fire clay walls

[cobpaul]

Is it ok to use just fire clay for the dome of an oven. I bought premixed bags from my builder providers and im ready to fill the form.

[brickie in oz]

Probably too late but fire clay on its own wont do the job.

[cobpaul]

yes too late....... it hasnt set yet though, so what do i add?

[david s]

50% sand and straw for reinforcing

[cobpaul]

the guy in the builder providers said it was premixed and all i had to do was add water. its taking its time setting. but it has definitly got sand in it and it looks the part. ill let it dry, if its no good, ill strike the form and use the fire clay/ clay cement for insulating the floor under the fire bricks.

[brickie in oz]

Originally Posted by cobpaul

the fire clay/ clay cement for insulating the floor under the fire bricks.

Clay and cement isnt an insulator, it will add more thermal mass.

[cobpaul]

ok so for the insulation under the bricks i should use FB, but what is fiberboard? is it like kingspan? or rockwool?

[brickie in oz]

I think its calcium silicate board, you could also use the peasants version which is vermicrete, vermiculite and cement.

[brickie in oz]

Originally Posted by cobpaul

ill let it dry,

You sound like you needed refractory concrete if you are forming a dome that way, refractory concrete sets much like ordinary concrete does, not dries.