My first attempt for 42" oven / changed to 36"

[david s]

Great suggestion by David. David - did you pour those countertops yourself? Is that crushed glass mixed in?

This is a customers oven, I didn't do the countertops, it was just a variety of aggregates no glass.

[George_M]

Guys,
How many days need to wait until the perclrete will dry?
Here the temperature is 30-40 oC.
As you can see in the photos,from the first day until today which is the sixth day.

[UtahBeehiver]

You should be good to start work,but if possible, leave the forms on to protect the edges of the p-Crete while you construct the dome

[George_M]

Yes,you are right.I will keep it to protect it.
I will start the oven floor and i plan not to build with mortar in case of need to replace any floor plate after the years.
I saw some builders(not here) that they use mortar to build the floor.I think this is wrong..

[UtahBeehiver]

Correct, no mortar on floor or first course of dome to floor. Want expansion of dome and floor to float.

[david s]

Regarding the drying of the vermicrete, you may like to read this little experiment on attachment that i did.

[George_M]

I will wait a week more david.Thanks for the file.

I made the perlcrete mix in a cement mixer,i know that many suggest to avoid this but the mix is better than my first try which made by hand.
Is more strength and not crush on the top now.
Also,perlite didn't crushed while i made it in the mixer..

[George_M]

I have a question about the expansion gap.
I will make the floor inside the dome so the bricks will go around of the floor.
Between floor and bricks how much must be the epxansion gap?

[UtahBeehiver]

Just put a piece of card board (abt 1/8" thick) around the floor and between the first course of the dome and leave in. This does two things, first gives you an expansion gap spacer, and second, it keep errant mortar from falling down and filling you expansion gap. The cardboard will burn out during your firings and the gap will eventually fill with ash.

[George_M]

Around the floor ok, i understand the purpose.
But why need between first course and dome?Have you got a photo from this?
I don't know if it is easy to build the first raw on cardboard..

[UtahBeehiver]

I don't think you and I are on the same page. Here is a pic/.

[RandyJ]

Here is another picture of the expansion gap.

Randy

[George_M]

Thanks!!
You are clear!

Why some builders put foil between perlcrete and floor?
Is it necessary to put foil?"

[david s]

If the foil is sitting against concrete then it is useless as an insulator. As aluminium is very conductive It needs to be surrounded by air or at least a material with very low conductivity to work as an insulator. It will work to prevent water wicking up from the stand and supporting slab and into your vermicrete. It is probably better to paint the top of your supporting slab with a sealer.

[George_M]

Floor ready!!!!!!!!!!!!

Tomorrow i will level it better and i will start the first raw!