Official Luthiers Forum!

Hey guys,
I'm building my first acoustic guitar and I think I'm gonna set up in my grandpa's old woodworking shop because he used to make furniture and he has a lot of the tools I think I will need. Anyway, the problem is that it is the humidity levels are not consistent. There is a gap under the door and I don't think that it is insulated. But he used to make stuff in there so I think it will be ok. Where I am storing the wood now has a humidifier at 45%. But it is humid in the workshop, so I don't know what I need. I think a dehumidifier would work maybe, but all I am wondering is do I need a humidifier or dehumidifier and how do I keep the levels consistent between night and day. Thank you!!

That is a problem we all face - at least buy a good hygrometer (and calibrate it) so you know what the RH is in your shop. You want to keep it somewhere between 40 and 50 percent. You might want to move your guitar in and out of the area that is controlled while you are not working on it - it won't hurt for brief periods to be higher or lower than optimum while you are working, but store it at 45% when you are not.

Btw I would also suggest asking at the main guitar building subforum how different builders do it - your question isn't really about kits as such and you'll get a much broader response.

I think it's great that you're using your grandpa's shop to build your guitars. I have the honor of using some of my great grandpa's tools (who also was a furniture builder) and I get a special feeling when I pull them out and make sawdust with them.
As far as humidity is concerned, get at least 3 different types of hygrometers and take an average reading between them. That will give you a good idea of what you're dealing with. If it is going up and down just keep the guitar in the house when you're not working on it.

Humidity control is critical! Invest in a hygrometer.

I say that because my first (a Martin kit) wound up with a cracked top & the bridge popped off because the humidity was too high when I braced the top.

Get a hygrometer first then figure out if you need a humidifier. You'll definitely need a dehumidifier in the summer.

Have fun.

Kevin Looker

_________________
I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

Welcome Newell!

As the guys have said humidity control is critical and much more important for Lutherie than making furniture because we deal much more thinner, more humidity change sensitive, plates such as the top, back, etc.

Something else that I battle with on forums way too often is the idea that woodworking in general and furniture making specifically has some very different goals requiring some different thought. Making a table or ottoman does not include the notion of building structurally pretty close to the edge - Lutherie does.....

So as mentioned it's critical to have a humidity solution in place prior to doing any building.

Google Sling Psychrometers and Wet Bulb testing and get a handle on these devices and what they will do for you. Today's commercial hygrometers very nearly all suck and are terrible in accuracy... Especially the digital ones. So there is no good way to know if you have the 40 - 50 range that Kevin suggested without first knowing if your hygrometer is accurate. Having a wet bulb testing capability will let you check any commercial hygrometer that you purchase and note the error and/or in some instances calibrate the stinkin thing too.

What you will need to maintain proper humidity levels will be a function of what your hygrometer(s) read when either corrected for error or calibrated. Here in Michigan I can be using a dehumidifier in the summer and I have to use humidifiers in the winter. YMMV where you are.

But securing a humidity stable work space is so very critical to building acoustic guitars because they will warp and crack and worse if you don't that to me it's the first step in approaching Lutherie.

Welcome aboard!

I just moved to Wisconsin from california and never had to worry about humidity. Now I have that to deal with, thanks for posting all the good advice!

Newell,

Here is a link to a post that actually has a link to a post in another forum where Mario talks about a cleaver way to check the humidity. This would be a good way to check the calibration of your hydrometer.
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=44922&hilit=mario+humidity

Getting a hydrometer is a good idea. This is one that was talked about being pretty good a few years ago. Actually back at the time of the discussion it was the Caliber III.
http://www.amazon.com/Caliber-Digital-Hygromter-Western-Humidor/dp/B00JXOKQVW/ref=sr_1_3?ie=UTF8&qid=1425001771&sr=8-3&keywords=hygrometer

So far I have been OK with keeping my wood stored in my house. Doing the glue up and brace carving inside, but the heavy dusty work out in the non climate controlled Florida garage. the first step is to find out what your situation is with the Hygrometer. The next it to figure out how you want to go about fixing it. You may be able to control things (and make it comfortable to work in) with one of those portable AC units. Or a dehumidifier. I have found that my dehumidifiers put out to much heat for use in the house, but they do help in the garage. Seasonally depending on where your shop is you may actually need to humidify. I don't generally think about humidifying since I'm in Florida.

All my stuff has stayed with me or in Florida. However, I'd love to make something for my dad who lives in Ohio. His house was built in 1901 and is anything but climate controlled. I don't believe a guitar would last there. My brother lives on a boat. There is another person I'd love to give something to that I probably cant and expect it to last. So one important part of your current shop and the humidity situation in which you are building in, is the future home of the guitar.

Good luck,

John