Abo heat treating

[Bear Claw]

Here are a couple of examples of some rock, burlington I think, that I heat treated abo style. I was experimenting with temp and how deep to bury them. All went well so I will be doing a big batch of it tomorrow. In the first pic there is a piece of the same type of rock, raw, under the heat treated rock for color comparison. The second pic really shows the color and how glassy the rock got after heat. Can't wait to get a big batch done.
http://i.imgur.com/agaMQ.jpg
http://i.imgur.com/ekrjo.jpg

[budmenchaca]

Bear Claw...do share the details of your abo fire pit setup. I have a good bit of that raw Burlington and I'm not sure how to heat treat it without a kiln or turkey roaster. My stuff is really light colored and a bit chalky but really pretty and crazy smooth. I've made a couple of points from it raw but I know that i'm not doing the rock justice without at least attempting a heat treatment.

[cowboy]

It does slick em up. I've got a batch simmering down out there right now. Some coral, coastal plains, pedernales, etc.. Kinda exciting . budman, you don't need anything fancy. Just dirt, your rocks and a bunch of wood. Bury your rocks in sandy type soil, and i like to walk it down for better heat transfer about two and a half inches. Get a fire going and keep it going half a day or so. The goal is to burn wood quickly to build up a good bed of coals. Let that soak overnight and the next day. Voila!

[budmenchaca]

Thanks for the insight Cowboy. If I get good results I'll def post some pics on here.

[Bear Claw]

Yep what cowboy said is just about exactly how I do it. I usually will experiment with temp/ depth with a few small pieces of different types of rock untill I find the recipe for the type I get from a given area. The Burlington that I am getting grow this spit is a very high grade. Works very well with no heat, but after heat it is awesome, and the color! I love the color change. Burlington, depending on the grade of it tends to only need about 500 to 650 degrees. I have been out tending my fire pit today and doing some knapping or I would have been on here sooner. I will post pics tomorrow when I dig up the rock. The hardest part is waiting for it to all cool down enough to dig it up without thermal shocking it. Lol.
I'll let y'all know how it turns out and show pics.

[cowboy]

I hear ya bearclaw on the waiting . I actually stirred my coals around most of the day yesterday to make em burn up faster and was able to uncover them late in the day - still too hot to touch. Dug em all out this am and beautiful results! Only one of them blew, sand may have been a tad shallower in that spot..

[StevenT]

Hey, while your taken pics, take on of your pit before you dig it up. Cool info.

[Bear Claw]

I didn't take a pic of the fire pit (sorry Steven) but I will be cooking more this weekend. Here is a piece of the Burlington grow this batch. Abo heat treat and abo tools to knap it with.

http://i.imgur.com/rPk76.jpg

I thought it turned out pretty good.

[Bevan R.]

 :oI would say a lot better than 'pretty good'. Nice looking point!

[Bear Claw]

From this batch. Lol. I need to start reading my posts before posting them. I can't make any sense of what I said in my earlier post. :-)

[Bear Claw]

Thank you Bevan R. The notches were a little uneven, I have been using a copper tipped flaker and haven't used antler as much lately. I like to do a few points every now and then all abo just to remind me how good us modern primitives have it. Lol.

[Bear Claw]

Cowboy, when you heat treat your rock do you usually preform, spall, or just put chunks in the pit?

[iowabow]

I think you will get a more even cook if you reduce them.  However Burlington can be cooked in a kiln without reducing it.  Leapingbare gave a recipe for cooking 30 lbs rock and it worked well and cooked all the way through.  I would guess that a larger piece would need to be cooked slower so the sand should be thicker.  The cook time should be longer so that the heat can do it's work.  I have some sand and a pyrometer I should do a post on rate and temp during heat treating as this subject seems to come up a lot. 

[cowboy]

That would be good John. Bearclaw: i always spall and bi-face before cooking unless their already naturally thin. Somewhere around an inch thick or in my experience they will blow. Of course you could experiment with diff thicknesses and deeper in the sand etc - there's so many variables. I like to go with what i know and i did do a lot of experimenting and had lots of failures in the past. I have no idea how hot the rocks actually get in the pit but Tower mentioned he put a temp probe down where the rocks were and registered somewhere around 700 degrees. That was news to me . Oh, nice looking point by the way..
 Steven T: I took a series of pics several years ago in a thread titled "cooking rocks the old fashion way" if i remember correctly. Think i'll do a story on this..

[Bear Claw]

Iowabow thank you for the info. A post on rate and temp would be great. Cowboy, thank you, I do the same as you on the rock as far as reducing it before heat, was just wondering how other guys do theirs and what results they get. The one thing that I have learned about primitive skills is that I have a lot to learn. Lol. I always enjoy exchanging ideas and information. I can't believe it took me as long as it did to find this forum. To think of all the gravel I could have avoided making by trying to learn this stuff on my own. Lol