Clay Oven floor

[Lake lover]

Hi all
Ok still trying to get materials. What a pain.

I have been looking at a cob style oven I can get a good quality clay from a local source, sand is plentiful.

Has anyone used a clay oven floor ? Do they hold up ?

Do they need many firings to harden up ( vitrify )

While asking questions can clay be used to make a chimmeny also Or should I use a piece of flue liner ?

Thanks

[James Meloy]

I built a cob oven with bench seats on the side. I used fire bricks on the floor and it works just fine- I used empty bottles and a cob mix under the bricks for under insulation also. I hope this helps you out.
James.

[david s]

You won't get the oven hot enough to begin any vitrification. That starts to happen at about 900C The clay becomes permanent (won't turn back into mud if made wet) starting at 573 C You are unlikely to reach this temp on the floor and if you attempt it you are likely to create cracking as the clay is unstable at around these temps.and it would only be the surface that you would get hot enough. You would be far better off using something that has already been kiln fired. Firebricks are best, or if you want to save money, clay pavers or solid reds. An unfired mud floor will also be prone to lots of wear.

[Lake lover]

Thanks for the info.

I finally found some fire brick at $2.80 each. So I bought 40 for the floor. Hi Temp Mortar and got some flue liner free.

I ordered clay from company out of Medicine Hat, Alberta. They offer many clays so I told them what I was doing and they recommended a blue,green clay. $ 15.00 for 20 KG.

I pour my lower base yesterday. !!!