kiln carts and track

[farmfromkansas]

Planning to use a reefer box to sterilize lumber, and do not want to handle the boards by hand, so interested in what to use for wheels and tracks?  And how wide to build the cart, and getting it down to the front of the box, pulley and rope? New project for me. Have skidsteer, dry outside, can make some frames to hold boards to avoid multiple times handling boards.

[farmfromkansas]

  Did find some pics by Yellowhammer, his setup looks interesting.  Was hoping to find some old farm implement wheels would work, or casters running on an angle iron track.

[YellowHammer]

Any kind of steel wheel would work.  If it's a flat wheel, then use channel for a track, or if you can find some grooved wheels, the angle iron will work well.  Main thing is easy rolling and weight capacity.  Get it level for the full 80 feet so you don't have a runaway train. 

Build the kiln carts from at least 4" channel, they will take the weight.  I didn't use a winch as the fully loaded carts will weigh more than the reefer, and if the winch is attached inside to the head end of the reefer, and hooked to the loaded apart, the reefer will move.  So the easiest thing to do is just pull it out with a tow strap and push it back in with the bumper of your four wheeler or skid steer. 

Definately build our use pallets or skids. 
I pushed this trainload of slabs in yesterday. 

I've got a long post on it in the archives. You may have already seen it. 

[slider]

Robert in the picture you posted of your kiln carts i noticed the top of each lumber stack is a lighter than the rest of the stack.  Are you topping each stack with dry lumber to reduce warping on top.

[btulloh]

Those are pavers or something like that for weight.  I remember that from one his earlier posts.

I'm wondering how the 8/4 slabs get along with that 12/4 lumber that's on the bottom.  Always working on my education.

[YellowHammer]

You guys are learning all my secrets.  The pallets on top of the lumber are stacks of marble.  They each weigh 2,700 lbs, or about 100 lbs per square foot.  I use them for a couple reasons.  Sure, they are weights to keep the top layers of the lumber noticeably flatter than without.  Very effective for reducing sympathetic twist in boards neighboring bad actors.  If one board has some twist or bow, especially on a higher layer, it will raise up and cause sympathetic twist and bow in the surrounding boards.  The "one bad apple" syndrome.  These weights overpower the bad boards and force them to remain flat so they cant raise up and affect its neighbors.  Huge board saver.

However, they also serve the purpose to allow me to cycle the kilns fast.  They serve as thermal ballast to reheat the kiln back up to operating temp very quickly on reloading.  Heat up the kiln to 150° for a sterilization cycle to finish a load, pre stage the next 4 packs on the gravel pad, and then do a speed swap.  Drag the carts out, forklift the packs off the carts, reload new packs of wood, reload the granite thermal mass, and push the whole mess back in while the rocks are still hot and slam shut the doors.  The kiln will come up to temp very quickly, so I'm drying the next load in a minimum of time. 

I tried concrete, but it doesn't work as well, as it absorbs too much water.  Still works, but....

I can dry 8/4 and 12/4 poplar in mixed air dried loads, especially if drying 8/4 wide slabs, and 12/4 edged stock, with excellent results.  I wouldn't do it with some other species, but do it routinely for basswood, poplar and pine. 

[farmfromkansas]

  Lot of good information, especially about the weight on top.

[dougan2469]

I made an angle Iron track and used these for wheels.

https://www.amazon.com/gp/product/B004071T40/ref=oh_aui_detailpage_o03_s01?ie=UTF8&psc=1

I used 6 wheels on an 12' cart. So far, they are working great....

[K-Guy]

Nyle has 6" caster wheels with a 2500 lb rating each.

[longtime lurker]

Have you noticed a variation between in kiln moisture levels and EMC when cold later Robert?

I had problems with that for a while, even with correct temperature corrections applied. Eventually figured out it was my speed swap kiln loading technique.... hot timber was leaving the kiln and hitting the cold wet air here and sucking her up like a sponge. EMC here is 14-16% though depending on season...  but it was throwing my moisture levels out by around 2%.

Now I've learnt to cover the stacks immediately with a vapour barrier. Cant stop the speed change technique... it saves 3 days on a cycle.

[YellowHammer]

Thats very interesting, I had not gotten into that scenario, but only by pure coincidence.

When we pull the loads out of the kiln, I let them rest and relax, cooling down, with lots of weight on them, typically for a day or two which doesn't affect our weekly planing schedule.  So we bring the hot stacks immediately into our building and place a few pallets of wood on them for weight, and forget about them for a couple days.  Thing is, we run dehumidifiers in the building to keep the humidity down because this building serves both as our warehouse and showroom and we want to keep our wood at the low moisture levels.  So there is no moisture to suck up when the stack cools down. 

This is a clear case of I'd rather be lucky than good.  8)

Yes, speed swap gets er done.

[longtime lurker]

The issue I face is I guess twofold:

Locally EMC is usually around 14%. Ambient humidity for the wetter part of the year is "sauna". The MC level I'm chasing for southern markets though is 10% (occasionally lower) so that its not an option to KD and hold stock for long. We do hold some wrapped in plastic and it does seem to hold but you shift enough stuff around and you get a tear in the plastic and back to 14% she goes.

The other thing being that because of the above I will not kiln stock on spec: we get the order from south and then KD to customer requirements. SO we can have timber sitting around here a long time between sawing and kilning and it can often be down around 16% going into the kiln.

With no free water in the wood to help convect heat and because most of my species tend to be quite dense it can take quite a bit to actually get a DH kiln up to operating temperature if the kiln is cold. Conversely because of the high ambient humidity I've learnt that for best results I need to allow the charge to cool down in the kiln. If, at the finish of cycle I start dropping my dry bulb back to ambient with the vents shut and leave the wet bulb alone it puts the wood through a reconditioning cycle which is also never a bad thing. If theres no moisture in the kiln its got to be still shifting the water around from the wood and certainly I get a lot of positive feedback on how "soft" my timber is... case hardening can be a bit of a problem in many of these species.

I am unhappy with my chamber anyway... it needs about another 4' in length and the plenum is right on the bottom limit of workable. It was always supposed to be a "shorts" kiln to augment a larger unit but its giving that good a product that I want to use it a bit more.  I am at this point unsure whether the next chamber will be an enlarged stick built type or whether I will just whack it all into a reefer with a couple extra fans and deal with the narrow plenum. What I do know is that rather then stone ballast I think that I will be installing a wood fired boiler with a heat exchanger in front of the fan deck... basicly use a hot water loop to bring the charges up to temp then switch it to DH once I'm at working temperature.

As it stands when we're taking wood from 16-18% to 10% it takes almost as long to get the chamber hot as it does to actually get it dry.

[farmfromkansas]

Found some reasonably priced 4" CI v groove wheels on ebay, 800 lb capacity, looks like would have to use lots of wheels, and looking at the pics of the carts, they appear to have double rails on each side, with holes drilled in both rails with the wheels between.  One concern is how to make the carts match the rails so that all wheels touch down on the rails, without one end up?  Looks like short carts should be built and then bolted together to avoid any twisting. Would you put a wheel every 4' or even closer?

[Crusarius]

The more points touching the more accurate everything needs to be. If you have a track that has 4 points touching those 4 points need to match if your track has 8 points touching then you need 8 points to match.

Regardless, you should have the track and carts as close as possible accuracy wise. But we all know that is not always easy as it sounds.

The other thing to consider is the weight of the stack on the carts will flatten the carts to match the bearing points on the rails. So if the carts are not perfect but the rail is you should still be ok.

Did I do a nice job of going in a complete circle? I should be in politics

[YellowHammer]

I built the carts out of 20 feet long 4 inch channel.  The issue with working with this length of steel is the dealing with the amount of flex, and making sure everything is assembled flat and true.  I marked and drilled each axle hole as accurately as possible, and measured everything axially from from two datum lines, the forwars end and top of each piece of channel.  This way, the holes were all in the same relative places on each piece of channel.  Then when everything was drilled, 1/8 shy of the finished diameter, I clamped the pairs together, web to web, front to front, and match drilled the final diameter.

I then separated the pairs, put wooden spacers between them, and welded the crosspieces to the tops of each channel, so they would all be in the same plane.  When I was done, I bolted the wheels on, and done.

One of the keys to easy loading is to make sure that there are "targets" welded on the carts to make sure the pallets of lumber get landed accurately.  I welded little stubs of channel at strategic places that matched the runners on my pallets.  All I have to do is line the runners of my pallets up with my targets on the carts, both side to side and front edge to front edge, and the lumber will be positioned perfectly every time.    A side shifting forklift makes hitting the targets a breeze.

It's very important for safety to get the railway tracks, both inside and outside the reefer, very level.  I used a transit for mine.  It's not unusual for the whole train to weigh it at a couple tens of thousands of pounds, and the last thing I would want is to have a runaway.    

[farmfromkansas]

 Thinking I should get the box set first, put the rails in the box as well as the rails outside, and weld up the carts on the track, to help get the carts flat.  Was thinking of setting up my drill press with a fence, and clamp the sides together and drill them clamped up. Pretty heavy handling, but they should be even.

[farmfromkansas]

Got a reefer delivered yesterday.  Set it on some 4x8 prestressed concrete panels.  The guy who delivered it removed the under carriage from the rear of the trailer, and I pulled it out from under with the skidsteer and he hooked it behind his wrecker and carried it back with him.  The trailer had 2 rows of steel underneath where the undercarriage attached, which was well welded, so had to turn one of the concrete panels long ways under the rear of the trailer, between those steel parts. Will have to block under the edges of the rear of the trailer.  He removed the reefer unit, so there is a 4x6 hole in the front, which I have to close up.  Interior of trailer is lined with plastic over the insulation, hope there are some  frame pieces I can screw a 2x4 to longways in the center of the ceiling to attach the plywood and fans to. There are some screw holes along the edges, so will check those to see if they will hold a screw. Now I need to collect the steel to continue this project.  4" channel and 3" angle are priced very close, so plan to use the channel iron.

[Tin Horse]

Sorry to interrupt this discussion with a stupid question. I only air dry but am thinking about kiln drying. I was told that after kiln drying the wood will not ever go back to EMC completely.  Like bread toasted it never will go back to bread. I this theory at all true or nonsense.
Again sorry to interrupt.

[K-Guy]

Not a stupid question Tin Horse. Once dried the wood will always try to get to whatever the RH of the environment its in. 

[GeneWengert-WoodDoc]

Tin Horse, What you say is true if you define the wood "completely."  The EMC values are for drying.  When you reverse and talk about moisture regain, the EMC values are slightly- -maybe 1/2%- to 3/4%- -too high.  So, if the final is 7% MC and then the new EMC is 10%, the wood will go up to about 9.25% MC.

[farmfromkansas]

The box is a Timpe, built 12/87, has some type of plastic interior liner.  Has a patch of damage on the ceiling at the rear of the trailer, with a little of the foam falling off.  Do I need to concern myself with the damage, or should I figure out a way to patch it up? Seems to have fibers, so assume it is some type of fiberglass sheeting. Box is 8' wide inside, 100" high inside, and 48' long outside.

[farmfromkansas]

The box is a Timpe, built 12/87, has some type of plastic interior liner.  Has a patch of damage on the ceiling at the rear of the trailer, with a little of the foam falling off.  Do I need to concern myself with the damage, or should I figure out a way to patch it up? Seems to have fibers, so assume it is some type of fiberglass sheeting. Box is 8' wide inside, 100" high inside, and 48' long outside.