Good stuff, kcardwel. Always good to experience and better understand how things like friction fire work. I've studied it for quite some time and have learned it's about as fickle as trying to understand women, ha ha. Usually lotsa experience helps makes some sense of it all, though.
Practising in the dark (or low light conditions) is good to do. It gives one the experience of learning how much harder it can be to be successful. May not be too bad with a ready made proven set, but could be really challenging if having to forage for materials, make the set and hope the unproven set will work with reasonable time and effort.
Generally speaking, good black find dust is ideally what ya want. Reading the dust can definitely help with trouble-shooting. Light colored dust usually means not enough heat; Too much or too little of one or the other (speed or pressure). Flaky or rolled dust is less ideal, but can still work if other variables can compensate (ie. brute effort).
Other variables to consider:
- Moisture in the wood - Dust will be sticky and clump up in the notch (and overflow around the rim of the fireboard divot)
- Resin - Similar to moisture
- State of Decay of the wood - The dust characteristics can be different if it's more rotted
Ideally ya want the dust to flow like a glacier through the notch. Kinda snake its way out of the notch so air (oxygen) can get to it to combust the hot dust. Note where in the dust pile the ember forms. Sometimes it forms in the notch at the base of the divot, other times it forms at the end of the dust pile. It usually forms where the 3 elements of the fire triangle come together in the dust pile (heat, fuel, oxygen).
The good thing about the bow drill is there's room for error. So, circumstances don't needs to be perfect. Some light colored grainy flaky dust in the pile won't prevent success. Some Moisture won't prevent success. Some resin won't prevent success. Just need enough of the right characteristics that can overcome the circumstances to get combustion.
