Author Topic: 80 pounds of dry obsidian (Read 4827 times)

caveman2533 · « **Reply #15 on:** October 24, 2015, 08:20:39 pm »

Nice, It has something to do with internal stress in the rock I think similar to when glass isn't annealed correctly. I think a higher temp could even be used.

Zuma · « **Reply #16 on:** October 24, 2015, 08:51:21 pm »

Agreed
Hope to see you with a few flakes in tow.
Thanks again

Zuma · « **Reply #17 on:** October 28, 2015, 10:21:43 pm »

Well, I got a different hammerstone (sandstone). The first one I used was quartzite.
My first spall removal with it was ok but the spall came off in two parts.
The larger piece is ok but has more curve than I would like.

Things went down hill from there. I tried a hit where the core was
not as long in the direction I was taking the spall.
Even so the spall terminated premature of what I had hoped.
(right side of first flake)
The next try was back to the right of the second spall.
I really beefed up the platform and gave It a hardy blow.
The platform just collapsed.
It's back to the drawing board for now.
Between the first go rod and the second I at least have some pretty
good material for the oven.
Zuma

caveman2533 · « **Reply #18 on:** October 29, 2015, 09:48:20 pm »

To hard of a hammer stone will split spalls

Zuma · « **Reply #19 on:** October 29, 2015, 10:14:19 pm »

Well, Steve,
I would'nt argue with you because both Quartzite (first hammer)
and my next best hammer (Sandstone) are pretty hard.
I think I will find a ladies bowling ball and give it a go.
Better hammer /platform contact I hope.
Zuma

Zuma · « **Reply #20 on:** October 31, 2015, 01:29:09 pm »

Well, Steve
I took the latest spalls and cooked
them longer and hotter. About 10 hrs overall
and a 3 hr soak. Not really much difference
for the extra energy. $:-\$
The upside-- nothing blew

Zuma

Zuma · « **Reply #21 on:** November 01, 2015, 09:49:16 am »

Here is the results of a piece I knapped
of the latest batch cooked.
Not to pretty but it came from a really square
hunk. It was pleasing to knap. Just percussion.
Zuma

Primitive Archer