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Hemlock weight after AD

Started by hillbillyhogs, May 22, 2013, 12:56:39 PM

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hillbillyhogs

Curious about estimate on what hemlock weighs after 30/60/90 days air drying? I know, I know many variables. Give me some educated guesses. THANKS GUYS

thecfarm

30 days those 2x8's are lighter,60 days is better,90 days my friend that was helping me enjoyed it alot more. Sorry no meter,just strong back.  :D
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

hillbillyhogs

Does it lose 1/2 it's weight in a couple months or ?

thecfarm

My friend Doug said it did.   :D  I agreed with him.I would think it matters if 1" boards or 2x8's.
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

hillbillyhogs

I'm surprised there isn't more info online about it.  I found a guy in PA with a WM @50/ft. fresh off the saw, most other places wanted .65/ft. so the 15cents difference covers the freight hauling green lumber PLUS I'm supporting the small guy!

hillbillyhogs

Comment removed by poster for fear it was/is being taken the wrong way. Sorry about that

Dave Shepard

Green: 50/lbs cubic foot.
20%: 28/lbs cubic foot.

Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"LogRite!

thecfarm

I don't think many use or like hemlock. Now if you was asking about white pine or southern white pine,you would probably find more information.
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

hillbillyhogs

Quote from: Dave Shepard on May 22, 2013, 08:33:39 PM
Green: 50/lbs cubic foot.
20%: 28/lbs cubic foot.

Thank you Mr. Shepard

Jay C. White Cloud

Hello Hillbillyhogs,

These links may be of use and/or interest.

http://www.extension.purdue.edu/extmedia/FNR/FNR-156.pdf

https://forestryforum.com/board/index.php?action=toolbox The original Wood Calculators<<<<  

http://www.engineeringtoolbox.com/weigt-wood-d_821.html

I would not say that Hemlock is my favorite timber framing woods, nor that of folks in our group, but for certain jobs (livestock and horse barns) we use it very often, and recommend it for such.  If the logs are select and of good quality, it can be a wonderful wood to timber frame in, and we have cut a few timber frame houses out of it, with much pleasure.  Good floors for workshops/sheds.  Great sill beam material.  Great matting/screen wood, right next to Cedars, and Tamarack, especially for out door applications.  Hope this helps.

Regards,

jay
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

GeneWengert-WoodDoc

As an average, bone dry eastern hemlock weighs 22 pounds per cubic foot.  You can figure that at an air dried MC of 20% MC, that will add 20% to the weight, giving 4.4 pounds more for a total of 26.4 pounds.  However, when going from 0% to 20% MC, the wood will swell and so there will be more than one cubic foot that weighs 26.4 pounds.  The swelling is estimated to be 6.4%, so we need to reduce the weight by 6.4% or 1.7 pounds, giving us 24.7 pounds per cubic foot at 20% MC.

Further, a 2x8x12 is 16 BF, but the actual size if 1-1/2" x 7-1/4" x 12' or 0.90625 cubic feet per piece.  So, a 2x8x12 at 20% MC weighs 24.7 x 0.90625 = 22.4 pounds.

A 2x4x12 is actually 1-1/2x3-1/2x12 or 0.4375 cubic feet and therefore weighs 10.8 pounds (and not 1/2 the weight of a 2x8).

At 30% MC, 26 pounds per cubic foot.  At 100% MC, 41 pounds per cubic foot.

Due to the high amount of bacterial wetwood in hemlock, the green MC can easily be around 100%.  So, if you were to saw a 2x8x12 that is exactly 2" x 8" x 12', or 16 BF or 1.33 cubic feet, the weight would be 54 pounds per piece.

If this wood dries to 20% MC, it will shrink some, but it will be bigger than 1-1/2"x7-1/4"x12', but the amount of weight of dry wood is constant, so the weight would drop to 32 pounds.

Bottom line, we need to know the size and at what MC you measured that size.

If you want the basic data and calculation method, go to
http://woodlandinfo.org/sites/woodlandinfo.org/files/pdf/FEM/FEM_069.pdf
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

hillbillyhogs

Dr. Gene,

                 5/4 x 8 x 12 GREEN , fresh off of the saw size.  What size are we left with when we get to 20%. LOTS OF INFO, my feeble mind can't process it all

beenthere

Flat sawn? quarter sawn? or somewhere in between? All will make a difference to final size, among some other variables as well. ;)
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

hillbillyhogs


rooster 58

    In my area, hemlock is used for construction material for camps, garages, additions and the like. Also, "ruff cut" 1x material is preferred for siding, and even for some interior applications. And larger cants are used for headers and beams. The biggest drawback to hemlock is shake. Soetimes it shows after it is nailed up and begins to dry, but usually is noticeable at milling time. Depending on where it is logged, entire hillsides of hemlock will have shake and therefore have alot of degrade

thecfarm

Gene,my 2x8 that comes off my mill are 2x8's.  ;)  No lumber yard dimensions coming off my mill.
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

clww

Quote from: hillbillyhogs on May 22, 2013, 03:00:56 PM
I'll tell ya something else.... There's a lot of people talking out their bung hole about what all they do, own and sell. I tried to find what I needed through the forum but, had no luck.
???
Many Stihl Saws-16"-60"
"Go Ask The Other Master Chief"
18-Wheeler Driver

hillbillyhogs

Quote from: clww on May 23, 2013, 10:15:11 PM
Quote from: hillbillyhogs on May 22, 2013, 03:00:56 PM
I'll tell ya something else.... There's a lot of people talking out their bung hole about what all they do, own and sell. I tried to find what I needed through the forum but, had no luck.
???

That was my rant about "keyboard sawyers"  Sorry

beenthere

hillbilly
QuoteThat was my rant about "keyboard sawyers"  Sorry

Don't think owning a sawmill is a pre-requisite to pulling up a stump on the Forestry Forum and contributing to the different discussions going forward in the many threads.
That is, if you are trying to sort it out that way. ;)
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

hillbillyhogs

Quote from: beenthere on May 24, 2013, 10:32:25 AM
hillbilly
QuoteThat was my rant about "keyboard sawyers"  Sorry

Don't think owning a sawmill is a pre-requisite to pulling up a stump on the Forestry Forum and contributing to the different discussions going forward in the many threads.
That is, if you are trying to sort it out that way. ;)

NO NO NO that's not what I was meaning I'll modify the comment as it may be taken the wrong way.

GeneWengert-WoodDoc

Flat sawn 1.250" x 8.00" Eastern hemlock green will be approximately  1.24" x 7.81" at 20% MC.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

Jay C. White Cloud

You,er the man Gene...

I don't know if you have time, but I was thinking it would be great, (especially for me ???) if I could see the math steps you took to arrive at that conclusion.  I am always second guessing myself, and would love to see a pro plug the numbers into the formula.  I kinda understand them, but alway think I am getting out of sequence; just not sure of myself.  Using Hillybillyhogs's question as the model?

Regards,

jay
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

GeneWengert-WoodDoc

To get the number, we have to make some assumptions.  First, at 20% MC, the entire piece is 20% MC...not the core at 30% and the shell at 10% MC, or similar.  Second, we assume that shrinkage satrts are 30% MC, whcih is true for a wood cell, but not for a piece of lumber.  Third, we assume that the large piece can actually shrink as much as it is suppose to and that there is no tension set.

So, now we use the shrinkage values from a book such as THE WOOD HANDBOOK.  In the 2010 edition, these values appear on page 13-16 and 13-17.   Note that it says these are for 6% to 14% MC, but if we use the total shrinkage values (p. 4-6). we will get the same answers.  For eastern hemlock, the values given are 0.00102 (radial shrinkage for each 1% MC change) and 0.00237 (tangential).

So, at 20% MC, we have the wood cells only shrinking from 30% MC to 20% MC, or 10%.  So, multiply the two numbers by 10.  The radial number is the thickness change for the flat sawn lumber.  So, 1.25 x .0102 = 0.01275".  So, the thickness shrinkage is 0.01".  For the 8" width, 8 x .00237 = 0.1896 = 0.19" shrinkage in width.  So, at 20% MC, the new size is [1.25 - 0.01] x [8.00 - 0.19] or 1.24" x 7.81".

OK?
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

Jay C. White Cloud

Thanks Gene, you are great!!
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

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