iDRY Vacuum Kilns

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New Kiln Build

Started by PA_Walnut, March 16, 2018, 05:44:25 AM

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PA_Walnut

Prepping to pour a slab for a new kiln build. Putting a WM KD250 in it. (Nyle 200).

Been back and forth...almost paralyzed by indecision on size. Let me explain:


  • I have decided that lumber over 12' isn't practical for me to deal with.
  • We do 8, 10, and 12' material in 4/4-20/4, with most being 4/4 and 8/4.
  • ALL of our many pallets for lumber stacks are 4' wide, as is our stickers.
  • Sometimes we have live-edge slabs that are 4-6" long, don't do shorter stuff--too painful.

These being the case, I'm considering my kiln to be 22' x 12' interior, 10' high.
This will allow an 8' and 12' wide, and two stacks/charges deep. (ie. I can put two 12's and two 8's in at once). Of course, I thought about two (2) 12's wide, but have to draw the line somewhere...space is not endless at my place.

Pouring concrete on Monday or Tuesday. Planning 4" thick, monolithic slab, rebar reinforced with plastic and 2" styro insulation under it.

My question concerns are: Seems like a pretty large chamber to me. Is heating it and retaining the heat going to be an issue? Can I get enough airflow through two (2) 4' wide stacks to dry properly. Planning 2x6 walls, R19.

The way it's oriented in my ops, I will front load it with forks and plan to weld-up a box/cage to save the kiln unit from impending doom of off-course forks. 

I'm hoping to hear words of wisdom from those who have gone before me. I'm interested in avoiding some "I wish I had..." or "if I'd do it over..." whoas. Fire away! 
I own my own small piece of the world on an 8 acre plot on the side of a mountain with walnut, hickory, ash and spruce.
LT40HD Wide 35HP Diesel
Peterson Dedicated Wide Slabber
Kubota M62 Tractor/Backhoe
WoodMizer KD250 Kiln
Northland 800 Kiln

PA_Walnut

p.s. The kiln plans call for 3' wide charges to spec the chamber sizing. Who does 3' wide stacks? :-\
I own my own small piece of the world on an 8 acre plot on the side of a mountain with walnut, hickory, ash and spruce.
LT40HD Wide 35HP Diesel
Peterson Dedicated Wide Slabber
Kubota M62 Tractor/Backhoe
WoodMizer KD250 Kiln
Northland 800 Kiln

David Freed

I had a 22' x 9 1/2' x 10' with a nyle 200. I got it up to 170* with extra heat.

K-Guy

Hi
Stan from Nyle here. Your chamber size is large. Normally 8x8x20 is the largest most customers make. For the extra length and depth I recommend adding the Heat Booster from Nyle, this doubles the the heat output. Also I would add at least one more fan kit. 
Nyle Service Dept.
A common mistake people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.
- D. Adams

Ljohnsaw

Quote from: PA_Walnut on March 16, 2018, 05:44:25 AMSometimes we have live-edge slabs that are 4-6" long, don't do shorter stuff--too painful.

Couldn't you just dry these in your kitchen oven? ;)

WOW, that is huge.  I know nothing about kilns but it sure sounds like it would be hard to get the airflow going through double stacks like that for consistent drying.  Not knowing what and how the cycles go, I'm just thinking out loud.  Is there a "cooling off" period at the end of a cycle?  What if... you build two "normal" sized kilns back to back (6' deep and 22' long each).  Put the Nyle in the back wall (probably where it was to be placed anyhow) and duct it such that you could switch between the two rooms.  Maybe even rob the hot air from the cooling room to pre-heat the current room?  You would only have one big wall (but twice the number of doors and roofing).
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Ford 545D FEL, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 42" capacity/36" cut Bandmill up to 54' long - using it all to build a timber frame cabin.

scsmith42

PA, personally I would go with a different sized chamber (narrower, taller, and maybe deeper).

A Nyle L200 is sized to dry a charge of 4K bd ft of 4/4 WO, about the same of 8/4 BW, around 2.5 - 3K bd ft of 4/4 BW, or around 6K bd ft of 12/4 BW.  

Take a look at the stack configurations that you would load into the kiln in order to achieve these quantities.  Add a couple of feet to each end to make it easy to baffle and to fork the stacks past your doors.  Have enough room on the front and back to equal the sum total thickness of all of your vertical stickers.  For instance, a stack 4' deep, 12' long of 8/4 material will contain around 100 bd ft per layer, which means that you will have 42 layers or so to achieve 4K bd ft.  8/4 BW planks will measure around 2-1/4" thick green, so if you add a 3/4" sticker you're at 3" per 100 bd ft of vertical height. 3" thick x 42 layers is about 125 vertical inches, or 10' of height.  

For 10' of height, you will either need a very tall chamber, or a deep chamber that allows you to put two stacks deep, or a wide chamber (27' or so) to put the stacks next to one another.

If you're drying 12/4 material, depending upon how tight your kiln is you may need to add a high pressure misting system to keep the RH% high during the initial drying stages so that you dont case harden the thick, slow drying planks.

One thing that is nice about loading the kiln to max capacity for the species and thickness is that you don't have to worry about damaging the lumber from drying too quickly.  The compressor literally cannot remove the water fast enough to damage the lumber.  You MAY need to worry about case hardening though in some circumstances, hence the misting system.

Best of success to you.
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.

PA_Walnut

Thanks for all the notes. I ended up chatting with Stan and Nyle and he imparted lots of good wisdom to guide the way.

Ending-up going 9x10x22 and adding extra heat.

I forgot to mention on my first post that almost everything that goes in, has been on sticks long enough to get below 20%. The exception may be maple, which I want to get in asap to minimize degrade. (Dr Gene will appreciate this with the maple!)   :D

Will post some pix along the way. Thanks.
I own my own small piece of the world on an 8 acre plot on the side of a mountain with walnut, hickory, ash and spruce.
LT40HD Wide 35HP Diesel
Peterson Dedicated Wide Slabber
Kubota M62 Tractor/Backhoe
WoodMizer KD250 Kiln
Northland 800 Kiln

Southside

@PA_Walnut are you 9' tall or deep there?  I am in the same planning spot right now myself.  
Franklin buncher and skidder
JD Processor
Woodmizer LT Super 70 and LT35 sawmill, KD250 kiln, BMS 250 sharpener and setter
Riehl Edger
Woodmaster 725 and 4000 planner and moulder
Enough cows to ensure there is no spare time.
White Oak Meadows

PA_Walnut

9' deep. I'm going 10' tall so I can stack two charges, one on top the other, rather than 2 deep. (per Stan).
This will allow me to put two 12's and two 8's in the kiln at a time. I'm adding aux heat. (again, per Stan at Nyle).

Best of luck!
I own my own small piece of the world on an 8 acre plot on the side of a mountain with walnut, hickory, ash and spruce.
LT40HD Wide 35HP Diesel
Peterson Dedicated Wide Slabber
Kubota M62 Tractor/Backhoe
WoodMizer KD250 Kiln
Northland 800 Kiln

Busysawyer

Are you also adding another fan? We are going with the same kd250 from woodmizer. I spent a awhile on the phone with a  very helpful gentleman named Byron who seemed to know all things kiln related. We were planning a 22x10x10 and were instructed to add a fan and heat as needed. After reading this I am thinking about going 9 wide instead of ten as well. Looking forward to seeing your progress!
Even a blind squirrel finds a nut every once in awhile

Davo2rich

I run a non-profit deconstruction company and have loads of wood (joists, beams ). Some of it sits outside and goes to waste. Looking to build large pole barn w/ kiln to process wood that is in most cases 70-80 yrs old... I dont even know where to begin! Will someone give me the primer on dehumidifying vs. kiln vs. vacuum? My aim is to take (primarily) heart pine, ash and poplar joist and framing from per-1940's homes and make it suitable for creating interior finished walls.
Thanks in advance.

Southside

Welcome to the Forum,

Sounds like you want to be in the reclaimed wood market.  Most of the wood you are dealing with is pretty dry to begin with, assuming you are removing it from under a roof, so for the most part you only need to knock it down a few points of MC and then heat treat it due to the insect issues.  I don't see the value of a vacuum kiln in that application.  

A few other points to consider.  How do you intend to resaw the lumber?  You have to de-nail this stuff, even then you will find metal.  Do you have a moulder or planer to do your final shaping / thickness?  
Franklin buncher and skidder
JD Processor
Woodmizer LT Super 70 and LT35 sawmill, KD250 kiln, BMS 250 sharpener and setter
Riehl Edger
Woodmaster 725 and 4000 planner and moulder
Enough cows to ensure there is no spare time.
White Oak Meadows

GeneWengert-WoodDoc

Welcome.

southside has great comments.  I would add that all you need is a hot room that will go to 150F.  Make sure you call it a kiln for tax purposes- -a kiln is a piece of equipment.  Then, control the humidity in your kiln to avoid over drying.

What state are you in?  I might have a contact that can help you.
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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