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making weights for top of stacks

Started by ozarkgem, September 09, 2014, 06:34:56 AM

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ozarkgem

I couldn't find any post on this. How much weight do you put on your stacks when you put them in the kiln?  I am pouring some concrete this week and will order a little extra. I am thinking of using 2x12 to make a form 4' long and put a lifting eye in it. This would be a little over 400 lbs. I was going to put 3 per 8' stack. I have some Sycamore I want to cut into 1x12's and keep if from cupping while it dries. Maybe if anyone has pics of what they use that would helpful also.
Mighty Mite Band Mill, Case Backhoe, 763 Bobcat, Ford 3400 w/FEL , 1962 Ford 4000, Int dump truck, Clark forklift, lots of trailers. Stihl 046 Magnum, 029 Stihl. complete machine shop to keep everything going.

GeneWengert-WoodDoc

If weights were really effective, we would see flatter lumber in the lower layers of a stack of lumber even without weights.  However, this is not seen, although keeping rainfall and direct sunlight off the top layers does indeed help reduce warp on the top layers.  So, discounting the effect of a roof, weights do little to help keep flatter lumber.

Research into weights showed a benefit with hardwoods when 10" thick concrete slabs were used.   Further, the benefit was seen only if the weights were used from the beginning of drying and then kept on the lumber stack for three days after the kiln was unloaded...moisture movement was still occurring after drying, so the weights were needed.  I saw this "post drying" effect at an operation in Arkansas drying southern pine.  They tried weights that were tied to the kiln roof and they failed unless weights were also used for three days after drying.  As pine warps a lot, so some benefits were seen with weights, but if there was a moisture change after drying, movement and warp were more...in other words, the weights do not stop warp permanently.

Ok?
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

WDH

I just put the best grade boards on the bottom of the stack and top it off with the lowest grade.  The lower grade provides some stack weight for the better grade stuff on the bottom. 
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

mikeb1079

i have very little experience drying lumber, but the little i do have seems to confirm that weight doesn't matter nearly as much as proper sticking, lack of direct sunlight and re-wetting, and the way in which to lumber was sawn (q sawn vs flat)

i try to do what danny does, just put the good stuff on the bottom.
that's why you must play di drum...to blow the big guys mind!
homebuilt 16hp mill
99 wm superhydraulic w/42hp kubota

WDH

I went from 24" sticker spacing to 16" sticker spacing.  That helps a lot, too. 
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

red oaks lumber

the only thing the weights do on top of bundles is make it dangerous. ;) if you take all the precautions while  stickering and stacking and storing you have a better chance of sucess than adding weight.
the experts think i do things wrong
over 18 million b.f. processed and 7341 happy customers i disagree

WDH

Every time that I go to Jake's for a project, I add weight  :)
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

logboy

Not sure about lumber, but if I dont put weight on my slabs when they air dry they curl up like potato chips. I have some white oak rocking slabs as proof. Now everything gets cement blocks right after it is stickered. I'm not sure its possible to have too much weight on top to keep them flat.
I like Lucas Mills and big wood.  www.logboy.com

Seaman

Logboy,
I just got a free bander yesterday, that uses poly banding. My idea is to band under the bearer on bottom of the stack, and put a matching bearer on top of the stack to band across. Three or four per stack. I plan to band as soon as I stack, and leave them banded all the way thru the drying process. If the bands loosen a little I can drive window wedges under the top bearer.
I am hoping this will reduce the movement.
Anyone ever tried this, think it will work ?

Frank
Lucas dedicated slabber
Woodmizer LT40HD
John Deere 5310 W/ FEL
Semper Fi

red oaks lumber

wood movement cant be stopped, you can put a mitlitarty tank on top if the wood wants to move it will. :) if a person feels better by adding weight go for it.not for me. :)
the experts think i do things wrong
over 18 million b.f. processed and 7341 happy customers i disagree

scsmith42

Quote from: Seaman on September 13, 2014, 07:14:01 AM
Logboy,
I just got a free bander yesterday, that uses poly banding. My idea is to band under the bearer on bottom of the stack, and put a matching bearer on top of the stack to band across. Three or four per stack. I plan to band as soon as I stack, and leave them banded all the way thru the drying process. If the bands loosen a little I can drive window wedges under the top bearer.
I am hoping this will reduce the movement.
Anyone ever tried this, think it will work ?

Frank

Frank, I know of folks that use ratchet straps between the bearers on each side of the stack instead of bands.  About once a week or so, they will give each ratchet strap a click to take up the slack and keep tension on the bearers.  Most of them just use inexpensive 1" wide straps. 

A band approach + shop made wedges is probably more cost effective if you have a lot of stacks to do though.
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.

Den Socling

I have in my notes that Gene said you needed only 50 lbs/sq'. That was on March 1, 2008.  ;D I have seen claims up to 400 lbs/sq'.

logboy

Frank,

I imagine you can use straps but you need to stay on top of tightening and never forget. Thats why I use concrete blocks. 50 pounds apiece, and I throw them on and walk away. I forgot to put them on a few times over the years (or took them off and forgot to replace them) and ended up with potato chips for slabs. In my experience if a slab is going to warp drastically it will do so in the first few months, not a year or two later. Another option is to saw some thick slabs out of your crappy logs that are split or just plain junk. If you open up a log with your slabber and realize its garbage, just saw it really thick and you have a big weight.  Some of the boys down under drying slabs told me they use jugs or containers and fill them with water or sand.
I like Lucas Mills and big wood.  www.logboy.com

Seaman

 Thanks all, I agree that it is the first few months that make all the difference. I guess all these methods wilkl work as long as you pay attention.
I am using straps now, but sometimes the buckles get in the way. I am going to ry the bander also. My slabber is cutting so smooth now, no planing will be needed as long as I can dry them flat.
Frank
Lucas dedicated slabber
Woodmizer LT40HD
John Deere 5310 W/ FEL
Semper Fi

scsmith42

Quote from: logboy on September 13, 2014, 12:21:38 PM
Frank,

I imagine you can use straps but you need to stay on top of tightening and never forget. Thats why I use concrete blocks. 50 pounds apiece, and I throw them on and walk away.

That is a very good point.  How many blocks do you put on top of the slabs?  To you totally cover the top, or space them X distance apart?
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.

Seaman

Lucas dedicated slabber
Woodmizer LT40HD
John Deere 5310 W/ FEL
Semper Fi

longtime lurker

A far easier to live with option then concrete blocks is to use 4 gallon plastic drums - the kind with the molded in handle - full of water. They're designed to stack on top of each other, individually are manageable weights, can have the water tipped out to make storage easy, etc etc. Cumulatively the weight in them adds up.

The best weight for a stack of timber though is another stack of timber  ;D just keep rotating the freshest ones to the bottom.
The quickest way to make a million dollars with a sawmill is to start with two million.

logboy

I sticker every 2' and put two blocks, 50 pounds each, every 4' or so. I may put more if its a wide crotch or something I suspect might cup. The thing I like about blocks is that they still permit airflow unlike a five gallon bucket or something that could leave a big black mold circle. Blocks are also cheap and easy to find. I got a couple ton worth for only $50 on craigslist. I've unfortunately sold a lot of discount slabs because I thought simply stickering them was good enough. The top slabs in the stack turned into potato chips or firewood. Now everything gets weight on top. Its definitely not like drying lumber. Slabs are easy to ruin.

I like Lucas Mills and big wood.  www.logboy.com

tule peak timber

An interesting thread....I rotate the drier lifts on top of the greener lifts as we mill . The drier lifts are probably 3-4 thousand pounds. I dry on an 80 foot log concrete slab , and after it fills up (about 20 25 kBF) I start rotating off on to less desirable ground storage on bunks . Round and round we go,,,,Yes there is still degrade ,,,but works pretty well for me.  Rob
persistence personified - never let up , never let down

YellowHammer

I'll add my 2 cents for what it's worth. In my experience, inherently bad acting boards are gonna warp as they dry, not a whole lot can be done about that.  They have internal stresses that can be overcome temporarily with weights and force, but not permanently. A bad board is a bad board.  However, the majority of the boards in a stickered lumber stack are mostly stress free and will dry flat if left in a situation where they have an opportunity to do so, but they can be forced to dry crooked or twisted if influenced by external forces, such as a bad board in the stack that is allowed to move and disturb the orderly spacing of the stack.  I have seen many times where a warped or cupped board in a stack will lift or twist off its sticker and apply pressure to its neighboring boards in the stack and cause them to all dry with some of the same issues, and take on the same warp or crook.  This is especially true near the top three layers of an unweighted or unbound stack and that's why it's a good idea to put good boards on the bottom layers of a stack, to protect them from warping, or more importantly, to protect them from being warped by other adjacent boards.  So a bad board that is warping when it's drying will move and ruin proper sticker spacing, will lift the boards above it, or it's adjacent boards, and warp them if there isn't enough weight or force to keep that particular board squashed flat so as not to disturb its neighbors. It's a domino effect. One bad board can ruin its neighbors.  However, if a stack as a whole unit has a lot of weight or force on it to remain flat, to keep the few bad acting board flat and straight, at least temporarily, then when the stack is later unbundled, the stressed board will still spring and twist and not be flat, but the adjacent boards next to it in the stack, or directly above, will have been protected and will have dried flat because the stack, as a whole, stayed dead flat. 



I use a pallet system to easily keep weight on my lumber stacks with little or minimal extra effort during each phase of the drying process,  Each pallet load of lumber weighs in at several thousand pounds and I typically stack my pallets in the air drying area for several weeks at 3 or 4 pallets high so there is a lot of weight on all but the top pallet of lumber.  With that much weight, a bad board in the middle of the pile may be trying to warp due to its internal stresses, but it doesn't have the force to lift the stack and mess up it's neighboring boards.  As the wood drys and it's time to cycle it in the kiln, I rotate the order of the stacks and put the top pallet of lumber on the bottom with the other pallets stacked on top of it.
In the picture, I put a couple pallets of already kiln dried, dead stacked wood on the right most pallet stack to protect the top stickered stack, and keep it flat.

YH

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

ozarkgem

Good ideas YH. I hadn't thought about a middle board putting stress on the other boards. I like your drying area.
Mighty Mite Band Mill, Case Backhoe, 763 Bobcat, Ford 3400 w/FEL , 1962 Ford 4000, Int dump truck, Clark forklift, lots of trailers. Stihl 046 Magnum, 029 Stihl. complete machine shop to keep everything going.

scsmith42

Quote from: logboy on September 13, 2014, 10:40:18 PM
I sticker every 2' and put two blocks, 50 pounds each, every 4' or so. I may put more if its a wide crotch or something I suspect might cup. The thing I like about blocks is that they still permit airflow unlike a five gallon bucket or something that could leave a big black mold circle. Blocks are also cheap and easy to find. I got a couple ton worth for only $50 on craigslist. I've unfortunately sold a lot of discount slabs because I thought simply stickering them was good enough. The top slabs in the stack turned into potato chips or firewood. Now everything gets weight on top. Its definitely not like drying lumber. Slabs are easy to ruin.



Good post and pix.  I like how you place some weight close to the ends of the slab too.  Also I noticed that your blocks totally span the width of the top slab - which makes sense as that way the weight is well distributed.

Thanks for sharing this.

Scott
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.

scsmith42

YH, that looks like a good system for drying lumber.  Nice air drying shed too!  I've noticed the same thing about a bad board (or a thick sticker) in the middle of an unweighted stack causing the rest of the boards to have a bend in them.

Pretty clever to store your dried inventory on top of the stacks for extra weight too!
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.

red

An old waterbed mattress can hold a lot of weight or 55 gal drums plus all you will need is a garden hose
Honor the Fallen Thank the Living

tule peak timber

Where my wood goes for the first couple of weeks...

   The slab is flat and full of steel, while the rest of my storage is on dirt. Rob
persistence personified - never let up , never let down

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