Making a fire hot enough to melt glass - just had a memory of going round a glass factory. For small work like bending a glass rod they would simply put it into a hot blue flame like a bunsen burner at school.
The difference between the flame that comes from burning wood (yellow) and a hot blue flame (e.g. bunsen burner, blow lamp, kitchen gas ring) is the air / gas mix. Therefore is may be possible to get a hot blue flame from ordinary wood.
First one must be able to control/ focus the gas coming off the burning wood. An example of this is when one makes char cloth. Put your material - be it cloth or wood or whatever in a closed tin with a hole and put it on the fire. Once it is hot you get a jet of gases that ignite and burn quite excitingly in a jet of flame.
So, now all I have to do if figure on the best configuration to get a good gas/ air mix before it comes out of the hole. It should probably not be under pressure, so a larger outlet hole would be good. Then I probably need a hole in the bottom or sides to draw in air. But then air around a fire is probably a bit starved of oxygen so better to get air input from an axtra source such as bellows. Also air coming into the tin would simply allow the wood in it to burn normally. So, I need the gas to leave the wood before adding the air. I see a tin with a bunsen burner sitting on top in my mind's eye.
I'll work on this. Has anyone else any thoughts or experience on burning hotly the gases coming off burning wood?