36" Pompeii Corner Build Surrey,UK

[PeteH]

Thanks Russell
Feel like I’m nearly there, we’ll at least cooking is in sight
Will deal with making whole thing pretty over next few months
I’ve a lot of jobs in the house which seems to be growing exponentially but hoping Pizza will appease the family for the past 8 months!
Pete

[UtahBeehiver]

Nice and tidy brick work.

[PeteH]

Hi Tim
not sure about furnaces think they’ve got insulation on the inside rather than the outside
pizzas would probably be done in a millisecond too

[Timothy_W]

So far, it looks cool. Is it possible to build a furnace with the diameter you intended? I came across the fact that the furnace ended up being smaller than it was originally on the drawings.

[PeteH]

Outer Arch Mk 2

Decided to use a combination of fire bricks and pressed red clay pavers to build the new arch/chimney, firebricks in the area which would receive most heat - the flue entrance and chimney, and the pavers for the support walls/buttressing
Flue depth now was 6" by 10.5" wide which I narrowed/funnelled to 6" by 6" over 2 more courses of firebrick, topped with a course of pavers to which I'd later attach an flue anchor plate far better than the 4" by 11" of archway Mk 1
Opted on a shallower semi elliptical /3 centred arch over a hemispherical shape as it would give me a little more room when cooking, and personally do prefer the shape, cut form to give me a good sized 1.5" reveal at top and sides and gave myself plenty of room to drop form when arch completed
Corner build so had to be a little creative with buttressed sides going round the sides of the squared off hearth
Build went well as much with clay pavers so much easier to cut than firebrick
Was running low on firebrick dust which I was using in my mortar so bought a bag of fireclay online to make some homebrew - why didn't I use this from the start!!! Much easier mortar to work with more give and a longer working time , also holds water better than firebrick dust homebrew which dries quickly to bricks even when they've been soaked. Didn't like the grey collar however, so I raked out a 0.5" from the joints and repointed using the remaining brick dust mortar mix I had left

[PeteH]

Had been thinking about the entrance archway/chimney/flue for a while now, admiring the numerous variations out there.
I'd originally wanted to attempt an arch leading to a serpentine shaped flue as I'd ordered pre tapered Vitcas archway bricks (cheating again - I know), and a lot of the effort of had been done for me, but decided on the simpler option as I was limited to 12.5" from the dome entrance to the edge of the platform and I wanted a decorative red brick arch fronting the oven. That with a heartbreak left me around 9" to play with so a narrow flue entrance of 4", a serpentine entrance I figured would restrict that flue entrance even more
Whole thing seemed a bit dainty when it was built, and when removing the form front section of flue opening part of arch came away!


Dismantled arch, opened a beer and had a rethink

[PeteH]

A few more pics

[PeteH]

Hi all its been a while since my last post (currently on the curing fires)
Ended a wet May with closing the dome, arch to dome transition went well as checking levels constantly to avoid the dreaded droop!
Gazebo finally caved in with the weight of water one wet sunday morning when I'd taken my lad to footie




Used a sand platform for the last couple of chains raised using the IT modified to give me the centre to the dome to work too
Created the keystone out of 3 pieces cut to templates made for the upper and lower holes in the roof, crawled inside to plug the gaps, glad now I opted for a 36' instead of a 32" diameter and that I'd cleaned the bricks after each build
Great feeling at this point but from the other posts realised i was a long way off cooking Pizza!

[PeteH]

not getting any better at attaching photos

[PeteH]

Been a while since my last post so thought I'd better give an update

Dome Entry Arch -

Spent a while on the arch build and decided to use Vitcas's pretapered archway bricks 3" (tapering to 2") x9'x4.5" to save myself time (a lot of effort and no doubt waste) also mitre saw not able to cut that depth and length as sliding mechanism gets in way, thought about using a 9" angle grinder (as seen on other posts) but came to my senses and went online & ordered enough for both inner and outer oven archways
opted for a hemispherical arch after playing around with a number of arch shapes
Built a form 4.5"deep x 11"high x 18 wide (arch will be 11.5 with ply hearth protector removed) and fixed to to the base ply with brackets allowing a 1/16th inch gap at bottom to drop the form after build
Had some fun dry stacking the arch bricks using shims/wedges to space them equally whilst fighting the outward forces trying to collapse the arch! and then used Russells (Utahbeehiver) handy guidelines, and the IT to mark out the cut lines from top dead centre brick down to the bottom brick in sequence
Spent the the following weeks spare time after work to cut and then mortar the arch together, trying my best to keep to to levels for the uncut vertical and horizontal sides, whist also aligning brick edges together using a rapidly drying mortar Crossed fingers a couple of days later and removed shims to drop form and found it was stuck! Fortunately I'd screwed the form together so dismantled it that way, I'll be more careful with the next arch form



Mortar mix -
decided to add 1 part portland cement to mix to add a little more rigidity to the hydraulic lime home-brew so now 9 parts fine sand : 3 hydraulic lime : 3 firebrick dust :1 cement
backfilling gaps at the back with 12:3:3:1 mix using equal parts fine and sharp sand and an extra component of 3 parts of crushed firebrick to fill the larger gaps

Soldiered on with dome (sorry) using this mix and currently at course/chain 5 (plus base course)

David s - thanks for your point about my IT design flaw being on a swivel and not fixed to the ply floor so bought a cheap level set, used a dinky oneattached with a sticky fixer to attach to the IT to help keep the build continuing on a level plane! am keeping an eye out for the dreaded droop constantly checking each brick tdc levels with a "guide/control" brick set at the back of the oven




What I have noticed is that the arch bricks which I spent a time marking out and cutting sits further out than expected now that its mortared together! so when i get to laying the dome bricks adjoining and overlapping the arch its about 1/2 inch out? (see pic) I can't figure this? the dome seems to have gone 'out of round' here at the arch, elsewhere I've noticed small discrepancies but only 1/16th inch waist laying bricks on top of each other
Am guessing shrinkage forces of the clay mortar mix might be to blame, maybe pulling things out of true?
I am going to end up with a slight overhang of the dome to arch brickwork which i may (or more likely may not) tidy up after I bridge the arch with a 4.5" grinder when I bridge the dome in a few courses time



Gaps ?
During the build I thought I was being careful to put plenty of mortar to bed the dome bricks on the bricks below to eliminate any void, but now on closer inspection of the joints am finding some gaps, not particularly deep , so before i go any further plan to grout these in with mortar. wondering of any of you guys or girls have experienced this?
Am wondering also a result of shrinkage of my mix due to a lower amount of cement?

[PeteH]

More on the build...(feel free to jump to pics)

Relaid all but the dead central 3" hearth firebrick which I temporarily replaced with 2.5", cut hearth ply template into quarters with a 'brick' shape cut out above central 2.5" brick (call this the "pivot plate') which will sit above this brick
Found dead centre (ground zero) of the hearth which was the centre of pivot plate - drilled 32mm hole for ball socket/cup
Need to show my IT (all stuff pilfered from various threads on forum!)

- 2 turnbuckles (linked through their reverse threads) with 10mm steel threaded rods, one end threaded in 32mm steel ball the other end threaded & welded to an angle bracket - both ends adjustable
Ball will sit in pivot plate and is easily removed after setting each brick
However, IT was not so good on the "soldier course / chain 1" as turnbuckle catches ply so removed ply protective cover and used an alternative IT (pic2)
Pivot point actually sits 4mm above hearth so dome height will be a little over 18" (18.2") which works slightly better 11.5" dome arch so I won't bother making any adjustments later

(Saw that Gulf had used a wooden brick later to get his pivot point at hearth height)



Mortar mix

I mentioned before about using hydraulic instead of hydrated lime, and omitting cement if possible, as hydraulic lime acts in a very similar fashion with a quick set like cement but much easier to remove if mistakes made and clean up residues later (found when changed mind on arch shape from vertical sides and shallow arch to hemispherical arch)
Did a few experiments using various ratios of Sand, hydraulic lime and fireclay first and found cement really not needed with this type of lime but clay is, sand and hydraulic lime not enough cohesion alone, but maybe work if using a sand form in construction?
Some light reading if anyone interested?
(Can't upload as webloc)

https://www.ecomerchant.co.uk/news/whats-the-difference-between-hydraulic-and-non-hydraulic-lime/

Have used Hydraulic lime on the first 3 courses with fireclay collected from cutting bricks and sieved dried plastering sand (dust-1mm) Ratio of 3:1:1 (Sand:Lime:Fireclay) and sets well, quite quickly, so making up small batches each time
Tapering and bevelling brick as outlined in dome calculator, and dry fitting before laying
I'll be filling the wider horizontal gaps with a coarser (sharp sand : lime : fireclay) mix with an extra component of smashed up firebrick slivers which will add a little extra thermal mass to the dome

Cut templates to the arch forms today, so I am hoping to do the arch cutting and laying this week - if work and family ties let me! Lockdown restrictions loosening in UK somewhat, this week so might be having a few beers with friends too!

[MarkJerling]

Good stuff. Henry must be made stronger than the three cheap angle grinders I killed with my WFO project! I do have an old vacuum cleaner I use in the Garage and it refuses to die!

[PeteH]

Thanks Mark
Henry ok he’s been busy vacuuming brick dust up again today

[MarkJerling]

Nice work! Is Henry the vacuum cleaner still alive? LOL

[PeteH]