Installation guide
Pompeii Oven Instructions
© Forno Bravo, LLC 2007. All Rights Served. Ver. 1.2 67
Appendix 6. High Heat Mortar
Overview
A Forno Bravo modular oven, or a brick Pompeii Oven is
assembled with a high-heat mortar. You have two basic
choices: Refmix, a commercially-produced refractory
mortar produced for Forno Bravo, or a mortar that you mix
at the building site, using locally sourced materials. The
site-mixed mortar can be made with standard Portland
cement, or with refractory cement, called Calcium
Aluminate.
The best solution is to use Refmix, or another pre-mixed
refractory mortar. Forno Bravo stocks Refmix in California,
and we highly recommend it. It is pre-mixed, so you just
have to add water. It sets hard, is easy to work with, cures
quickly, and is heat resistant to 1700F. It's made
specifically for pizza ovens and fireplaces (there is even a
pizza oven graphic on the bag).
If you don't want to worry about shipping Refmix, or want
to save money, you can make your own mortar, using
either fireclay and Portland cement or fireclay and Calcium
Aluminate. Fireclay is heat-resistant clay made up of
aluminate and silica. When you mix fireclay with Portland
cement, sand and lime, you create a product that is more
heat resistant than basic mason's mortar (Portland cement
with sand and lime).
Measure your ingredients by volume (use a bucket or
shovel to measure), and mix only the amount you will us
within an hour or so.
Portland cement Fireclay Mortar Formula
1 part Portland cement
3 parts sand
1 part lime
1 part fireclay
Still, fireclay mortar is less heat resilient and thermally
conductive than a true refractory mortar. If you are building
a commercial oven, or simply want to "go the extra yard,"
but do not want to use Refmix, you can make your own
refractory mortar with Calcium Aluminate.
First, a word of caution. Working with calcium aluminate
can be challenging. If you get the mix, or water wrong, it
won't set correctly. It partially sets very quickly, and you
cannot re-hydrate it, so you have to mix it and use it in
small batches. Still, if you are trying to save money and
want or need the heat resilience, heat conductivity and
longevity of a true aluminate mortar, it works.
Calcium Aluminate Fireclay Mortar Formula
1 part Calcium Aluminate
3 parts sand
1 part lime
1 part fire clay