Thoughts on a wooden built kiln

[deluxestogie]

I would appreciate advice from any carpentry-wise members on approaches and precautions regarding a wooden tobacco kiln that I expect to construct.

Below, is a concept for a tobacco kiln, built of 2" x 2" framing. It is not to scale. My likely dimensions will be ~4' height; ~30" width; 20-24" depth. This is dictated by the available space in which to stand it.

I was hoping to build this in such a way that it could be disassembled (if needed) for storage, but that may involve the use of tools that I don't possess. It will be built using simple hand tools, and a hand-held power drill.

The diagonals pictured, would likely only be required if the exterior sheeting was not structural. That is, if it's just thick foam sheeting, then the diagonals would be needed. If sheathed in plywood, then the sheeting would serve for diagonal stability.

The door is separately framed, so that the closure can firmly support a gasket of some kind.

I don't need suggestions on the workings (electrical, heat source, etc.), but the box itself.

So:

• suggested sheathing materials
• joining methods
• potential issues
• are there sandwich insulation boards that are affordable?

Thanks,
Bob

 

[darren1979]

Bob looks a good simple construction, my only concern would be the moisture on the inside of the kiln.
Maybe you could sheet the inside with some plastic membrane or even marine grade ply but that does not come cheap.
I would use some good quality screws to hold together, easy to take apart as well. As for insulation polystyrene sheets come pretty cheap compaired to celotex or kingspan insulation.

 

[FmGrowit]

The knee brace on the door is upside down. A knee brace is used to support the weight of the door (in this case), so the brace should start at the top (opposite the hinge side) and terminate at the point of the lower hinge. This way the weight of the door is transferred into the lower hinge.

I always thought old insulated garage door panels would make a nice kiln.

 

[ChinaVoodoo]

I've been contemplating how you could make it dissasemblable, and have concluded that if you build it from plywood on the sides, or something else that would perform the same structural function, that it would be easy. The 2x2s that run front to back at the top and bottom could be screwed permanently into the plywood. They would be shorter than the plywood by two times the width of a 2x2,
The rectangle attached to the door in the front, and attached to another piece of plywood in the back would be screwed, not to the plywood, but into those 2x2... You could, also have vertical boards screwed into the plywood. If that doesn't make sense, I will draw it.

 

[Jitterbugdude]

Bob, That pretty much is exactly like mine. I used rigid board insulation for mine. The issue with rigid board is since it a basically foam there is no real way to tightly secure the pieces to each other. I used metal flashing and added them to the inside corners. I then ran screws all the way to the outside. Also, you might want to consider a small peep door on your main door. Big enough for you to open and fill your crock pot or check on things in general without having to open the main door.

Keeping the humidity up was difficult until I sealed the box with the metal flashing. I have some pictures if you care to see them.

 

[deluxestogie]

...moisture on the inside of the kiln.
I would use some good quality screws ...polystyrene sheets come pretty cheap...

My existing small kiln is made of solid pine board (decades old wood), and has not suffered from the moisture over a number of years of use. Plywood is a different matter. I'm still pondering that issue.

The knee brace on the door is upside down.

...old insulated garage door panels would make a nice kiln.

Good point about the knee brace. I haven't seen old, insulated garage doors or their panels show up on Freecycle over the past 5 years.

If that doesn't make sense, I will draw it.

A drawing might help.

I have some pictures if you care to see them.

If you could post some pics in this thread, that would be great.

Bob

 

[ChinaVoodoo]

Here is my idea for letting it be able to be disassembled.
I didn't include the door, top, or back.

 

[chuditch]

I just used an old chest freezer and it is working perfectly for me I had everything done and it working in less than half a day. Once all the things had come from china to work it

 

[deluxestogie]

Here is my idea for letting it be able to be disassembled.

I understand now. Thanks.

Bob

 

[Brown Thumb]

I like Jitterbugs way. Foil covered foam. Glue it together with a good urethane glue. Your Not able to take apart tho .
What's the matter with the old one, If its Heart pine that's Good Stuff. They built boats out of it . Lots of pitch in it.

 

[nishot]

Dude, I just found an old used mini wine fridge. One with a glass door. It works great for my needs. Hope picture comes through.

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  image.jpg (55.7 KB)

 

[deluxestogie]

BT,
My sole surviving kiln (after the unfortunate death of Cozy Can) is way too small. It was a "large" hand-held toolbox from the 1950s.

I've thought about using the foil-coated foam board panels attached to screwed-together frame segments. This could make a container that can be taken apart, but only if I can come up with a method of interposing an effective, compressed gasket into all the contact surfaces between the panels.

Focus:
While I appreciate that there are other containers that can successfully be used for kilning (I've read every single post on FTT--approaching 100,000--since its creation, and all the posts on kilns in the old HTGT.), this thread is about building a kiln from scratch, using a wooden structure. So far, the comments on that subject have been helpful.

Bob

 

[Jitterbugdude]

Bob, Here's a few pics of my rigid board kiln. I disassembled it a few years ago when I started using my beehive kiln.



A closer shot of the flashing:



And the other side. I had to using a small piece of wood to distribute the pressure of the nut/bolt on the Styrofoam.

 

[deluxestogie]

Randy,
How thick was your foam, and how would you rate its thermal efficiency? Also, did the foam panels overlap at the corners?

Bob

 

[leverhead]

The stated R values are, 1/2" = 3.2, 5/8" = 4.0, 3/4" = 5.0, 1" = 6.4.

 

[deluxestogie]

A curious notion is that if the R value is infinite (perfect thermal isolation), then even the tiniest heat source would work for even the largest size kiln. With good sealing, perhaps 2" of foam would be suitable. I guess that depends on the ambient temp (indoor or outdoor kiln).

Bob

 

[Knucklehead]

If the panels are foil coated, aluminum duct sealing tape could be used at the corners. http://www.homedepot.com/s/aluminum+duct+tape?NCNI-5

 

[deluxestogie]

Foil on the inside or the outside?

Bob

 

[Knucklehead]

Foil on the inside or the outside?

Bob

I'm not sure which would help the insulation value, but foil on the inside might prevent any smells from off gassing of the foam penetrating the tobacco.

I've been needing a kiln for quite awhile now. This thread may be what it takes to get me off my lazy butt and build one. I need to reread DGBAMA's thread as his kiln is built more in line with the direction this thread is taking. 1x4's with some diagonal bracing should provide plenty of strength for the structure if height is kept down. 4-5 ft. tall is all I would need also. I'm thinking exo-skeleton to keep rot at bay as long as possible. The only wood needed inside would be the supports for the hanging sticks. (plus the sticks themselves)

 

[Jitterbugdude]

Randy,
How thick was your foam, and how would you rate its thermal efficiency? Also, did the foam panels overlap at the corners?

Bob

It was a mix between 1 inch and 2 inch foam. The thermal efficiency was excellent once I got the box to seal. I used foil lined foam, putting the foil on the inside. I tried initially sealing the corners with metal duct tape but the moisture caused the metal to peel off. I also used foam for the floor.

For actually hanging the tobacco I cut small holes in the walls and just put my tobacco stick thru them. I then covered the outside of the hole with duct tape which worked pretty good but I still got some tape peeling off.

I did not overlap the corners, just butt joined them.