I got a chainsaw mill and have been hard at it cutting slabs.
I'm a bit impatient and don't want to wait two plus years to be able to use them or sell them.
I've seen all sorts of different ways you can dry lumber. I'm mostly looking for ways to dry slabs that are 2-3"
They range from 20-34" wide and 4-10' long. I'll be doing bigger ones soon.... haven't put on the 8' bar yet. Been getting the kinks all worked out with the smaller bar.
I was really interested in the sauno kiln that logosol sells but can't seem to find anything in the USA
I welcome any input or experience anyone has
I do it by leaning against a wall, and or in a stickered stack, and forgetting about them for a year or so. too fast and you will get more defects, unless it is for rustic then we call it "character". this is one area where the vacuum kilns sound interesting. the key is not have a large gradient between the core inside and the outside. the thicker the piece, the harder that becomes unless you have lots of time. @GeneWengert-WoodDoc (https://forestryforum.com/board/index.php?action=profile;u=20498) . I stack them and if someone wants one, they take their chances with the level of moisture. most are wanting a bit of rustic. do you plan to flatten the slabs?
I've messed around with a router sled before... I have a buddy who put a pretty nice one together I will try out. Also looking at Some drum sanders to get it somewhat flat. That 25-50 that Supermax puts out looks nice. Figured you could put some real course paper to start with then work up once it's flat
need a really big microwave. :) you need a way to move the water without creating a large gradient of core to outside. you can watch recorded seminars on the NHLA on drying, and understand better the challenge. so in a kiln, the heat would go up, but you keep a lot of the humidity in the kiln so the gradient is not so big. (dry bulb/wet bulb difference). It takes time to move water sideways across wood fibers. to go fast with high heat and low humidity and you have really good firewood. to the extreme and you have lump charcoal. :D :D :D. without special equipment, you will need tincture of time. you should begin researching moisture meters on the forum. lots of good info on the forum, and in the webinars. you can get a head start if you start with a seasoned log. standing dead for 5 years, or up off the ground with end sealer for a few years, then mill.
Got ahold of some nice elm and some good size silver maple.... haven't cut up maple yet. Trying to remember how to upload photos.... it's not working. Have some nice pics of the elm.
Do you have to load them in your gallery first?
Look at the bottom of the main page on the FF, there is a great simple tutorial on how to upload photos, they need to be uploaded into the gallery so they are always there even if you leave the forum, which once figured out, makes it real nice in lieu of those other sites that several posts have broken links all the time.
Get the pics into your gallery and post em up, everyone loves pics... 8)
Welcome to the FF.
Time or Money
A large bank account will replace the time.
Time is the 1st choice to dry your slabs. Mother nature does it, all you need is a place to stack, cover and let mother nature blow air through the pile. Very simple. Keep it out of the sun and wait.
Vacuum kilns are the next choice.
A Radio Frequency vacuum kiln is the fastest choice, It has its pros and cons. It micro waves the wood, boiling the water out of the wood. I have used an RF kiln and was never exicited by the results. It takes money.
A simple vacuum kiln like the IDRY is an accelerated air drying system . Put the slab under partial vacuum, blow air around the slab, as the moisture comes off, it condenses on the walls, collects on thr floor and is drained out on a regular interval. It is slower than the RF kiln, so it takes more money,
A DH kiln will also work, it just takes longer, so it takes even more money.
I have a thread about my adventure drying 3 and 4" pecan slabs and 4x4's. I don't know how to put the URL on here but it's near the bottom of page 1. The gist is after agreeing to dry the slabs I found out that it will take much longer than I originally thought. My Nyle L200 will likely be tied up for a year or so. The owner has agreed to cover all expenses during drying, and we will settle up when they are dry. I was thinking about 4 months, but to get the best results patience is the best bet.
Currently I'm trying to maintain temp in the 70's and relative humidity in the 90's. With no heat on- only fans running- temp is about 83 and rh is about 91%. After 2 months of this no degrade is yet visible, but it may no show until MC is about 30%. Stack has lowered about 3/4".
My Electrophysics moisture meter is showing mc from 99% to 85% but is probably not accurate.
a solar kiln is cheap and will take some time, but is also forgiving as it cools at night and relieves some stress. I have even had luck with sticker wood under plastic to simulate a cheap solar kiln. I will try see if I made a thread or just posted. this will give you an idea.
Simple Solar Cycle Kilns at Timbergreen Farm (http://www.timbergreenforestry.com/Simple%20Solar%20Cycle%20Lumber%20Dry%20Kilns%20at%20Timbergreen%20Farm.html)
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here is a stack that went under plastic. had a 14 dollar remote temp and humidity gage in there.
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live edge elm dried to 7% under plastic. and remember the key is to forget about it, but I think it was around 8 months.
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The maximum rate at which you can dry any species of wood is generally governed by the species and the thickness. If you look online, or even on this Forum there are many references to the Maximum Allowable Drying Rate of species. When drying wood, its good to commit some of these values to memory. If you are over the max allowable drying rate, you will crack and otherwise defect the wood. If you are under that, in some species, it will cause gray stain and sticker stain. if you are right on, everything works fine. It just so happens that in many species, the atmospheric conditions of the ambient air are about right, and generally won't dry the wood too fast, although, it may be a little slow. That's why air drying is so useful. In some cases elevated temperatures will increase the moisture removal from the wood, as well as lowering the atmospheric pressure (vacuum kiln).
With a conventional kiln, and even some hybrid vacuum kilns, this relationship applies, and it doesn't matter how fast a kiln can come down in conditions to dry wood, they have to be slowed down, or throttled back, to account for the wood species and thickness. So, in other words, generally, the wood itself dictates how fast it can dry, not the kiln itself.
@doc_henderson is showing the right way to sticker wood.
https://forestryforum.com/board/index.php?topic=105726.msg1646583#msg1646583
Elm? Pecan?
Two woods which are notorious for drying challenges and defects. Add to that thick, wide slabs?? You can't put enough weight on that stack to keep them flat.
I cut and stacked 2-3" thick spruce and Fir last spring. I wrapped the sides in that black breathable stuff you use for weed barrier in dirt. Let the sun and wind bake em all summer and they were down to 12% this fall. Covered with metal roofing so the sun couldn't really get to em but the black sides really got hot. I'm in Montana at 7000 ft so that my have something to do with it, dry here.
Quote from: Segerdog on March 28, 2021, 10:25:59 AM
I've messed around with a router sled before... I have a buddy who put a pretty nice one together I will try out. Also looking at Some drum sanders to get it somewhat flat. That 25-50 that Supermax puts out looks nice. Figured you could put some real course paper to start with then work up once it's flat
I have the Supermax 25-50 and do not believe that it is suitable to flatten thick slabs. I would not even think about trying that with mine. It would take umptene passes if you built a set of large infeed and outfeed tables. Way too much handling of very heavy wood and way too time consuming I would think.
WDH, I was thinking the same thing. Those are just finishing sanders. Large, industrial belt sanders at cabinet shops might be a way to go if they will fool with it for you.
Working with slabs is so much more work... starting from the log all the way to handling it in the shop. If I were to guess at the extra amount of work and effort? I would say 5x's the amount of working with dimensional lumber. No equipment in the shop is designed to work with such large and heavy pieces. It's all hand tools and/or handheld power tools. Add to that the extra physical effort? I'm tired just thinking about it. :D
I was thinking the sander after flattening with the router sled.... to clean up router marks
Has anyone tried using those adjustable work tables at home Depo for infeed or out feed? Or in side support if running a large piece through the sander
They adjust up or down with quick crank and seem to roll pretty easy
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Here are some of what I've done so far.
I didn't think it was to bad for urban logging😃
Would have been a shame to see these as firewood
I use a porter cable 6 inch random orbital sander. it floats on top, and i have good luck once the slab is flat. A drum sander does not tolerate much variation. I have a 20 inch grizzly, and you can go from barely touching to pulling down the motor or blasting off the wrapped paper. slabs are usually rustic anyway. slabs are beautiful. nice book matching. lots of character. the pretty parts are where you will have trouble in elm. some splitting and or warp. you can also dry them a bit oversized and then put them back on the mill to flatten them back true.
After the router sled, I use my 6" ROS starting with 80 grit. But, I have been eyeballing this thing.
http://www.gem-industries.com/ss.php
segerdog, I don't think the drum sander is going to help you with large pieces. The sander will most probably put lots of sniped spots into the surface which you will then have to hand sand to get rid of anyway. Not to mention handling the heavy slabs over and over to feed into your setup.
A Router Sled is probably the most practical way for a home workshop operation. Reason is that although it's slow, loud and messy, it's cheap and produces a good result. Perfectly flat, and smooth enough that you can carry on with handheld sanders.
For commercial work, the idea gets scaled up with things like the Woodmizer Slab flattener, a CNC machine (that can be used for other work, or a planer blade fitted to your swing blade mill. Varying cost, speed, automation.
But they all work on the same basic idea, rotary cutter moving over the surface of the stationary slab. Cutter can't remove any material below it's cutter tips, and if a spot needs 1/16 or 1/4" removed, that's what happens. If the slab has a slight bow, cup or even twist, within reason, it gets flattened out. Put a slightly bowed or twisted board though a large sander, it will come out slightly bowed or twisted.
I also have used my 4 x 24 inch belt sander going in many direction to take out high spots ect.
When sawing slabs, the thing to keep in mind is that the change in grain slope of highly figured wood is one of the major causes for slab movement when drying. Knots will pull and kink the wood, cause it to zig zag, sapwood will pull also, and anything sawn near the pith will cause cup and stress cracks.
To put it in perspective, if a slab is sawn to 2-3/8" it will generally barely clean up both sides to 2". This means that from one side or the other, nearly 3/8" of wood must be removed from the entirety of the dried slab. That's a lot of wood for any sander to eat.
Flattening slabs is part of sawing and drying them, and can be a major headache. The more slabs that are sawn and produced, the bigger the headache and the faster and easier it must be done.
I believe the universal technique that will always work is the router sled slab flattener that folks have discussed. I have a buddy who uses a full size walk behind flooring sander, and does pretty good, but he's been sanding floors for 20 years.
For a step up, both Baker and Woodmizer make automated router sleds.
With a bandsaw mill, I don't think I've ever flattened slabs faster than with a carbide band.
We have invested significant money into a 20 inch wide jointer, and a 25 inch wide double sided carpet planer, which we use to flatten slabs by the pallet load.
Has anyone messed around with steam drying on wood?
I've been reading about how hardwoods do better when steamed at beginning of the process. Supposed to relax the wood and release the water faster from the inside thus causing less stress warping checking etc.
Anyone have experience or thoughts on that? Is there a way to make one to do it that's not crazy hard or expensive?
Just exploring ideas.....
Another thing I was curious about is if anyone has ever tried using a water heater to rig up a radiant heat source for there kiln?
I use radiant to heat my house and was thinking a small circulation pump and some copper tubing could heat things up pretty efficiently. You could add a thermostatic control switch to keep it at whatever temp you want it.
Haven't seen any mention of anyone trying it.... so I was just wandering
Steaming or using a "Steam Cycle" is a common step in wood drying. However, if you overheat or steam some wood, especially walnut, it will cause the pigments in the wood to "run" and significantly changes the overall appearance of the wood, and reduces its desirability. Steamed walnut looks significantly duller than unsteamed walnut. Same with cherry. However, if the maximum drying rate of the wood is exceeded with any heat source, the wood will crack. The higher the temperature of the wood is heat din the initial stages, the weaker it gets, so although heating will increase the amount of moisture the wood can release, it also makes the wood more susceptible to cracking defects. A kiln schedule generally runs at the coolest temperature possible to achieve the maximum allowable drying rate for a certain species and thickness.
Hot water systems, usually fed by an Outdoor Wood Boiler, is a common method for heating kilns.
we have radiant heat in our house and shop, and I would not have it any other way. you can open a big garage door, and as soon as you close it, the room is warm again. not so with forced air heat. In a kiln it has been stated the radiant floor heat with warm the lower stuff first, the upper stuff is "in the shade" so to speak. I think for a kiln using an OWB, you would want a water to air heat exchanger. Or an old wood furnace that blows hot air in. thoughts? @YellowHammer (https://forestryforum.com/board/index.php?action=profile;u=11488) @GeneWengert-WoodDoc (https://forestryforum.com/board/index.php?action=profile;u=20498) .
I was actually thinking radiator style radiant heat.... actually running copper along the three walls so it wouldn't be as blocked. Along with a fan to move the air.
May as well put the radiator in front of the fans, so all the moving air gets warmed and then blown over the stack.
But the Control of the drying is the trick. You have to both remove water (vent or condense with a D/H), but make sure you aren't removing the water too fast. So there is this ratio of heat / humidity / air flow that makes up a kiln schedule, and what's acceptable depends on the species (and thickness).
Dry too fast and you risk degrade (checking / case hardening / internal collapse etc). Dry too slow and you are wasting kiln time and $S.
The solar kilns make use of the Cheap / Fast / Good - pick any 2 principle, They are cheap, and good, but not fast. Vacuum kilns are fast and good, but not cheap. You get the idea. You can make a cheap kiln, and get good results, but the wheels fall off when you want to make it fast.
Another question I should have asked earlier..... what's the minimum thickness the stickers should be?
I didn't have any and Home Depot had bundles of slats pretty cheap. There only around 3/8" or so thick. I have been putting them 16" oc. There's a nice even gap all the way but wasn't sure if it should be larger.
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(https://forestryforum.com/gallery/albums/userpics/61600/A55E725D-E48F-4704-B11C-80018F95D0EB.jpeg?easyrotate_cache=1617371332)<here are some my latest.
Got into some birds eye in an elm tree. It looks amazing!!!
Can anyone tell me what they think the other wood is?
Had a thick rough bark and big growth rings.
elm is under rated and very beautiful. I think what you are seeing is common in elm and Danny can give us the scoop. some sort a epicloic somthin or other. is corresponds to the little pointy area on the outside, and with the leaves that appear on the trunk of the tree. @WDH (https://forestryforum.com/board/index.php?action=profile;u=4370)
Those slats you Mentioned are too thin, IMO. Air needs to move through that gap you are creating across those very wide boards. If you're buying from the home center, then just rip some 2x4's down. 1 1/2" thick stickers isn't too thick for those wide pieces.
I use 3/4 inch, but we do want it to dry slow, but do not want moisture to set on the surface. lift and edge and feel for moisture. do not smash your fingers. smiley_carpenter_hit_thumb
The difference between making kiln dried slabs and kiln dried firewood is control.
Doc, the term is epicormic. The buds buried in the bark are called adventitious buds. The resulting sprouts are called epicormic branches.
sorry, in medicine we have a finding called epiploic appendigitis. not to be confused with appendicitis.
Epiploic appendagitis - Wikipedia (https://en.wikipedia.org/wiki/Epiploic_appendagitis)
Epicormic shoot - Wikipedia (https://en.wikipedia.org/wiki/Epicormic_shoot)