Humidity and hygrometers

Okay, I'm new at this...

I bought a Hisense dehumidifier for my 250 square foot garage shop. I have a propane furnace on the ceiling. The dehumidifier is set at 32 to 36 %.

Now I find I may have a problem with 'telegraphing' of braces through to the top of the soundboard in this tenor I've been working on for the past 2 years, apparently because of humidity that is fluctuating. I have a hygrometer across the room (10 feet) from the dehumidifier. I brought one in from the house awhile back as well and there was no agreement between the three.

Questions:
1. I will buy a decent hygrometer if I can figure out what that is.
2. How long does wood need to be at a certain humidity level for things to be stable fir glueing, sanding, etc.? (hours? Days? Weeks??)
3. Does the humidity vary from one part of a room to another??
4. And, with the previous question, I mean, how sensitive is this stuff? Is it realistically do-able for me to build in my little garage shop?

Forgive the frustrated tone... I really do want to win this battle.

Chuck Barnett

Hey Chuck, the missing piece of info for you is “ how dry is the wood you are working with?”. There are moisture meters available that will tell you that. Anyone that is serious about building instruments should have one and use it. The wood should be dried to a moisture content between 6 to 8%. By using it you will learn how effective your dehumidifying program is.
Bradford

Thank you. I do not have a meter for that but I think the wood is quite dry. And that raises yet another what to buy question

I have a Lignomat Mini ligno that I bought 30 years ago and is still going strong. Woodcraft sells them for $119. The big decision in buying is whether to go with pinless or pinned. Mine is pinned, and does require that you test the wood in non exposed areas. Until you get and use a moisture meter, you are only guessing about how dry the wood is, and in any given situation may be right or wrong. Using the meter regularly will teach you how to properly dry and assemble your instruments.
Bradford

Chuck, I built something similar to this from scraps of thicknessed tops/backs. I referenced it against my 2 Oregon Scientific hygrometers to get some kind of calibration. It's my main reference in my garage now. I don't control my garage, but if the wooden hygrometer tells me no, then I either take things into the house for a couple of days to glue up, or wait until the weather changes(which could be a while). https://www.youtube.com/watch?v=FCiltGTHANc
if you make one of these, after a while you'll get to know your optimum range , and because it's made from wood, you can see exactly the effect the humidity would have on your builds.
good luck, Mike

Mike, thank you for staying with me on this! I hate to wear something into the ground but it seems to be my nature.

I looked at online reviews of hygrometers and Oregon Scientific does not appear on any lists. And so I have no idea if I buy a hygrometer whether or not it is accurate. If I buy two I reduce the percentage of inaccuracy. If I got ten I would expect that I should be within 10% accuracy in going with what the majority of them. This all seems pretty relative to me. www.nwclimate.org selects Extech 445815 as the most accurate. I don't know how to know if these devices are accurate. In the same way that, as I understand it, in the Smithsonian in Washington DC there is a platinum yard stick that is one yard long. If we must be accurate about how long is a yard then we have to compare to that standard. Are you with me?

But, I trust the opinions of people on this Purim. So now I'm asking myself, "What's wrong with Oregon Scientific?"

Hi Chuck, I can't really say for sure my hygrometers are accurate but I'm confident that they are close enough. I have observed them over a period of time, and compared them outdoors with local weather forecast reports, and since using them as a guide for my building, I've not had any problems with this regard. The first was integrated into a OS weather station with a remote sensor, it was around £90. The second one is just the sensor with it's own humidity display, which I was lucky enough to pick up from a charity shop for £3.
I can't advise you what to buy, as you will have to research what is available over there. It may be that (despite the name) OS products are not available in the US. I would advise you not to go for the cheap Chinese ones seen on auction sites. My friend bought a couple and they were way out.
Good luck, Mike.

Chuck, you are way overthinking this. Try to keep your shop at 40-50% year round. A hygrometer next to a heat or moisture source will read a bit differently from one across the room. I have a StewMac hygrometer. I have no idea if it is scientifically accurate and I don't care. If you breathe on it the level should shoot up, then slowly fall back to where it was. As long as it stays within a comfortable range I trust that everything is fine. I spent last winter away from home and shop. The humidity fell to 27% inside, but my instruments survived nicely. On the other hand, one summer my store room rose to 80% and work in progress began to pop apart, though the controlled part of my shop was fine.

I've never owned a moisture meter. Most don't work well on thin stock. If you started laying in wood two years ago it would all be ready to go by now. I think that beginners start off with fancy instruments so they can show them off online and be part of the club, but it's far smarter to knock out some basic instruments, then play them, live with them, and study them to see what happens. Experience is the best teacher, but you won't acquire much at 2 years per instrument.

I have two of the StewMac temp/hygrometers, I'm satisfied with them. I bought several of them and kept the ones that were all in agreement and sent the others back. Some read almost 10% different from the others.

ChuckBarnett said:

I trust the opinions of people on this Purim."

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"Purim!" ... Great job voice-to-text! FORUM! I trust your experience and wisdom, folks.

Thank you, John for taking the time to help me with this. Yes I I have tended to overthink all of this. Helping me with a few numbers gives me something to Anchor to. I read somewhere that a difference of 30% humidity or greater is a problem for instruments. If they leave the building process at 60% humidity and go to a dry place where it averages 30% humidity there could be problems with cracking. On the other hand it seems like instruments can handle greater humidity better. So I have opted for setting my little dehumidifier at somewhere between 35 to 38% based on the gauge on the control panel. You're suggesting 40 to 50% would work. I trust your experience. Once I'm done with this project I may bump this up a little bit. It seems a number of people have the stewmac hygrometer And so that may be the direction I go.

Your observations about rookies building those first instruments are likely valid. I don't think that they hold in my case, for the record. I stumbled across a tabletop made of quilted maple that I could saw into boards of 5 to 5 and 1/2 inch width. I asked myself what could you build if you made a back from bookmatched panels from those boards. That's how I came up with a tenor ukulele. I traded a burl that I found hunting firewood for a slab of vertical grain Redwood and that's what determined the soundboard material. My son lost a nice Maple floor to a flood which was pulled up. And me, being the scavenger that I am, harvested some wood from those boards. That is becoming the fretboard, rosette and ultimately the bridge for this instrument. Another son had a contact at Pacific tonewoods in Washington State. He learned that they had a scrap pile of wood that they could not take the time to develop. He stopped by there one day and found some Koa. That is what I'm using for the stripe up the back and for the center lamination of the neck and for the binding, as well as that beautiful figured headstock veneer. Hence my choices of material we're not driven by a plan start with basic stuff and make it simple.
Regarding things like binding the fretboard, and body, center laminations, and other challenging aspects of building, I figured that ultimately I would want to do some of that so why not learn it now. That's my fault, subjecting myself to more pain and aggravation than I needed to to actually have an instrument. But I have learned so much! Once again, credit goes to this forum!
No, I don't believe that I will be strutting this finished ukulele too broadly. I will certainly post pictures on this forum. I don't plan on having a website with my name on it. It will not leave my family (I've got two granddaughters that are strumming and I'm getting older by the second! )

Good story, Chuck. Thanks for telling it. I write an occasional column called "The Lutherie Curmudgeon" where I sometimes harp about the way beginners decide to learn lutherie. Like many others, I wanted to play fancy instruments that I suspected I would never be able to afford, and building them seemed to be the most affordable way to get them. Along the way I lost my taste for gobs of pearl, and also realized that the difference between great tone and just really good tone sort of happens by itself. The range of variables is so great that we can't really control them all, even if we truly know what they are. After we can build consistently wonderful instruments an occasional one is bound to stand above the rest. Trying to chase that lucky instrument can lead to serious frustration.

For most beginners just making a clean glue joint is frustrating. Trying to accomplish cutting-edge work right off the bat is super frustrating. Most newbies don't have the tenacity to spend years building their first instrument. It's much more satisfying to finish a string of work within their current skill set, note how the tone improves and how much better they look and reach that two-year mark feeling accomplished and pleased with their efforts.

jcalkin said:

...the difference between great tone and just really good tone sort of happens by itself... Trying to chase that lucky instrument can lead to serious frustration.

For most beginners just making a clean glue joint is frustrating...

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Good perspectives for me to lock into.

I began this journey without the benefit of woodworking experience of any kind (beyond a circular saw and a claw hammer... and not too good with those!). Thus I'm pursuing a degree in two disciplines at the same time. I must take it slow to get the brain up to speed on both hows and whys. And yes, over two years at this and starting to get excited for the finish line. I'll let speed take care of itself.