Heat treating chert with fire, (another thought)

[iowabow]

Wednesday at around 6pm was the last time fuel was added to the fire. I believe that the coals were burning still when I went to bed on friday night. These numbers indicate the temp below 2"of sand therefore  the temp above must be like between 800-600. This would suggest that the fire was continuing to burn. I am going out to check it now will post temp in a few minutes.

[iowabow]

To my disbelief but I do feel heat from the top. I told Josh Barnes last night that this post is making me look really bad because the data sounds unbelievable. I personnally dont know how this is even possible.

[iowabow]

I will redo this in the coming week (myth bust my on data) to see if it really can be repeated.

[iowabow]

Maybe I will order another pyrometer and run them at the same time. One can be places with the flint and the other at the surface just above the sand to help answer JWs question.

[iowabow]

Food for thought... If I did not have a pyrometer on the project then the following might have happened...I would have walked out and place my hand above the fire, having felt a surface temp of 140-120 decided that the flint must be cooler. With this thought yesterday I would have scooped away the ash to discover that the fire was still going and the sand still hot. I would have destroyed the delicate insulating barrier of the ash and cause the flint to prematurely cool.  the chert may have been distroied. Perhaps falure by many who have tried this in the past may be linked to this "false" but logical conclusion.

[iowabow]

Many reading this post might say well I have built campfires and it doesn't burn past noon the next day (including me) or they might say I have burned large brush fires that only burn a day or so but my fire is designed very differently and entire structure of the pit would be different than those examples.
My modern kiln is constructed with a very light wt fire brick. This brick has many air pockets and is highly efficient. My fire in the backyard is a primitive rendition of the modern day kiln in its construction. Perhaps the ability of my design prevents rapid cooling and bakes/cooks the charcoal and allow a complete combustion of material in the fire place. We have all seen the charcoal that remains in the pit of the fire yes? Perhaps this is the fuel that is burning very Slowly and in an enviroment that is efficient in two ways. First it allows limit oxygen to reach the fuel second it retain to a high degree energy produced by the combustion to keep the fuel hot while the fire continues to burn lower and low toward the sand.
The ability of the fire to retain heat and thus continue to consume fuel must be aided by a highly efficient design.
So as I suggested in an earlier post the pit was constrcted on the site of an earlier pit. In fact I have been building fires on this spot for years in effect seasoning the material that will make up the floor and wall of the pit. The next couple of post will cover the initial composition and their transformative quality of this material as it is fired.
..I should have written all of this in an article and gotten paid for it lol.

[iowabow]

I will take this line of thinking one step further and suggest that fires in their homes would have used this technology to reduce the use of fuel. Here is a fire that will produce heat for days and is not smoky. I would use this in my hut or structure rather than a raging smoky fire. I wonder how warm a  small structure could be kept using this kind of technology.

[iowabow]

Ok so here is how a house/hide sturcture could be kept warm and smoke free. Fire is created outside the tent and charcoal transfered to inside of the tent. Once the coals ignite the charcoal would burn with much less smoke than wood as ash formed over the charcoal a long slow burn would continue for days as my fire has if the structure of the pit was simular.

[Poggins]

It has been suggested that a common fire pit may have been how heat treating rock was discovered , I've seen brush piles burn under dirt for days when the brush had been dozed up and let set long enough for the wood to die off and dry out.
When I was young we would build a fire and let it burn down during the day and them dig a shallow pit beside the fire and pull the hot sand into the pit and cover with a thin layer of dry cooler sand and sleep on that spot on cold nights with just a light sleeping bag and stay warm all night even with a heavy frost on everything .

[iowabow]

Pictured below clay with small charcoal pieces and burnt clay without charcoal. The first picture has the samples oriented in a manor that reflects there location in the pit  This was what the pit was constructed and shaped with. The other sample show the material transformed into a light wt and fluffy material with a high insulative quality.

[iowabow]

In the third picture one can see pieces of charcoal in the sample. I pulled one piece to the right side and middle of photo.

[iowabow]

Is anyone finding this post interesting? I think it is mind blowing data. I cant wait to do it again!

[iowabow]

8:52 temp 518 so now we are dropping and at a nice rate. By tonight we should be looking at some cooked flint.

[RickB]

I uncover heat treated chert 48 hours after the last fuel (charcoal) has been added to the fire. Don't know the temps then - it will still be pretty warm but won't burn the hands. Rick B

[iowabow]

9:55am temp 509 so it appears that we are dropping 5 degrees per hour for now.

@ Rick B did you dig a pit? If so it would be interesting to know if it was located in the same spot as a previous campfire or better yet pit because that would cause the particles to be mixed.