How to control temp and humidity

[thio]

Hello everyone. I am just finishing a Stew Mac Ukulele kit and am getting ready to build a Martin 000 mahogany kit that showed up a few weeks back. I have the 000 sides in the mold i purchased and the neck and tail block clamped in place but not glued sitting out in a cold garage. I am trying to figure out if I am making a mistake building the kit in my garage that fluctuates in temp quite a bit during this time of year - I am in Oregon. I have a gas heater I can turn on when building but that doesn't solve the dramatic temp fluctuations I will see. I also understand keeping the humidity relativley the same is another key to pay attention to.

Anyway in a garge that is mainly a shop for me (we do not park cars in it) it is the perfect place to build and not have the distractions of kids/wife etc. I really don't have the space to take up in the house but not going to be happy building the kit only to see issues down the road if I don't pat attention to the temp/humidity thing. I built a Kayak kit in my garage over about a year and had no issues so not sure why the guitar would?

As a hobby player, I have never paid attention to humidity etc and have never used a humidifier on my acoustics. Maybe it's just me, but I like having my guitars hanging on my wall and set out for ease of playing. I am finding articles on the interent saying this is a bad idea in the winter months.

Sorry for the long post - thanks for listening.

[Kevin Sjostrand]

I am in central California. I also build in my gargage shop. I do not control anything in there. The temp varies from 100 F in the summer to 50 F in the winter, and humidity swings from 20 to 65 or so. My wood stays out there, and it seems to stabilize pretty well. If my wood is flat I use it. I did build two guitars that went to India where the humidity is pretty high most of the time, so I kept the wood in a large tub with a wet sponge and a monitor to keep the humidity level around 60%. This seemed to work pretty well as the guitars are doing fine over there. Alls to say, if the guitar you build is going to be in the environment you are building in, and I would think the humidity probably stays relatively high where you are, then you should be okay unless the guitar is going to see some really dry times, then you best put it in its case and keep it humidifed.

Kevin

[Jim_H]

I live in western Washington state, without any humidity control, it's a tad to dry on cold winter days, and some summer days can be too humid.

I have two parts to my workshop. I have a basement that is about half below ground level that I keep heated between 64 and 69 degrees. The heat is central air, which has a humidifier on it. It keeps the humidity up around 40% to 50%. It never gets below that. I store all of my tonewood, do all of my glue ups, and hand work on the benches here.

The outside shop is half of a two car garage. I have all of my power tools out here. Bandsaw, router table, jointer, drill press, two workbenches, and storage for non-tonewoods. It's not temp or humidity controlled, although since it's attached to the house on two sides it stays warm enough to work on unless we have a serious cold snap.

[Darryl Young]

I'm trying something different this year to see how well it works. On Monday I ordered a whole home humidifier and I received it and hooked it up last night. It can put out up to 13 gallons of water per day.......but that is with the fan on high and it makes considerable noise on that setting. It has 9 fan speeds and has 2 bottles that together hold 5.5 gallons of water. I filled both bottles last night and ran it on fan speed 4 and it emptyed on bottle over night. I refilled this morning and set the fan on speed 8 before leaving for work (no one is home today so noise isn't an issue). Be interesting to see how much water it puts out during the day today. It has a digital sensor that mesures and displays the humidity and you have a humidity setpoint (5% increments). The sensor isn't that accurate (showed 40% when I turned it on last night and actual humidty was about 32%-33%) but it doesn't matter much as you just set the setpoint a bit higher and it still works fine. Here is a link to the one I bought. It's the best one I could find at the time at it was about $175 with free shipping.

http://www.essickair.com/products/humid ... e/4d7-300/

If I can keep my home in the 30% range over the winter instead of dropping into the low 20% range, I'll be happy. Should be much better on my instruments and better for my building.

[Kevin Sjostrand]

I seem to have the opposite problem of most people around the country. Our humidity is LOW in the summer, and HIGH in the winter.
Go figure.

Kevin

[kencierp]

I am thinking the bottom line here is that constructing a kayak and constructing a fine musical instrument, in this case a guitar, are only vaguely similar.

In the case of the guitar humidity control both during and after construction is extremely important if one is to expect longevity and comfortable, precision playability.

To that end like the major builder's who spend large sums of $$ to get their facilities at a good mean RH environment (most about 45%) the hobbyist should shoot for something similar.

The instrument needs to be assembled when the parts are near their smallest size (low RH and moisture content). Generally when wood expands it only affects set-up. On the other hand when the wood shrinks cracks tend to occur. Taylor has a nice web page that explains this in detail. Solid wood guitars that are not cared for in this regard will at some point suffer damage or develop playability issues.

[David L]

Here is how I operate. I am not an expert and I don't have a lot of experience so I'm not saying that this is the best method by any means. I basically live in a swamp on the edge of the Gulf of Mexico so high humidity is my woes. I have learned to work with this instead of try to fight it. My credo is "patience is my best friend". When I am working on a guitar I keep all of the components inside the house where the temp and RH are mostly stable. When an Rh window opens up that is low enough to do glue-ups I take the components out to the shop and perform those tasks and return them inside the house after the adhesive is cured. The humidity should never get lower than what I built it at. I shouldn't worry too much about contraction as my humidity never dives below 40% or 45%. This has worked for me so far.

David L

[kencierp]

http://www.youtube.com/watch?v=vd5mGrV6 ... re=related

[Coach]

The instrument needs to be assembled when the parts are near their smallest size (low RH and moisture content). Generally when wood expands it only affects set-up. On the other hand when the wood shrinks cracks tend to occur.

Cold canadian winter. My house currently has a RH of 27%. So I'm not okay to build at this RH, correct? Or....

[kencierp]

Personally I would not hesitate to assemble a guitar at 27% RH your components are likely at a really low moisture content and that is a good thing, since as mention they are at or near their smallest size. Get an inexpensive (or expensive) humidistat for your work area -- you can bring up the RH a few % points simply placing a couple buckets of water in the room.

Now a guitar that is constructed in dry conditions will obviously be likely to react to very high humidity (stormy day) -- the action will change, generally higher since the top will dome a bit more. But -- cracks and failed glue joints probably will not be an issue.