mortar for 1 inch gaps and larger up to 4.5cm

Posted by Glen (64.54.101.12)

Hi Rado!

Thanks for your beautiful pages. I already mailed you few months before, thank you for the help you sent back to me.

Last autumn I started to build 80cm igloo shaped firebrick bread oven. I am at the very beginning (I finished foundation, walls with granite cornerstones and insulation under the hearth the way as you suggested). I bought Kiko Denzer's book first, and then Alan Scot's "Bread builder". I am still not clear, one problem is that each mortar which both books describe, must be used in gaps no greater than 1/4", and in igloo style dome it is impossible. I placed bricks on the floor around the marked line to see how much mortar will go in but the gaps are far too big. So, can you please answer me: If Kiko use only sand and clay (3:1) for whole dome, can I use it as mortar for fire bricks?
If not, can you give me any suggestion about materials (not to expensive if possible) for mortar in which gaps should be at the outer end about one inch, or more?

Thank you for your answer, and best regards, Glen.
PS I am sending for your building cdrom

Mortar for 1 inch gaps and larger up to 4.5cm