Last year at BOSS, the field director gave us an ice cream challenge - for every 5 'new-to-us' woods we managed to bust a coal with, he would award us a pint of organic ice cream (in Southern Utah, this was quite appealing :) Suddenly we were all trying woods we had never thought to use before, with mixed success.

I read one article (will try to properly reference it later) in which the author had conducted scientific experiments on friction fires. He concluded that the challenge was to heat the wood to 800 degrees before it started fragmenting. Many woods in his experiments started coming apart at around 700 degrees, which is why (he argues) many woods give lots of smoke but no ember.

So - my question to all of you is what woods have you tried and with what success? Hopefully we will get responses from all over, and learn some new ones to try.

Equally important - what was the secret to busting a coal with each of these woods? Some (like aspen) require more speed and less pressure, while others respond well to a lot of down pressure. I theorize that the woods that want to fragment before 800 degrees can sometimes be finessed with high speed/light pressure, combined of course with endurance and patience :)