damage from all the humidity on the windows. Is this an issue for anybody else?

John
Author:  Hesh [ Fri Jan 25, 2008 6:12 pm ]
Post subject:  Re: Ideal shop humdity?
An accurate, calibrated hygrometer is essential and Waddy is right that these things are usually way off.

Stew-Mac just started carrying the Caliber III hygrometer which is excellent. I have three of them and they all read within 1% of each other and within 1% of my calibrated, and expensive Aberon hygrometer. I think that they cost about $20 and are highly recommended. You can find them at Stew-Mac under the "new products" link on the home page.

Tracy of Luthier Suppliers a sponsor here told me about these a couple of years ago and that the cigar guys love them too. Thanks again Tracy!

Yep 42-48% is a good range to maintain and yes as well John my friend my windows are full of condensation around the edges but my guitars don't crack...... Let's face it, what is more important a beautiful guitar of a stinkin house....... :lol:
Author:  burbank [ Fri Jan 25, 2008 6:24 pm ]
Post subject:  Re: Ideal shop humdity?
John Elshaw wrote:
I keep the house around 45% humidity, but the big question I have is how in the heck do you keep all your windows from fogging up all winter long? The humidity is fine but I'm worried there might be long term water damage from all the humidity on the windows. Is this an issue for anybody else?

John


Sure is for us. Our house was built in the 50s and has storm windows, but not true double-pane. We have insulating shades that make it worse because they keep the windows much colder. It's usually OK until the overnight temps drop to the single digits. Then we raise the shades an inch or two and that helps, but doesn't eliminate it. I wipe the windows and frames on those cold mornings. A real pain though. The double-pane windows we had put in downstairs when we remodeled the basement have much less of this problem. I think if we stay in this house, we'll get modern windows.
Author:  Anthony Lembo [ Fri Jan 25, 2008 6:50 pm ]
Post subject:  Re: Ideal shop humdity?
Does anyone have a recommendation on where to get a good sling psychrometer? Everything I've seen online has been rated at +/- 3% RH. Is this normal for these things?

I've been using digital humidity gauges for years, without a cracked top coming back (knock on spruce?), but I'd still like to have something to check them by. Thanks.

On another note, the occasional drippy window is something that I live with.

Anthony J. Lembo
Lembo Custom Guitars
Author:  WaddyThomson [ Fri Jan 25, 2008 7:24 pm ]
Post subject:  Re: Ideal shop humdity?
I keep my house nailed at 45% too, and I have Aluminum Sliding Double Pane windows on my porch. They are like freaking faucets in cold weather. We have to wipe down the frames, and sop up the pools of water on the sills nearly every day when it's below freezing outside. But like Hesh said.......

On the Sling Psychrometer thing. If you can find a decent thermometer, keep it in the shop. It will then be stabilized to the shop temperature. When you want to test, record the dry bulb temp, then put a piece of an old cotton tennis shoe lace over the bulb, wet it, and draw air across it (not blow, but draw - they are very different)(A vacuum or dust collector is OK). When it stops going down, record the temperature. Then, take the difference, and look up the humidity on a chart, There is one here, but I do not know how accurate it is.
Author:  Mike_P [ Fri Jan 25, 2008 7:35 pm ]
Post subject:  Re: Ideal shop humdity?
John Elshaw wrote:
...but the big question I have is how in the heck do you keep all your windows from fogging up all winter long? The humidity is fine but I'm worried there might be long term water damage from all the humidity on the windows. Is this an issue for anybody else?

John


keep them caulked and painted and wipe them as necessary...such is the 'cost' of home ownership ;)

@Waddy...I wonder about your situation...I have a house that was made by Centex Homes (surely not a high dollar builder) and is 7 years old...the only time I had problems with my double pane windows and sliding door was when I first moved in and the domicile was wet as all hell from the built up moisture of an unheated home being built and completed...admittedly I live in Central Texas so it doesn't regularly get all that cold, but even during ice storms and such I haven't noticed any problems with either the windows or the slider...so I am thinking that possibly the slider you mention is leaking air and the result is that it is condensing on the unit...
Author:  WaddyThomson [ Fri Jan 25, 2008 8:27 pm ]
Post subject:  Re: Ideal shop humdity?
Yeah, it's just the windows on the porch, and they are aluminum clad, double pane, but installed over 20 years ago. I have been in my house 30 years, and it was built in the late 50's.
Author:  Mike_P [ Fri Jan 25, 2008 8:52 pm ]
Post subject:  Re: Ideal shop humdity?
WaddyT wrote:
Yeah, it's just the windows on the porch, and they are aluminum clad, double pane, but installed over 20 years ago. I have been in my house 30 years, and it was built in the late 50's.


then check out the caulking around the exterior, it is quite possible that is has failed and a simple reapplication will solve your problem...since I can't look at the situation I can't say exactly, but check the caulk as the trim touches the siding and where it touches the unit....if the track is sealed by a piece of felt or somesuch then you should be able to fix that also...
Author:  WaddyThomson [ Fri Jan 25, 2008 9:29 pm ]
Post subject:  Re: Ideal shop humdity?
I keep em caulked. It is the aluminum that is conducting the cold inside, and the 45% humidity in the house condensing on the aluminum. The insulated glass stays dry.
Author:  Rick Turner [ Fri Jan 25, 2008 10:22 pm ]
Post subject:  Re: Ideal shop humdity?
If you have the opportunity to rework interior walls, then staple some heavy Visqueen to the studs on the inside wall where you will then put sheetrock. Be pretty anal about it and then you'll be able to do a pretty good job of dehumidifying or humdifying as needed. Just remember, the vapor barrier goes INSIDE, then the insulation, then the exterior cladding.

We did this on an interior room in my shop and that's the humidity controlled room. It's about 20' x 20' with 10' ceilings, and we keep it at about 46% to 47% @ about 70 F.
Author:  Mike_P [ Sat Jan 26, 2008 1:32 pm ]
Post subject:  Re: Ideal shop humdity?
also caulk around all outlets on exterior walls (take the plate off and apply caulk where the sheetrock and box meet) and even go so far as to carefully pull the outlet or switch (maybe throwing the breaker might be a good idea) out and put some caulk in the holes in the back of the box...an electrician at a later date might curse this, but hey.....
Author:  Daniel M [ Sat Jan 26, 2008 9:26 pm ]
Post subject:  Re: Ideal shop humdity?
You could build a storm window out of 1X2s & some 6 mil poly. Make it fit tight inside the window frame & it should control your condensation issues.
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