Homemade pizza oven

[Allie]

Can someone clarify something for me in making an oven?
1. Can I use just hydraulic refractory cement as the dome mould or should fire brick grog or vermiculite be added? Ratios?
2. Same for floor? I planned to use clay fire bricks (more affordable)
Thanks for any help.

[david s]

1. The refractory cement is calcium aluminate cement (CAC), But you can’t use it alone, it needs to be mixed with other stuff including water to make a workable mix. Don’t add vermiculite as the inner cast needs to be dense and strong, keep the vermiculite for insulation. An expensive premixed castable refractory containing a suitable blend is available from any refractory supplier, you need to ask for a dense castable refractory. A cheaper alternative is to use the homebrew mix, and cheaper again use a cob mix (2 parts sand 1 part clay with straw reinforcing).

2. Use firebrick.

[Allie]

Thanks for info. Should CAC be food grade? IveI read refractory mortar should be used sparingly inside, between bricks not as a dome "lining". I'm not doing bricks.only layers of cement, blankets, etc.
i guess I'm confused why some are using Portland cement / vermiculite and it's ok, but CAC is not. Ty

[david s]

No refractory materials are classified as “food grade”. The high temperatures are sufficient to make them safe.
Commercial refractory mortars are recommended for thin joints for the following reasons IMO. They do not contain coarse aggregate material and no burn out fibres, both of which produce a greater propensity for steam spalling. Commercial refractory castables by contrast do contain coarser high temperature aggregates with more compatible thermal expansion characteristics and burnout fibres and are therefore suitable for thicker castings provided the temperature ramp up is done slowly. If you make up your own castable brew which is much cheaper, you are flying blind to some extent, although quite a number of builders have successfully used the homebrew mix and found it quite serviceable. How it stands the test of time (extended) is anyone’s guess.

[Allie]

Thanks David S. I'm just trying to find a way to make an oven I can do at my skill level and strength. I don't think I can do a brick oven. Too involved.

[Theo_Dot]

I built a half brick half vermicrete oven and it took a lot of the skill out of it send me a message if your interested in some pics