Jim,
I like the terminology "Triangulate" as that more accurately describes what I have been doing.
I have two wood samples one for inside the box and another for outside the box as a control.
BTW, I have ditched the Hot Box per se. I have included in my arsenal an inexpensive closet dehumidifier I bought off of Amazon for $30. I have reduced my electric bill quite a bit. Instead of hovering around 120 degree, it seems 80-90 is getting me in the zone. In fact, i had to back off today as at my last reading I was down to 1.2% EMC.
By accident, I think I discovered why 4% for compression boards. Using a steel bar with pins, I make divots in the soundboard before it goes in the box (again part of the triangulation method !) and I have noticed that below 4% there is not much more noticeable shrinkage. I also have not noticed any damage occurring from going down to 1.2% either. So maybe extreme accuracy is not needed.
The new analog gauges arrived today. For some reason I thought they were 8" in diameter.
They were not.
They are tiny little 2" diameter gauges. But they are nicely made, and they are "certified" accurate too. Again, i got two. One for inside, the other for outside the box.
The other gauge i use is the widget. I think mine is a Gravagne design. I like the idea that the wood tells you what the EMC is. Of course getting it calibrated is the trick.
So, yes what is the Nossaman tool you were referring too?
-chris
#caveman ------------------------------
A hunter's drumbeat steers the stampeding herd,
His belly growls in hunger to what he sees.
The mammoth aware blows his mighty trumpet,
But alas, the caveman tickles the ivories.
chernobieffpiano.com
865-986-7720
------------------------------
Original Message:
Sent: 03-12-2018 21:55
From: Jim Ialeggio
Subject: Hygrometer
Chris,
I have been all around robin hood's barn on this one...its a toughie. The hygrometers are just not trustworthy enough to rely on exclusively. I have three of the digital kinds in the shop, and they give a range of readings depending on how old they are. I have a cheap analog one like the one you posted, and it always disagrees with all the other hygrometers...so I have no clue really what the RH in my shop is unless you say +/-20%. You might ask, "why the cheap one"? And I would say at the temps and RH we need to read, in wet weather, the extreme ends of the scale are simply not trustworthy. If a hygrometer is going to be inaccurate, it might as well be a cheap one. I never use the digital ones in the hot box, because high temps fry their digital brains. The moisture meters are completely useless, for our needs, as they read to the center of a 3/4" board at +/-2%...which is huge. I never use mine at all.
Instead, I triangulate. I bought a small bench top lab oven, lab thermometer, and ammo loader's grain scale to take accurate empirical MC measurements, throughout the drying process, of each individual board I rib. Associated with the accurate oven dry samples, I have a Nossaman dial indicator tool, which records the length of a piece of cross-grain spruce on the dial indicator. I calibrate this Nossaman tool for each board too, as its readings relative to MC are mobile too. Calibrating it is simple and takes no time at all when I'm taking oven dry samples from the box. Then I also measure the width of the board and compare that as it changes dimension, relative to the pieces I removed to oven dry. I have a remote reading hygrometer in the box, but every time I look at it I say..."yeah right". I'll post a pic of the Nossaman style gauge if you think that would be useful.
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Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
Original Message:
Sent: 03-12-2018 19:59
From: James Kelly
Subject: Hygrometer
try lignomat excellent products with various types that can be used for different wood groups they offer moisture meters with built in wood temperature corrections so you do not need to use a conversion chart
I have a pin meter mini-ligno E/D that can check moisture in lumber, veneer and fiberboard with a measuring range of 6-45% for moisture value below 6% the meter will read 6.0 with a blinkingdecimal point call 1-800-227-2105 or go to lignomat.com
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James Kelly
Pawleys Island SC
843-325-4357
Original Message:
Sent: 03-12-2018 14:32
From: Chris Chernobieff
Subject: Hygrometer
Here's the moisture meter i'm using. Once 6% is reached it worthless. So, i end up only using it on firewood.
------------------------------
A hunter's drumbeat steers the stampeding herd,
His belly growls in hunger to what he sees.
The mammoth aware blows his mighty trumpet,
But alas, the caveman tickles the ivories.
chernobieffpiano.com
865-986-7720
Original Message:
Sent: 03-12-2018 14:27
From: Chris Chernobieff
Subject: Hygrometer
That's what i'm doing now. Using a digital RH hygrometer along with a chart to guesstimate EMC. I'm also: using a wood widget, Measuring wood weight, and using a moisture meter which only goes down to 6% unfortunately.
Just looking for better scientific equipment, that perhaps someone else is using and are happy with. Like a review.
-chris
------------------------------
A hunter's drumbeat steers the stampeding herd,
His belly growls in hunger to what he sees.
The mammoth aware blows his mighty trumpet,
But alas, the caveman tickles the ivories.
chernobieffpiano.com
865-986-7720
Original Message:
Sent: 03-12-2018 13:37
From: David Skolnik
Subject: Hygrometer
I suppose it depends on the level of reliable accuracy that you want. It challenges my deep need for a sense of cosmic order to think that you would get the same results with the item you showed as you would with something considerably more expensive. But I'm also a bit confused by your question, as you are asking about a hygrometer that would read 5% MC. Hygromters read RH. For 5% EMC you would need to maintain around 25%RH at 80 degrees.
https://www.finewoodworking.com/FWNPDFfree/equilibrium-moisture-content-chart.pdf
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David Skolnik
Hastings-on-Hudson NY
914-231-7565
Original Message:
Sent: 03-12-2018 12:20
From: Chris Chernobieff
Subject: Hygrometer
I'm looking for a hygrometer that is accurate below 5% MC. Anyone have a model that they are happy with? I will be putting it in my kiln. In the meantime, I purchased the one below just to try it out.
Thanks
------------------------------
A hunter's drumbeat steers the stampeding herd,
His belly growls in hunger to what he sees.
The mammoth aware blows his mighty trumpet,
But alas, the caveman tickles the ivories.
chernobieffpiano.com
865-986-7720
------------------------------