Tandoor, giving strength to ceramic pot

[tttman]

I just covered two ceramic pots (top to top) with chicken wire. To that I slathered on 1" of mixed Portland cement, clay, perlite and sand. I did this to give it strength in case the pots crack. I don't think this is going to work as the "grog" mixture is getting very cracked and crumbly as it dries.

The pots will be insulated with perlite and lava rock.

How can I strengthen the pots?

Is lava and perlite a good insulator?

thanks