humidity control

[Bob Schmidt]

I recently converted our old 3 stall barn to a woodshop. This is close to the coast in NJ so the relative humidity can get pretty high. I know I will have to do something about humidity control for the wood but the old barn is airy as most old barns are, and running a dehumidifier all of the time out there seems wasteful. How long does it take wood to stabilize before it can be glued? What have others done to address this?

[Folkmusician.com]

Will the finished instrument stay in the same climate? If they are going to any place that is dry, it could be a big problem.

A lot of people here in Reno have bought small builder Ukes from Hawaii. These were built in high humidity and self destructed within months of coming to Reno..

[Bob Schmidt]

I don't expect that the instruments will spend a lot of time in high altitude climates, but the humidity does get below 20% in the winter in NJ. I had to have the top of my D35 replaced because it warped, I also had to replace a back on a Gibson J45 because it split one winter, so even in this climate it will be better to put the instruments together around 40% humidity.

[HoGo]

No matter where your shop is you need to have it insulated ffrom outside humidity and temperature.
Old barn can be quite big for proper control so it would be best just to isolate your workplace and instrument parts storage. You can leave most of the wood and rough work devices in the uninsulated parts of barn and just move it to controlled part few months before you use the wood.
I know of makers who don't have humidity control in the shop for some reasons but thay have at least large cabinet or small storage room with control (small dehumidifier/humidor) where they keep all the parts under construction and only pul them out for the necessary time to do the work and put them back in after clamping or finishing step.
My shop is very small and all I need is small room dehumidifier that keeps humidity at 45%, temperature is kept at 25°C all the year round as well.

[Bob Schmidt]

Adrian,

Thanks for your reply. I was considering partitioning off a section of the shop for the wood if I can not control the entire shop. It was only 3 stalls, but being a barn it is pretty airy.
I was not sure how long the wood needed to stabilize so it looks like a couple of months is needed based on your post.

Thanks again,
Bob Schmidt

[HoGo]

I't certainly better to have small part that is reliable than large uncontrollable room.
If your wood is already air dry (12-15% humidity) then top/back billets need two months or so to stabilize at your humidity controlled part, neck billets are bit larger and need at least twice the time.
For fresh wood there is rule of year per inch to air dry if the air flow is good - barn should be good for storing fresh wood after it loses free water.

[Joe Bartl]

I live in Adamstown, MD. Humidity is very high during the spring and summer, especially in my old house with its dirt-floor basement. Last year, following some expensive mando repairs, I put a dehumidifier in the "music room". It did a great job of keeping the humidity down to 45%, but it heated the room (during an already hot summer) with its exhaust. Putting in an additional air conditioner would be (electricty-wise) expensive considering the hot exhaust from the dehumidifier. Any solutions? Are there dehumidifiers that do not exhaust hot air? Or, are there air conditioners that will dehumidify to the proper extent? As we are heading into another hot one, I'm worried.

Thanks,
mandogio

[HoGo]

I would check if your dehumidifier is OK. I've got pretty common cheap dehumidifier in my shop and it doesn't heat the room perceptibly.
They work by cooling the air below dew point and then the dry air continues through the condenser to get back to temperature. If your unit heats air too much there may be problem with pressure in the system.

[Wes Brandt]

There are some window air conditioners that also dehumidify at the same time and have controls for it... not the really cheap ones but worth looking into.

[dschonbrun]

I would try to keep your entire workshop at around 45% RH, and a temp around 65-75F. If that's not feasible, consider creating a box/case that you can maintain at 45% and store the instruments there when not on your bench.

You'd need to invest in a dual humidification and de-humidification system if you're committed to a workshop that is climate controlled for luthiery. Wine-cellar temperature and humidification systems should give you some ideas (although they tend to maintain 50-70%

Paul has some good reference material on his site:
http://www.pjguitar.com/just-pass-it...-for-luthiers/

You might take a look at AMCO:
http://www.amco.com/spacehumidifiers.php

Best,
D

[rfd]

at the the very least, a digital humidity gauge should be present wherever acoustic instruments are kept in order to keep on top of pending wood disasters. summer a/c use will dry out a room super quick, and kill an acoustic in the process. keeping acoustics in a closed case with some form of added humidity control is good insurance, but humidity level monitoring is always a must.