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Post by mikeb21 on May 23, 2020 15:46:48 GMT
Hello from a new member. I built a BBQ / Wood Store a couple of years ago and now planning to add a Wood Fired Oven, here's a few photos of the original BBQ build. Foundations (about 1 foot deep concrete into thick clay): First layers of engineering bricks: Top layer of bricks and concrete floors: Reinforced (with rebar) concrete slabs added: Complete with doors: Has stood well for the past couple of years as just a BBQ and very well used now! Thought / plan is to build Wood Fired Oven onto the left slab, was thinking of vault style using a bunch of old storage heater bricks I've already got, similar to this design: ukwoodfiredovenforum.proboards.com/thread/2895/build-using-storage-heater-bricksWill need to extend the slab back towards the fence as the top isn't really that deep, depth will be a bit of a compromise unfortunately due to the original design. Just slowly collecting the materials at the moment so maybe a while before the build fully starts. Got a few questions.... What to use to join the bricks used to create the vault, Fire Cement says that it cures under heat but will it cure enough during build to hold it in place? Was thinking of building a wooden former/frame to form the bricks around during construction and then burn this one first fire up? In the build above the OP uses foamglas insulation below and around the bricks, trying to work out what best to use myself. Was thinking of a layer of vermiculite bricks under the floor to add extra insulation underneath and then some kind of insulation mat around the vault covered in chicken wire before rendering but would appreciate any suggestions / opinions.
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Post by oblertone on May 23, 2020 17:02:36 GMT
Forget fire cement, it's meant for furnaces and kilns where temperatures exceed 900c, your WFO will only get to around 550c so fire cement is an expense you don't need. Instead, use 'home-brew' which is Sand/Cement/Clay/Lime in the ratio 3-1-1-1 by volume, cheap, easy to use and perfect for WFO.
The rest of your plan appears sound, the aim is encapsulate the oven in insulation, how you go about that varies from build to build but it's the goal you should strive for.
I used vermiculite sheet below a layer of heater blocks and it has worked well for me so far.
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Post by mikeb21 on May 24, 2020 19:13:11 GMT
Thanks for the reply and feedback on fire cement. Where do you buy the lime / fireclay from for the Home Brew mix? Vermiculite sheet sounds interesting, could cut it to size for insulation under the base and even initial insulation around the sides of the vault. Have been looking at this sort of blanket for the outer insulation: www.amazon.co.uk/Ceramic-Fibre-Blanket-Furnace-Forge/dp/B004644HBE/All good input - thanks!
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Post by oblertone on May 25, 2020 19:44:54 GMT
I bought my vermiculite sheet from eBay but doubtless there are other sources, try a stove shop as that's what they cut firebricks from to reline stoves. Lime you can get from any builders merchant, clay can be more tricky but I ended up using a pottery supplier.
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Post by mikeb21 on May 26, 2020 18:24:41 GMT
Thanks - the clay was something I was considering, should have saved the clay I dug out to build the original foundations! Think I might have cornered the market in Storage Heater Bricks: As I have so many, I did wonder whether just using two layers would provide enough insulation without the vermiculite board.
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Post by oblertone on May 27, 2020 17:49:08 GMT
Think about it logically, storage heater blocks are designed to store heat energy, not act as an insulator. Using two layers will mean your heat will migrate and you'll have to store twice the energy to get up to temperature, which is hard enough anyway. Use one layer, and insulate underneath it would be my advice. Thermolite building blocks are a cheap alternative to vermiculite board.
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Post by simonh on May 28, 2020 9:05:34 GMT
But by the same token if you want to use your oven for more than just pizza the more thermal storage mass you have the longer the heat will stay (assuming correctly insulated of course) That is the trade off, but useful if you want to use the oven for bread following day.
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Post by mikeb21 on May 29, 2020 20:27:48 GMT
Any opinion to Skamotec fire panels instead of vermiculite for the under floor insulation: www.opiesuk.co.uk/skamotec-blue-225Maybe able to get hold of some relatively cheaply locally.
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Post by oblertone on May 31, 2020 10:52:32 GMT
Calcium silicate insulation; seems to tick all the boxes, give it a go and let us know how you get on.
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Post by mikeb21 on Jun 1, 2020 20:11:56 GMT
Calcium silicate insulation; seems to tick all the boxes, give it a go and let us know how you get on. Saw a few other threads where people said they had use Calcium silicate boards so went for it. Two boards 1000mm x 600mm for £25 which isn't bad considering I was looking to buy sheets @ £40 each. Unfortunately still not found a source of fireclay locally/cheaply but almost got all the bits needed now.
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Post by mikeb21 on Jul 12, 2020 20:20:45 GMT
Well I managed to locate a supplier of fire clay, but with delivery not cheap at £26... I now have all the other bits I need for the build, aside from the aggregates (Sand/Cement/Lime/Clay) have bought everything else cheap via marketplace / gumtree and accumulated: - 48 Storage Heater Bricks
- 32 Used Fire Bricks
- 2 x Chimneys (not sure which I'll use)
- 2 x 1000x600x25mm Skamotec Calcium Silicate insulation
- Approx 2.5m of 25mm Ceramic Fibre Insulation blanket
- Loads of wood
Just need to finish plans and then take a few days off work to crack on
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Post by gwmckay on Jul 14, 2020 20:06:45 GMT
Calcium silicate insulation; seems to tick all the boxes, give it a go and let us know how you get on. Saw a few other threads where people said they had use Calcium silicate boards so went for it. Two boards 1000mm x 600mm for £25 which isn't bad considering I was looking to buy sheets @ £40 each. Unfortunately still not found a source of fireclay locally/cheaply but almost got all the bits needed now. Can you tell me where you purchased the Skamotec boards at this price?
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Post by mikeb21 on Jul 14, 2020 23:21:48 GMT
Saw a few other threads where people said they had use Calcium silicate boards so went for it. Two boards 1000mm x 600mm for £25 which isn't bad considering I was looking to buy sheets @ £40 each. Unfortunately still not found a source of fireclay locally/cheaply but almost got all the bits needed now. Can you tell me where you purchased the Skamotec boards at this price? As per my last post in the topic, I've bought all the stuff from Facebook Marketplace/Gumtree etc. The boards were bought from someone selling, there was scaffolding and a skip outside when I picked them up so I assume leftovers from building work!
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Post by gwmckay on Jul 15, 2020 9:31:37 GMT
Sorry I missed that in the post, that was a lucky result then! I’m slowly building up materials myself, I found over 50 storage heater blocks on Gumtree for £5 which is my oven floor sorted 😎
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Post by mikeb21 on Jul 16, 2020 7:06:44 GMT
Sorry I missed that in the post, that was a lucky result then! I’m slowly building up materials myself, I found over 50 storage heater blocks on Gumtree for £5 which is my oven floor sorted 😎 My oven won't be that big as didn't really plan for a pizza oven originally but should be big enough for what I want. I think all my Heater Bricks cost me total of about £15. Not sure where in the country you are but there are a couple of people selling Vermiculite insulation boards relatively cheap on Facebook Marketplace - have sent PM.
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