Which kiln design works the best?

Lance in Ontario · April 18, 2007, 08:29:26 PM

I am looking at building a kiln in the next 2-3 weeks and I am trying to decide on an end load system with a cart or a side load without a cart. The problem I can see with a sideload is you will need alot bigger doors, and the end load you need to construct a cart and rail system. I am looking at around the 2500bdft range with a nyle 200/woodmizer dh4000 system.Any info or other design ideas would be great
Thanks

BBTom · April 18, 2007, 08:37:54 PM

Lance, I built mine as an end loader with cart. Next one will be side loader. When I get it built and use it for a year or so, I will be glad to tell you which I like best.

TexasTimbers · April 19, 2007, 08:34:54 AM

Lance - I just have a little shop kiln right now - but I have the big kiln waiting for me to add the equipment and decide where I want to put the doors also. IOW I can't speak from experience but you aren't getting many opinions so I'll throw in an idea or two.
I have given alot of thought based on alot of research and reading on this subject, and for my time invested I am going with the cart and rail and end doors. But my kiln will hold 4000BF and is a condensation kiln. My little shop kiln opens from the front but we aren't discussing those types.

You do not say what kind of kiln you are building. If it is a solar kiln, building a cart and rail system is not worth it IMO especially up there in Canada as you will not be loading/unloading very often. If you are building a DH kiln then you might consider the cart rail because stacking/unstacking and moving by hand can get cumbersome and time consuming once you start running loads through it every few weeks. And if you are keeping some runs of boards together (bookmatching) from the mill through processing this is just two less step and possibilities of getting them all mixed up.

OneWithWood · April 19, 2007, 10:58:40 AM

Lance, did you happen to read the recent thread on building a cart? The kiln in the pics is a Woodmizer 4000. I opted for end loading from both ends with a cart rail system. When all is said and done I will have three carts so I can have one in the kiln while one is being unloaded and one is being loaded. I think this will minimize wood handling and down time. The actual construction of the kiln chamber can be found in this thread:

https://forestryforum.com/board/index.php?topic=1400.0

One caveat: Though I have great confidence in my design I have yet to run a full charge through the kiln. I should get that accomplished within the next month. Stay tuned.

Brad_S. · April 23, 2007, 09:24:49 PM

I went with a front loading design. I stack and sticker right off the saw, then shed dry the lumber in the same barn the sawmill and kiln are in until it gets down to less than 20% or I have a need for it. The door is 11' x 16' and is raised by a winch in the joists.

oakiemac · April 23, 2007, 10:23:56 PM

I like Brad's design. I have an end loaded system right now and I have yet to build the carts although I do have the wheels and the track. Right now it is all boy loaded, as I hire high school kids to load it up.
It is time consuming and I really want to get the carts built but I have no time as of late. When I build the next kiln, it will be like brads that way I can just load with the bobcat. I think even with the carts it will be more hassle then just using a loader to set the stacks in.

scsmith42 · April 23, 2007, 11:02:36 PM

I have an end-load design, with three carts and a track system. I think that my operation would be more efficient (ie cost-effective) with a side load system, rather than end-load.

The reason why is the amount of time that it takes to install the baffleing on the ends of the carts. I think that this process would go much faster - and easier - in a side loaded kiln. AND - I have found that quality of the baffling is key for maintaining targeted airflows through the stacks.

Brad - I like your design.

Scott

beenthere · April 24, 2007, 12:23:57 AM

A few years back, I've seen where the kiln was on tracks, and the loads were made up in the open, then the kiln rolled over the load. The dry lumber was then unstacked while the green was being dried. Not a popular way to dry wood, but seems it would have its advantages over stacking inside a kiln.

Kind of a 'portable' kiln idea. :

Brad_S. · April 24, 2007, 03:30:12 AM

Quote from: OneWithWood on April 19, 2007, 10:58:40 AM
When all is said and done I will have three carts so I can have one in the kiln while one is being unloaded and one is being loaded.

OWW, isn't 3 carts one too many? You only have 3 spots, left outside, right outside and in the kiln. Two carts can move back and forth, three carts would occupy all three spaces and not allow for any movement. ???
I originally wanted to go with a two cart, end for end design, but after pricing cart material coupled with the fact that I have very limited fabrication skills, I went with the large door and am glad I did. I can get it unloaded and re-loaded before the slab has a chance to cool down and I only hand handle the lumber once off the saw.

Lance in Ontario · April 24, 2007, 04:33:28 AM

I think the sideload would benefit me more,due to building design.
I am using a nyle l200 system,were can/should I place the system? Can it be placed at the end of the kiln or halfway down the side?Another question is should I have a floor drain in the concrete pad?
When I go to dry my first load can I do a mixture of white pine and basswood?
Thanks for all the input,it really helps!

scsmith42 · April 24, 2007, 08:53:42 AM

Lance, stick your DH unit halfway down one side where it can mix the most effectively with the air inside the kiln. I think that if you placed it on one end you'd have a problem with the wood closest to it drying more rapidly than the wood at the opposite end.

Leave enough room between the DH unit and your wood stacks so that you can easily move around to take MC measurements.

Skip the floor drain - you want to be able to control the entire amount of MC reduction with the kiln unit.

BRAD - I noticed in your photo that it looks like your stacked lumber will be very close to the door (when it's closed). Have you noticed any differences in airflow through your stacks based upon the dimension from the edge of the stack to the door?

Scott

Brad_S. · April 24, 2007, 09:23:50 AM

Scott,
The stacks are closer to the door than I would like, but it looks worse in that picture than it really is. I have about a foot of clearance and have not had any problems. The kiln looks well used in the photo but in reality, it's only been done 6 weeks and in that time I've had one run of mixed hardwoods dry from 12% down to 7% and one run of cypress from green to 6%. In both cases readings from next to the door, the center of the stack and near the DH unit were very close. I'm thinking of shortening my stickers and opening up some more room there but I think I'll do a few more runs to see if there really is or is not a problem. As it stands now, I fit two stacks of 40" widths in, if I have to I'll shorten them to as little as 36". I also plan to install a deflector on the door to steer air down much like the one OWW has, not too big because I don't want to lose head room. When loading with the Bobcat, it's easy to forget about overhead fork rack clearance if I'm too busy watching my edges when loading the top stacks.

TexasTimbers · April 24, 2007, 10:07:58 AM

I have been planning the end load and 2 cart system too, but after actually seeing yours Brad I think a little copy-catting is in order.

Do you have a frontal shot without the bobcat there? I'd like to see the baffles more clearly if you have a picture handy. Particularly the side baffles.

Thanks for the posts and pics.

OneWithWood · April 24, 2007, 02:09:34 PM

Brad, for my material flow 3 is the right number. The carts get rotated. The mill is located at the loading end and the finshing equip is at the unloading end. There are doors at each end to facilitate the movement of the carts. Of course when I actually have 3 carts I may find that moving them is more hassle than using two carts and carrying the lumber from one end to the other. Time will tell.

Brad_S. · April 24, 2007, 07:25:28 PM

OK, I see now. You are actually going to pick up the empty cart off your finishing end and move it to the other end after moving the kiln load out and moving the next one in. I can see how that would work better for the work flow you describe.

Kevjay,
I'll get a shot tomorrow, but there isn't much to see. I have a friend who was General Manager at a Gortex® plant and got me a roll of that material. I have it fastened to the fan assembly and to the walls, then pull the material over to the edge of the stack and pinch it between a board and sticker. I also place some stickers running from the stack to the wall to minimize the Gortex from billowing when the fans are on. I may someday replace it with something more substantial like sail canvas, but for now I need to use whats cheap (to me anyhow, I'm told Gortex is $35 per yard!) and available. :D)

MikeH · April 24, 2007, 09:59:20 PM

I have one with two doors (9'wide x 10' tall each) that swing out. They work good but one that hinged up would be more out of the way I think.

brdmkr · April 25, 2007, 11:32:31 PM

Brad,

I like your door design. Did you build your own hinges? How does the door seal when the kiln is running? Are there latches of some sort? I couldn't tell from the pics.

Brad_S. · April 26, 2007, 03:45:03 AM

The door is hinged with 9 of the largest strap hinges Home Depot sells. There is a bulbous garage door gasket attached to the inside perimeter of the kiln and one strip attached to the bottom of the door to seal it. Sheer weight keeps the door shut but I do plan on adding some latches.
The door itself is built of 5 1/2" x 5 1/2" beams half lapped and carriage bolted in the corners. Another 5 1/2" x 5 1/2" is butt fitted vertically up the center and is held by a few lag bolts and a number of Timberlok screws. Two 2" x 5 1/2" studs run vertically up at the 4' center between the beams. A soy based spray insulation was used to fill the cavities, then a Low E barrier (much like those "space" blankets), a vapor barrier and then the ply. A large piece of angle iron spreads the stress of lifting across the bottom of the door but I may make two lift points rather than just the one central point.
As mentioned, this chamber is new (I used to have the kiln in an old meat locker but I had to give up that space to a tenant who needed the extra space) so the long term durability of the design has yet to be tested. :-[

brdmkr · April 26, 2007, 08:56:48 AM

Brad,

Thanks for the details 8)

I have been designing a kiln chamber in my head for some time, but the door had been giving me fits. I think you may have solved that one for me. If you think of any additional mods you would like to make, I'd appreciate hearing about them. If I ever get around to actually building a kiln, I may PM you for an update.

Mike