Gold Coast supplies?

[microbe]

Yes, you're probably right. I glue it on the topside because it might fall off on the underside. I might have to rethink that one, Thanks.

I like those mud wasps, They are also known as Potters wasps, they look really big and scary but rarely sting unlike the nasty little black paper wasps who work in groups so you get hit by about 4 instead of just one. The Potters wasps love potteries because it gives them a ready source of processed soft clay.

I love them...except when I can't get my mower or brush cutter or chainsaw or fire pump or some other small engine started because they have built a nest in the perfectly sized exhaust pipe.

[david s]

I reckon the screen is needed on the underside to stop those damned mud-wasps

Yes, you're probably right. I glue it on the topside because it might fall off on the underside. I might have to rethink that one, Thanks.

I like those mud wasps, They are also known as Potters wasps, they look really big and scary but rarely sting unlike the nasty little black paper wasps who work in groups so you get hit by about 4 instead of just one. The Potters wasps love potteries because it gives them a ready source of processed soft clay.

[Gulf]

What david s said about "the holes", + elevate the insulation off of the structural hearth.

[microbe]

I reckon the screen is needed on the underside to stop those damned mud-wasps

[david s]

OK then do your oven a favour and drill some holes near the centre so underfloor moisture can have an escape path. Better to drill from the bottom up so when the hole blows out a bit it leaves a depression that will help the moisture to pool in that area. Do a pilot hole first, say 6mm and then drill out to about 12mm. Hope that you avoid the steel reo. Glue some patches of insect screen on the upper side of the slab to prevent insect entry to your insulation.

[microbe]

Awesome...I have finished my base and hearth, I have my bricks, I have my info from you, I am ready to go

[david s]

Thanks David,

Your contributions are always insightful and of value.

Would a 100mm 5:1 vermicrete floor with 25mm firebricks be adequate for the floor?

How many 35mm 10:1 vermicrete layers instead of blanket?

Is there a recipe for homebrew mortar?

The one problem for those of us doing it from scratch, especially where supplies are not readily available, is that there is lots of conflicting information and not all in one place. Cue David writing "The Ultimate Aussie Pizza Oven Guide"

I think 100 mm of 5:1 vermicrete and 25mm floor bricks is a decent solution, although I'm about to start a commercial oven kit install that recommends 200 mm cal oil board insulation.

For whatever insulation you use over the dome the adage that you can never have enough is often used, but of course is also subject to the law of diminishing returns, as well as increased costs and labour. Provided you keep the cement content of a vermicrete layer really low it will insulate as well as blanket at a given thickness for 10:1. Some go as low as 13:1, but I've found a 10:1 mix as about as lean as I can handle and still have a reasonably workable mix that's solid enough to act as a firm substrate to render against. The downside is that it takes on lots of water, in fact a 1/3 of its volume will be water to make up the mix ie by volume 10 parts vermiculite, perlite or a combination of the two, to 1 part cement and 3 parts water. As water is an enemy to insulation this needs to dry thoroughly to allow it to insulate. I've found that if you make the mix too thick the stuff deeper in won't get a chance to dry, so applying a layer of around 35mm then allowing it to dry for a week, then apply another layer. A little powdered clay added to the mix also helps a lot to make a lean mix more sticky and easier to apply. I actually use a blanket layer against the dome then do a layer of 10:1 over it. This way I don't have to wait ages drying subsequent vermicrete layers and the blanket acts as an expansion joint. Too much wet vermicrete can swell and even crack the outer rendered shell if heated too fast.

Homebrew recipe 3:1:1 sand, hydrated lime, GP cement, bricklayers clay

Here's an experiment I did with drying a vermicrete slab that you may find informative.

Vermicrete insulating slab PDF.pdf

[microbe]

Thanks. Just yesterday I scored my bricks via Gumtree from someone pulling up an old driveway. I was the 3rd person building an oven to come get some

I did call Warwick brickworks and I forget exactly the response, but there was some reason they weren't able to supply.

[cobblerdave]

G’day
ddbs
Warwick brickworks makes dry pressed brick commons which I’ve heard back in the day were used for brick ovens. They used to do an oven kit. Be worth while investigating as it’s a local supplier
regards Dave

[microbe]

Thanks David,

Your contributions are always insightful and of value.

Would a 100mm 5:1 vermicrete floor with 25mm firebricks be adequate for the floor?

How many 35mm 10:1 vermicrete layers instead of blanket?

Is there a recipe for homebrew mortar?

The one problem for those of us doing it from scratch, especially where supplies are not readily available, is that there is lots of conflicting information and not all in one place. Cue David writing "The Ultimate Aussie Pizza Oven Guide"

[david s]

If cost is an important factor, there are some cheaper alternatives. A 10:1 vermicrete mix will give you the same insulation value as blanket, but needs drying time and because of this preferably applied in 35mm layers with a week’s drying between. A 5:1 100mm vermicrete for under floor insulation is equivalent to 50mm cal sil board.

Solid reds usually suitable for the dome, (although no guarantees), but use firebricks for the floor.

Homebrew mortar is cheap as chips and far more user friendly than proprietary refractory mortar. It has also proved effective in service as 100’s of homebuilders will attest.

Paying freight on sand and water, both of which can be obtained locally is something I avoid. Get your quotes and do the sums.

[microbe]

I have made a lot of phone calls to interstate refractory suppliers. None of them have local distributors, shipping would be a killer.

Someone gave me details for a bloke named Jim Bennett who sent me this info. I don't think he has a web site. Jimbennett949@gmail.com


Firebricks $5 ea. 230 x 115 x 75mm

Mortar.thick joints $35.00 bag

Thin joints $55. Per bag.

Ceramic Fibre 25mm $120 roll 7200 x 600mm.

Call sil boards 1000 x 600 x 25mm $45.00 ea.

All plus gst if applicable.

Generally ex stock Caboolture

[Gulf]

Hi Svetlana Barbina ,

I moved your post to this new thread in the Australian section of the forum. You may find the answer above. But, there has been no feedback if microbe was successful in locating supplies.

[Svetlana Barbina]

Hi I'm looking to buy ceramic blanket for pizza oven in Brisbane can you help me to find where to buy?

[cobblerdave]

G’day
Since the brickworks at Dinmore closed now I’m not sure where to get your oven needs.
I’d try Total Refractorys at slack creek. A friend bought some ceramic blanket off them a few years ago so I’m fairly sure they are still open.
If you could post what you find that would be great as we could do with some up to date supplies.
Regards Dave