Paul's 42" WFO - Canberra Australia

[tinaloven]

Re: Paul's 42" WFO - Canberra Australia

Sorry Muscats,

Those calculations were for a freestanding arch without any support or load. For a dome its much stronger so you wont have to go 8.4". render and the

I get my material from "Johnny the oven man" who's on this forum. Much cheaper than Sydney field furnace.

I did cut a slot in the tube with the angle grinder. You only have to cut the inner tube and not do both like I did.( Then get yourself a wing nut and hey presto a accurate measuring guide. Also make sure your post stirup has a flush 90o angle as usually the are slightly curved as they are bent into shape. Use a grinder to make a small slice in the joint for this and check the angle level.

My insulation board comes friday so I have 2 days to make an executive decision on my dome and arch opening measurements. Pressure is on.

I'll post some pics when building.

[Muscats]

Re: Paul's 42" WFO - Canberra Australia

Finally found some more time to work on my oven and have completed the stand and poured the hearth slab today, photos attached.

[Muscats]

Re: Paul's 42" WFO - Canberra Australia

Formwork removed and have cut the slab insulation bricks and floor tiles ready to set the floor on fireclay and sand mix then the fun begins with inner arch and the dome

[Muscats]

Re: Paul's 42" WFO - Canberra Australia

Dry stacked inner arch and half height soldier course.

I have it dry stacked with spacers and it is holding it self up and is the height I was after.

A question on the arch, is there a minimum thickness of mortar I should use in the arch?

[tinaloven]

Re: Paul's 42" WFO - Canberra Australia

Hey Paul, looks great. Nice craftsmanship.

I think the minimum thickness you can go is about 6mm. As the bricks will expand and contract over time and giving a little mortar will limit cracks forming. This was using the "ciment Fondu" refactory mortar. Availably only at CE industries in fyshwick at the moment no other supplier carries it. Its temp rated at 1000deg c so its good stuff ($45 a bag). Otherwise you can buy fireclay at bunnings for about $15 a bag mix with sand and cement to get the equivalent substitute.

I think its 8 parts sand, 3 parts cement and 2 parts fireclay. Need to check that ratio.

Im just about to finish my chimney. My floor and dome pics are what I did at your stage. The front arch was cut to wedge the brick which held freestanding. But I made a mock door as a guide cause what happened is that when I placed my 6mm mortar on the arch bricks I pretty much lost a brick space. Although they fitted perfectly without mortar before with mortar you loose a brick. So build it from side to side and when you get to the "keystone" arch brick you may have to custom cut it and use a rubber mallet to tap it down. Hence the mock door as it will hold the tapping down force and the overall arch support.

You ideally want to lay that arch in one go. making sure your bricks are wet(pre soak them or wet them before mortar as that ciment fondu is super strong and dries out like a dead dingo's donga super fast.

I'll post some pics of my dome insulation and final skin render later.

[tinaloven]

Re: Paul's 42" WFO - Canberra Australia

some other pics of floor and dome.

I had 4inch (100mm) concrete base on top of that was as follows,
5mm of powdered eggshell (97% calcium carbonate) natural insulation. I washed the egg shell in bicarb soda to get rid of any leftover mucus and proteins. Left to dry then put in a food processor to get to fine powder. My mums a cook and we have plenty of eggshells after her daily baking.
next 40mm calcium silicate board for insulation,
Solid canberra red bricks,
and on top 50mm cooking tile.
all worked out previously to give me a cooking height of 900mm, Standard bench height.

ready to go.

curing was done with a cast iron gas burner for 6 consecutive days straight and increasing temps each day

[dmun]

Re: Paul's 42" WFO - Canberra Australia

5mm of powdered eggshell (97% calcium carbonate) natural insulation.

There's a new one. According to Wikipedia, calcium carbonate is the principle ingredient in chalk, limestone, and marble. In other words, I wouldn't count much on it as an insulator. The good news is that it's pretty much non-combustible.

Good looking oven, by the way.

[Muscats]

Re: Paul's 42" WFO - Canberra Australia

some other pics of floor and dome.

WOW, it looks great!
Looks like you have plenty of thermal mass in that baby - should keep hot for a while.

[czaunb2]

Re: Paul's 42" WFO - Canberra Australia

Great idea with the eggs! Looking great.

[Muscats]

Re: Paul's 42" WFO - Canberra Australia

I have been working on by Indispensable Tool (lazy susan variant) - photos attached. this should give me a lower dome height 480mm (just under 19 inches).

[Muscats]

Re: Paul's 42" WFO - Canberra Australia

Inner arch and soldier course mortared in, now starting on the first ring

[tinaloven]

Re: Paul's 42" WFO - Canberra Australia

your going to have a great looking oven. well done keep it up.

[tinaloven]

Re: Paul's 42" WFO - Canberra Australia

dome with isowool (insulation fire blanket) 25mm thick. x 2 layers.
i sat and pondered for quite a while with the application of mortar shell straight onto the insulation. i erred to the side that i'd try and avoid sticking wet mortar straight onto the insulation but how could i do it. Solution was to use fiberglass fly screen! I laid it all over the dome see pics.

it introduced a breathable material and wholes small enough that the mortar would not overall drip through and stick to the insulation.

then I laid the chicken wire around for strength and support for the final mortar. The mortar I used was called "skim render" it dried a nice white colour.

I did two skins one at 25mm which pretty much covered all the chicken wire and the 2nd coat covered the rest as I made it as round and smooth as possible

[tinaloven]

Re: Paul's 42" WFO - Canberra Australia

continued work, moving on I did a second arch slightly lower that the first arch. I rendered this front as well i'm still trying to get all my photos sorted.

[Muscats]

Re: Paul's 42" WFO - Canberra Australia

In between days of 43 deg celsius and today down to 12 degs, I have managed to get a few bricks into the dome.
Now working on ring 4 and 5 - photos attached