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Post by devokewater on May 12, 2018 19:22:52 GMT
Right, the oven has begun.
After quite possibly two years, I am finally at a point where I have enough time to devote to this project and I really want to enjoy the construction. Being in the Lake District, my walls are dry stone and the predominant roofing material is slate so it's important for this to blend in. Therefore I'm building it into the actual corner of the wall and it will eventually be covered in more stone after the insulation has been added. I also intend to use some slate for a roof construction but we'll see what makes sense nearer the time. The plan is for the oven to be 90cm with half bricks (1/2 x 230mm) used for the dome. I have built the base, don't worry about the scrappy block-work, it will all be stone faced eventually, hence the wall ties here and there.
I will no doubt need a bit of advice now and then and hopefully when this is finished I may be able to reciprocate somewhat. The images show the base built and some of the shuttering work going on. There will eventually be an oak beam directly in front of those concrete lintels so again, none of that is planned to be on show.
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Post by devokewater on May 15, 2018 16:56:38 GMT
Having cast the supporting slab, with plenty of reinforcement, I'll now leave it to cure for a week or so, that seems to be the recommendation.
In the meantime I need to order the materials for the dome so I've followed peoples general suggestion that Kilnlinings are worth using. However it looks like you need to get your quantities right at the start as with their minimum order of £200, just topping up on anything that you've got wrong isn't that easy without a long drive! I've read loads on this really useful forum, so thank you to everyone who puts the time in to share their ideas. I am following, to a certain degree, The pizza oven handbook by Andrew Thompson, that was referenced on here.
I seem to have come up with the following requirements for a 90cm dome: Insulation below oven floor - Calcium Silicate board - 2 sheets 1000 x 50 x 50mm thick? Insulation over dome - High Temp Insulation Blanket - 1 roll of 3.6m x 610 x 50mm (Density 96kg)? Mortar - I'm following the the Homebrew recipe in the handbook - 1.5 scoops sand / 1/2 scoop cement / 1/2 scoop lime / 1/4 scoop fireclay. How many bags of fireclay at 25kg am I likely to need? Will 1 bag do? Firebricks - 42GD 230 x 114 x 64 Approximately: Dome base - 45 (although mine is a 90 cm diameter, I've based that on 100cm squared to give plenty of spares and cutting)
Landing area - 8
Arch - 34 Walls 90 Total of 180 so if I went for 200 I would have plenty spare for mistakes, etc. Does this seem too many?
Does anyone think that I've over or underestimated any of these materials?
Here's some pics of the slab coming together.
Many thanks
_
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Post by oblertone on May 15, 2018 17:03:20 GMT
I think 25kg of fireclay will suffice, especially at the ratio you quote; most 'home-brew is 3-1-1-1 using sand-cement-clay-lime and that'll be easier to remember than your recipe.
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Post by devokewater on May 15, 2018 17:12:22 GMT
I think 25kg of fireclay will suffice, especially at the ratio you quote; most 'home-brew is 3-1-1-1 using sand-cement-clay-lime and that'll be easier to remember than your recipe. That's great, thanks and yes, you're right, now I think about it, sort out the fractions!!
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gez
valid member
Posts: 32
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Post by gez on May 15, 2018 19:13:34 GMT
Hi , I ordered two insulation sheets and that wasn’t enough for me . Mind you I planned on putting it under the floor and outer walls plus vent . My plan is a 90cm dome
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Post by devokewater on May 15, 2018 19:52:49 GMT
Hi , I ordered two insulation sheets and that wasn’t enough for me . Mind you I planned on putting it under the floor and outer walls plus vent . My plan is a 90cm dome Ok thanks. I thought it may be tight. I envisaged the bits around the edge perhaps being enough for the archway. Perhaps I'll go for 3 and then there's plenty to go under the first row of bricks as well, which I was tempted to build straight onto the slab. I suppose it gets to a point where you invest so much in it that another few quid to do it right makes sense! What thicknes did you go for and have you built your dome yet? If so, how many bricks did you buy?
Cheers
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gez
valid member
Posts: 32
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Post by gez on May 15, 2018 20:23:15 GMT
I ordered the 50 mm board insulation, I also ordered 230 fire bricks but that was purely a quess , 76mm thick think I’m going to have fun cutting them 😂 . I plan to start laying bricks this weekend. I have finished the roof over the stand today.
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Post by oblertone on May 16, 2018 6:51:55 GMT
FWIW I used a sheet of 25mm thick vermiculite board underneath my oven floor (heater blocks) and while it works, more is always better unless we're talking pizza toppings.
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Post by devokewater on May 16, 2018 7:24:10 GMT
FWIW I used a sheet of 25mm thick vermiculite board underneath my oven floor (heater blocks) and while it works, more is always better unless we're talking pizza toppings. Yes having a bit of a rethink, as you do, and perhaps the 76mm might be better. I'll redo my spreadsheet containing 2 x pie x radius squared divided by the larger brick surface area to see if it makes much difference. Why didn't they give you nice fun real life examples like this to work with in school!
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Post by devokewater on May 16, 2018 11:35:12 GMT
That's interesting, using a 76mm rather than 64mm thick brick calculates (without gaps, purely on surface area), at 73 rather than 87 bricks for the dome. Not much of a saving, admittedly, but then you notice that the bricks are the same price!
Also with this going into the realms of £500, by the time delivery and VAT goes on, I wondered about perhaps using storage heater blocks just for the base and landing area. I have enough for that and wondered what peoples thoughts are. I notice from Oblertone's comment above that he has used them. What are they like to cut?
Also is it that important to use fire bricks for all of the opening and arch? As mine is going to be faced with stone, to blend into the dry stone walls, is it acceptable to do the outer arch and in something other than fire brick?
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Post by oblertone on May 16, 2018 19:38:46 GMT
If you're intent on using firebrick then just do the dome in those, my outer arch is made of roof tiles cut longways and stacked around a former with home-brew in-between each one; and as you've said, my floor is un-cut heater blocks. The build thread is linked below, unless you're on a phone in which case I don't think you can see it.
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Post by devokewater on May 17, 2018 10:05:30 GMT
Thanks for the advice. Yes I've had a look at your mobile build, love the mosaic, very snazzy! I think I may just do the dome then in firebricks but yes the rest can be made from materials I already have and tie in with the stone. It's funny, you read so much and get a particular method in your head but there are so many variations on a theme. So I'd better adjust my order accordingly and get in in while the weather is reasonable!
The concrete slab seems to be curing nicely, I've just taken the shuttering off.
I'll keep you posted.
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Post by james9 on May 17, 2018 13:14:44 GMT
I used 224 bricks for a 90cm but was doing a lot of cutting and with a high chimney, standard build methods will use less. I mixed Vitcas & Kilnlining bricks and once they're dirty you can't tell the difference. Vitcas are more expensive but better quality and they were more flexible with order quantities. The main advice is soak them well before cutting otherwise you'll go through blades ridiculously quickly. Screwfix have currently got some great deals on blades, £6 special offer v £14 normal www.screwfix.com/p/erbauer-diamond-segmented-blade-230-x-22-23mm/71137
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Post by devokewater on May 18, 2018 13:37:55 GMT
I used 224 bricks for a 90cm but was doing a lot of cutting and with a high chimney, standard build methods will use less. I mixed Vitcas & Kilnlining bricks and once they're dirty you can't tell the difference. Vitcas are more expensive but better quality and they were more flexible with order quantities. The main advice is soak them well before cutting otherwise you'll go through blades ridiculously quickly. Screwfix have currently got some great deals on blades, £6 special offer v £14 normal www.screwfix.com/p/erbauer-diamond-segmented-blade-230-x-22-23mm/71137Thanks for the advice James re. soaking the bricks, I'll certainly do that. Unfortunately my blades need to be 25.4mm bore for my Rage 3 mitre saw so I've had to get a proper one so can't make use of the cheaper Screwfix ones, shame. The blade can be used wet or dry so we'll see how that goes. I did however, come across FFX Tools of Folkstone, who had very competitively priced blades for a whole range of grinders and saws so they're certainly a company worth looking out for. I got my respirator and goggles from the as well.
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Post by devokewater on May 18, 2018 20:51:08 GMT
Is there a preference for hydraulic or hydrated lime in homebrew? I have read all around the subject and all I'm really coming up with is that hydraulic is less flexible but in the smallish proportion does this really matter.
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