Laying Insulation & Hearth - Pompeii

[Oven_Man]

Hi Guys

I'm ready to lay the base of my oven (Insulation and Hearth)

I've been reading some threads and found this in the pompeii guide as well. I've already purchased High Heat Mortar to use beneath the Ceramic Board and the Hearth but some threads I've read say to use only fireclay and some say not to use anything. My concern is the oven is a mobile oven and I would think this may be detrimental to the oven if i have loose parts.

Basically, I am going to do the following, please tell me if I'm heading in the right direction.

1) Layer of Mortar on a steel sheet upon which the Ceramic Board will sit.
2) Layer of Mortar on the Ceramic Board upon which the Hearth will sit. No Mortar between each brick as advised in the guide.
3) Surrounding the Board and Hearth will be Vermiculite just to hold everything together.

Hope thats the right track I'm heading.
Thanks
Regards
OM

[david s]

Originally Posted by Oven_Man

Hi Guys

I'm ready to lay the base of my oven (Insulation and Hearth)

I've been reading some threads and found this in the pompeii guide as well. I've already purchased High Heat Mortar to use beneath the Ceramic Board and the Hearth but some threads I've read say to use only fireclay and some say not to use anything. My concern is the oven is a mobile oven and I would think this may be detrimental to the oven if i have loose parts.

Basically, I am going to do the following, please tell me if I'm heading in the right direction.

1) Layer of Mortar on a steel sheet upon which the Ceramic Board will sit.
2) Layer of Mortar on the Ceramic Board upon which the Hearth will sit. No Mortar between each brick as advised in the guide.
3) Surrounding the Board and Hearth will be Vermiculite just to hold everything together.

Hope thats the right track I'm heading.
Thanks
Regards
OM

1. I think high heat mortar underneath the insulation board is overkill. That area should only get mildly warm never hot.
2. Sound idea for a mobile.
3. I think this layer should be vermiculite, cement, water (5:1:3.5). This would hold things together better than vermiculite alone.If you want to make that mixture stronger you can add sand which will increase its strength, but reduce its insulating capacity. Because it's not in a place where you need insulation anyway, then you can use it to make a strong, but lightweight concrete. eg. Add equal parts sand and cement ie. verm, sand, cement,water (5:1:1:3.5)

Dave

[Oven_Man]

Hi David

Thanks so much for your reply.

What can you suggest beneath the ceramic board between the Ceramic board and the metal sheet?

If I were to go ahead and Mortar this area, can I anticipate any problems?

I'm just being over cautious and trying to make sure everything is secured well to the base to accommodate the mobility.

Thanks again
Regards
OM

[david s]

if it were mine I wouldn't use any mortar there. I'd just place the board on the steel and let the weight of the whole thing hold it there. Mortar is not going to adhere particularly well to the steel anyway. Perhaps a contact adhesive would be preferable.