A young entrepreneur friend of mine makes spear guns, spears, etc. He has been getting his spears heat treated at a commercial treater, but the costs are eating him up.
Here is the requirements... a stack of 6 foot long spear blanks has to be kept at 925F for 2 hours. They are about .30 in diameter.
Pretty simple.
Now the problem...making an oven 6+ feet long that will reach that temp fairly uniformly over the entire length.
Propane is probably the cheapest way, or even city gas.
We were thinking of a 7' length of 6" Sched 40, slid into a 7' lenght of 12" Sched 40, using either ribs welded to the outside of the 6" pipe to keep it centered, or something similar.
Now the big issue...how to make a burner(s) that will uniformly heat the inner pipe.
I recall seeing a set up many years ago, that somehow managed to get a spiral of flame down the inside of the outer pipe that actually wrapped around the inner pipe. It was fascinating to see. But we would be happy to get any sort of unifiorm flame...
Anyone with any hints, links ideas on how to accomplish this task?
I do have a 350' roll of .065 x .125 nickle flat resistance ribbon..but think it would be a bitch to make this thing run on electricity, and expensive to operate.
Help!
Gunner, actually starting a thread on-topic
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