How should I start my first course? Soldier?

[stevef22]

Here are a few updated pics of my build. Have floor completed. How should I start first course.... full brick, half brick, etc. Much appreciated!

[Petter]

It looks like you don't have any under-floor-insulation. Is it so?

[stevef22]

5" of pcrete and .5" homebrew moter

[UtahBeehiver]

Where was the home brew mortar used? What was the ratio of the pcrete?

First course, half header or half sailor. A full sailor has a lot of horizontal load at the joint and may require buttressing of the outer wall. I can't tell from pic, did the floor get mortared? It should be free floating to allow for thermal expansion.

[stevef22]

Thank you for info and picture Utah.

Floor did get about .5" of home brew 3:1:1:1 ( Sand, lime, fire flay, portland)



Where was the home brew mortar used?
A: Under the firebrick, between pcrete and fire brick.

Reason: Table top not completely flat. I had to "float" the floor to make firebrick level.

What was the ratio of the pcrete?
A: 5:1 as per diagram



Thanks for the help!

[stevef22]

Side question:

What is effect on home brew if ratio of portland is low.

For example (3:1:1:.5) Sand, Lime, FireClay, Portland)

Portland being 1/2 of what is called for.

[Petter]

Aha, okej. The slab looked so smooth, so I had to ask.

If the portland is lowered, the initial mortar strength will be less. Once fired, the mortar strength is dominated by the fireclay and lime since the portland breaks down anyway as I understand it.

[david s]

I'm concerned that with 5" of home-brew under your floor bricks you will end up with a floor thickness of 9"of dense conductive material. As it is important to balance the floor thickness and the dome thickness you are likely to end up with an unbalanced oven. Most cast domes are usually only around 2" thick so this will exacerbate the difference. You could cast the dome to 9" thick but you'll end up with a monster that will take a long time to heat up as well as using a lot of fuel, as well as costing a great deal if you are intending to use castable refractory. That's fine if you intend cooking bread for the village but not if you intend on cooking three pizzas for the family. If you laid the floor bricks loose then they would be easy to remove and take out the home-brew layer.The oven needs to be insulated under and over so it is totally encapsulated in insulation. By the look of it your home-brew layer extends out to the perimeter which would result in acting like a heat sink sucking the heat out of the floor. If you do remove the floor bricks, do yourself a favour and drill a few holes through the supporting slab either from the top or the bottom so the insulating 5" perlcrete has somewhere to vent its moisture.

Regarding altering the home-brew recipe, although I'd be interested in hearing how it would perform, why alter it when so many have found it to be so successful?

[stevef22]

Sorry for confusion. Here is diagram of my layers.

[david s]

Hi Steve,

Sorry, my error, i didn’t see the decimal point (normally it would be preceded by a 0). That much shouldn’t be a problem then, forge on. Drilling up from underneath into the perlcrete would be a good idea though.

Dave

[UtahBeehiver]

I mistook the .5 as 5 as well. Ditto on David's comments

[stevef22]

Thanks David! I will drill up into the pcrete from underneath. How many holes would you drill? My concrete bit is 1/2" inch.