New Guy Here!!

[beckj]

Hello, I plan on building a simple pizza oven, and I had a few questions:

1) Where is the best place to find firebricks? And what kind are the best for use in the hearth and the dome?

2) What is the type of sand to use with vermiculite for the void spaces around the dome? And what is the ratio of sand to vermiculite for the insulation space?

3) How thick should the layer of insulation be between the dome and the outside wall in order to not feel burning heat on the outside of the structure? I have a fence a few inches from where I want to build my oven, and naturally I do not want to create a fire hazard!! (I'm also a Reno Firefighter, and that would look pretty bad!!)

To anyone out there who takes the time to respond, thanks a million- I really appreciate it!

Respectfully,
John

[dusty]

Re: New Guy Here!!

Welcome John,
If you plan to build a wood fired oven, you have come to the right place.

Best place I know of to buy firebricks is H.C. Muddox in Sacto. They manufacture them and sell "seconds" for 30 cents each - cheap. Low to medium duty are considered best for an oven.

The Forno Bravo oven plans that I built my oven from did not suggest adding sand to the insulating layer under the oven floor. It is simply a mixture of portland cement and vermiculite. Two inches is the recomended thickness.

This is what I used and I am pretty sure I lose most of my heat through the floor. I am very happy with it but if I ever build another I will use an insulating board material (available from the Forno Bravo on line store) under the floor.

Hope this helps.

dusty

[dmun]

Re: New Guy Here!!

No sand in the vermiculite concrete. It doesn't need it and it reduces the insulation value dramatically. And you need four inches under the floor, not two. If you are limited to two inches, you should go with one of the insulation boards, either cal-sil or mineral fiber.

Similar guidelines apply to the outside of the dome. Four inches of vermiculite concrete, or two of mineral fiber blanket. Many of us have used both on the top of the oven, since heat rises.

[beckj]

Re: New Guy Here!!

Thanks for the information guys! Dusty, I live in Reno so visiting H.C. Maddox in Sacto is no problem. I will shoot for 4 inches thickness for my hearth (bottom). Also, I was still wondering, is it better to use refractory concrete over Portland cement? Does it really matter, especially if you aren't firing your oven more than, say, once a week? And I'm assuming at least 4 inches of insulation all the way around the dome will be enough to not really feel the heat to touch on the outside of the structure?

Thanks again,
John

[Les]

Re: New Guy Here!!

John - Just noticed you are in Reno. If you don't want to make the drive over the hill, you can buy the brick at Basalite.

Les...

[RTflorida]

Re: New Guy Here!!

If you choose to use vermiculite for the hearth insulation - 3 1/2" is recommended. The simplest way to achieve this is to use 2x8s to frame your hearth pour; then pour the 4" rebar/mesh reinforced support slab and fil the remaining 3 1/2" with the vermiculite. I believe this is per the FB plans. Download the plans from the FB store (they are FREE) and read them over several times...this should clarify a lot of the questions you have/will have. This is what I did 20 months ago.
If I were building today, I would choose one of the ceramic fiber boards (FB board - as it is called on the forum). The pricing has dropped considerably since my build and is available through the FB store (if you can't find a cheaper local supplier). As mentioned, you only need 2 inch board to equal the insulating value of 3 1/2"-4" of vermiculite.

RT

[beckj]

Re: New Guy Here!!

RT,

Thanks for the information, I will be picking more brains like yours' in the future as I get closer. I think I will utilize the FB as it saves me height (and work!) as I can only go a certain height due to CCR restrictions. I would like to go with a gabled roof, but again, I am limited by height, so I may have to end up with something flatter. I will check Basalite for vermiculite and firebrick.

Talk to you soon!

[christo]

Re: New Guy Here!!

Saw no answer to your portland quesiton so far. I'll take a whack.

Portland breaks down with high heat. So it's not so much the frequency of use as the temperature that makes it unacceptable.

Some of the home brew mixes have portland in them and that is so there is some inital set or strength in the mix.

Christo

[Les]

Re: New Guy Here!!

I will check Basalite for vermiculite and firebrick.

I'm not sure if they will carry the vermiculite, but you can get it at Moana Nursery.

Les...

[beckj]

Re: New Guy Here!!

Les, you are from Carson City (I grew up there). You built a pizza oven there? Maybe some time I could take a look at it (if that isn't too forward!!). Anyway, nice to have locals on this site, especially in order to take a look at some real life examples at some point!

Thanks, look forward to talking with you some more!

[Les]

Re: New Guy Here!!

No problem - just let me know when you would want to come by.

Les...

[beckj]

Re: New Guy Here!!

Les, John from Reno here again (sorry to stalk you!). Anyway, the space I have planned for my pizza oven is pretty narrow with a fence about 3-4 inches from one side. Unfortunately, I don't have a whole lot of room to work with- my rough footprint is about: 60 inches deep x 55-60 inches wide. Do you think this is enough room to build an oven? I mean, I guess I could make it pretty small inside the dome, maybe even go for a rectangular cooking oven instead of circular. I just want to make sure I have enough room for adequate insulation so I don't burn down my fence!

And thanks for offering to let me look at what you built, I will definitely coordinate something with you in the future. What part of Carson do you live in?

Thanks again, sure great to have someone to ask questions to!

[dmun]

Re: New Guy Here!!

I built a 36 inch dome on a 60 inch square. It was tight, and I used a dome style with bricks on edge to reduce mass and diameter. I didn't have a lot of room on the entry, and had to build my chimney supports on the top of the dome it's self. So the short answer is that yes you can do it, but if you can squeeze even a few inches more it will make for an easier build.

Just a note on the sixty inch square. Masonry units are eight inches. Blocks, for example, are 7 1/2 by 15 1/2 to yield an eight by sixteen unit with mortar. Sixty isn't divisible by eight. A sixty-four inch square will give you a bit more breathing room, and be an even masonry unit size.

[Les]

Re: New Guy Here!!

John - I live on the North/West side of Carson - right next to Silver Oak Golf. 60 inches is a little tight for a 42 inch oven. That's using only 2 inches of blanket and no enclosure - you would have to build a dome. You may consider using 1/3 bricks - give you a little more wiggle room

Les...

[beckj]

Re: New Guy Here!!

Les, my folks just sold their house in Silver Oak a couple years ago, small world! Thanks for the photos.

Dmun- thanks for the gouge, I will take a look at your pics here, too.

Les, I looked at your pics- outstanding work!! I have looked at hundreds of different oven pics recently, and I haven't seen brickwork as clean and tight as yours in your dome!!! How do you make your cuts? What kind of tool(s) do you use to make those odd angled cuts? I have cut THOUSANDS of pavers in my day, but I am perplexed at how you made those cuts. Did you have to halve all the bricks in your dome?

Sorry for the volley of questions, but unfortunately for every pic you have, "its worth a thousand words!!"

Talk to you soon... (thanks for taking the time)