hi i went on a flint knapping course with natural pathways a couple of years ago- it was wicked.
a bit of advice- if you're having problems producing flakes suitable for arrowheads during the course, go and scavenge some of will lords debitage and make sure you keep and any possible arrowhead flakes you produce during the handaxe session.
ive had a go at doing glass knapping recently aswell(was finding it hard to get good flint as i can't drive yet to get to the quarry)- is really delicate as you'd imagine but is far more responsive than a flint- a good way to practice your pressure flaking because if you do it wrong you just break the arrowhead rather than just mullering the edge as you can with flint.
use thickish beer or wine bottles and a fine pressure flaking tool like a steel nail or one of those mini screwdrive awl thinks you get in christmas crackers. note though that the shards produced are really fine- you need to be carefull about shaking them off your clothes and getting them stuck in your hands. dont aim to make really big arrow heads outt of glass- make them tiny 1.5-2cm long at the most
the advantage of bottle glass is that its already in thin, even sections so you can concentrate on the delicate work- the disadvantage is that being bottle glass it is usually curved which is why it is easier to make smaller arrowheads
if anyone has any tps about how to get really long flakes off with pressure flaking, i'd be interested to hear them
cicely the potter