Kiln heating source.

[Arturro]

I'm planing to build a small fermentation kiln and can't decide what to use as a heat source. Kiln dimensions: 23\23\46 inches insulated with 1inch styrofoam/aeroboard. I will ferment in sealed container, so no need for any kind of humidifier. I'm considering two heating options. First is a ceramic heating bulb usually used by reptile keepers with a oscillation fan constantly blowing at. Have any of you used that method? Bulbs come in different wattage. Will 100watt be enough to heat up that size of a kiln? What about safety? It runs very hot I presume.
Second option is a 120 watt crockpot running dry all the time with oscillation fan blowing to circulate air. Is it safe to run a crockpot dry? Will 120 watt one heat up that kiln?
Greetings.

 

[Knucklehead]

Most of us have gone with a digital temperature controller from eBay, cost about $12 US. We set the controller to cut power to heat source at 128F and turn on at 123F which keeps the temps from getting dangerously hot and also keeps the temps too hot for mold but not so high that it ruins the tobacco. The crock pot can run dry, especially with the controller cutting power off and on. You could also experiment with a bulb.

 

[ChinaVoodoo]

I use light bulbs. They are cheaper than reptile bulbs or any other "heat lamp".

Whether you use a lightbulb or heat lamp, the radiation should not be directly exposed to the leaf because the surface of the leaf will be absorbing way more energy than the rest of the leaves.

You prevent this by containing the light within something else, like a steel pipe. Combined with a fan blowing air through the pipe, you get a much more even heating inside your kiln. Also, because of the fan, you get good circulation.

The question of should I use heat lamp or lightbulbs, (which I say lightbulbs), comes down to 4 points.

1. Lightbulbs are not directional, but heat lamps are. This means that with the same wattage, you get a more evenly distributed heat with a lightbulb.

2. Despite the fact that one is explicitly manufactured to produce heat, they are basically equal. In an enclosed space (the steel pipe and the kiln itself) since little light escapes, the law of conservation of energy dictates that the visible light spectrum of the bulb doesn't simply cease to exist when it hits the pipe, tobacco, and walls of the kiln. It turns into infrared energy.

3. Cost and redundancy. Incandescent bulbs are cheap, so you can have spares. You can also have multiple bulbs running, so if one blows, the others will still be running. In other words, if you are using a temperature controller like Knucklehead explained, you can maintain the same temperature with say 4 bulbs running 25% of the time, 3 bulbs running 60% of the time, or two bulbs running 100% of the time. (don't quote me on those numbers, this is just an example)

4. Tighter temperature control. Lightbulbs heat up, and with a fan blowing on them, cool down almost instantly.

 

[deluxestogie]

Vegetative mold growth cannot occur above 122°F. That's my bottom. My set point is 128°F, above which, the controller cuts the power off, until it reaches 122°F again.

My kiln uses 2" thick polystyrene foam insulation board, and could probably benefit from more. But the gasket seal surrounding the door closure, as well as the seal of each of the joints (corners) of the kiln are critical. My kiln measures about 24" x 36" x 48", and was easily heated with a small (2 liter) Crockpot, set to its "low" setting, which I estimate to be about 75 Watts. I replaced it with a 6 liter Crockpot for two reasons: 1) longer time between water refills [not important when using sealed containers], and 2) to more easily raise the temp as high as 165°F for the times when I use the kiln for flue-curing.

But the top priority is fire safety.

Bob

 

[ChinaVoodoo]

But the top priority is fire safety.

Bob

I recommend lining the floor and walls around the heat source, whatever you use with cheap ceramic tile, broken plates, brick, cement board, or whatever is cheap or free, and handy.

 

[ChinaVoodoo]

Either of your choices, crockpots or bulbs, have been demonstrated effective and safe by multiple forum members. You're on the right track. Do whatever works for you.

 

[Arturro]

Thank you for answers. If running a crockpot dry is safe I will tend toward that option. Fire hazard is a main issue and a ceramic heat bulb gets extremely hot.
So with a crockpot without water will I keep a lid off or on? Do I keep a pot inside or remove it?

 

[ChinaVoodoo]

Thank you for answers. If running a crockpot dry is safe I will tend toward that option. Fire hazard is a main issue and a ceramic heat bulb gets extremely hot.
So with a crockpot without water will I keep a lid off or on? Do I keep a pot inside or remove it?

Personally, I would leave the ceramic in, lid off, and have a fan blasting into it.

 

[deluxestogie]

My Crockpot (crockery in, lid removed, regardless of the presence or absence of water in it) rests its legs on a couple of narrow planks inside the kiln, so that it does not rest directly on the foam board. Otherwise, I use no fireproofing materials. My fan directs air upward. [Gosh! It seems like I've written all about this in this very forum.] The heat from the Crockpot rises in my universe.

My concern regarding fire safety is with regard to properly wiring everything, and assuring an adequate electrical ground.

Bob