Forum / Using castable refractory cement between bricks?

Greg Karas

Hi, newbee "mason" here. I have castable high temp mortar that I tried to use to butter between the bricks on the arch entrance and the mortar slipped off. Then when filling the wedge spaces between bricks, gravity wreaked havic. Seemed like the mix was to dry on flat surface and to wet when applied vertically. I felt like Lucy trying to rebuild Ricky's BBQ! Thanks in advace for any advise. PS- I did wet the surfaces but ever so slight.

Eli · 1 month ago

Hi Greg. What mix are you using for the mortar, and are you using a temporary support for the arch? Even something simple like this might be good to hold the bricks in place rather than try and get the mortar perfect.

Greg Karas · 1 month ago


Thanks for the pic and getting back to me. (A picture speaks a thousand words)

Well... I'm planning to use perlite and ? (still deciding on mortar). I found a source nearby that sells "HeatStop" for $70 which I haven't yet researched the product.

Ideally what I'm trying to achieve with minimal investment (cough) is using a cement/mortar type of drymix to that which I'll mix in perlite, then add water and apply to the oven.

Also, for the bricked arch opening I was thinking using the same cement or mortar mix between the bricks but this time without perlite.

I already bought a 25 lb tub of Rutland castable refractory cement which as I mentioned in  my initial comment gave me a heck of a time.

I also have a tub of Hercules furnace cement which I read that I can use that for in between the bricks on the arch and to make it stable I'm to add sand in various ratios depending on the thickness.



Bender942003 · 1 month ago

If u cut bricks at compound angles you will use minimum expensive cement. Get a tighter dome. I was lucky to borrow a wet saw. Every brick has 3 cuts for a puzzle fit