Deluxestogie's Endoskeletal Wood Tobacco Kiln / Flue-cure chamber

[Smokin Harley]

I hadn't. I installed the fan mostly because I knew I would eventually need one for flue-curing, and because I found one really cheap. In small kilns and small flue-cure chambers, heat convection seems to do an adequate job of maintaining circulation. Now, with the larger kiln, a constant fan appears to make a significant difference.

The remaining hurdle for flue-curing is to devise a vent that does not impact the seal and insulation by its design.

Bob

Bob, I hope to build my kiln soon since I think my job will end in a week or two . I have the controller just like you have (thanks for the tip on that) and I also picked up some old computer fans on a sidejob over the winter ,4 to be exact. I would like to install those as circulation fans but I think I would have to scrounge and salvage a power converter from a computer to run them on their what I assume is 12v supply requirement. I wonder if I could just buy or use a cheap cell phone charger and some type connector to gang them up or find a 12v adapter to run them , run the adapter with the controller box .

I just had a theory about your humidity reduction for flue curing using the same kiln...
Theory is if you mount some kind of a metal (aluminum) thin radiator type of deal up near the top and cycle cool water through it , it will then act as a condenser of sorts . Mount this piece as far as you can at the top and angle it so the condensate runs off and add a drip rail (gutter type of system) with a tube to run the condensate away and out of the kiln.
Other theory is to add a bunch of those packing envelopes full of silica gel...might be able to find a bucket full of bulk crystals at a florist supply. As the packets become damp with absorbed humidity, remove and dry /reuse. I think it could end up becoming like a giant humidor and self regulate humidity and absorb or give off humidity without a huge swing in levels.

What do you think of those theories?

 

[DGBAMA]

Not sure if the second theory. But for the computer fans, any 12-15v DC power source will work fine. Each fan will be marked with an amperage rating likely Ma rating (quantity of current they use). As long as your power supply has a rated output of more than the combined amperage of the fans you are using, it is fine to gang them together from one power source.

 

[deluxestogie]

...for flue curing...
...thin radiator type of deal up near the top and cycle cool water through it...

...silica gel... As the packets become damp with absorbed humidity, remove...

I think cooling coils seem way too complicated a solution for a problem that a simple vent will solve.

As for the desiccator packets, once the yellowing phase of flue-curing is complete, the subsequent steps require a steady reduction of humidity. Also, after the yellowing phase, you no longer have the luxury of opening the kiln--until the cure is complete.

Bob

 

[Smokin Harley]

well, it was an idea ..mainly to keep the heat in and let the moisture out.

 

[Baylor]

Great job Deluxestogie! Impressive build. Thanks for the write-up. Very helpful. Ive ordered the same digital controller as you for my chest freezer build. Just waiting for it to come in.

 

[USHOG]

You can use any dc charger as long as it doesn't have to high of a voltage to over heat the motor. If the voltage is 6 the fans will be slower but it will not hurt the computer fans. I use a cell phone charger and it runs 6 fans and leds off of a humidistat to control the humidity in my stem dryer (fermentation chamber converted to do other jobs).

 

[deluxestogie]

This is just a view that shows the extensive interior taping, taken mid-batch (about 2 weeks after start of batch). I've noticed that when the ambient temperature remains above 70ºF during the night, and in the high 80s during the day, the Crockpot does very little work, and needs to have the lid a bit off center, in order to maintain adequate humidity. During cooler nights/ cooler days, the lid remains completely closed to maintain the proper humidity. The enclosed back porch, which is heated during the winter, but not air-conditioned during the summer tends to show these ambient temp effects only during the very hot summer days.

Bob

 

[Knucklehead]

Did you tape over your screws? The zinc plated washers that I used with my coated deck screws are rusting. The screws are fine but the washers are rusting. I should have used stainless washers. I did countersink them slightly so I'm going back over them with some Tyvek tape while they are dry. Hopefully the red rust will quit running down the inside of the kiln.

 

[deluxestogie]

All of my fender washers are on the exterior.

endoSkeletal = exoFenderWasheritos

My piano hinge, which is exposed to whatever gets past the silicone door gasket, is rusting.

endoSkeletal = semi-endoPianoHinge

Bob

 

[deluxestogie]

No hand wringing over long hands

I just started this kiln load today. I had some 32-33" long tied hands of Long Red and Swarr-Hibshman which were way too long for even my lower compartment. So I removed the middle shelf (actually, I positioned it at the bottom of the kiln). Since the bathroom exhaust fan is ordinarily suspended below the middle shelf, I ran wire stringers from the top shelf to support it. A wire basket is hung above the fan, to hold some smaller items.

On the bottom, I did not want the rubber coated shelf to rest directly on the ceramic of the Crockpot, so that shelf rests on a second wire basket. This shelf provided somewhere to place two more large hands of leaf, now that the middle shelf is not at the middle position.

For the previous kiln load, it took me about 1 hour to remove the leaf, and package it properly in poly-nylon bags. (The mid-stalk leaf of 2014 Brasil Dunkel is smelling mighty nice.) Some leaf was bagged as tied hands, other leaf was stacked and flattened. My 2014 Xanthi Djebel smells ready to go, whereas the 2014 "Cyprus Oriental" still smells a bit raw.

Bob

 

[deluxestogie]

The Incredible Shrinking Door Gasket

April 15, 2015

August 7, 2015

August 20, 2015

I have the distinct impression that the silicone door gasket is shrinking. Notice the progressively wider gaps at each of the 4 corners (where the gasket is cut to 45º), and also at the center bottom.

Bob

 

[Knucklehead]

Perhaps the wood is swelling?

EDIT: Na, that wouldn't explain the gap in the middle at the bottom.

 

[deluxestogie]

You may be on to something. In each photo, the kiln is larger!

Bob

 

[DGBAMA]

I use EPDM closed cell gasket material. So far, no shrinkage.

 

[deluxestogie]

I use EPDM closed cell gasket material. So far, no shrinkage.

How well did it hold up to flue-curing temps?

Bob

 

[deluxestogie]

Six Months of Stupid

I've been enjoying my endoskeletal kiln for about half a year now. Today, after emptying a completed batch from it, I decided to wipe down with vinegar some of the wood that is exposed to moisture, but may not reach a high enough temperature to prevent mold growth. These are areas just outside of the door seal.

These two photos reveal what I noticed for the first time.

After a half-year of using this kiln, I just noticed that my door gasket at the top and the bottom of the doorway makes no contact with the top and bottom frame of the door itself. Six months! No seal at either the top or the bottom of the door. The framing of the doorway used a different width of lumber than the framing of the door.

How many times have I preached about a "well sealed kiln"? I spent extra money to buy premium silicone fire-door gasket. Six months!

I still had some of the gasket material. My solution (after recovering from my attack of stupid) was to add a strip of gasket along the top and bottom of the door itself.

So, it's back to the experimentation phase, to determine how long the water will last in the Crockpot.

Doh! If you look back to the photos in post #71, the problem was obvious then. We see what we expect to see.

Bob

 

[romanko]

Yeah, nothing harder to get that perfect seal on a project, that kiln looks really good, nicely insulated!

 

[dchiang]

It is good to know that the design is robust enough that even without complete seal on the door the kiln performed well. I am in the process of building a wooden kiln. I won't spend a lot of time on trying to get a perfect seal on the door. It would be interesting to hear how well your kiln performs after you have fixed the door seal.

 

[deluxestogie]

It is good to know that the design is robust enough that even without complete seal on the door the kiln performed well.

ProfessorPangloss got me thinking again on this kiln design. During the past year, with the kiln in my enclosed back porch, I noticed that when the outdoor temperatures are cold (porch still in the low 60s), the water in the Crockpot evaporates about 1/3 more rapidly. I attribute this to cooler ambient temperatures--i.e. the insulation is still not ideal, or the seal is incomplete. With cooler temps, the Crockpot is required to spend more of its time heating, so more water is driven from the kiln.

With 2" insulation foam on all sides, the kiln's external dimensions already consume 4" of space laterally and in height. Perhaps improving the seal is all that's needed. But perhaps it needs even more insulation.

Regardless, it continues, day and night, kilning batches of leaf. I suppose that the only added cost of its present state is its requirement to add water with greater frequency. Currently, refilling the Crockpot (with very hot tap water) every 2 days keeps the leaf fully in case during the summer, and allows it to mostly dry down between refillings during the winter. So in summer, each run is 4 weeks. In winter, I go with 5 weeks per batch.

Bob

 

[ProfessorPangloss]

Now that everyone has had time to digest this thread, with your thoughtful updates about how the device has aged, would you suggest any modifications? Had you thought you might change anything before flue-curing? It's obvious that you have a top-notch kiln there.