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Soundbox Losing Moisture
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10101&t=25179		 Page 1 of 1
Author:  Ken C [ Fri Dec 25, 2009 6:15 pm ]
Post subject:  Soundbox Losing Moisture
I am working on a claro walnut J-185. About a month ago I closed the box and routed the binding channels. It then sat until this week when I finally glued on the bindings. Yesterday as I was leveling the bindings with the scraper, I noticed the back seemed very flat. I grabbed my 15' radius gauge and saw the back had lost practically all its radius. I quickly checked the top, which was built with a 40' radius, and it had actually sunken just a tad.

I have never been too concerned about humidity. Our furnace has a humidifier on it. I store my wood and build in the house where humidity varies between 45% and 60%--I have a humidity gauge in the basement where I build. The current humidity is 55%, so I am a little perplexed as to where all the moisture in the wood went. I bound the guitar with titebond glue. Previously I used CA. Will titebond draw out the moisture as it dries?

I can work on the fingerboard and neck, but I need to dial in my neck set, and I don't want to do it with the body seemingly dried out. This is my fifth guitar, built under the same conditions as the others, and the first time I have run across this. The end grain hadn't been sealed, which would have made the back and top adjust quickly to humidity changes. But the humidity, as shown on my gauge, hasn't changed a whole lot, so I really can't figure out where the moisture went.

Ken
Author:  Tom West [ Fri Dec 25, 2009 7:39 pm ]
Post subject:  Re: Soundbox Losing Moisture
Ken: I would suggest that somehow you braced the top and back at a higher RH then you currently have in your shop.Maybe your humidity gauge is at fault.
Author:  Ken C [ Fri Dec 25, 2009 10:17 pm ]
Post subject:  Re: Soundbox Losing Moisture
You're right about bracing at a higher RH. According to my gauge I braced with humidity closer to 60%. It now shows around 50%. I am surprised a change of 10% could take my back from a 15' radius down to a 40' radius. Might be time to invest in a new gauge and perhaps some supplemental humidity for the basement.

Ken
Author:  Rene [ Sat Dec 26, 2009 12:29 am ]
Post subject:  Re: Soundbox Losing Moisture
Ken,
I also suspect your hygrometer. I presently have two cheap digital hygrometers sitting on my closed box. One reads 38%, the other 16%. I think they are both way off as it's not that cold and my heat is not running very much. Also I've not been experiencing any ill effects of too low humidity like your situation and static electricity, dryness, and such.
I'm going out saturday and get a couple of thermometers and try this homemade wet/dry bulb rig to see how it works.

http://www.salemclock.com/weather/wet-dry.htm

René
Author:  Fred Tellier [ Sat Dec 26, 2009 10:14 am ]
Post subject:  Re: Soundbox Losing Moisture
Hi Ken

With the humidity in this area we need to be real careful in our humidity control, especially in the spring and fall as it can vary huge amounts from day to day. I find my AC in the summer and furnace humidifier in the winter keep the house at the 40 to 50% range but if I intend to build in the non heating and cooling seasons I need to have alternate control, I so far have avoided this as I normally only build in the winter but seem to be getting more into the other seasons, so a purchase of a humidifier and dehumidifier is on my tools list.

Fred
Author:  James W B [ Sat Dec 26, 2009 12:42 pm ]
Post subject:  Re: Soundbox Losing Moisture
I build in a shop that has heat and air so the RH is semi stable,but I also have a room where all my woods are stored and all the bracing is glued up in that is RH controlled.After a days work in the shop ,the days work always goes back to controlled RH.This seems to work well for me.
James
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