And so it begins...

[DBinnema]

Hello, just signed up - I'm starting a 36" Pompeii oven...
I will add pics as I go along (since I feel I benifit looking at the pics of others)
I've got no real background in building stuff, so am a little tentative.
But - this forum seems most helpful, so... First question:

I am planning to order 185 standard fireplace fire bricks (9? x 4.5? x 2.25? @ $1.23 each - deformation temp 2754F) and refractory mortar - which comes premixed in a 55lb tub for $63.10. Will two tubs (110lbs) of refractory mortar be enough, or should I get three? The supplier (BC Bricks) says you can lay about 115 bricks with one tub - but that may not account for the rounded shape of the oven?


I live on an island and have to have supplies sent over to me from the mainland on a barge - getting the wrong stuff, or running out and needing to get more would be an awkward, time consuming and expensive undertaking. So I just want assurance me that I'm getting the right amount of the right stuff.

[v12spirit]

Re: And so it begins...

Hi DBinnema,
You are right on the money. I'm not a mason, but I did some maths for you.
My math says that 100 bricks are going to fit into your oven, so 185 is pretty good, you know, you will be spoiling some bricks here and there, and it's your call. If you can pay for 185, why not? I'll not encourage you to buy less than 185 but I will not recommend to buy more.
As for mortar, I did the math too for the rounded shape, I'm not sure, all I know is that you need about 1000"^3 of (mortar mixed with water and ready for mortaring) Ask your supplier what the volume of the ready mortar is. It should be more than 1000"^3 i.e 17L, make them 20L just in case.
As for the right material, I reckon you are purchasing the right stuff. You must be as generous with insulation too.
Here is the draft of my calculations you can justify them, I'm not a mason neither a mathematician. I'm just trying to help.
The machine is losing the uploaded images. I'll post them to you a few hours later.
Hope that helps.

[v12spirit]

Re: And so it begins...

Here is the mortar calculation

[v12spirit]

Re: And so it begins...

and here are the brick calculations

[DBinnema]

Re: And so it begins...

Wow! That was an impressive answer. Intimidating, if that is the sort of numerical skill level required to build this baby, yet also comforting, because this forum is quickly proving invaluable. Thanks!

[cobblerdave]

Re: And so it begins...

G'day
That sounds a little tight on the bricks there v12spirit. You forgotten the entrance hearth and entrance way
If you go back to the plans for a 36 in dome it calls for 60 firebrick for the hearth ( and entrance way hearth. 120 firebricks cut in 1/2s for the dome and a further 30 common bricks for the entranceway. Its a bit over in its calculations in one way as accounts for a bit of waste for cutting the bricks sides.
My own oven 42 in consumed 160 firebricks for oven and entrance hearth and dome. I used commons for the entranceway. That's with minimal cutting as well
So DB your going to be very close at 185 bricks if you don't do to many fancy cuts of course. I recon you could find yourself just few shy though you just can't tell.
Regards dave

[stonecutter]

Re: And so it begins...

If you cut the brick to fit tight you'll use more than you think. I've been asked how many brick for ovens that size, and I tell them 200. That number covers incidentals like bad cuts or junk brick. You'll also have enough to build a flue transition and maybe have a few left over to use as a panini press or something.

[NCMan]

Re: And so it begins...

If you cut the brick to fit tight you'll use more than you think. I've been asked how many brick for ovens that size, and I tell them 200. That number covers incidentals like bad cuts or junk brick. You'll also have enough to build a flue transition and maybe have a few left over to use as a panini press or something.

I was just figuring up my firebricks a few days ago for my 36"oven. I just bought 175, ($1.56 +tax each) knowing I'd be fairly close. They are readily available locally, so it's no big deal to go buy a few more if and when I need them, which I am guessing I will. So, I guess I was pretty close. Nice to know.

[deejayoh]

Re: And so it begins...

I'd say don't bother with the refractory mortar. Go with homebrew. It's much cheaper and the supplies you need (portland, sand, lime, fireclay) are generally readily available - with the possible exception of fireclay, which you can harvest from cutting your bricks.

[CV_Oven]

Re: And so it begins...

Homebrew works great and is inexpensive. Used it on our WFO and on a Dutch Oven/grill some years back and never had an issue.

[v12spirit]

Re: And so it begins...

G'day
That sounds a little tight on the bricks there v12spirit. You forgotten the entrance hearth and entrance way

Dave,
Thanks for paying my attention to those omitted calculations. I am embarrassed by not reading the plans carefully, but you know I'm building with steel so I skipped the chapters that don't concern me so far. After considering those omitted calculations I end up with 10 more for the vent landing, and 13 more for the door entrance the total is 95+23 = 118 or 120 say provided that the chimney itself is not included. BTW when I did the math for your 42" oven I got exactly 155 bricks.
DBinnema,
Dave has given you an elegant, simple, and reliable answer so go with it. You may use my papers as a concept if you plan one day to build an "immense" oven that no body has built before to be able to tell how many bricks will be needed
When you use my equations, add half of the result to get how much to buy so that junk bricks/cuts are considered:
120+60 = 180.
That sounds natural to waste third of your bricks being not a mason.

[DBinnema]

Re: And so it begins...

Well, it sounds like 185 should be good - i see the "plans" call for 180. Even so I may round it up even further, to 200, to be on the safe side, it it fits within the weight limit for shipping a pallet. I think I pay per pallet. Having never cut a brick before, I'm bound to mess up my fair share. And I will consider the home brew option - sounds the more popular way to go. More complicated if I ship up the ingredients.

[DBinnema]

Re: And so it begins...

Another question - I get charged a fee of $170+/- to ship a pallet up here on a barge; after fire bricks and mortar there is still room on the pallet for more stuff. To make the most of these shipping charges I thought I'd add some stucco to the order. They sell a premix stucco (see below). I plan to make an igloo - is this stucco product the sort I could use to cover the oven base and the oven itself after the isulation is in place? Any idea how much I would need?

DESCRIPTION
IMASCO PREMIX 1000 is a mixture of portland cement
(conforming to ASTM C150), hydrated lime (conforming
to ASTM C206), inert aggregates, and additives
specially blended to provide improved workability, better
coverage, colour consistency, and increased water
resistance.

COVERAGE
Varies with thickness and texture. Approximately 8-
10yds2 (6.7-8.4m2) at ⅛” (3.2mm) thickness. IMASCO
PREMIX 1000 is ideal for most trowel textures.