Replies

1. 
   UncleDunc | Jan 03, 2003 04:39am | #1

   >> Anyone agree?

   Maybe. Maybe not. Density within a given species can vary widely. Why don't you dry it in the oven overnight and tell us what you come up with.

1. 
   PlaneWood | Jan 03, 2003 04:42am | #2

   U got a 49" oven?

   PlaneWood by Mike_in_KatyPlaneWood

1. 
   UncleDunc | Jan 03, 2003 05:48am | #3

   You got me there. :) Is that the shortest piece of walnut you have in the shop, or is it that you want to know MC of that particular piece? I could describe a setup with a cardboard box and some light bulbs and muffin fans and cautions not to burn the house down, but you already know all that stuff.

2. 
   Dale | Jan 03, 2003 05:54am | #4

   Hey Mike,

   I like to play with #'s myself as you know.  But, 20% does sound high........even for the tropical Houston area.  At about 20% is were the green fuzzes begin to grow on wood.  So wooden homes in Houston would probably "melt" over time, Also, 20% mc equals to about 90% RH on the average, shoot... I know Houston is a sweat box but thats close to a sauna Possible the walnut lumber was in a wet spot in the kiln?? But, still 20% is still high???........Dale

   Bring that piece up here and I'll check it with a moisture meter, if you don't mind small holes.

   
   

   ---

   Edited 1/3/2003 12:16:35 AM ET by Dale

3. 
   ian | Jan 03, 2003 04:06pm | #5

   Mike

   Here's the data from the Collins Good Wood Handbook by Albert Jackson and David Day.  "American Walnut (Juglans nigra) - average dried weight 660 kg/cu.m (41 lb/cu.ft.)

   My calculator gets about 9.63 lbs at dried condition, so you're looking at 2+ lbs of moisture - seems an awful lot for such a small piece. 

   The data from the internet looks odd - specific gravity is density, compared to a material that is 1000kg/cu.m - to first order accuracy 1 cu.m of water weighs 1000 kg, so a specific gravity of 0.55 should translate to about 550 kg/cu.m. 

   Accepting that the density at 12% is 609 kg/cu.m, this translates to 543.8 kg of wood and 65.2 kg of moisture.
   Your piece comes in at 736.8 kg/cu.m, so there is 193 kg of water in it.  This is equivalent to 35% moisture - 193/543 = 0.35

   I think my maths are OK

   Ian  

1. 
   PlaneWood | Jan 03, 2003 07:36pm | #6

   Ok, I whacked off a piece 12" long.  It weighs 2#14.1ozs, or 2.88 lbs.  It's now it in my shop oven at 350 degrees.

   Any guesses what it'll weight after about 4 hrs in the oven?

   PlaneWood by Mike_in_KatyPlaneWood

1. 
   riverr1 | Jan 03, 2003 08:19pm | #7

   2.38 lbs---just a wild guess

1. 
   PlaneWood | Jan 04, 2003 01:30am | #8

   Well, after a good cook, It now weighs 2.69 lbs.  After one hour it weighed 2.72 lbs and after 4 hrs it was 2.69 lbs, so most of the moisture was cooked out in the 1st hour.

   So, what does that mean the original moisture content was??

   It originally was 2.88 lbs, so it lost 0.19 lbs of moisture.  0.19/2.88 =  0.066, or 6.6%  ??

   Can that be right??  My oven is electric, not gas.

   I would think that it would have gained a lot of moisture setting here in my non controlled environment.

   PlaneWood by Mike_in_KatyPlaneWood

1. 
   Dale | Jan 04, 2003 02:50am | #9

   Mike,

   6.6 is the correct answer, you win the lollipop, ; ' >    So was the walnut kiln dried to 6% orginally???   Dale

2. 
   PlaneWood | Jan 04, 2003 05:33am | #10

   Dale -

   It was kiln dried, but I don't know to what %.

   PlaneWood by Mike_in_KatyPlaneWood

3. 
   ian | Jan 04, 2003 07:39am | #11

   Your assumption is that on cooking you removed 100% of the moisture.  This is unlikely as most of the residual moisture is bound up in the wood's pores and hard to remove unless you break the cell walls.  You probably only reduced the moisture content to about 10%. 

   An the assumption that you removed ALL the moisture the original sample was at 7%, (0.19/2.69 = 0.0706) but this is drier than Kiln dry

   Assuming that you got the moisture content back to 10%, a piece weighing 2.69 lbs still contains 0.24 lbs of moisture. The piece lost 0.19 lbs of moisture, so originally it had 0.43 lbs of moisture (0.19 + 0.24) so its original moisture content was 17.5% (0.43/2.45=0.175)

   Ian

4. 
   PlaneWood | Jan 04, 2003 08:15am | #12

   hmmm, I guess the only things certain in life are death and taxes?

   PlaneWood by Mike_in_KatyPlaneWood