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jrgpots

making petrified wood

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An article in Feb 2005 at PNNL www.pnl.gov described a way of making petrified wood in a week. Pieces of Poplar and pine were soaked in an hot acid wash for 2 days then allowed to dry. They were then placed in a hot silicate solution for 2 - 4 days, then allowed to dry. The dry pieces were fired to 1450 celcius in an argon furnace. The argon prevented the carbon from burning out and the silica bonded with the carbon, forming a silicon carbide replical of the wooden pieces...petrified wood.

 

This got me thinking... How hard would it be to pump in Argon into a kiln during firing? Argon is a nobel gas so it will not explode. It is heavier than air and will displace oxygen. So one would need to have the firing area well ventilated. A small tube could be inserted into the kiln to instill the gas, kind of like instilling carbon monoxide or propane into an electric kiln during firing.

 

My next thought was that 1450 is a very high temp, above cone 12. What if one were to and fluxes and colorants to the silicate soaking soln. Could you lower the silicate melting point to fuse with the carbon at a lower temp?... This is done all the time with glazes.

 

Fianlly, If Argon prevents carbon from burning out of an piece of wood, then could I use an Argon infused kiln for carbon trapping in glazes?

 

 

Has anyone ever use Argonn in the kiln or read of this process?

 

Does anyone here have experience or thoughts about trying to add Argon to the kiln and its possible benifits?

 

 

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Using argon in furnaces is a dream for people who do heat treatment of steel at home. In this case, however, we're talking about small electric kilns (which is not what you'd use, of course). A few people tried injecting argon into the chamber, but none of them liked it: it took a way too much gas, and the results were not spectacular.

 

In industry they use controlled atmosphere furnaces for heat treatment of metals. Among those are vacuum and inert gas ones.

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Using argon in furnaces is a dream of people who do heat treatment of steel at home. In this case, however, we're talking about small electric kilns (which is not what you'd use, of course). A few people tried injecting argon into the chamber, but none of them liked it: it took a way too much gas, and the results were not spectacular.

 

In industry they use controlled atmosphere furnaces for heat treatment of metals. Among those are vacuum and inert gas ones.

 

 

 

How about injecting Argon through the ramping and then turning it down during transition and hold time? Would that help in carbon trapping or allow reduction as some oxygen returns to the kiln. Some of the carbon would be burned to act with other reducing agents?

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How about injecting Argon through the ramping and then turning it down during transition and hold time? Would that help in carbon trapping or allow reduction as some oxygen returns to the kiln. Some of the carbon would be burned to act with other reducing agents?

 

 

I'd think that loss of carbon, especially on or close to the surface, is a realtively quick process.So as long as you have oxygen around and the tempearture is sufficient, decarburization is almost inevitable. Naturally, if you shorten exposure time to oxygen, you may, potentially, keep more carbon deep inside, but will you achieve your goal then?

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How about injecting Argon through the ramping and then turning it down during transition and hold time? Would that help in carbon trapping or allow reduction as some oxygen returns to the kiln. Some of the carbon would be burned to act with other reducing agents?

 

 

I'd think that loss of carbon, especially on or close to the surface, is a realtively quick process.So as long as you have oxygen around and the tempearture is sufficient, decarburization is almost inevitable. Naturally, if you shorten exposure time to oxygen, you may, potentially, keep more carbon deep inside, but will you achieve your goal then?

 

 

 

How about this... Place a piece inside of a saggar. horse hair or other combustables on the pottery. Low fire it in an Argon environment. Continue the Argon until about 600 degree on the cooling cycle, then stop the Argon. The result, horse hair pottery in an electric kiln?? OK, Ok I realize my dream is fading fast. WHy would anyone go to that much effort when the original method of horse hair pottery works so well?

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I'm sure you can go the route of a closed container with the item buried in a carbon monoxide producing media. That is how mild steel is surface hardened in the furnaces.

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What a fascinating idea....It never occurred to me. However I did try Carbon Dioxide. I got great reduction up to the first inspection vent...then the CO2 leaked out. So I would imagine your Argon would do the same thing. Please keep us updated....Thanks

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How about injecting Argon through the ramping and then turning it down during transition and hold time? Would that help in carbon trapping or allow reduction as some oxygen returns to the kiln. Some of the carbon would be burned to act with other reducing agents?

 

 

I'd think that loss of carbon, especially on or close to the surface, is a realtively quick process.So as long as you have oxygen around and the tempearture is sufficient, decarburization is almost inevitable. Naturally, if you shorten exposure time to oxygen, you may, potentially, keep more carbon deep inside, but will you achieve your goal then?

 

 

 

How about this... Place a piece inside of a saggar. horse hair or other combustables on the pottery. Low fire it in an Argon environment. Continue the Argon until about 600 degree on the cooling cycle, then stop the Argon. The result, horse hair pottery in an electric kiln?? OK, Ok I realize my dream is fading fast. WHy would anyone go to that much effort when the original method of horse hair pottery works so well?

 

 

If you really want to do horse hair in an electric kiln, place pots on top shelf, heat to cone 019 remove with tongs and place on firebrick. Then drape the hair on the pots. The whole process takes about 4 hours including cooling.

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