Heat treating chert with fire, (another thought)

[iowabow]

I was just thinking that the fire you build over the pit is not for the purpose of heat treating the chert but rather a process that creates charcoal. It is this charcoal that fuels a long and even burn that lasts for hours and hours  trapped between sand and insulating ash above. This ash blanket holds heat in and allows oxygen to enter slowly so it burns effeciently (because charcoal is more pure than wood) over a long period of time.

[iowabow]

513 degrees and it is 12:28

[iowabow]

Just wondering if anyone has ever done this on PA with a pyrometer.

[iowabow]

Well it is 1am I am going to bed and the pit is at 512 degrees. It blows my mind that this crude process can hold a material within 20 degrees for hours and hours...how smart they were.

[iowabow]

6 am see pic

[iowabow]

As soon as my phone gets a little charge I will make a video of the infrared meter going over the surface. It would be the only way I would believe this post.

[iowabow]

In trying to find answers I found this website http://flintknapper.com/Heat%20Treating.htm
It says that it took three days for their pit to cool. So maybe this is not too far off base

[iowabow]

Well I shot a video but Derick wanted reading with photos so he could follow along.

[twisted hickory]

Simply amazing. Who would have thought the fire would last this long

[iowabow]

Here is the current temp

[iowabow]

Simply amazing. Who would have thought the fire would last this long

I wish I did then I would have gotten a little sleep lol.

[iowabow]

As you saw in the video the flakes are thin so there should be a good cook on this stone if I did not crack it during the ramp up.

[iowabow]

8:24 temp 528 surface temp 168. Looks like the surface temp drops as internal temp continue to go up. Maybe as the charcoal burns it create more insulation.

[iowabow]

Other stuff to think about. My pit was dug from the pit of many fires. This rim mound and wall are composed of crushed burnt clay earth ash and unburnt particle of charcoal. As the fire heated the wall and mound it burnt out any unburnt charcoal pieces and thus created dead air spaces. This may also contribute to the efficiency of this firing.

[iowabow]

I am doing this again sometime this summer for sure with a much larger pit and more stone it is more fun than loading a kiln.