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Well, I've made a start, sort of.
I've studied hard, read lots of posts, and checked out lots of commercially available ovens. In an ideal world, I'd probably grab a FB Primavera 70 (28") and be happy, but the FB Oz website doesn't list them and I doubt I'd be able to justify the outlay if they did sell them here.
Still, I like the look of the primavera ovens. I've given it lots of thought. I realised that pizza is the main concern, bread and roasts almost nil priority.
So the general plan is this: steel framed stand, on heavy duty castors. Aiming for an oven 700-800mm internal, so the stand will be 1200mm across, giving about 200mm/8' either side for dome wall and insulation.
Vermiculite insulating layer.
Clay paver floor.
Fire bricks are a horrendous price, ones at work seem mostly the insulating type, house bricks with no holes in them seem rare as bunyips, so adobe dome, as per Better Homes plans. 1 part fat sand, 1 part terracotta clay (fire clay unprocurable in South Oz except for one mob in Adelaide who quoted $115 + freight for a 15 kg/33lb bag) 1 part crusher dust, mix it then add 5% cement (optional). May substitute lime for cement.
Vermiculite insulation over the dome, followed by render. As mentioned, I'm in country South Oz. Therefore, there is another resource available that no-one seems to mention on the forum. I've been thinking, next time I drive past a farmer renewing his fences, I shall jump out of my ute and beg some used barb wire from the old fence. I believe old barb wire will make an ideal shapable reinforcing for a dome. There may even be a part roll in my mums shed.
$57 worth of steel tubing duly sourced from bro-in-law.
Just scored enough white brickies sand to fill two 55 litre garbage bins. Free, from a guy who trucked it 150 miles so he could have white mortar between the bricks of his new house. Cost him an extra $800 over using the local yellow stuff. Beautiful sand, never quite understood the expression fat sand, til I saw this stuff.
In proper Oz outback style, the frame will be tek screwed together, and the supporting sheet under the vermicrete will be corrugated roofing iron left over from my new chook house.
Due to the size of tubing available, vermicrete layer will be 76mm/3". Not perfect, but it won't have to stay hot for days.
Pavers - leftovers, $25 per square meter from local contractor. Haven't bought them yet. They are 2 inches thick, and they seem heavier than any of the firebricks at work, so, if you want to do mostly pizzas and not radiate heat for days, they should be enough thermal mass.
Crusher dust is cheap as, as little as $18 for a bobcat bucket (half a cubic yard) I believe I may achieve a workable oven for around $3-400.
They tell me adobe isn't waterproof hence the frame on wheels. Perhaps a decent addition of lime might help. I did wonder if the FB homebrew mortar recipe would work with terracotta, instead of fire clay.
Anyway, the job is on. Can only work at nights, due to painting house on weekends as per instructions from She Who Must Be Obeyed.
I've studied hard, read lots of posts, and checked out lots of commercially available ovens. In an ideal world, I'd probably grab a FB Primavera 70 (28") and be happy, but the FB Oz website doesn't list them and I doubt I'd be able to justify the outlay if they did sell them here.
Still, I like the look of the primavera ovens. I've given it lots of thought. I realised that pizza is the main concern, bread and roasts almost nil priority.
So the general plan is this: steel framed stand, on heavy duty castors. Aiming for an oven 700-800mm internal, so the stand will be 1200mm across, giving about 200mm/8' either side for dome wall and insulation.
Vermiculite insulating layer.
Clay paver floor.
Fire bricks are a horrendous price, ones at work seem mostly the insulating type, house bricks with no holes in them seem rare as bunyips, so adobe dome, as per Better Homes plans. 1 part fat sand, 1 part terracotta clay (fire clay unprocurable in South Oz except for one mob in Adelaide who quoted $115 + freight for a 15 kg/33lb bag) 1 part crusher dust, mix it then add 5% cement (optional). May substitute lime for cement.
Vermiculite insulation over the dome, followed by render. As mentioned, I'm in country South Oz. Therefore, there is another resource available that no-one seems to mention on the forum. I've been thinking, next time I drive past a farmer renewing his fences, I shall jump out of my ute and beg some used barb wire from the old fence. I believe old barb wire will make an ideal shapable reinforcing for a dome. There may even be a part roll in my mums shed.
$57 worth of steel tubing duly sourced from bro-in-law.
Just scored enough white brickies sand to fill two 55 litre garbage bins. Free, from a guy who trucked it 150 miles so he could have white mortar between the bricks of his new house. Cost him an extra $800 over using the local yellow stuff. Beautiful sand, never quite understood the expression fat sand, til I saw this stuff.
In proper Oz outback style, the frame will be tek screwed together, and the supporting sheet under the vermicrete will be corrugated roofing iron left over from my new chook house.
Due to the size of tubing available, vermicrete layer will be 76mm/3". Not perfect, but it won't have to stay hot for days.
Pavers - leftovers, $25 per square meter from local contractor. Haven't bought them yet. They are 2 inches thick, and they seem heavier than any of the firebricks at work, so, if you want to do mostly pizzas and not radiate heat for days, they should be enough thermal mass.
Crusher dust is cheap as, as little as $18 for a bobcat bucket (half a cubic yard) I believe I may achieve a workable oven for around $3-400.
They tell me adobe isn't waterproof hence the frame on wheels. Perhaps a decent addition of lime might help. I did wonder if the FB homebrew mortar recipe would work with terracotta, instead of fire clay.
Anyway, the job is on. Can only work at nights, due to painting house on weekends as per instructions from She Who Must Be Obeyed.
I'm mostly frustrated by the availability of things. Freight charges kill everything, so its been a compromise from day 1.
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