New pizza oven build

[Cameroonian Kid]

Hi,
So I’ve bitten the bullet, and am making a WFO. Initially I was sure that I was going to build a half barrel oven– then more and more reading on this site convinced me that the pompei was the way to go…
This weekend I’m planning on pouring the concrete base behind (and slightly on top of) a heavy limestone retaining wall.
Next step insulation board, then 38% alumina fire brick base, under a 42 inch Pompei dome. I’ll then use Isofrax blanket, and eventually render the dome. I’m hoping to be finished by Anzac day (April 25^th).
Some questions though…
a)I live in a generally dry area, and the oven will be built on top of compacted sand that drains water well. Would you do anything special (I Was going to put plastic sheeting underneath the concrete base) to stop water getting into the concrete base. I will waterproof the dome, - but for other sections on top of the concrete base, not under the dome (eg the edges and corners) do I need to do anything special?
b)Are there any issue with using brick size 230X115X75mm (7.1x4.53x2.95)?
c)Would it be advisable to order many more bricks than what is calculated on the pompei oven spreadsheet? I have altered the spreadsheet to take into account my brick size. I live a long drive from where I am getting the bricks, and don’t want to make multiple trips…. It would be better to order more bricks, and some spares, but how many??? The pompei oven spreadsheet indicate that I will need to order 135 bricks, and that it will take 9 courses, plus one soldier course to complete the dome.
d)Any idea how much refractory mortar that I would use, and therefore need to order?
Thanks for all of your help, and the great site.
The Kid

[UtahBeehiver]

Welcome to the satisfying journey of building a WFO. I understand the pain and cost of sourcing materials you downunders face from previous member builds but it will be worth the effort. I would order some contingency brick for oops and such. The calculator is just an estimate so say a 3-5% contingency is not unreal. Brick size will work just fine with dome thickness 3.65 inches. I can't remember for sure if DJ's spreadsheet factors in brick for the vent arch, chimney or outer arch so this needs to be factored in too. Consider "home" brew" for your mortar, the hardest item for you to find will be the fire clay. Many southern hemi builders have had luck sourcing fire clay from potter supply stores.

Review this sticky for some of the more documented builds on the FB site as well as JRs, or SableSprings builds. David S is a good source for materials in Aussie land but he is located on the other side of your country in Queensland.

[JRPizza]

Russell, I think you may have forgotten the link to the newbie forum so I'm attaching it. I also got some value from a post of what builders would change in their oven if they had a chance, so I attached a link for that too..

https://community.fornobravo.com/for...change?t=12453

[UtahBeehiver]

Must of had a brain freeze, thx.

[Cameroonian Kid]

Thanks a lot guys.

I'm thinking of using this product as the mortar - you just mix with water, which I think will be a bit easier. Would you have any concerns regarding safety with this product?

http://aakilns.webs.com/msds/SHIRABOND_50_DRY_REV1.pdf

[dakzaag]

Unless you absolutely cannot afford it, I would get at least 10-15% extra firebrick. Esp considering how far you are from the supplier. (I would buy 200 myself, but that is just me not wanting to make more than one trip) The mortar listed is fine for tight joints less than 1/8 ". You will need a refractory mortar with some sand in it for area's where the joints are bigger than 1/8. Home brew works fine for this or a flu setting mortar will also work if you can find some. Recently used typical sairset for a build and then added sand and clay to the sairset to fill in bigger voids. It seemed to work ok, haven't had a chance to see how well it is holding up yet, so time will tell on that.
You mention concern about your corners and edges and I think this would be an issue of water penetration, so I would plan to render and waterproof any exposed area, and of course slope the corners so they drain. Other than that, you seem to have a good start.

[VanessaWalsh]

Hi! Did you finish your pizza oven?? I would love to see photos! I'd like to know how much refractory mortar you decided to use for the oven of this size? I want to build an oven of the same size and I need to know how much refractory mortar to order. Thank you in advance. I'll probably have to create a new thread. By the way, I would like to share some good news with you. Those of you who also buy products at ALDI, like me, can participate in the tellaldi.us survey and thus have become eligible for winning a prize of $100 Aldi vouchers.

[MarkJerling]

Hi Vanessa. I'd suggest posting a new thread as you may not get a lot of replies in an old thread.