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Kiln size.

Started by customsawyer, October 02, 2015, 05:27:08 AM

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customsawyer

I know this should be in the drying section of the forum but I thought more folks might read it over here.
I bought a good used L200 Nyle kiln awhile back and am getting geared up to install it. I am wondering what would be the best size of kiln. I am leaning towards 10'X27'. This would allow me to put different length packs of lumber in the kiln. Two packs of 12' or one of 10 and one of 14 or one of 8 and one of 16. It would also let me dry a little longer stuff if that special order comes in. I have zero experience with kilns so feel free to tell me I'm nuts if you know better. ;D
Two LT70s, Nyle L200 kiln, 4 head Pinheiro planer, 30" double surface Cantek planer, Lucas dedicated slabber, Slabmizer, and enough rolling stock and chainsaws to keep it all running.
www.thecustomsawyer.com

drobertson

Howdy there jake we were just talking last night at dinner about this, I have the same, not hooked up, Logboy  has one the same, his advise was 22' if not 25' by 12' deep, and a ceiling of 12' he did say the electric bill jumps up
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

YellowHammer

Length doesn't matter too much as long as you have enough circulating airflow through the stack, and that means fans every few feet so there are no stagnant areas. You also typically need a minimum of 18 inches in front and back of the stack to the nearest wall (for a stack of 1 MBF 4/4 high, stickered), for the air to get all the way down to the bottom layers, and not shortcut through the top layers.  The taller the stack, the wider the plenum space required. There are equations to calculate all these distances and parameters.

Depth of the stack is crucial, as the air gets wetter the further it goes through the stack and picks up moisture and doesn't dry the far side of the boards as well as the near side, so 8 feet of wood is generally regarded a typical maximimum depth (two 4 foot wide stacks side by side) for these DH style kilns.  You can go wider, but need a different fan configuration.  A single depth of a 4 or 6 foot stack is even better.

Height doesn't really matter within reason as a drop baffle (tarp or plywood) is used from the bottom of the fan baffle to the top of the stack to cut off cheating airflow and set up the circular airflow pattern. 

The ends of the stacks should have very little space to the end walls of the kiln, or baffling will have to be placed to keep the air from going around the stack instead of through it.  Sometimes the stacks of wood can be over lapped in the middle to have each end nearly against the side walls. 

It's all about airflow and forcing evenly distributed dry air through the stack and not having it cheat around.  Other critical aspects are an absolutely flat floor, lots of insulation, and a perfect door seal that still allows for machine loading by your Deere skidsteer or new forklift. 
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

Sixacresand

Jake, I am surprised that WDH isn't already at your place, laying out a foundation for your kiln.  He knows what size both of you need.   :D
"Sometimes you can make more hay with less equipment if you just use your head."  Tom, Forestry Forum.  Tenth year with a LT40 Woodmizer,

WDH

All I know is that he better build it big.  I need a whack of lumber ;D
Woodmizer LT40HDD35, John Deere 2155, Kubota M5-111, Kubota L2501, Nyle L53 Dehumidification Kiln, and a passion for all things with leafs, twigs, and bark.  hamsleyhardwood.com

YellowHammer

Quote from: WDH on October 04, 2015, 08:50:24 PM
All I know is that he better build it big.  I need a whack of lumber ;D
And he needs to hurry up. :D
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

scsmith42

Good post by Yellowhammer.

Jake, some things that I have learned from operating a Nyle for 12 years.

First - forking directly into place is much better than a cart system.  Faster, less hassle.

Second, size (and especially width) matters.  The wider your kiln, the less consistent drying will be from end to end.  I would suggest that you make your kiln "door opening" about two feet wider than the longest board that you will commonly dry, and then whatever extra that you need between the edge of the door and the wall.  If the longest board that you will commonly dry is 20', then make the chamber door 22' wide.

A Nyle L200 is good for up to 4K bd ft of 4/4 green oak, about 2,500 bd ft of green 4/4 maple, or 1500 bd ft of green 4/4 SYP.  The size of the load is based upon the MC% and the drying rate.  You put more in the kiln when you have a green, slow drying species and less in the kiln when you have green, fast drying species.  Air dried fast drying species can be loaded the same as green, slow drying.  In other words, if you have 20% MC air dried pine then go ahead and put 3,500 bd ft into the nyle for a finish off run.

I had a long conversation with the folks at Nyle a couple of months ago about the optimum kiln chamber size.  My take away from that conversation was to size the chamber for two stacks of lumber, approximately 2000 bd ft per stack, side by side (4K bd ft total).  For ease of handling the weight, I would suggest a layout that had two 1000 bd ft stacks next to one another, with two additional 1000 bd ft sitting on top of the first two stacks.  Same thing as Nyle recommended, but 6K lb stacks instead of 12K.

The rule of thumb regarding plenum size (the space between the front and rear of the stacks and the outer walls / doors) is that your plenum needs to be equal to or greater than the sum of the height of all of your stickers.  Let's say that you're drying a load of 4/4 lumber and you have 40 layers with standard 3/4" thick stickers.  Your plenum needs to be at least 30" (40 x .75) wide.  So, if your stacks are 4' deep, and you have a 30" plenum on each side, your chamber needs to be at least 9' deep.  Since the L200 itself will be placed in the rear plenum area, I would suggest increasing the depth by a couple of feet so that you have adequate room to easily walk between the DH unit and the lumber.  This would mean an 11' inside depth (12" external with 2 x 6 studs).

The drawback of oversizing your chamber is that you have to heat up all of that volume when you are sterilizing or setting the pitch of the lumber.  Another problem is that if the chamber is too wide from side to side you can experience inconsistent drying along the outer edges.

Plan on at least 3 if not 4 fans for a chamber 24' wide.  Put doors in front of two of the fans to allow you to choose the number to run.  Usually you shoot for around 350 fps air flow through the stack. The quick and easy way to measure airflow (if you don't have an anemometer) is to suspend a handkerchief befind the stack.  It should deflect around 30 degrees.  Turn on/off fans as needed to obtain the correct air flow.  Height should be equal to the stacks plus the fans and baffles above the stacks (typically 26' or so for the fan and baffles). 

Put two doors into the side walls of the kiln that will allow you to easily check each side of the lumber stacks during the drying process.  Insulate well.

In addition to loading, baffling the kiln takes time.  The larger the chamber, the more time that baffling will take and this costs money. 

In summary - don't make it wide enough to handle anything.  Make it wide enough to handle the board lengths that comprise up to 90% of your business.
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

WDH

No matter how big you build it, somebody will want you to dry something that is too long for the kiln.  It would seem that kiln drying lumber over 16' would constitute such a small volume over time that it would not be worth it to comprise the efficiency of the L200 just to dry those longer lengths.  Also, who needs hardwood or pine lumber kiln dried to 7 - 8% that is longer than 16'?  If it would be for external use of framing, joists, rafters, etc. air drying would be sufficient as construction lumber is only dried to 19% anyway.  I would think that 16' lumber would be the sweet spot. 
Woodmizer LT40HDD35, John Deere 2155, Kubota M5-111, Kubota L2501, Nyle L53 Dehumidification Kiln, and a passion for all things with leafs, twigs, and bark.  hamsleyhardwood.com

OneWithWood

When sizing the kiln remember that 8' lumber is usually 8'6" - 9' long.  So two stacks side by side will be 17'-18' wide.
I know you know this but I thought I would throw that out there anyhow.
One With Wood
LT40HDG25, Woodmizer DH4000 Kiln

drobertson

onewithwood, this was the point of the point in my conversation with logboy,, there is no easy go to answer, but often times, at least with milling and building, having bigger capacities has it's advantage.
it really boils down to where one wants and needs to go with the finish product.  Custom is custom, lots of variables.  The issue is money for the construction of a proper kiln chamber.
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

pineywoods

I built mine with a 13 foot opening....mistake...Planman copied mine and extended the rear opening to 19 ft. Mine is in a sad state of need repair, so...on the to-do list is a rebuild to19 feet ie a 20 foot beam across the door opening...I think I'm gonna go with a 20 foot truss instead of a solid beam...
1995 Wood Mizer LT 40, Liquid cooled kawasaki,homebuilt hydraulics. Homebuilt solar dry kiln.  Woodmaster 718 planner, Kubota M4700 with homemade forks and winch, stihl  028, 029, Ms390
100k bd ft club.Charter member of The Grumpy old Men

YellowHammer

I think some folks will remember my hi-cube shipping container kiln build thread...it has been cranking out loads about every week non stop.  I have been very pleased with the results, it's been an absolute joy to load and unload, very fast (with a side shift forklift) using a full length flush loading dock style approach, and the lumber quality has been excellent, better than my other Nyle kiln.  I was worried about even drying and wet spots, but with the adjustments to the width, the fans spacing, etc, it dries very evenly and fast.  It's also enegy efficient, and made of a stainless steel interior, aluminum exterior, and solid foam core insulation with refrideration quality double airtight door seals. 

It has two 18 foot carts, so can dry two 8 foot stacks side by side of a full 16 foot stack.  It can also take an 8 foot and a 24 foot long set of stacks, spanning both carts (they can be locked together) as well as full length 36 foot boards, (I can't saw them that long but I can dry them ;D) or multiples of anything in between. I designed the carts to be flexible so I could dry multiple lengths, at the same time with no configuration changes.  The interior baffling will also allow me to dry a half height load, or two full height, two half height, etc.  I even did a 3 half height and 1 full height load of maple for an experiment and it turned out fine.  Here's a recent finished full load of cherry just rolled out of the kiln, all 8 foot long, dried, sterilized and ready to go.

YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

POSTON WIDEHEAD

I'm impressed! I really am Yam. Good job.  :)
The older I get I wish my body could Re-Gen.

WDH

Robert,

That is outstanding  8).
Woodmizer LT40HDD35, John Deere 2155, Kubota M5-111, Kubota L2501, Nyle L53 Dehumidification Kiln, and a passion for all things with leafs, twigs, and bark.  hamsleyhardwood.com

scleigh

Hammer, you need to change your name to " cant touch this"  :D

beenthere

Really a neat setup... looks great.
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

customsawyer

Thanks for all of the replies. Lots of food for thought.
YellowHammer very impressive.
Two LT70s, Nyle L200 kiln, 4 head Pinheiro planer, 30" double surface Cantek planer, Lucas dedicated slabber, Slabmizer, and enough rolling stock and chainsaws to keep it all running.
www.thecustomsawyer.com

Peter Drouin

With that much drying going on YH, you must have at some wholesale going on too?
A&P saw Mill LLC.
45' of Wood Mizer, cutting since 1987.
License NH softwood grader.

YellowHammer

Quote from: Peter Drouin on October 07, 2015, 06:23:11 AM
With that much drying going on YH, you must have at some wholesale going on too?

No, I don't sell wholesale, although I sometimes sell to businesses, they have to pay full retail price, and I impose a quantity limit on them.  I have regular customers that drive from several states to get here, so selling wood isn't the problem, the real problem is producing enough high grade to feed them.
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

Peter Drouin

Quote from: YellowHammer on October 07, 2015, 10:11:02 PM
Quote from: Peter Drouin on October 07, 2015, 06:23:11 AM
With that much drying going on YH, you must have at some wholesale going on too?

No, I don't sell wholesale, although I sometimes sell to businesses, they have to pay full retail price, and I impose a quantity limit on them.  I have regular customers that drive from several states to get here, so selling wood isn't the problem, the real problem is producing enough high grade to feed them.



High grade logs are hard to find sometimes.  Good job. smiley_thumbsup
A&P saw Mill LLC.
45' of Wood Mizer, cutting since 1987.
License NH softwood grader.

YellowHammer

Quote from: Peter Drouin on October 08, 2015, 06:26:24 AM
Quote from: YellowHammer on October 07, 2015, 10:11:02 PM
Quote from: Peter Drouin on October 07, 2015, 06:23:11 AM
With that much drying going on YH, you must have at some wholesale going on too?

No, I don't sell wholesale, although I sometimes sell to businesses, they have to pay full retail price, and I impose a quantity limit on them.  I have regular customers that drive from several states to get here, so selling wood isn't the problem, the real problem is producing enough high grade to feed them.



High grade logs are hard to find sometimes.  Good job. smiley_thumbsup

Yep, that's what limits my production, finding the right logs.  Of course, that's my niche, if it was easy, all the mills around here would do it.  As I had one of my logger guys told me, he'd drive by a single tree of gold to get a couple trailer loads of silver, and his gold isn't necessarily my gold.  So now, when these loggers have gotten to trust and know me, when see a tree or whack of trees they know I want, they will cut them down, roll them aside, and when they get a load, call me up and I tell them to bring them in.  As far as I can tell, I'm the only one crazy enough to do this around these parts, but I know of another guy in this Furum who's equally  smiley_whacko "teched" to work in this high grade market, but he's a lot smarter than I am and gets to sleep at night.  He and his professional sawmill buddy live in Georgia.    ;D ;D
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

Peter Drouin

I have some loggers that save me trees too. YH. And call to see what length I want when they find them. 8)
A&P saw Mill LLC.
45' of Wood Mizer, cutting since 1987.
License NH softwood grader.

WDH

Quote from: YellowHammer on October 09, 2015, 03:56:47 PM
As far as I can tell, I'm the only one crazy enough to do this around these parts, but I know of another guy in this Furum who's equally  smiley_whacko "teched" to work in this high grade market, but he's a lot smarter than I am and gets to sleep at night.  He and his professional sawmill buddy live in Georgia.    ;D ;D

DanG!  I need to meet this guy!
Woodmizer LT40HDD35, John Deere 2155, Kubota M5-111, Kubota L2501, Nyle L53 Dehumidification Kiln, and a passion for all things with leafs, twigs, and bark.  hamsleyhardwood.com

Sixacresand

"Sometimes you can make more hay with less equipment if you just use your head."  Tom, Forestry Forum.  Tenth year with a LT40 Woodmizer,

Sixacresand

Quote from: WDH on October 09, 2015, 09:24:43 PM
Quote from: YellowHammer on October 09, 2015, 03:56:47 PM
As far as I can tell, I'm the only one crazy enough to do this around these parts, but I know of another guy in this Furum who's equally  smiley_whacko "teched" to work in this high grade market, but he's a lot smarter than I am and gets to sleep at night.  He and his professional sawmill buddy live in Georgia.    ;D ;D

DanG!  I need to meet this guy!
It would not surprise me if these two guys were at the GA National Fair doing demos for WoodMizer Mills.
"Sometimes you can make more hay with less equipment if you just use your head."  Tom, Forestry Forum.  Tenth year with a LT40 Woodmizer,

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