Raw Materials Around the House

What you are basically looking for is something with the propeties of glass, so why not try glass? Broken beer, wine, or pop bottles work well, especially the bottoms, which tend to be thick and flat. Working on curved bottle glass is good practice for working on curved flakes. Broken bottles give you an endless supply of material with which to practice pressure flaking. They also come pre-thinned, so that even a beginner can turn out nice flat arrowheads. Thick window glass can also be used. Safety glass doesn't work at all. Broken head lights work well and I've also had theatrical spotlight glass recommended to me. Check pet stores for large chunks of glass, some people like to put them in the bottoms of aquariums. Some are sold by the pound, so you might want to shop around a little (if they want more than $3.00 or $4.00 per pound you might as well just buy obsidian at a rock shop). I recently got lucky at a pet store that was practically giving the glass away because the employees kept cutting themselves on it.

You can also try to find a glass blower or a college, university, or art school where glass blowing is taught. Some of the cullet they use is large eough to knap. (Carl West posted this idea on Knapper)

Some ceramics, such as porcellain, can also be knapped. This can be found in large quantities as near as your closest toilet bowl. Don Crabtree called this john-ite. I like working with porcellain because it is similar to tougher materials, like cherts, jaspers, and so forth. If you only practice on obsidian or other glass you might not aquire the skills necessary to cope with coarser material. John-ite is also the perfect size to practice soft hammering, which is one of the most challenging reduction methods. It doesn't pressure flake very easily, but again that is good practice. Broken bowls, plates, and other dishes can be turned into practice materials. One of my favorite pieces is harpoon endblade I made on a broken coffee mug.