relative humidity question

[shofu]

Hi everyone.  My name is George and this is my first post.  I am an an aspiring bowyer and have learned much from this great community already (long way to go).
To get me started, I was given some seasoned staves from DC and TreeNinja from PA (thank you!).  I bought 2 humidistats and after taking the wood from 70degrees 50% RH at DC's, I got home and my house registered at 70% RH everywhere I tried and one stave developed a crack (Ocean Spray).
Not sure how to proceed - is wood stable? Any advice greatly appreciated.
Thanks,
George

[bradsmith2010]

really depends on where the crack is,, need more info and pic if possible,,if that is on the back,, or end put more sealer on, glue paint varnish,, something,,

put the stave in a cool room for now,, till we have more info to go on,,

[DC]

Hey George. My first suggestion would be to calibrate your hygrometers(not humidistat). I found them to be rather inaccurate. Just do a Google search on "calibrating hygrometers". It's quite a simple process. Cigar guys are paranoid about RH. Table salt will give 75% and calcium chloride gives 25% I think. That said OS can be fickle. Was it one that wasn't already cracked? Where did the crack form, in the handle? I've seen some crack from a quick change in RH.

[shofu]

Thanks Brad.  I can't figure out how to load pics yet.  I guess  I am wondering is when is wood dry and can I start building a bow in higher humidity?  My shop the humidistat redlines to 100%
Cheers,
George

[Springbuck]

  Yeah, like Brad said, if in doubt....more sealant.

[DC]

Is your shop heated?

[shofu]

Thanks DC.  I saved and bought hygrometers and a scale to check weight. Also traded for a small bandsaw.  Just want to start building but don't want to wreck anything!  The roughed out OS stave was not cracked before and did crack on the belly at the fadeouts and through the centre of the belly of the handle. Back is not cracked.  Thanks for tip on calibration - will do.
Thanks Springbuck and Brad. Hopefully I can figure out pics and try to contribute something soon.
Cheers,
George

[shofu]

Shop is not heated but dry and closed so keeping staves in stablest part of heated house. Want to build a bow but wife doesn't like me carving in the kitchen. Is it safe to work in shop?

[DC]

At 100% I would suspect the calibration. If your shop is unheated the RH should be the same as outside, maybe a bit drier. Weather Network says your RH is 90% at the moment. That's pretty high. You can go ahead on the bow but expect a little set. Keep the stave in the house when you are not working on it. Living on the coast can be a PITA. You may have to build a hot box. Look on "Poor folks Bows" for instructions.If you can find a spot that's a few degrees warmer it will help.

[shofu]

Thank you! Coast can be a PITA true but lots of great wood!
G

[DC]

You said you bought two hygrometers. Do they agree with each other? They look like a lot better quality than mine. They may be accurate. Apparently even the good ones disagree by 5-10%. The calibration test involves closing up the meter in a bag with wet salt. That might not be very good for an electronic device

[willie]

george
I have a hygrometer ($20?) that was sold for a humidor. It is a bit better than the general use variety, but still is really only useful for helping to gain an understanding of how to store wood, longer term, in a particular environment. the scale is your day to day friend.

my hot box uses about half the foam as the po folks because I substituted a couple of old fluorescent shop fixtures for the incandescent.


 

[DC]

Does the heat come from the ballast? I didn't think the tubes warmed up. I used waterbed heaters in mine.

[shofu]

This is the other one - they do not agree which is why I bought 2.  They were both $11 ea at Home Hardware so not sure of quality difference.  I will try salt trick with manual one and try to borrow a third to see if any 2 agree!
g

[George Tsoukalas]

The RH went from 50-70% RH and your stave cracked?
Staves do not usually crack from absorbing moisture. It's the other way around.
Jawge