Anyone interested in moisture readings?
Dug out a pile of #2 knotty pine I’ve been saving for a few years today. Going to build the kitchen cabinets for our new house with it. So I check the moisture content and it reads 16% most boards, 18% a few. Now this is KD material, so I believe it’s been to…what…8% at least, right? Maybe lower.
Anyways, I take it up to the new house and sticker it to dry and acclimate. Some fir flooring I’ve been drying up there all fall read 10-12%, the few trimmers I tested read 10-12% and the subfloor reads 10-12%. Good enough for me – I’d say the house is about 10-12%, right?
So here’s why I’m posting. How long do you think it will take for that 1×8 pine to get acclimated? Any theorys? Rules of thumb?
And. Tomorrow I’ll be taking a bunch of rough sawn VG Fir (have to bow my head when I say that) up there to sticker and dry – that will be 2x, 5/4, and 1x. I had that milled from logs a few years ago and it’s been stickered, protected from sun and rain and air drying since…since…I’m gonna say…about 1999. Never been through a kiln. I spot checked a few boards today and they were 16-18%. How long you think that will take to acclimate to the house?
Might be kind of interesting to track. Maybe post readings once a week or so? Anyone interested in that?
Replies
I'm interested
know you're suppose to acclimize wood but often wondered how long really.
what are the conditions? heated, unheated,etc?
bobl Volo, non valeo
Baloney detecter
The furnace has been on in the house for a few weeks now, bobl. The wood is stacked upstairs where I'm guessing it's about 65 degrees.
something like this might make a nice short piece for FHB, if it didn't take 3 years to get published.
bobl Volo, non valeo
Baloney detecter
jim... i'm thinking it will take two weeks... just a WAG..
but if it's spread and stickered that would be my goal.. at least during the heating season indoorsMike Smith Rhode Island : Design / Build / Repair / Restore
I'd be plesantly surprised if it were that quick, Mike. It'll be interesting to see.
bobl - notice my restraint?
a huh
bobl Volo, non valeo
Baloney detecter
Mike
did u get an email from me?
bobl Volo, non valeo
Baloney detecter
bob.. my email at work is fine
mfsmith1 at cox.net
this one at home is still down.... but i'm working on it..
i'll check tomorrow morning for your emailMike Smith Rhode Island : Design / Build / Repair / Restore
I did a private reply to a post so it went wherever BT sends those things
bobl Volo, non valeo
Baloney detecter
It'll be 75% of the way there in 6 weeks - 3 month to equalize...a box fan stirring the air in the area will help...
what instruments are you using? - - always assumed that there would be a gradient from outside to inside - in a couple of weeks the outer 1/4" may read pretty dry with the heart not as much?
I have a hand held, pin type moisture meter.
"3 months"? Guess I'd better line something up for this winter, huh?
ya, but that's my WAG (altho somewhat educated) - I wouldn't let it stop me if I needed kitchen cupboards...(February is still winter, isn't it?)
"there's enough for everyone"
jim is assuming this was already KD and has absorbed some moisture to boost it back up to 18% +/-
i would defer to you, wood master, but my thinking has always been that once it takes an initial dry , the wood can cycle faster than green wood
so i'd sticker it .. and.. close the room with a dehumidifier in it..
bet i could have it ready to lay i two weeks
we use dehumidifiers and tents to bring PT 4x4 posts back to dry enough to paintMike Smith Rhode Island : Design / Build / Repair / Restore
The readings on a pin-type meter can be misleading. My preferred method is to acclimatise the timber until readings [whatever they are] are constant across the piece -- indicating that it has reached equilibrium.
The timber will dry out quicker from the end grain so any variation between a reading at the end and a reading in the middle, for example, indicates the board is still losing or gaining moisture.
IanDG
> The readings on a pin-type meter can be misleading.
OK, time for some education on moisture meters. What makes/models are good? Any tips on using them?
Thanks --
-- J.S.
The pin types work by measuring the electrical resistance of the timber between the pins. A correction has to be made to the reading for the type of timber and the ambient temperature.
On the better types, the pins can be driven deep into the timber to record core values but even then the accuracy isn't that great.
Most of us need to know moisture content for acclimatisation purposes and for that the value of the readings is irrelevant -- the consistency across the board is what shows the moisture content has stabilised to the surroundings.
If you're measuring moisture in concrete then the pin types are only a rough guide -- I use a measurement of relative humidity as my guide for laying flooring [less than 75%] which is far more accurate.
IanDG
cant tell you a specific make, but a good moisture meter is going to cost you. The new ones are non invasive and sell for about $200-400. You just put the meter up to the wood and it reads, then you can adjust the number with a chart depending on the wood type.
John - keep your eyes on the woodworking magazines (there are quite a few nowdays). About once a year I see a review on moisture meters in one or another...kind of a regular feature article for them, like circular saws or framing guns for FHB or JLC.
I believe the KD drives out the intercellular water, which is more tightly held than the intracellular - of course it actually removes both, but it's the interc. that is very slow to remove air drying - at least that's my understanding - - let me be clear - I am no more an expert on this than... well, I really don't know much about anything, ya get right down to it...
anyway, I believe that vapor pressure is the operative principle leading to equalization of moisture content - I always have assumed that the closer to equalibrium, the slower the process goes, but as I type this and reconsider, I'm not positive that that is case....gonna have to crack a book..
anyway in this specific instance, we need to define when it's 'done', partically vs theoretically - -
I think your de-humidifier trick is just the thing for Jim if he wants to work this stuff soon...
"there's enough for everyone"
Yeah, I don't depend on the meter to tell me the exact %, Ian. I just read it in relation to the building in this case, or chart the readings to check for stabilization, like you said.
David - In the case of the KD material I'm thinking the center of (most) boards are probably drier than the edges/faces, which have absorbed moisture from the air sitting in the pile the past few years. But you're right, have to check the surface, then rip a few boards to check interiors as well.
Mike/David - I was a little nervous about using a dehumidifier for fear of drying surface moisture off of this wood too fast...you guys think there's any danger of that? I'll put a fan on the pile today.
I'm really interested to see what happens with the air dried fir. In fact, it's getting light, gotta go start digging through that stack. See you guys later.
So many interests. So little life.
Edited 12/16/2004 9:50 am ET by jim blodgett
I used to buy lumber from a ratty little sawmill in NJ that had a homemade kiln. It was an insulated box in which the proprieter ran an oil filled electric heater, the kind you can buy anywhere, a box fan and a dehumidifier. He'd dry a load of green 4/4 oak down to 8% - 10 % in about a month.
I found another guy who had a $30,000 vacuum kiln. He'd dry the same load in about 2 weeks.
AndyAndy Engel
Senior editor, Fine Woodworking magazine
Other people can talk about how to expand the destiny of mankind. I just want to talk about how to fix a motorcycle. I think that what I have to say has more lasting value. --Robert M. Pirsig
Yeah, I have a nice set of plans for a kiln I got out of "American Woodworker" a couple years ago, Andy. Very similar to the one you describe, heated with light bulbs, with a home style dehumidifier. I was THIS close to buying the parts and putting it together - had vowed to do it for processing the trim for this house in fact - but things are a little up in the air right now so I'm still making do with duct tape, tie wire and an oscillating fan.
If things settle back to normal this summer, and we start the next house like we had planned, I'll build it for sure for the next house. Lord knows, I got a heck of a lot of that fir to dry.
How's the new job treating you?
Not bad. I've learned that measurements smaller than eighths exist, I'm getting paid to sit home on Christmas eve, I've been able to bicycle to work, and it's warm where I sit.
AndyAndy Engel
Senior editor, Fine Woodworking magazine
Other people can talk about how to expand the destiny of mankind. I just want to talk about how to fix a motorcycle. I think that what I have to say has more lasting value. --Robert M. Pirsig
Andy,
Where was that ratty old mill at?
Tranquility, which is in Green or Allamuchy Township near Hackettstown. It was Orr's Sawmill, but I think they're gone now.Andy Engel
Senior editor, Fine Woodworking magazine
Other people can talk about how to expand the destiny of mankind. I just want to talk about how to fix a motorcycle. I think that what I have to say has more lasting value. --Robert M. Pirsig
Lived in Fredon a long time ago. I know the mill your talking about but I was pretty young then.
Try wrapping the pile in plastic with a dehumidifier for a few days than test it.
8% MC is right if it was dried for cabinet, molding or furniture work. Look for the stamps on the lumber for clues. SD means the surface was dried to 18% and KD means dried to 18% internal in construction lumber. KD in hardwoods means 8% and for pine it's sometimes called furniture grade or molding grade if it's dried to hardwood standards. So, KD could mean a couple of things, one is that the wood was dried to an internal moisture content of 6% to 8% and the other is that it was driven through a kiln at a high rate of speed (SD). 18% is the point at which mold no longer grows so the construction industry has settled on it as their standard
I ran two kilns and dried many thousands of board feet of lumber, much of it pine. Two weeks is enough for 4/4 pine, it gives off moisture readily and shrinks camparatively little. Start working it at 12% and you'll be fine.
When you're using your moisture meter be sure to use the charts to compensate for temperature and wood species.
Edit: Here's an EMC chart I've been hosting for years. EMC stands for Equillibrium Moisture Content. It means simply that once the wood is in equillibrium with the relative humidity this is the moisture content the wood will have. http://www.furniturecarver.com/emc.html
Lee
Edited 12/17/2004 10:29 am ET by Lee_Grindinger
Thanks, Lee. Nice to see your name on our board again.
Funny thing about those grade stamps - just a couple weeks ago I posted something similar to what you just said about "SDry" and another poster said he thought that meant that the lumber was surfaced after is was dried, as opposed to "SGrn"...
...all of these specific terms and regional variations for hardwoods and softwoods and semantic variations reminds me of why I get a head ache trying to keep track of all this stuff and just look for stabilized moisture readings, within a per cent or two of the moisture levels in whatever building I'm working in. Not a perfect science, but I've squeeked by for this long that way.
Thanks Jim, I'm still around, just less inclined to get into threads.The abbreviation for surfaced lumber is S1S, S2S, S3S and S4S, Surfaced one side, surfaced two sides, surfaced three sides and surfaced four sides respectively.SD can also mean Shipping Dry but this is generally for export. Again, it means around 18% MC, below which lumber won't mold.Lee
Okay, here's a report after one week.
I built three seperate stacks, at least 3/4" between every board, every direction. The boards on the outside of the piles are consistantly drier than those deeper in the pile.
Ambient moisture in building Dec 15 read 10-12%, Dec 21 read 6-8-10%
Dec 15 Pine read 16-18%, Dec 21 read 8-10%
Dec 16 4/4 Fir read 18-20%, Dec 21 read 10-12-14%
Dec 16 8/4 Fir read 16-18-20%, Dec 21 read 10-12-14%
so jim... do you draw any conclusions from that ?
do you have any projections as to when the wood will be stable enough to install ?Mike Smith Rhode Island : Design / Build / Repair / Restore
"conclusions"?
Well, I'm surprised how fast it's coming down, Mike, I'll tell you that. As far as conclusions...no, not really, just that it hasn't stabilized yet. I think I want to wait until it flattens out so I get very little reading differences one week to the next.
David - you asked about cutting into one piece. That's a good idea. I'll try that next time I'm up there, maybe Friday.
Edited 12/23/2004 4:38 pm ET by jim blodgett
Jim,As an aside....How do you get the nice face with a hat next to your name?Rich BeckmanAnother day, another tool.
Huh?
Rich,I think you earmarked J.B. as one of your "friends".If you view his profile you can select "add to friends". I'm not sure what this does for you other than warm and fuzzy feelings of camaraderie.
Jon Blakemore
"I think you earmarked J.B. as one of your 'friends'."ROFLMAO!!!!I did do that!!! LOL!! I completely forgot about it!! Geez, that was a couple of weeks ago!I'm sure a few days went by between my doing that and seeing a post from Jim!!I was trying to figure out what point there might be to designating someone a "friend". I guess that hatted face is the whole point!!LOL!!!Thanks, Jon!Rich BeckmanAnother day, another lesson learned.
wow ,
wish I had an answer
this is the most time Blodget has spent here talking in months
obviously this is something imprtant to him
I really wish I had an answer that was any better then what I have read already
other then good stickers, a heavy top load and a wood stove ( dry heat ) cranked up till the metalbestos was red
probabally not a good answer, but different
hey
I know your in Seattle area
maybe starbucks can lend you a dryer
looks like it's time to edit my WAG - - I'm amazed to see that much difference in this amount of time - - do you have a sacrificial piece you could cut and measure toward the center of the board?
"there's enough for everyone"
Took some more readings today. Still coming down. Worked late and forgot to cut into a board until after I had packed up for the day. Sorry David, I'll try to remember to do that tomorrow.
Ambient moisture in building Dec 15 10-12%, Dec 21 6-8-10%, Dec 29 6-8%
Dec 15 Pine 16-18%, Dec 21 8-10%, Dec 29 6-8%
Dec 16 4/4 Fir 18-20%, Dec 21 10-12-14%, Dec 29 8-10%
Dec 16 8/4 Fir 16-18-20%, Dec 21 10-12-14%, Dec 29 8-10-12%
wow, jim .. those sure are low ambient readings ?
how do you measure ambient ? sling psychrometer ?, hydrometer ?..
those are "dryer thatn a bone "Mike Smith Rhode Island : Design / Build / Repair / Restore
I belive that those are EMC of existing wood in the house.Not the ambinet air RH.
that's not the way i read it .. bill ..
he had two series.. the first series is ambient taken on three different dates
the second series is the moisture content in the wood from three different stacks... on the same corresponding date: pine, 3/4 fir & 5/4 firMike Smith Rhode Island : Design / Build / Repair / Restore
Yeah, Bill's right. I checked moisture % of several exposed framing members - subfloor, trimmer, pocketdoor frame, a couple headers...
Sorry for the confusion. Used the wrong terminology again I guess.
i'm relieved.. i was going to suggest putting a wet waqshcloth over your nose if you were going to work thereMike Smith Rhode Island : Design / Build / Repair / Restore
I brought the pine down to the shop last week and cut it up for doors, face frames and end panels - it had stabilized at 6-8%. I did take some readings of the fir today, though. The 4/4 seems to have stabilized at 8-10% (far more 8% readings than 10%). The 8/4 is still coming down. There was quite a bit of 10%, some 8% in that pile.
As a side note, I did take a few readings of the heart of that pine when I milled it, like David Doud asked about. Some of the readings were as much as 2% higher than the surface of the board...some of those boards look like propellers, too. I think the surface dried too fast. Next time I'll get an earlier start and dry them slower.
Anyways, here's the readings -
Moisture in building Dec 15 10-12%, Dec 21 6-8-10%, Dec 29 6-8%, Jan 17 6-8%
Dec 15 Pine 16-18%, Dec 21 8-10%, Dec 29 6-8%
Dec 16 4/4 Fir 18-20%, Dec 21 10-12-14%, Dec 29 8-10%, Jan 17 8-10%
Dec 16 8/4 Fir 16-18-20%, Dec 21 10-12-14%, Dec 29 8-10-12%, Jan 17 8-10%