Clay/saw dust insulating layer over fire bricks?

[mfugee1234]

Can you use a, clay slip/saw dust mixture, at the insulating layer over the firebricks or do you have to use vermiculite/perlite? Any advice would be helpful, thanks.

[stonecutter]

Re: Clay/saw dust insulating layer over fire bricks?

It would work but it wouldn't be very efficient. Save that technique for a cob dome.

[mfugee1234]

Re: Clay/saw dust insulating layer over fire bricks?

Thanks Stonecutter. Why do you say it wouldn't be very efficient?

[dimitrisbizakis]

Re: Clay/saw dust insulating layer over fire bricks?

Perlite and vermiculite is very cheap, don't risk with having insulating problems...this will make your oven unusable!

[david s]

Re: Clay/saw dust insulating layer over fire bricks?

Kiln builders often use clay and sawdust mix as insulation. It is a matter of cost. If you have access to free clay and free sawdust then free is the cheapest. Light straw clay, which is straw and slip (liquified clay) using just enough slip to bind the straw has been used for centuries as a very good insulator. Again if it is free then it's good. Probably not quite as good as vermiculite or perlite, but then you just make it a little thicker to achieve the same insulating value. The problem with all these mixes is the addition of the water. Suggest you do it in one inch layers with a week to dry in between and do it in dry weather.

[cobblerdave]

Re: Clay/saw dust insulating layer over fire bricks?

Gudday
Talking obout cheap and available .... Those 65 odd firebrick would be worth $4 each, easy a $250 investment. Availability.... not here is Ozzie unless your in a capital city, transport would then add to the cost and frustration.
Regards Dave

[stonecutter]

Re: Clay/saw dust insulating layer over fire bricks?

Thanks Stonecutter. Why do you say it wouldn't be very efficient?

If you compare it against other types of cheap insulation that do a better job..ie: perlite or vermiculite. But if that is what you have go for it...I would be interested to hear how it does.