Fireclay/sand substitute for oven floor

[chris_jones]

I'm currently in the middle of my pizza oven build and I've run into a supply issue. First off, I live in Canada so materials are not nearly as readily available here as they are in the US. I'm mostly following the Pompeii PDF and I'm at the point where I need to lay my oven floor on top of the 4 inches of vermiculite that I used for insulation (ceramic FB is impossible to get up here).

The manual calls for a 1:1 mixture of fireclay and sand, however, it is almost impossible to get fireclay up here at the moment. Do I have any other options for laying down the fire brick on top of the vermiculite?

[david s]

The fireclay/sand mix is only used as a leveller because the heights of some firebricks can vary a bit. If the bricks are all the same, no leveller is required. Sand on its own would be ok if you can’t get any clay. Just make sure it’s as fine as possible.

[deejayoh]

Many of us have used the cuttings from our firebricks as fireclay. You may need to sift them/crush them a bit so it's fine enough - but seems to work even in the mortar. And trust me, you'll have plenty of cuttings!

[chris_jones]

Thanks for the responses. It doesn't sound like the fire clay is that important, is there a reason why the 1:1 ratio is recommended over using just sand if it's just for levelling? I have some multi-purpose construction sand left over from an interlock project that I'll use.

[UtahBeehiver]

When a slurry is made, the clay makes the mixture stay in place vs sand alone move more easily. It is used for leveling floor bricks only. However, if you are using a home brew mix for the dome then fireclay is a requirement.There was another Canadian poster recently who posted where he got his fire clay, I think it was a place called Shaws but not certain, you will have to search the posts. Also fire clay can be procured from pottery stores and brick suppliers as well. Brick cuttings can be used but there have been several reports of using cuttings making the mortar more difficult to work with.

[chris_jones]

I'll be using a premixed high heat refractory mortar for the dome. I thought about the home brew mix but $55 Cdn per 50lb bag seemed reasonable to me, given the difficulty of finding fire clay. I've looked at a few local pottery stores and they do have low-heat clay, however, I'm afraid it would fire from the heat of the oven.

I can order a 50lb bag of fire clay on amazon from Whitacre Greer, which will be here in 3 weeks, for $75 Cdn. This is a bit high for my liking plus my build has already been delayed several weeks because fire bricks have been difficult to procure where I am, however, I managed to get some a few days ago at a premium from a local masonry store.

[Baza]

Hey Chris!

As a fellow Canadian builder - I feel your pain!
It is unbelievable how difficult materials we read on this forum are to get around here!! I found a great deal of my own build was sourcing the materials that appear readily available in the US!

I, too, went with premixed mortar for my build - but had to drive over an hour away to get it! sigh.
Notwithstanding - I admire your tenacity in working through the supply issues that have only become greater! It will all be worth it when you enjoy the pizza of your labours!

Barry