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Heat Source for Drying Chamber

E

Ed Weingarden

Joined
Mar 17, 2006
Messages
297
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141
Location
Canton, Connecticut
I built an insulated drying chamber a number of years ago (about 50 cubic ft) and have been using incandescent bulbs as the heat source. Those bulbs are pretty hard to find these days.. What's another method for heating the box? TIA
 
Heat lamp bulbs, e.g. for chicken coops, reptile habitats, etc. are still readily available. The heat is the point, so these aren't likely to be subsumed by cool lights like LEDs anytime soon. See also "ceramic heat emitter", which fits in a standard bulb socket but emits only heat.
 
My chamber is 25 cu. ft. I have two 75 watt bulbs and I can get to 140 F. They are on separate switches so I can turn one off. I only need 1 to get to 100F. With two bulbs I have gone to 140 F and might have been able to go higher. You can get 150 watt. It would only be a guess, but I think a 150 watt would get you there. Of course your insulation will play a part in your temperature.
 
Wood won't burn until way past these temps. But something is itching the back of my brain about not drying wood at temps higher than xxx°, and 140° is what I'm thinking. Something about the wood fibers and... I dunno. I could be completely wrong on both accounts, but worth considering.
 
Steve Tiedman said:
Wood won't burn until way past these temps. But something is itching the back of my brain about not drying wood at temps higher than xxx°, and 140° is what I'm thinking. Something about the wood fibers and... I dunno. I could be completely wrong on both accounts, but worth considering.
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The 140F was for when I was trying to do Windsor chairs, not for drying wood. You “super dry” the dowel ends before assembly. I was just saying what temperatures I could get to in my system. To kill insects I think you need to get to 133F for at least 30 minutes.. My wood generally does not have insect activity and usually my final temp is 125F. I run 4 cycles one week each starting at 95F, 115f, 120F, and finally 125F. Weight is checked and sometimes I need an additional week at 125F.
 
My box, a converted commercial freezer, is approximately 75cubic feet. Depending on their size, I can dry 35-50 bowls at a time. My drying process starts at 80* and winds up at 110* although that happens over a course of weeks. I have learned that slower is better. I weigh in grams and when they quit losing weight, I know they have equalized.
 
To sterilize wood, you must get the center of the wood block up to 133 degrees for at least one hour. I start drying my wood at 90 degrees and incrementally take it up to 150 degrees at the end of the cycle. I’ve see way too many powder post beetle infestations in my 50+ years of woodworking to not sterilize my own harvested wood. This is the exact reason I went with a hot plate. Sure a 100w bulb will dry wood, but it won’t get the center of the wood hot enough to kill the eggs and active larvae.
 
If your using a space heater in a confined space with lots of combustible material near it you might want to consider one of these automatic fire extinguishers. https://www.amazon.com/dp/B0G4HPH1FJ?ref=ppx_yo2ov_dt_b_fed_asin_title I have one in my laser engraver enclosure and just bought another one to mount into the top of my dust bin. They trigger when the temp gets over 200F and release a gas that depletes the oxygen.
 
William Rogers said:
I use the lizard ceramic “bulb".

This is an example, https://www.amazon.com/LUCKY-HERP-Ceramic-Reptiles-Amphibian/dp/B096TTB7B3/ref=sr_1_6_pp?adgrpid=190247115790&dib=eyJ2IjoiMSJ9.cH4RNfzNVOIYrRsPtE9cTOecrlGGjhv1iAqMbTYXNfG0dY-wLSLIpI25E7qaFJYQBdkpAImRC_YCaoxgxmRqsAT8vpb3tNs2FvwqI_5C0iT9N60AhvTbgZL_j19IP76SPR6I1hef7I_3JCNZqCPwfjiF6kpComggc0p_BVh1Gei0NNgXR7dthVJ8UAPTOOZLkj2g-7Ndry9tviqZ9UVz_WOSkP6xOy1KK9I-zBtpcMFdjrNZ2oxSmz-kja6CM0SlXuLQ7TT6uSTblW8_DzQ3ryaYvUBo_w3IZIgvAnI9-sw.Tnnq1PPxVfaeYUDyRrGvBXYoDgBiKOF4NFTm5h2cEo0&dib_tag=se&hvadid=779596680855&hvdev=c&hvexpln=0&hvlocphy=9016665&hvnetw=g&hvocijid=15930054833818776164--&hvqmt=e&hvrand=15930054833818776164&hvtargid=kwd-325775295114&hydadcr=16856_13576665_1320704&keywords=lizard+heat+lamp&mcid=d75fb5308a2f3880adb7e8d4b2989f51&qid=1766264378&sr=8-6&th=1
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I bought that one, too. I haven't tried it out yet, but it should do the job nicely.
 
Chris Lawrence said:
If your using a space heater in a confined space with lots of combustible material near it you might want to consider one of these automatic fire extinguishers. https://www.amazon.com/dp/B0G4HPH1FJ?ref=ppx_yo2ov_dt_b_fed_asin_title I have one in my laser engraver enclosure and just bought another one to mount into the top of my dust bin. They trigger when the temp gets over 200F and release a gas that depletes the oxygen.
Click to expand...
You really think 150 degrees will start a solid wood fire? I’d like to see the science on that. Wood combusts between 400-600 degrees F. If you expose soft wood to continuous heat, the combustion point lowers to 200 degrees F. That’s 50 degrees over the 150 degrees that I use. Plenty of safety factor.
 
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