Lining the furnace

Recently, I lined the furnace with our refractory.

I bought a bag of Playground sand from home depot, and mixed it half and half with clay.
I got the clay from under my friends deck and it was in a powder form. I mixed the dry clay and sand together and then wetted it to the right consistancy. I have heard of using cement also for bonding but I never did.

I let the refractory sit for about 5 days and it was only about an average of 5 degrees C out.
To bake the refractory I lit a fire inside it after taking out the form. I let it baked for about an hour.
Here is a shot of the inside of the furnace being baked,

Before lining: