Homebrew NE England. Help needed please.

[TonyPizza]

Firstly, like many say, the information on this site is incredible, so thank you to everyone who shares their superb knowledge.

I am at a stage where I have moved away from a traditional clay cob idea. Instead I plan on making a home-brew cast.

Apologies in advance for a lot of questions, but I have spent a couple of days on and off reading the posts, yet there are still a few knowledge gaps, so any help will be massively appreciated...

I have already made the base and the concrete plinth (100mm deep).

I have bought some Quinn Lite Super blocks - 0.12W/mK Thermal rating. These are (unless someone tells me otherwise) a direct comparison to the Thermalite blocks, just a different brand. I intend to use these as the insulation.

Next step is to lay 64mm fire bricks, using a thin layer of kiln sand between the fire bricks and the thermalite blocks, to achieve a perfectly level cooking surface.

I hope to use the kiln sand to fill any small gaps between the fire bricks and the house bricks that make up the external wall / barrier which surrounds the fire bricks and below them, the thermalite blocks.

Q: will I be ok taking the fire bricks up to the edge of the house bricks (i.e. filling the whole area I have made available - as this would be easier for me than cutting the bricks to the dome shape), therefore meaning the fire bricks will protrude out from under the edges of the dome, or must they stop at the edge of the dome (I have asked this because I gather that there may be possible heat loss if I do it this way).

Q: The overall width and depth of the available surface the dome will sit on is 108 x 108cm. As I had intended to make a clay cob, with walls potentially 20cm thick around the dome, I estimated that I would have a cooking area of 68cm. AS I now plan to make a home-brew, I understand that the overall wall thickness will be less, therefore, more cooking area. Can anyone advise me roughly what the cooking surface will be?

I plan on making two brick walls for the gallery entrance, with a cast section on the top (I have seen a photo by DavidS somewhere that gave me this idea).
Q: DavidS advised me to drill some holes through the concrete plinth to allow for drainage. I have drilled five 10mm holes, within a 20cm diameter area. Will this be suffice? (Pic attached)

Q: What will I need exactly and where will I get it from in the UK please?
I have stolen the following list (slightly amended) from Robarb (thank’s for that).
Sand
Clay
Cement
Lime
Fibres
Needles
Twin-walled flue
Firebricks
Vermiculite
Insulating blanket
If anyone can help me to understand quantities and suppliers, I would be very grateful. Also, if there are any material specifics I need to be aware of.
I think my overall sizing will be very similar to that of Robarb’s oven, judging by hos external sixes, indicated in this thread: https://community.fornobravo.com/for...rew-cast/page2

Please accept my apologies if I am asking people to repeat what they have already posted (pretty sure I am), but I have had a good look around the forum, yet it still hasn’t ‘clicked’ with me enough to just get stuck in myself without a helping hand or two.

Tony.

[TonyPizza]

[UtahBeehiver]

I am have been seeing a lot of UK builders using Thermalite or equiv. materials but I have yet to see anyone list temperature rating of the materials. Some builders have opted to place a 25mm layer of CaSi between the blocks the the firebrick floor to solve this question.

In one of the recent UK cast post, the builder listed where he or she procured all of the materials in the UK.

[Robarb]

Hi Tony,

I bought Clay, Firebricks, Insulation Blanket, CaSi Boards and needles from here : https://www.kilnlinings.co.uk/
I bought Sand, cement, lime, fibres, concrete lintels and vermiculite from a local builders Merchants called Berry's, you'd have to look near yourself for one of these but good ones usually sell whats needed
I bought a twin-walled flue off facebook marketplace but got lucky as i found one for £25 instead of the usual £60.00 off ebay and other sellers.

Just need to get some wire now to hold the blanket in place but i can probably pick that up from a local farmer. I got lucky with the base materials (bricks/blocks/flags) as they where all free from friends/colleagues/freecycle websites.

I start building mine soon, just waiting for the weather to improve!

Good look with yours, i know i spent hours reading on here before i took the plunge.

Thanks

[TonyPizza]

Robarb Thank you for the reply and info. Can ou advise if the attached cement is ok to use?
Also, do you know what the best wood to use for the gallery mould is please?

Thanks again,
Tony.

[TonyPizza]

OK, I have most of the materials on the way, so I hope to get the moulds done and casting this weekend.

Can anyone help with my Flue spec? My internal diameter cooking surface will be 800mm. Shall I get a six inch flue for this? does it need to be twin wall? Can anyone point me in the right direction please?
Also, what about flue length? 500mm?

I have come across this one, for sale on Victas, but I am not sure about length or width.
https://shop.vitcas.com/chimney-flue...nd-damper.html


Thanks in advance,

Tony

[UtahBeehiver]

In the Forno Bravo eplans, which you should download and review, 32-36" ID oven uses a 6" ID vent. Stainless steel double wall is the best but some builders have opted for single wall SS as a cost savings measure or availability.

[TonyPizza]

UtahBeehiver Thanks for the reply. So, if mine is just under 32” (800mm) should I go for a five inch pipe?
also, can you advise if I should go for 50cm or 100cm
?

[UtahBeehiver]

Can't oversize vent but you can undersize vent. You have to make the decision. Longer length can sometimes offset small diameter.

[TonyPizza]

Please will someone advise with the following:

I intend to use 100mm Thermalite blocks, with 64mm firebricks on the top.
I have built the brick oven base with a basin in the top and the thermalite blocks, with the fire bricks on top will pretty much perfectly come level with the top.

Right now, just before I set the final plans in stone, I am wondering if I should use CASI board between the thermalite blocks and the firebricks?

I understand that it may protect the thermalite blocks (At least I think that's the reason to use it?), but it will mean that the firebricks are 25mm higher than planned. This may mean I need to create a small ramp, rising from the very front edge of the brick, going up to the edge of the firebricks. I guess I could come up with a nice tile, but I just don't know if it will be worth the additional work, especially if the thermalite blocks and firebricks alone will be good enough.

(Photos above in this thread should help explain whet I am trying to say)

Any thoughts and help, once again, will be greatly appreciated.

Thanks,
Tony.

[Nick J C]

I doubt you will degrade the Thermolite, although it is less time tested that Vermicrete. I chose to put CaSi board to insulate better, as the Thermolite blocks are only 100mm wide and assuming similar insulating properties to Vermicrete, would possibly not be enough....if you see my build, the casi sits on the blocks, and the cast arch hides it

[Nick J C]

You could use 3" Vermicrete, and 1" casi board to make it flush

[david s]

As you have insulation below the top of your countertop the basin will be prone to picking up and holding moisture more easily. Drill some drain holes near the centre of the slab below the floor to act as drain holes.

[TonyPizza]

As you have insulation below the top of your countertop the basin will be prone to picking up and holding moisture more easily. Drill some drain holes near the centre of the slab below the floor to act as drain holes.

DavidS Already done, as per an earlier recommendation from yourself. Thank you.

[TonyPizza]

You could use 3" Vermicrete, and 1" casi board to make it flush

Good shout, but already got the Thermalites. Thanks though. I think I will just go without the casi board.