Savannah River Chert Heat Treating Questions

[bigbird583]

     Hello All.  Hope everybody had a good Easter.  I went to my sisters house down in GA and stopped along the way and scored me some Savannah River Chert.  I filled an old milk crate full and 3/4 of a Girl Scout Cookie box so I'm pretty stoked.  My questions are about how do I go about heating this stuff.  I have searched the site for info but couldn't find anything about this kind of chert.  I have a turkey oven that I will be using and just wanted to get your opinions on temp and time for Savannah River Chert.  This will be my first time trying this so I figured I'd ask the pros on here. 
     I also found a nice big slab of petrified wood somebody turned into a clock that I'm going to recycle into some points.  It is a nice kinda transparent smokey look to it.  Is this stuff knappable?  Can I heat it right along with my chert or does it need to be heated by itself?
     
     Bird

[Hunts with stone]

Did not find a temp in my tables. But remove cortex and soaking in water after heat treatment will impove it's knapping. Check back on the PSK web site they may have more info. Someone else may key in.

[bigbird583]

     Thanks Hunts with Stone.  But what is the cortex?  Is that the crusty stuff on the outside of some of these rocks?  And how do I remove it?  Also I'm not familiar with those initials for a web site.  Would you mind spelling it out for me so I can find it?

Bird

[JackCrafty]

Break up one of the rocks into chips.  Throw them into the turkey roaster.  You don't need to fill up the entire thing.  You can bury the chips in a bed of sand or cat litter, in the roaster pan, if you're persnickety about heat transfer issues but it's not critical.

Cook the rock at 200 degrees for 24 hours to burn off the water.  Then crank up the heat to 400 degrees for 4 hours.  Then turn off the roaster and let the rock cool for 12 hours.  DO NOT OPEN THE LID FOR ANY REASON DURING THIS PROCESS.

Remove the stone and go to town.  You'll know if the heat treating worked or not in about 5 minutes of looking at the rock and flaking it.  If you can't tell, then you need more practice knapping glass.  Experience with glass knapping will give you a good background for knapping heat treated stone.  If the treated stone knapps similar to glass, then the heat treating was a success.

Experiment and don't be afraid to waste a bunch of rock.  You can't learn flintknapping without a lot of trial and error.  Especially error.
 


Try a search for heat treated on this forum as well.  This type of heat treating question comes up periodically.

[bigbird583]

Thanks Jackcrafty, I've had it soaking at 200 for almost 24 hrs. now and am getting ready to crank it up.  I made some boppers the other day and when it quits raining I'll get out and make me a couple pressure flakers.  I'm gonna practice on some glass for awhile but just wanted to try this and see what happened.  This rock seems like you could work it without heat treating but tomorrow I'll know the difference.  Thanks again.

Bird