What size should I be shooting for when trying to make preforms? How thick, and what circumference etc. I have been using my smaller pieces(pieces knocked off the preforms) to practice my hitting but when I try to move to my larger pieces I simply reduce them to smaller pieces so not making much beyond really sharp gravel. Working on obsidian, texas chert(ebay purchase) and ohio flint ridge material. The second two have been cooked in a new turkey roaster.
Thanks, Paul