I have some obsidian and some dacite, and was wondering how you guys work each one.
You work all materials basically the same, except for the amount of force, and maybe billet material on some stone. The principal of conchoidial fracture is pretty much the same on all stone that breaks that way, you just have to hit some rock harder to get the same effect. Obsidian and dacite are both very easy to knap, and don't require much force to detach a flake.
I have a couple antler billets/pressure flakers that I have been experimenting with.
what is best pressure or percussion?
It depends on the situation. Both are used in making a typical point, except that points can be made from small thin flakes or slabs by all pressure flaking. Percussion is used to thin a large piece and get it to the late preform stage. Pressure flaking is used for final smoothing, shaping, and sharpening, and to set up platforms for percussion flaking.
I have a hard time getting the flakes to go even a 1/4 the way across a piece.
Maybe you can give me some pointers.
Platforms, platforms, platforms. Make sure your platform is below center line of the piece, and at the correct angle. Use more inward than downward pressure when pressure flaking. Flakes follow ridges and convex surfaces. Flakes don't run through concave spots, nor do they run far on a flat surface.
