Then using a string and marking pen build a compass half the diameter of your oven 18 or 21 and mark the circumference of your oven floor.
Tiling a pizza oven dome.
Construction of an igloo dome does not necessarily require a frame if completed by a competent brick layer.
I love in the north east of england in the uk we have an outdoor pizza oven which i am looking to mosaic tile.
The dome itself a series of self supporting circular brick chains that curve inward until they meet at the keystone at the oven top.
You can also frame and decorate the front portion of the dome arch with granite or other materials.
Reading through your replies to various comments it looks like glass or porcelain tiles are best to use and to use a thinset mortar to bond and grout the tiles.
To get a perfect shape dome put the sand in the shape of a dome.
Tiles of different designs can be interchanged on same oven.
It is to do with the sand and afterward place the bricks onto them.
Given the variety of colors and styles of tiles available at hardware stores the design possibilities are huge.