[ApprenticeMan]

Originally Posted by RainsFire

seems kinda deep with alot of wasted space, unless the blade is proportionate to a smaller blade.. but I'm assuming it is a full length-28in +/- so ya.. Don-fogg has a controlled propane heat treating furnace, but I cant remember what it looked like.
wouldn't the blueprint for the tube furnace or whatever it was where the burner blasted down the length of the forge instead of through the side work relatively well also?

Originally Posted by m_brothers

Why not make the furnace smaller so that it needs less heat and you waste less propane/natural gas/energy. Anyhow, it's a nice design. What would you use for a shell to put the kaowool in?

It is easier to heat a large space evenly than to heat a small space evenly. It is not a forge, so it doesn't need to heat the steel to a proper forging temperature, only at most 1600F-1650F. That tunnel forge design is WAY too hot, again we are not talking about forging temperatures, and the heat would NOT be evenly dispersed in any way. great for forging when temperatures don't need to be so closely controlled, but ruddy for HT. MB, an old compressor tank or a 45 gallon drum.

Originally Posted by RainsFire

I have a feeling he would just lay the kaowool in place to be held down by the refractory(which you might want to do without if possible). Refractories are usually more just as a protection from flux, and I have found kaolwool to distribute and achieve heat faster than firebrick and satanite refractory.
you might also want multiple burners too..I dont know how you would engineer that, but ya.. more heat disperesed.

refractories are much more than protection against flux, heck flux eats thorugh quite a few. It is all about keeping the heat in. Multiple burners would make for more heat, and make it harder to tune both for an even heat along the whole length and not end up with hot spots. The idea is to heat the AIR inside evenly, which will give you your even heat. The flames should not even be heating the blade directly.