BrritSki's Build in Italy

[BrritSki]

Originally Posted by BrritSki

1. The instructions say Portland cement, the bag of Italian vermiculite says use refractory cement - I'd prefer Portland, will this be OK ?

2. Is the vermicucrete strong when it's set - it will have the full weight of the oven on it ?

3. Is the ratio of vermiculite:cement 5:1 by volume or weight

4. How would you define "oatmeal consistency" to a limey ?

Any answers on any of the above or do I just go for it when it has stopped raining ?

Christo: thanks for the answer on thermometers...

Ciao Roger

[rlf5]

1) I believe everyone here used portland cement or regular mortar.

2) Yes

3) I believe its by volume.

4) Thick, not runny at all. More or less holds its shape when not disturbed.

[berryst]

Roger
Portland cement should be find. 5-1 is the generally accepted ratio. It looks like it would not hold up but in fact it has a high compressive strength...like 100psi. The oven is probably 1 to 2 psi.
berryst
by the way your photos are beautiful how about pics of the build?l

[BrritSki]

Thanks to rlf5 and berryst for their replies - I bit the bullet and did the job yesterday evening !

Photos of recent stages of the build have been added to the Album: "BrritSki's Pix".

Progress has been slower than expected with various diversions with visitors and other vital jobs like extracting and cutting a pile of wood for the winter, car at garage for new exhaust pipe, tile/brick cutter being broken when I unpacked it and needing replacing, thunderstorms etc etc etc.

Roger

[BrritSki]

Well, our last visitors have now gone and no more for a while and we had a nice holiday last week in Denmark for my svigrmor's (mother-in-law) 90th birthday, so it was back to work today.

I laid out the brick floor and marked what cuts were needed and then assembled my brand-new brick cutter and set to work. Everything was fine except that I couldn't believe how much water it needed - I had to setup a drip-feed to keep it topped up. It was only when I removed the tray to empty the mud that I realised that the tray was cracked. Taped up now and it's fine.

So, all the floor bricks are cut and also about 40 bricks cut in half, so I will have more have enough for the first 2 courses of the dome. Attached photo shows the dry layout - I will lay the first dome course (not soldier course) on top of the floor, so I'm not worried about the rough finish - that will be hidden under the insulation.

Mud was all saved of course and I've pounded some of the brick offcuts and added that and some sand to make a nice paste tomorrow for laying the floor and the first course.

Ciao Rog

[christo]

Looks good. I was really excited when my oven got to that stage.

Any particular reason why you didn't go with the herringbone pattern for the floor? I got advice that it helps to prevent the pizza peel from hanging on a brick edge and so far it's working very well for me.

Christo

[BrritSki]

I would have gone for a herringbone with square bricks, but a rectangular herringbone doesn't look right to me - I am a genuine Virgo and very obsessive about detail as my wife can confirm

I understand about the peel catching an edge and I've been very careful to ensure there are no raised front edges that will cause a problem.

As you say, this is the really exciting stage.

Ciao Rog

[james]

Ciao Rog,

Your vermiculite layer came out very smooth. Nice. How would you describe the Italian vermiculite? Was it fine, or a little bit lit porridge (Scottish Oats?)?

You oven will be fine using Portland cement, rather than refractory cement. That layer just won't get that hot.

Keep going.

How's the weather when it isn't raining?
James

[BrritSki]

Good day today - floor laid and first course laid out dry ready for mortar tomorrow.

I had real problems with the paste - I used the mud from brick-cutting mixed with very fine sand and some pounded brick offcuts. It was very hard to mix (separated out into water and solid fireclay/sand layers) so maybe I got the proportions wrong, or maybe it was all too fine.

When I spread it out on the concrete floor I couldn't get a nice comb effect either - it was either too dry and I scraped it all off or it was too wet and it just settled back into a level layer of gloop. I eventually just got it to about the right thickness and then put zigzag lines into it with the edge of the trowel to allow for some tamping down with the rubber persuader (aka mallet). It's not perfect, but it's close enough - level and flat with no raised edges to catch the peel.

The two bricks on end define the inner entrance, they are 18" apart and 11" high, but there will be a very gentle 1/2 brick deep arch to raise the height to 12" in the centre.

The rest of the oven opening will be 2 bricks deep, set back an inch to give a reveal. The outer entrance will be 1/2 brick deep and will have the same arch height as the inner entrance as I figure I can tilt the fire-door forward to clear the front arch as it goes in or out.

This will leave an inner slot 1/2 brick deep (plus mortar) which will taper up into the chimney.

Ciao Rog

[BrritSki]

Originally Posted by james

Your vermiculite layer came out very smooth. Nice. How would you describe the Italian vermiculite? Was it fine, or a little bit lit porridge (Scottish Oats?)?

Vermiculite was probably a little bigger than oats, but not by much.

Originally Posted by james

How's the weather when it isn't raining?

Haven't had rain for some time now. Nice and hot, but not too bad under the tarpaulin shade and with a breeze most of the day. Plus when it's too much I just go and take an outdoor shower and jump in the pool

Ciao Rog