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Heat treating by radiation

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Santanasaur:
I’m not saying I have any special heat treating solutions, or start a contest, this is just amateur experimentation. So far I’ve played with cheap flexible heating coils, one was for a dryer. I never found a nice support and it felt like an awful fire hazard, but would definitely be a solution if safety was managed. These are cheap, I bought them for $5-10 a piece. Silicone heat pads only get to around 250f which isn’t hot enough, but many of the cloth coated heating tapes/cables get to 1000. I’m waiting in the mail for one that gets to 900 and is a 1/2” by 48” strip, so hopefully that will cover a limb at a time. Supposedly it remains flexible through use. Ive also seen several tapes/strips for heating frozen pipes that claim to get around 400, but need a temperature controller which can be expensive.

DC:

--- Quote from: simk on September 26, 2019, 01:28:02 pm ---DC: I'm no scientist nor have I any special education...On wikipedia I can read the following about quartz infrared heaters: Electrically-heated infrared heaters radiate up to 86% of their input as radiant energy

--- End quote ---
I think I remember reading that conventional heaters are about 75% efficient but that was in the context of heating a house. No idea where the other 25% went ;D

I think the wire coil will do the job and if we come up with something better we can change up. I did two or three bows with mine but for wiggly reflexed staves i went back to the gun. I will try the radiator again but it will be a while. The horn bow is about ready to shape and I seem to be building an "N" gauge model railroad for/with my grandsonm ;D

simk:
DC: I dont think those %-numbers are really important. it's only about bringing the wood to a certain temperature, which can also be done with lower efficiency - i dont care about the electricity-bill in this case  8)
santanasur: i really think you could be on a good run - alone i^m not talented in tinkering electrical devices but will be the first ordering yours  ;D
cheers

scp:
I occasionally used a heat gun in the way Badger does. But it was too noisy and tiresome. I started collecting heating coils and even fans to make a heating panel to be hung over the limb. I thought about using a radiant heater. Too much energy and somewhat dangerous. Finally I decided to buy the silicon heating blanket used to bend wood for string instruments. It does go up to 200C (392F) using just 300W. I think all I need is 170C (338F) that will make the wood plastic. But the belly started to burn at 150C. The belly was almost black and smoking probably after 30 minutes. I did put some wood blocks on top to keep the blanket in contact with the belly. Not a good idea? That was the first try about two weeks ago. I have not stringed the bow yet.

willie:

--- Quote from: Badger on September 25, 2019, 06:17:26 pm --- If someone could build a flexible radiant heater that could be adjusted to any shape I bet we would all get one.

--- End quote ---

the refrigeration industry uses long resistive elements marketed as "evaporator condensate heaters".

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