Temperature at the bottom of the kiln

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Mimi1

New Member
Mar 5, 2021
11
Northern VA
Hi,
I hope you can answer some questions about my kilns. I have wrapped 2 of my stacks and they are 130 and 127 degrees at the top and 82 degrees at the bottom. It is 80 degrees outside.

One stack is 2 rows, 5 ft high and 16 feet long on landscape timbers on cement blocks. The other is 3 rows "log cabin" stacking, 3 1/2 ft. high 17 fly long on pallets. Both have plastic on the ground underneath since the ground can get pretty wet. The stacks get a good breeze from the field behind and full sun.

Will the wood at the bottom get dry? I sure hope you are not going to tell me to restack in a month moving the top to the bottom and rewrap them ; ).
When I wrapped them yesterday the red maple was 21% moisture and the oak was 27 to 29 % moisture.
Also will the maple get too dry before the oak gets to less than 20%? I am guessing I should have put different species in different stacks.

Thanks, Mimi
 

stoveliker

Minister of Fire
Nov 17, 2019
6,165
Long Island NY
In my view too dry does not exist.
I am not sure button me this does not sound not normal; you should have air flow up, meaning ambient air comes in at the bottom and leaves hot at the top. So at the bottom you should be just above ambient.

Do make sure (now humid) air can exit at the top. And make sure the water condensing on the wrapped sides can drip down and not puddle on your bottom plastic but drain in the ground.
 

Mimi1

New Member
Mar 5, 2021
11
Northern VA
Thanks. I did cut the vent holes at each end and I will check that the plastic on the ground is tucked in far enough not to catch any drips. I think it is because I wanted to be sure the weed wacker would not get the plastic. There is definitely air coming in and going out the vents. When a breeze blows, the cover puffs up. Does the wood at the bottom of the stack at ambient temp get dry? Or do you just plan on the top half drying to less than 20 %?
 

stoveliker

Minister of Fire
Nov 17, 2019
6,165
Long Island NY

Woodsplitter67

Minister of Fire
Jan 19, 2017
2,455
Woolwich nj
So the wood at the bottom will dry. The wood at the bottom has a constant air flow the air is what will dry the splits. You will see a difference in how much seasoning you get from top to bottom. For example.. the top 3rd may be about say 14%mc.. the middle 3rd May be 17%mc and the bottom 3rd may be 19%mc when your done and open up your kiln. Even drying is not expected if your kiln is a copy of the ones that I have put together. There are so many days with very little air movement during the late spring summer and early fall. The sun heating the kiln and the constant air movement over the wood is what's making the bottom rows dry.. but not as well as the top portion.. the middle and top dry better because as the aire gets heated its ability to hold more moisture goes up making the air dryer as it goes through the stack..
 

Mimi1

New Member
Mar 5, 2021
11
Northern VA
So the wood at the bottom will dry. The wood at the bottom has a constant air flow the air is what will dry the splits. You will see a difference in how much seasoning you get from top to bottom. For example.. the top 3rd may be about say 14%mc.. the middle 3rd May be 17%mc and the bottom 3rd may be 19%mc when your done and open up your kiln. Even drying is not expected if your kiln is a copy of the ones that I have put together. There are so many days with very little air movement during the late spring summer and early fall. The sun heating the kiln and the constant air movement over the wood is what's making the bottom rows dry.. but not as well as the top portion.. the middle and top dry better because as the aire gets heated its ability to hold more moisture goes up making the air dryer as it goes through the stack..

Thanks. We seem to have had a lot of windy days so far this spring and early summer. There are two unwrapped stacks in the same area so I will have a good comparison.
 

nortcan

Feeling the Heat
Sep 9, 2016
279
Quebec
Just curiosity, if the outside stacked wood is suppose at 20% humidity when entered in the house, stack there and the ambiant humidity is 35/40 inside of the wood room, will the wood get to the room humidity level or keep the initial 20% humidity?
 

andym

Feeling the Heat
Feb 6, 2020
440
Hicksville, Ohio
Just curiosity, if the outside stacked wood is suppose at 20% humidity when entered in the house, stack there and the ambiant humidity is 35/40 inside of the wood room, will the wood get to the room humidity level or keep the initial 20% humidity?
Humidity and moisture content are not the same thing. The 2x4s your home is built with are probably around 5% MC even though the humidity in your home has likely never been below 10%.
 
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andym

Feeling the Heat
Feb 6, 2020
440
Hicksville, Ohio
Some pics of your kiln would be nice as well....Make sure the plastic is not making contact with the ends of the splits, or those splits will soak up the condensation and not dry. I had that happen last year on a kiln full of maple. I did it for curiosity sake so it didn't matter. It was all below 20% except for any that touched the plastic. Those were 25-30% on that end. I uncovered it and will let it season another year or two. I think my set up also needed more venting.
 

peakbagger

Minister of Fire
Jul 11, 2008
7,679
Northern NH
If you look at the Virginia Tech wood klin (for boards), they have circulating fans to move hot air from above the stack to the bottom of the stack. I think they also have baffle cloth to keep the flow from short circuiting. it will dry wood quicker but cost a lot more to build.
 

Poindexter

Minister of Fire
Jun 28, 2014
2,814
Fairbanks, Alaska
What @Woodsplitter67 said. I have a few, gosh cubbies I guess, some scraps of 2x6 and 3/4 ply screwed together so I can set one on the floor of a kiln, put one split in it, stack over it and pull a piece from the bottom of the kiln without a lot of drama. After a few seasons I don't even check them any more.

My best guess is WS67 has it exactly right, you are getting plenty of airflow for the bottom to dry out. You will know for sure in a couple or three months, but I think you are going to be both pleasantly suprised and quite pleased.
 

Mimi1

New Member
Mar 5, 2021
11
Northern VA
Sorry I never told you my results. I moved the wood to my wood shed in October I think. It was 9% moisture content. We barely got any creosote build up and didn't use nearly as much wood as I expected. Also, I had to watch how much wood I put in the stove ( Woodstock Ideal Hybrid) or else the temp would get too high even with the dampers closed.
 
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