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General Forestry => Drying and Processing => Topic started by: firefighter ontheside on June 10, 2018, 01:28:01 PM

Title: Pallet racks
Post by: firefighter ontheside on June 10, 2018, 01:28:01 PM
Anybody use pallet racking to air dry lumber.  A guy at work bought some pallet racking and put it in his auto shop.  He's got extra and asked if I was interested in the extra.  It occurs to me I could set it up on piers and then put a roof on the top.  I would have 2 or three shelves where I can set pallets of lumber to dry and save space.  I think it could work for me.
Title: Re: Pallet racks
Post by: Dave Shepard on June 10, 2018, 03:55:37 PM
I like to see a direct load path to ground for each row of stickers. If you put a big pack of lumber in the racks,  I would be concerned about sagging between the supports. 
Title: Re: Pallet racks
Post by: firefighter ontheside on June 10, 2018, 04:20:36 PM
My loader can only lift 1500 lbs, so it wouldn't be that big of a pack.  I'm not sure what the lateral supports would be in the rack, but I plan to use a 10' pallet loaded with lumber and set that on the rack.  I don't think sagging will be a problem.  I haven't seen the rack, but it's supposed to be very stout.
Title: Re: Pallet racks
Post by: Tom the Sawyer on June 10, 2018, 08:10:35 PM
I have been using pallet racking in my barn for pallets of air-drying lumber.  My beams are 5" and there is no sagging.  Not likely to sag when the load is spread over the full length.  I use 9' beams for 8' lumber pallets, 13' beams for 12' pallets.  I will be adding pallet racking for drying outside, once the concrete contractor gets me his bid.  Concrete pad 4'x65' long.  42" pallet racking, 10' tall.  Planning on a barn tin roof and shade cloth draping.  Custom-made pallets, 8' and 12' long, 44" deep, on 16" centers with the lower deck boards also on 16" centers so they will stack.
Title: Re: Pallet racks
Post by: clintnelms on June 10, 2018, 09:26:47 PM
I work for a distribution center with millions of square feet of pallet racks. I'm assuming they're the same style racks. If you look on ULINE.com they sell them and you can buy the steel supports that go across the racks. We have equipment weighing 5000lbs in the racks. You're not going to get sagging.
Title: Re: Pallet racks
Post by: firefighter ontheside on June 10, 2018, 09:53:32 PM
That's great Tom.  I won't be doing 65', but maybe one or two sections.

Thanks Clint, I'm sure I won't be even putting 5000lbsup.
Title: Re: Pallet racks
Post by: mike_belben on June 11, 2018, 08:38:40 AM
The C channel racks are much much better at staying straight than the stamped out welded 2 piece type.  I have repaired many.  

I use pallet rack mesh for all sorts of fabrication, theyre great to have around the shop.  

Title: Re: Pallet racks
Post by: YellowHammer on June 11, 2018, 09:06:01 AM
I think pallet racks would be great, however, the only reservation I have with them is that they would prevent the stacking of other pallets of wood on top of others to serve as weights.  If air dried with no weights, generally, the top layer or two of boards will jack up, warp, or bow, which if stacked one unit at a time, can be between 60 or so bdft of every pack that gets out of shape.  So generally, I like to stack on top of other stacks so that all the boards stay constrained and flat.  Taken to the next level, this is how the big mills do it, I do the same thing, except only on a smaller scale.  


(https://forestryforum.com/gallery/albums/userpics/21488/275209A2-6A4A-42F4-9BDA-75E5F6823C85.jpeg?easyrotate_cache=1517514552)


For 8/4 and thicker, multiple stacks on top of each other are even more critical, at least in my experience.

We have, however, spent a small fortune on pallet racking for dead stacked, dried wood.  It is perfect for that, and it allows easy access, organized stacks, and a measure of safety.  I would get every piece he had and use it for that.

 
Title: Re: Pallet racks
Post by: firefighter ontheside on June 11, 2018, 09:31:54 AM
I hadn't thought about the weights.  I guess I would still plan to use concrete blocks for weight like I've been doing, but I may not be able to lift the whole stack with weights on top.  I'd have to put them up after the fact.

What about using straps instead of weight?

I've seen lots of huge stacks like that in southern Missouri where they make flooring. Some of them lean so much, it looks like they will topple over.
Title: Re: Pallet racks
Post by: YellowHammer on June 11, 2018, 10:26:50 AM
Weights are best, I've used straps and pallet banding and actually damaged boards in stacks because the boards will move where not strapped and will be constrained where the straps are and will take on a lightly zig zag wavy shape.  It will become more pronounced as the wood dries, and generally only influences the top couple layers, but that still adds up pretty fast.  


   
Title: Re: Pallet racks
Post by: GeneWengert-WoodDoc on June 11, 2018, 03:24:24 PM
Another concern with pallet racks made out of iron (steel) is that water (rain or melting snow) can pick up some iron particles and drip or blow on, especially after the paint begins to wear, from the racks to oak lumber and cause substantial iron tannate stain.

I also agree with YH that straps do not put enough weight on the entire top to be very effective.  They are good for controlling the few pieces that like to fall off the top.  In order to get substantial warp control with weights, we need a substantial amount of weight...75 or more pounds per square foot.  A roof on top is also very effective for controlling warp...keep the sun and rain off the lumber.  

Also, remember that warp will occur after drying if the lumber's moisture changes and the weights are off...an issue if straps are used and tightened in air drying but not kiln drying, and an issue especially for softwoods as they often are dried to 15% or 12% MC in the kiln.  I recall a softwood kiln in Arkansas with weights fastened to the ceiling that were lowered on top of the lumber stack;  after drying, the 15% MC lumber was rolled out of the kiln without weights and warp occurred as it dried a little bit more in storage.  The weights were removed quickly and discarded.
Title: Re: Pallet racks
Post by: firefighter ontheside on June 11, 2018, 05:53:21 PM
Thanks, Gene, for the thoughts about my plan.  It will definitely have a roof.  
Title: Re: Pallet racks
Post by: mike_belben on June 12, 2018, 12:39:56 PM
Weld the racks solid, load the lower rows and top with tapered timbers wedged together at every sticker point to turn the rack into a lumber press.  Problem solved. 
Title: Re: Pallet racks
Post by: firefighter ontheside on June 12, 2018, 06:59:55 PM
That's an interesting idea, Mike.  
Title: Re: Pallet racks
Post by: Tom the Sawyer on June 12, 2018, 08:13:10 PM
I would think that the tapered wedges would have the same issues as banding or strapping... as the lumber dries the pressure drops.  Initially, you would have to tighten the wedges, or straps, every couple of days.

I plan to stack pallets on the racks, at least within the rated limits (108"x5" beam - 7500 lbs./pr.).  That is why I specified the bottom deck boards to also be on 16" centers, so they line up with the pallet below.  Gene's recommendation of 75 lb/ft2 could be met by concrete slabs, 4'x4'x6" (1200 lbs.), two for 8' pallets, and 3 for 12'.
Title: Re: Pallet racks
Post by: firefighter ontheside on June 12, 2018, 09:22:21 PM
Another member here used boards across the top and attached to vertical pieces that were attached to the bottom.  Bolts are then tightened occasionally to keep the pressure.
Title: Re: Pallet racks
Post by: YellowHammer on June 12, 2018, 11:21:31 PM
I use marble slabs, stacked on a pallet, which are then put on top of stacks of lumber.  I've used concrete and it work good for air drying, but I didn't like it as much for kiln drying as it has a tendency to to pick up moisture if left outside the kiln, so must be redried when the wood is being dried.  Marble is denser so takes up less height.    

Either one works very well.  It's important to put the weights on a copy of the the same pallet the wood is being stickered on so the runners of the weighted pallets line with the stickers of the lumber pallets.  

Here's some stacks being fed out of the kiln. You see in the picture how flat the 9/4 wood is.  


(https://forestryforum.com/gallery/albums/userpics/21488/IMG_1128.JPG?easyrotate_cache=1516162445)


Or just put other stacks of wood top.  That's what I do in out air drying area, and rotate the top stacks to bottom occasionally.  
Title: Re: Pallet racks
Post by: mike_belben on June 13, 2018, 12:30:58 AM
As the wood shrinks youd just smack the wedges another round.  Less of a chore than doing dishes i reckon. Also takes up less space than rows of ballast tops and less time than threaded rods or straps.  


(https://forestryforum.com/gallery/albums/userpics/43722/1107171228.jpg?easyrotate_cache=1528821435)

I get these bundles for free from the handle mill and there are always a bunch of perfect taper cut pieces i use for shims, jacks and bucking wedges. Theyre what im talking about basically.  
Title: Re: Pallet racks
Post by: GeneWengert-WoodDoc on June 13, 2018, 08:37:00 AM
For warp control, it is key that the flattening force be large ALL THE TIME, especially above 35% average MC when the wetness allows easier bending of wood..  Once warp occurs, it is nearly impossible to apply force to flatten the lumber.  So, any system that loosens with time, which will allow warp to occur before the system is re-tightened, is not the most effective.

One issue with the racks is that many fork lifts and drivers are not too accurate.  Plus...The loading area will require a fairly flat surface.  A side shifter would seem essential, especial in the winter when surfaces can be slippery.

Warp control with the standard stacking allows a lot of weight on the middle and lower layers of lumber in a tall stack.  Only the top five layers have lower weight with a stack that has 60 total layers (three stacks with 20 layers in each).  It would seem that in a pallet rack, each rack would need additional weight or force.  To tighten straps or wedges would require some climbing up on the racks, unless they are only one rack high.

As mentioned or implied, the weight is transferred by the stickers, so they must be aligned almost perfectly in any system, and also the 4x4s.

Also, we know that 24" sticker spacing allows for good weight at each sticker and good warp control overall.  If we increase the number of stickers to 12" spacing, with twice as many stickers, the weight at each sticker location is reduced about in half, so warp control is actually a bit more difficult.  In fact we will see warp issues in the top 8 to 10 layers and not just the top 5.
Title: Re: Pallet racks
Post by: Crusarius on June 13, 2018, 11:20:29 AM
if your going to have the tall pallet rack you can setup a winch system to lift the weight straight up. Then load underneath it and set the weight on the pack. takes care of all the concerns listed above.
Title: Re: Pallet racks
Post by: mike_belben on June 13, 2018, 02:02:58 PM
It seems like a sort of car crusher press would have been invented by now for air drying.  
Title: Re: Pallet racks
Post by: Crusarius on June 13, 2018, 02:21:46 PM
They have those. its a laminate press. they are quite pricey.
Title: Re: Pallet racks
Post by: btulloh on June 13, 2018, 04:00:02 PM
Gravity is free and relatively dependable.
Title: Re: Pallet racks
Post by: Don P on June 13, 2018, 05:24:17 PM
And unusually strong today.
Title: Re: Pallet racks
Post by: firefighter ontheside on June 13, 2018, 08:46:36 PM
Apparently gravity has gotten stronger as I've gotten older and out of shape.

If I do the rack, it will be on a very small scale.  One or two racks.  Most likely I would put the lumber up on the rack and then lift blocks up there with the loader and then I climb up and set them on the stack.
Title: Re: Pallet racks
Post by: GeneWengert-WoodDoc on June 13, 2018, 11:53:28 PM
A winch system as described would indeed be beneficial, but it sounds like an expensive operation.  

Why use pallet racks with a winch at all?  I seem to be missing something with the winch system described used with pallet racks.  Seems like you would not need or use the racks.  The OP mentioned that he would load a pallet with 1500 pounds or 300 BF of stickered lumber and then put the pallet on one of the three shelves.  Can You explain?

The winch would have to be pretty hefty to lift quite a bit of weight...6000 pounds per MBF for green oak.  Would you have a winch for each rack or have a winch that could move around?  If it moves, then you would need a motor for that?
Title: Re: Pallet racks
Post by: Crusarius on June 14, 2018, 07:25:28 AM
My thought was to just use the pallet racking as a tower. have the 2 ends vertical and then put 2 cross pieces at the bottom and at the top.

With the frame in place you could setup a hand winch that could raise and lower your weight that would be free hanging in between the uprights.

Set the first stack of lumber on the bottom cross braces that would be situated just off the ground for better air flow underneath. Then lower the weight on top of it. As you cut more lumber lift the weight and put another stack on the first stack then lower the weight.

Makes it so all you have to do is move stacks of lumber and not worry about the weights.

Gives you a nice clean organized place to stack lumber and set weight on top. As the stacks dry nothing needs to be adjusted such as strapping or banding.

If you really want to get fancy and have a nice smooth floor you can put casters on the racks and be able to move them around to get to the ones stacked behind the others.

Come to think about it this would work really well in a crowded showroom / lumber store. Just remove the weight.
Title: Re: Pallet racks
Post by: Crusarius on June 14, 2018, 07:29:38 AM
After rereading your  post and mine I missed a key point. The only reason for the winch would be to raise and lower the weight. The tractor would be used to place the stacks of lumber on the rack.
Title: Re: Pallet racks
Post by: mike_belben on June 14, 2018, 07:54:47 AM
Gene,

Perhaps the OP may not have the ground space to lay out piles of stickered wood all over the place for 6 months at a time.  Maybe there are small piles that will be stacked and unstacked at different durations and the racks will make accessibility easier without having to move one to get to the other.  Etc etc.  Why does anyone want pallet racks? To fit more stuff in a given size area.    
Title: Re: Pallet racks
Post by: firefighter ontheside on June 14, 2018, 02:41:57 PM
You kind of nailed it Mike.  While I have several acres of space, I do not want to clear more land.  What I want is covered space without having to stack it out in the open.  I can set these up close to my mill.  I have a covered deck 30x14 deck and have stacked all I can fit under there.  I have had lumber stacked next to my camper, but that's a pain and it's in the way under the carport for the camper.  Until I build/put up other structures I'm look8ng for alternatives.  Someday I'll build a new woodworking shop and have lean to on either side to store lumber and house the mill.  My current mill carport would become for my kids to park under.
Title: Re: Pallet racks
Post by: Don P on June 14, 2018, 05:44:45 PM
I've got 3 set up in the shop, handy things. I have oddball wood stacked above and workbench space below one, the other two have big stuff on the floor and then wood on various shelves above by species. They are bolted to the walls and I made a narrow catwalk in front of them up at about 8'. We'll install two of them over in my sawing partners open sided drying shed soon, they will also be bolted to the building, overturning a top heavy unit is my concern. For odd slabs piles don't really work safely.

Hmm, if you really only need the weight of 5 layers, that isn't many psi in some type of airbag. As far as shimming up or even airbagging them, if the rails don't really lock in, and the locking mechanism on mine is pretty cheesy, you could possibly wedge the rail up and off.
Title: Re: Pallet racks
Post by: mike_belben on June 14, 2018, 08:05:25 PM
Yeah thats why i said weld em.  You may be able to bolt some styles but not all.  Blind hole.  

Airbag is a clever idea but theyre a bit spendy.  I wonder how much force an air mattress can exert  :D
Title: Re: Pallet racks
Post by: nativewolf on June 14, 2018, 08:33:59 PM
Quote from: mike_belben on June 14, 2018, 08:05:25 PM
Yeah thats why i said weld em.  You may be able to bolt some styles but not all.  Blind hole.  

Airbag is a clever idea but theyre a bit spendy.  I wonder how much force an air mattress can exert  :D
Not as much as the kids jumping on them  :D :D :D
Just loan him your kids, they will be flat flat flat
Title: Re: Pallet racks
Post by: Don P on June 14, 2018, 09:29:19 PM
Quote from: mike_belben on June 14, 2018, 08:05:25 PM
Yeah thats why i said weld em.  You may be able to bolt some styles but not all.  Blind hole.  

Airbag is a clever idea but theyre a bit spendy.  I wonder how much force an air mattress can exert  :D
In reply #10 Gene mentions 75 lbs per square foot or better. Divide 75/ 144 " per square foot = about .5psi, an air mattress might get it. Or firehose/ layflat tubing between boards on top of stickers at higher pressure. You would need some kind of reservoir tank to keep them up as the pile shrinks. This is sounding sort of elaborate compared to a box o rocks, I was thinking of the weight and hassle of getting the weight up on the shelves. We had a glue press in one shop that was basically clamping with inflated firehose.
Title: Re: Pallet racks
Post by: GeneWengert-WoodDoc on June 15, 2018, 06:29:52 AM
RE: Mike Belben Reply #28...my thoughts exactly.  So, I did not see how a winch (that would have each short stack sitting on top of one another, instead of separately on a shelf) would work.  Also, getting a short stack out from the middle of the pile, using the winch, would not work, so the cool idea of using the racks for air drying does not seem like a reasonable idea if using a winch.  But, I thought maybe I was missing something.

Question for firefighter...so, have you decided about how you might control warp in the top layers of each short stack?  I am thinking that even a small amount of weight might be better than using nothing.

I did see one idea where the person used a wood 4x4 that was longer than the width of the pile and extended across the width on the top, and then had a spring at each end of the 4x4 that he pulled down and clipped into the pile a few layers (Maybe 10?) below the top.  The problem with the 4x4 is that it warped a little and then applied very little weight in the middle of the pile, but lots near the edges.  He then changed to a metal I-beam to get force more uniformly along its length.  I did not go back and see this in use.  To get 70 psf, with one beam every 12" on the top with a 4' wide pile would require about 140 pounds from each spring, so that would require a fancy way to extend and hook the spring.  I do wonder of some sort of adjustable strapping system could be used instead of a spring.

A couple of posts have talked about racks inside for displaying dried lumber ready for use or sale.  Maybe we should start a new thread about that and get some pictures too?  Safely displaying lumber is an issue for sure.
Title: Re: Pallet racks
Post by: GeneWengert-WoodDoc on June 15, 2018, 06:58:40 AM
Don P.  I did see about 30 years ago several large commercial kilns that had air bags on the top between the top of the pile and the ceiling or roof.  I believe they were Irvington Moore kilns and they were patented.  They also were on the sides.  I have no idea how they worked.  The idea was to use them as baffles and not to supply weight on the top of the stack, but maybe they could supply weight if they didn't lift the roof off the building?
Title: Re: Pallet racks
Post by: mike_belben on June 15, 2018, 10:09:35 AM
Gene, a lot of ideas flying around in this one..  Winch wasnt me, i was for welded racks and tapered wedges or some mechanism that uses the rigid structure in the rack to push down on the pile like the airbag kiln you just mentioned potentially could have.  

I think id top the wood with say wax paper or some kind of scuff barrier, then a 3" C channel turned up into a U at each sticker point.. And then taper shims pounded in there from front and back.  So 4 channels would take 8 wedges.   If the rack isnt full youd need top spacers which is a downside, the weight system is better in that respect whether you are loading it by fork or some suspended cable rigging.  Id buck firewood for spacers personally just to get the length i wanted without fooling around.  

A friend of mine has a septic tank casting company.  There are always narrow rectangular reject pieces in the junk pile.  Thats where i would look for weights and hed be thrilled to load em up and send em off.


Edit: i just took a picture of what im talking about when i say wedges.

(https://forestryforum.com/gallery/albums/userpics/43722/0615180911.jpg?easyrotate_cache=1529072429)

Theyre taper cuts from a handle mill.  I pound them into the pockets to keep firewood logs on the trailer, then just unstrap, knock wedges out and tip the whole trailer sideways with machine to roll them off the deck at home.
Title: Re: Pallet racks
Post by: Dave Shepard on June 16, 2018, 03:15:06 PM
Air bags from trailer truck suspension would work well. Put them on regulated air and they would automatically maintain pressure as the wood dries. 
Title: Re: Pallet racks
Post by: GeneWengert-WoodDoc on June 16, 2018, 04:30:21 PM
We do want the pressure to be applied rather uniformly to the top of a pile.  With stickers, this means that each sticker would carry the weight and about equal weight on each sticker and uniformly along the sticker's length.  So, with a pile that is 4' wide and 12' long with 7 stickers and a total of 70 pounds per square foot with is 70 x 48 = 3360 pounds, then the weight on each sticker would be 70 x 48 /7 = 480 pounds.  If a sticker is 1-1/2" wide and 48" long, that is about 60 psi on the sticker along the entire length.  Now, we could put a flat cover (plywood?) over the top stickers and then apply weight uniformly on the 4' x 12' cover; a total of 70 x 48 = 3360 pounds.

Would straps apply the weight on a sticker or cover uniformly?  Probably not.  Would a 6" thick slab (4' x 12') of concrete or other heavy material?  Probably yes.  Would wedges apply uniformly along the length of a sticker?
Title: Re: Pallet racks
Post by: Peter Drouin on June 16, 2018, 10:03:11 PM
I looked at them, But I don't think I can fit all the lumber I have on them. So I went this way.

(https://forestryforum.com/gallery/albums/userpics/22511/SAM_1666.JPG?easyrotate_cache=1513122293)
  

(https://forestryforum.com/gallery/albums/userpics/22511/SAM_1905.JPG?easyrotate_cache=1524999632)
 
Works for me, 
Title: Re: Pallet racks
Post by: firefighter ontheside on June 16, 2018, 10:07:18 PM
Gene, I would be simply placing concrete blocks on the stacks just as I do anywhere else that I stack wood to dry.  I'm sure I'm not getting the psi that you are talking about needing.

You guys have some grand ideas, but I think I'm gonna stick with the "box of rocks".

Mike, in my structural collapse training we learn to use 4x4 wedges to apply pressure to our strut systems.  We rip an 18" 4x4 from corner to corner and then keep those sets together so they mate perfectly.  Then we can place that and use 2 hammers to drive from the sides and apply pressure.  A person could go out and bang on those every few days to keep the pressure, but like you said, you may need spacers if the stack doesn't go all the way up.

I'm still waiting to see what my buddy is gonna have extra as far as amounts of racking.