Fire brick mortar

[Carleton]

Hi, I am looking for some help with the thicness to apply the mortar between firebricks, the guidelines indicate 1/8" maximum, but It will need to be thicker towards the outside of the dome where the bricks splay out.
Is it okay to use a thicker joint here.
I would welcome any help
Carleton

[dmun]

Re: Fire brick mortar

Yes you can use a wider joint at the outside, you will need to unless you go crazy with cutting and fitting. What mortar are you using?

[Carleton]

Re: Fire brick mortar

Hi Thanks for the reply, I am using Vitcas heatproof mortar,
Carleton

[DrakeRemoray]

Re: Fire brick mortar

From the Victas site:
Victas heat proof mortar is suitable for all kinds of INTERIOR use, but must not to be used outdoors.

This looks like a premixed air-set product. Some people have used this successfully, but it will remain water soluble. Better to get a dry refractory product if possible...

[Carleton]

Re: Fire brick mortar

I will look for a dry refractory product as suggested, not easy to find in the Uk so far, Vitcas assured me it would be okay as long as it was weatherproofed.
This is a great site, really helpfull.
Carleton

[james]

Re: Fire brick mortar

I'm with Drake on this.

It's very difficult keeping an outdoor oven dry -- no matter how hard you try to weatherproof it. The issue is that the binder that holds the mortar together comes apart when it gets wet. Not good.

James

[MK1]

Re: Fire brick mortar

Doesn't burning the wood and baking produce water vapor. Is it enough to damage the air dry mortar or are things too hot in there?

Mark

[james]

Re: Fire brick mortar

It's the rain, fog and mist. The mortar can't ever be exposed to water.
James