obsidian breakage?

[wildman]

Does anybody know the best way to cleave obsidian off where its workable?

[sailordad]

i dont understand what you mean by "cleave obsidion off to where its workable"
are you trying to spall from a larger nodule of obsidion?

[wildman]

Yes sir, not up on the terminolgy only knapped about a dozen heads or so wasting alot of rock thanks for any input

[rileyconcrete]

Cut it.  thats what I do. It seems to work pretty good.  Plus you dont waste hardly any obsidian.

Tell

[sailordad]

all the obsidion i work is cut into slabs
like riley said,youl waste a heckof a lot less of it
i am not very good at spalling rock,especially obsidion
i just sent out a nodule of peacock obsidion to be slabbed

im sure one of the more experienced folks would be able to help you out

[jamie]

if you can post pics we can walk you through spalling it.

[Outbackbob48]

Spalling is alot like percussion flaking only on a larger scale you need angles an platforms to be set up or find natural ones. If you ever get a chance to see Craig Rizatt at a knapin you can learn all about spalling obsidian, this man has spalled a mountain of obsidian, hope this helps. Later Bob

[wildman]

Thanks guys ,you read my mind about cutting it do you think a tile saw would work didn't know if it is as hard as glass when it comes to cutting. Im sure Ill bother you some more

[sailordad]

it all depends on the size of bosid nodule, and the size of the tile saw
i have a little 7" tile saw,i use it for cutting slabs down to smaller pieces
this way i waste even less material

if the nodule is sitting next to the blade and the balde is still a little taller than the tallest part of the nodule it should work for slabbing it
however dont push to hard  to fast,let the saw do the work,use a diamond blade and always use the fence dont free hand it
if you push to hard or sideways a little its is possible to warp the blade

good luck

[caveman2533]

Sailordad,
Its in the saw right now as I write this. Just about done too. Maybe one more pass then clean off the oil and I'll send it back.
Steve

[sailordad]

cool beans 

[david w.]

you wont waste it cutting it but busting up rock is half the fun.  Pressure flaking slabs doesnt have as much action

[sailordad]

you wont waste it cutting it but busting up rock is half the fun.  Pressure flaking slabs doesnt have as much action

i do it both ways.i find differant materials are worth slabbing
as far as flaking slabs goes.its got action plus it has things you learn from it that you wont from spalls and veisa versa
slabs can snap a whole lot easier than spalls when pressure flaking.you also learn to "turn the edge" when working slabs
but to each his own.i think every style of knapping has its merits.i still want to learn abo, and  FOG. jmho

[wildman]

Got a diamond tile blade today worked like a dream,cut alot of slabs going to get some flint next weekend its alot easier to come up with than the obsidian figure Ill learn to do it the right way on the flint I will post some pics when I can figure out how to get pics down small enuff to post thanks again for all the help 

[caveman2533]

The flint will not cut as easy and if you push it to hard it will trash your blade. Use lots of coolant and take your tiime. I got to get one of them small saws for trimming.
Steve