35 inch Pompeii Oven Build Saga

[Mistertoy]

Re: 35 inch Pompeii Oven Build Saga

Ok getting ready for first course...

I cut out a template to lay on the floor so I have a guide for the first course plus to keep the floor clean and provide allow mounting for the indispensible tool I made. I am going to use both the tool and a wooden template of the oven wall profile.

Last picture in this post shows the hole I have drilled in the firebrick floor to insert a thermocouple. I purchased some K type thermocouples from a company in the US which are 6 inches long, made of Inconel 600 alloy and used for glass kiln or heat treatment oven. The maximum working temperature is 1100C (2000F) and the cable insulation is fiberglass with stainless steel overbraid (rated at 900F). They were US$19 each but I had to buy and fit a k type mini plug as they only come with a cripped end suitable for a screw fitting. I will do a photo in a later post.


Brett

[Mistertoy]

Re: 35 inch Pompeii Oven Build Saga

I had laid my calcium silicate board directly on the vermiculite/cement but I was not happy with how level it was and I had also decided to put a thermocouple under the floor insulation.

So I lifted the calcium silicate board out and leveled the surface with a 1:1 mix of sand and fireclay. I know it is not insulating but that is all I had and it is really pretty thin layer. In the first picture attached, I have leveled and floor and you can see where I have put in the thermocouple.

Now to lay the firebrick floor...

The firebricks I used were 9"x9"x3" (actually in mm 230x230x75) laid in an offset pattern. On top of the calcium silicate board I used a thin layer of dry 1:1 sand and fireclay to level the firebrick floor. I decided to use a dry mix because the calcium silicate board just sucks up the water and I could not see how a wet mix would work. I had read a number for threads where dry mix was used. It worked fine and I was happy with how they went down and the result - very much like laying pavers (but with a very thin bed).

For those that are wondering what all the drawing on the floor blocks is... it is where I was drawing and doing trial set outs of the oven floor and then they got all out of order when I laid then properly.

The black around the laid floor is a small grout of refractory cement around the bottom outer edge just to seal in the leveling layer of the floor. You can also see I have added some extra Calsil board to insulate the ends and the sides. I pushed the base size quite tight and the floor is inside the concrete surround, so I wanted to have a 2 inch Calsil inch layer or 6 inches of vermiculite/cement between the floor and the outer concrete.

I have used a calcium aluminate home brew mix of crushed firebrick (instead of sand) and fireclay and calcium aluminate cement (CAC). I am still playing with the mix and will do the post just on that subject.


Brett

[Mistertoy]

This is a build log or is it blog of my pompeii oven. I am using the standard plans as my basis with some changes I have seen on the forum and a few twists of my own.

The internal diameter is 900mm which is 35.4 inches, so nearly a 36 inch oven !

The base is made of blocks with a ground smooth finish plus two brick arches. So there is plenty of room for wood underneath. The blocks were a small lot from a factory outlet and really well priced.
Boxing for floor is made of blocks cut down the centre so the floor is contained withing the blocks. This worked well but cutting was really dusty and you could not do it without a diamond wheel.

I have set up the floor within the block work so the oven floor will ultimately be level with the coping bricks that will finish on top of the blocks.

On top of the concrete floor I have about almost a 2 inch layer of vermiculite/cement 5:1

I know this is thin but I am using 2 inch Calcium Silicate board which by the plans is sufficient insulation by itself. The only reason I used vermiculite under the Calsil board is to get my floor level where I wanted it.

I have read about making the vermiculite/cement and tried both methods dry mix with cement then add water and mix cement and water then mix with vermiculite. I prefer the dry mix with cement first but either way I found it is difficult to work with.

Pictures are attached .... more to follow soon.

Brett