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Advice on small cord wood kiln.

Started by actonusa, November 10, 2017, 01:41:02 AM

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actonusa

I plan on building a wood shed/solar kiln next year but have run into a problem for this season.  My hired help split and stacked in the wrong order and all my wet wood for next year is in front of my dry wood with no good way (except back breaking labor) to get at it.

I have been doing a bit of research about small DH kilns and have picked up the lumber and R26 polyiso insulation to make a small one.  It will hold about a facecord plus a milkhouse heater and a DH unit.  I have read that this sort of kiln should dry to an appropriate level in about 3 days and since a face will last me 7-10 days, I should be able to more than keep up.

Couple questions before I complete the build.  I don't really want to use my everyday DH and struggle with spending $150.00 when I only need the kiln for this season. 

1.  Will heat and ventilation alone do the trick?  I was thinking even possibly getting a cheap bath fan and ducting it into the kiln?

2.  Would a simple chilled radiator inside the kiln work?  I already have the copper and a small circulator pump.  Was thinking about letting ambient outside air cool the piping, then circulate inside the kiln where humidity would then condense on the cool radiator.  The condensate could be collected in a drip tray and gravity fed outside the box.

Seems like both ideas might work, but what would it do for my dry times? 

Crusarius

I like this idea. I really have nothing to add but I want in on the journey.

Can you just cut a door in the other side of the storage area to get at the dry wood? never hurts to have multiple access points.

TKehl

Crusarius beat me to the door idea.

Could also tunnel in and use some horizontal bracing to hold up the piles.  Like mining, but with sidewall braces instead. 

Either seem like less work than building a kiln.  And you would have to double handle the wood to get it in and out of the kiln anyway.
In the long run, you make your own luck – good, bad, or indifferent. Loretta Lynn

actonusa

Current wood storage is a 3 sided "crib" made from unused industrial machine guarding.  Each section of the guarding is a rectangular heavy duty c-channel frame with expanded metal welded and covering the inside of the frame.  Each section weighs about 300 lbs and there are 12 total making up the crib.  So the back breaking labor would be removing 2-3 sections to get at the dry wood or pulling all the wet wood out.

The small kiln I am building will measure approx. 4' tall x 6' wide x 2' deep.  Since all the materials are already purchased, I am going to build it regardless, just wondering how well the different methods of moisture extraction will work.

Think I will just use the K.I.S.S. method and progress from there.

GeneWengert-WoodDoc

Lots of air will certainly dry the wood quickly when over 50F and if you run the fans only during humidity under 90% RH, which will be daylight, roughly.

The benefit of drying is about 9% more heat.  The issue is that with DH, you will spend quite a bit of electricity...more than the energy savings if you supplemented with electric heaters in the home.  Of course, dry wood does have a few other advantages...insects, odor, weight, plus easier to light.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

mike_belben

I was just about to post nearly the exact same question.  I too need a firewood kiln, in my case because i sell it and when supply is low im running it right off the splitter sopping wet.  No one wants that. 

So i built a 4x8 shed that will hold a cord on two caged pallets and be loaded by my bobcat. The floor is a foot off the ground and made of pallet racking.  So the kiln is also my measuring stick.  Two processes achieved with 1 unit of labor. 

There is an 8 inch smoke pipe travelling under the shed at ground level the long way, then vertical stack goes up over the roof.  It is a sidedraft rocket stove using a propane tank chamber and works great.  I burn the splitter chaffe and odd pieces that are always piling up.  Stuff i normally have to burn for disposal.

What i am needing to know, is it really worth putting fans in there (lot of extension cord) or will forced heat then opening the doors to let moist air out be effective? I dont want to run power if i can avoid it but im not sure if humidity will be an issue.  Just about to try first batch in a few days.  I dont want to cut all sorts of experimental holes in this nice plywood for nothing.
Praise The Lord

Gearbox

Mike let us know how that works . I am still trying to figure out how the big boys around me can wholesale kiln dried wood for $4to5 a cubic ft. and haul it 100 miles . Don't compute with my numbers maybe I need more computer classes.
A bunch of chainsaws a BT6870 processer , TC 5 International track skidder and not near enough time

barbender

Too many irons in the fire

Hackermatack

Quote from: mike_belben on November 17, 2017, 01:19:29 PM
I was just about to post nearly the exact same question.  I too need a firewood kiln, in my case because i sell it and when supply is low im running it right off the splitter sopping wet.  No one wants that. 

So i built a 4x8 shed that will hold a cord on two caged pallets and be loaded by my bobcat. The floor is a foot off the ground and made of pallet racking.  So the kiln is also my measuring stick.  Two processes achieved with 1 unit of labor. 

There is an 8 inch smoke pipe travelling under the shed at ground level the long way, then vertical stack goes up over the roof.  It is a sidedraft rocket stove using a propane tank chamber and works great.  I burn the splitter chaffe and odd pieces that are always piling up.  Stuff i normally have to burn for disposal.

What i am needing to know, is it really worth putting fans in there (lot of extension cord) or will forced heat then opening the doors to let moist air out be effective? I dont want to run power if i can avoid it but im not sure if humidity will be an issue.  Just about to try first batch in a few days.  I dont want to cut all sorts of experimental holes in this nice plywood for nothing.

Saw one that a firewood dealer built with a shipping container, some fans and a outdoor boiler. The wood was put in metal cribs that he could handle with his skid steer. The container had vents cut around the to let the moist air out. Basically just circulated hot air around the wood for a few days. 
Jonsered 2230, 590, 70E. Kioti DK 35 /w fransguard winch. Hudson Oscar 236

mike_belben

Well it can get the interior to 100F in an hour burning hickory slabs.  Im only using a gas grill bottle for a burn tank and it easily turns smoke pipe orange, so its the type of stove you have to load often and resist packing it up to meltdown.  I have the pipe going through sand and clay where it passes under the walls to prevent a fire.

  I dont have any means to measure humidity and am flat broke right now.  With a load of wood all dumping moisture at once the thing may turn into a swamp.  I do like the idea of using a copper coil and a drip pan.  Fishtank pump and a fan on a timer to run a few minute at a time would be cheap.

Sorry for the hijack.  Hoping to get some insight that'll serve us all well at the same time.  Seems like the OP and i have just about the same needs.
Praise The Lord

GeneWengert-WoodDoc

Using fans will slightly increase drying speed, but money spent to raise the temperature will be more helpful than money for electricity. The reason is that for most of the drying cycle, the speed is controlled by the time it takes for the water molecules to wiggle their way to the surface and not for the air to scrub the molecules off the surface. So, temp is most important followed by humidity.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

LeeB

'98 LT40HDD/Lombardini, Case 580L, Cat D4C, JD 3032 tractor, JD 5410 tractor, Husky 346, 372 and 562XP's. Stihl MS180 and MS361, 1998 and 2006 3/4 Ton 5.9 Cummins 4x4's, 1989 Dodge D100 w/ 318, and a 1966 Chevy C60 w/ dump bed.

GeneWengert-WoodDoc

I think that the wiggling of water vapor molecules is called Brownian motion, and the net movement is diffusion.  But who cares?

In Wisconsin it is called the "Doing the polka"; or maybe  "Doing the Hokey Pokey" and that's what it's all about.  Maybe.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

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