Primitive Archer

Main Discussion Area => Flintknapping => Topic started by: Lee Slikkers on December 03, 2011, 10:08:01 pm

Title: Cold Temps and rock
Post by: Lee Slikkers on December 03, 2011, 10:08:01 pm

I was wondering if it mattered if I kept my rock out in the cold and worked it whenever I had some free time...It seems like my obsidian is fracturing rather easily and is breaking (more than normal and not where I want it too...)

Anyway, just something that was kicking around in my head and I was curious...Thanks!!!

Title: Re: Cold Temps and rock
Post by: Bill Skinner on December 07, 2011, 12:36:13 am

Rock gets brittle when it gets cold, you don't need near as much force in your swing.  If your rock goes below freezing and it has moisture on or in it, the freezing will cause micro fracturing which becomes macro fracturing when you hit it.  That is why the ancients mined or picked up from non freezing creek bottoms and they usually spalled and bifaced on the spot, they didn't want to carry something back that would not be suitable for tools.