copper bopper problems

[carpenter374]

hey all. i think i've pretty well got the pressure flaking down but the copper percussion flaking has got me pulling my freakin hair out. i can use the tool to take good flakes but i incessantly break spalls when im trying to thin them. i use a small bopper and still break tough chert with them. it tends to break right at the time when its still too thick to pressure flake but its getting close. what are some of the finer points of the technique?       thanks               -carpenter

[Hillbilly]

Sounds like mainly either a support problem, or hitting too high. Always make sure a platform is below the centerline, and support the piece evenly, but not tightly. If you pinch the point too hard, it will invariably break when you hit it. Endshock is another major cause of breakage. Try to thin the ends before the center, the ends are the most dangerous place to hit a point. Have you tried using antler instead of copper for percussion?

[carpenter374]

id like to try antler. i have a few deer antlers but they're kinda small. bout an inch in diameter. will those work?

[D. Tiller]

Antler will still cause the same problems untill you learn how to support the preform and create your platforms before striking. Also the ammount of abraiding you use is really important. A little abraiding can go a long way. If you use to much the flake will have trouble detaching and too much energy will be imparted into the pre-form causing it to snap. Also, dont put to much presure on the center of the platform from above as you stike it. This will cause presure to build up a that point and snap! Also put a finger or some part of your hand against the opposit edge, make sure you have some type of protection on your finger, this will take out some of the excess vibration from the strike.

Hope this helps!

David T

[carpenter374]

thanks ill work on that.

[carpenter374]

i was watchin videos on you tube and  i noticed the way they seem to have a different purpose for supporting the platform right under the striking edge on the thigh, or supporting with the fingers under the striking edge while holding the peice in the hand. what is the purpose of this? 

[D. Tiller]

Usually its the size of the piece being worked. Large pieces need the extra support to dampen vibrations. Smaller ones can be supported in the hand. Its basically the same principle.

[Hillbilly]

Yep, I usually do primary thinning on my leg and secondary thinning in my hand. It's important when doing freehand percussion to not grip the piece too tightly or "pinch" it in one spot.

[cowboy]

Support, below center, abraid, and accuracy. Theirs all kinds of ways to support a peice. I do it like most I guess. Once your bi-face is worked down kinda thin and your using smaller boppers, I start using the pinch and pull method. You can get up to 30 percent longer flakes by applying just enough pressure and pulling.

[Outbackbob48]

I,ve only been Knapping for 2yrs. so I have limted experience but I would say that most of my broken points came from accidental high hits. It sure is easy to miss just by a little an opps its broke in two. Later Bob

[D. Tiller]

Just did that tonight on a nice peice of purple glass I was working on!