Mixing fireclay dust with refmix

[jcg31]

Hi folk,
Like anyone constructing the oven I have buckets of fireclay dust. I am also likely to have an extra bag or so of refmix. I am thinking of combining the two to give the oven dome a final covering once done (the fb dust to extend the refmix). Can anyone advise me on this move? What would be the correct portions? Should I add portland cement? etc.

Thanks for any help.

Jim

[christo]

Re: Mixing fireclay dust with refmix

This looks like it deserves an answer or at least comment. I'll offer my opinion (which is not worth much on this topic) and see if anyone will confirm or refute.

I think you'd possibly end up with a mix that would harden more quickly, but would have not much more strength that unfired fire clay by its self.

My vote would be no...

Christo

[RTflorida]

Re: Mixing fireclay dust with refmix

I mixed a small batch of brick dust with Heatstop 50 as an experiment. I mixed about 25% dust with 75% Heatstop (to try and stretch the Heatstop); wasn't happy with the result.
Heatstop sets up pretty quickly on its own, adding the brick dust accelerated the set up. Not sure how it would be with the Refmix.
I ended up adding more water to get a few minutes of working time. Adding extra water is never a good thing with a cement base product.
I wasn't actually using it for anything structural, just an extra 1/2" of mass over the already completed dome. I switched back to straight Heatstop on the next batch.

RT

[wlively]

Re: Mixing fireclay dust with refmix

Second the other posts. Don't see anything to gain by adding brick dust. Heatstop and refmix are supposed to be formulated to have the same thermal characteristics as brick.