My Barrel Vault Oven Build - Durham

[moonhead]

Now its time for the business end of things.

40mm Cal Sil boards wrapped in heavy tin foil. Not the best to work above an a sunny day!



First string of the oven floor set on a thin mortar of Fire Clay/Sand/Cement 1:1:1 mixed to a consistency a little thinner than peanut butter applied to the boards with a wide toothed tile adhesive spreader.



and the second under the Gazebo, much easier on the eyes



Half way there



The second half of the floor went down and the area under the entrance / chimney with the ash hole.





The rear wall of the oven, almost up to it's final level. The two last bricks I cut on the wrong face and it was to late be re-cutting so that will be first job today, then on with the vault arches.
The fire cement seems pretty easy to work with. Again I'm using a medium tooth applicator which is keeping the mortar to a 2mm thickness. I know anything approaching 5mm or above will cause problems with it curing.

The white cover over the base is the final size of the vault, just to keep the vault floor clean, as the mortar is a pig to scrub of once it starts to cure.



The Rusty Stove door I sourced at the start of the build has been soaking in a mixture of Molasses and water 1:9 for about six weeks.
here is the before and after result.



The rust turns to a sludge and just blasts off with a pressure washer.

[cannyfradock]

Moonhead

Thanks for sharing....another brilliant set of pics.

I've never used cal sil board.....or any other board come to that, so I'm learning a lot from your build....thank-you. Have you laid the 40cm cal-sil board directly on the concrete slab?......I'm not about to contradict anything, I'm just improving my knowledge.

Terry

p.s.....nice work on the door!

[moonhead]

Terry, yes I decided to place the Cal Sil board directly on top of the concrete slab after checking it was good and level. I'm using 40mm thick board.

Managed to get plenty done yesterday. All arches up and the chimney/entrance under way.
The form I made for the arches worked really well. I had real fears that as I brought both side up they'd either be to close or to far apart, but checking the fit by dry laying as I got near the center allowed for any adjustments to be made. The Keystones all needed a firm tapping into place, so all is nice and tight.

The arches are each made up of 21 fire bricks. 2 normal fire bricks, 17 tapered with a 54mm internal face and 4 tapered with a 64mm face. Before starting each arch the bricks were sorted into their order of installation.



First arch under way and on target with the template.



First one done



Nothing better than sharing this project with my son. He's pretty enthusiastic and really enjoyed mucking in and cleaning up! Bit of a pizza fan too.



Two down



Three, one to go



The Final one complete an looking like an oven





Just enough time left to get a start on the Entrance / Chimney.



Four courses gives an oven entrance height of 305mm. With the arch peaking at 430mm this gives me a 71% ratio - to high. So I'm thinking I could apply some 30mm shims to the underside of the bridge over the entrance bring it down to 275mm (64%). Or I could shave a 30mm channel to each side of the underside of the spanning bricks, so they'll have the appearance of a fat 'T', so they sit through the steel angle supports. I'll have a look this morning and decide.

Rick

[adm]

Very nice work indeed.

How did you taper the bricks - seems like an awful lot of cutting - or did you source them already tapered?

[moonhead]

Cheers adm

No Cutting - the bricks are pre tapered from Kiln Linings, supplied ready to go

kilnlinings.co.uk/wood-burning-pizza-oven-kits/42gd-firebrick-arch-section-710mm-span-arch-internal-diameter

[moonhead]

So here's how I decided to get the ratio of the entrance to vault height down to 64%.





A channel was ground into each side of the bricks and a shoulder removed to allow it to be slung between the channels as well as sit on each side of the chimney supports. This left these two bricks 30 mm lower than the rest of the bricks so I also cut some shims to bring things back to the same level.
It would have been easier to have ordered some narrower firebrick from kiln linings had I thought earlier when ordering as the supply a 38mm brick!

Here you can see the bricks between the channels and just about make out the two shims on the top of them.



The fire cement got a little messy at this point. I scraped up the thick oozy bits when the were a bit dryer, but as the chimney wont be seen and will soot up, I wont kill myself trying to scrub it off.

Things start to become a bit of a stretch at this point so its up on top from this point.



I'm stepping the sides of the chimney in over 25-30mm each course to narrow it down, as at its base the opening starts at 400mm wide.



A view through the entrance into the chamber. Looking forward to seeing a fire in there



I had the whole thing under a cover overnight and was surprised how much moisture there was on it from the bricks sweating, so I have decided to get a start on drying things before starting the insulation layers and while I continue tidying things around the oven building the chimney and the like. Starting with a couple of candles for a few days to see how they work. I don't want to light a fire in there yet but a little warmth at this stage can only help.



Next stage is to complete the course of brick around the slab which I will then fill with vermicrete before starting on the insulation atop the oven

Rick

[bookemdanno]

Nick work Mr.Moon!
You look like you have trade skills?
Very resourceful in your problem solving and nice cut work. What did you use to use the bricks you had to?

Looking forward to the next bits!

How are you finishing your oven?

[cannyfradock]

Rick

I like the way you got the height of your entrance down to the correct height. Also like the way you formed your chimney vent....there are so many different ways I've seen people do this stage on a Barrel/Vault oven.

I do like those voussoir's (pre-cut arch bricks) from Liam. I keep pestering him to supply (cut) 4" trapazoid fire-bricks for us Pompeii oven builders.....he's thinking about it.

Terry

[nixie]

Looking good. I must remember to get some cheap candles for drying out!

[bookemdanno]

do you think you could just cut those bricks in half Terry?
not full traps, but half traps?

[DuncanM]

That is great work Rick, looks like a great build so far. I tried the candle route (albeit lots of tealights). I'd suggest you use as many candles as you can get your hands on for drying out. 2 will have relatively little effect.

Keep up the great progress and the pictures coming!

[DuncanM]

Also meant to add that door looks fantastic and I didn't realise molasses could be used in such a way.

[moonhead]

Thanks for the comments.
Bookemdanno, I have had no previous experience other than the odd job in the garden but I've always enjoyed working with my hands. I loved building models as a kid and never really stopped.
I must say though that before starting on this adventure, because that's how I feel about it, I have read thread upon thread of the builds on this forum. So really its all the guys on this forum I have to thank for getting me this far.

I've just used an angle grinder with a diamond blade to cut the bricks. As to the final finish, I was researching the 'devil' that is commonly known as vermicrete the other day and came upon pete123's build. Though it's a pompeii build its pretty similar to where I'm heading. The chimney will be enclosed in the same bricks I've used for the base and I intend to clad the oven and render finish. I quite liked pete's idea to include conduit for possible lighting as well.

Terry, your right abut the voussoir's, they made the whole vault build pretty quick. Each arch only took around 40 minutes to assemble between my son and myself. I also have to agree regarding trapezoid fire-bricks for Pompeii oven builders. If they had been available I may have gone down this path instead.

I found the molasses tip on you tube, looking for tips to get rid of rust. A local Equestrian supplier supplied the molasses £9.00 for 5 litres which I mixed with 9 parts water. the end result is after a six week soak. I just need to find a suitable coating to protect it now.

Cheers
Rick

[moonhead]

I've finished off the course of brickwork to bring it up more or less level with the top of the Cal-Sil board, Then cast a 4"ring of vermecrete surrounding the board then finished up to the outer edge with standard concrete. So that was Saturday afternoon taken care of. Not allot of progress but between work and a night out looming, a little was better than nothing.

Sunday has seen a big change.
The 50mm Ceramic Fire blanket plus some left over Cal-Sil board covers the vault exterior. I have a load of the fire cement left over so I have used a 5mm toothed applicator to screed over the brickwork and hold the blanket and keep it tight to the vault face.





After that chicken wire has been fixed over the top starting at the chimney end. I found that unrolling it over the barrel shape and fixing against it's spring kept it nice and flat over the the curve.



I used 'U' shape pins and fixed into the vermiculite at the base to hold all in place. Another section cut and folded then fixed across and over the back face to complete.



Wired this to to the back section an tightened it all up. you can just make out the central section of cal-Sil board on the back face which allowed the wire to be pinned nice and tight across its face. The front edges are tucked in between the blanket and brick and some smaller 'U' pins used into the brick joints



The straws in the entrance are to cut into 3" lengths to keep the vermicrete screed an even thickness.

After reading up on various suggestions regarding the method for mixing the vermicrete I opted for a dry mixing the vermiculite and cement in the wheelbarrow, then adding the water until a suitable mix was achieved at a ratio of 6 verm - 1 cement. Once the first mix was prepared I had the idea to add a small amount of fire clay. I felt this would add a little stickiness to the mix which it seemed to. so I stuck with this for the remaining mixes. This is how it looked. Yeah exciting I know ;D



Using a Flat plasterers trowel the mix was built up from the base, and tamped in with a wooden block, using the trowel to keep things in place.



Pretty slow going at first but the higher up it goes the quicker it became as gravity starts working with you not against you.







Now that look of concentration on my face isn't the final stage of application it's concentrating on not falling backwards off my knees!

So eleven hours after starting the last hand full, and I mean last was in place. All 400 litres of the stuff. I thought I had too much!



The Back of the oven is a 30", 3" thick vertical wall so not the strongest while wet so it is being supported while it sets.

Definitely starting to look like on oven now. So I intend to let this dry naturally for a couple of days, then start on the drying process.

In the mean time I'll continue with the chimney and find a render to finish over the vault.

Cheers for now - Rick

[bookemdanno]

Terry swears by K-rend, Mr.Moon.
I'm getting tempted to splash out on it for a repair on my Oven.

Nice tidy work there, my man!