Casting?

[Kosmo's Q]

Has anyone made there own casting of an oven?

[gjbingham]

Re: Casting?

What do you mean Kosmo? Casted an oven dome?

[SpringJim]

Re: Casting?

Yes, do some searches...castable refractory....Ed schmidt built his dome from pieces cast....and some of the ovens James sells are also cast I believe.

[david s]

Re: Casting?

I cast mine. I get away with it because my oven is small. Trouble is with a larger oven you will have uneven heat rise and therefore uneven expansion. So you then need to cast the dome in multiple pieces. This can be tricky for a one off design. The castable refractory is hard like concrete but never truly fired unless you fire it in a kiln and you need to go to 573 C to make the material change.

[Kosmo's Q]

Re: Casting?

David what size is yours?

[david s]

Re: Casting?

535mm diam interior.

[dmun]

Re: Casting?

Most builders in the US make their domes from firebrick because it's cheap, and widely available, and castible refractory is an expensive specialty item. This is oddly reversed in some other countries.

[Kosmo's Q]

Re: Casting?

I talk to 2 different places selling brick 1 told me $1 per brick (1600deg) adn the other told me not to use that because it could chip and flake. O the brick they wanted me to buy was $2 and rated at 3700 deg. I really don't see it getting up to more than 1200 deg on any given day.

[dmun]

Re: Casting?

The low duty firebrick are fine. They don't "spall", or chip. There is a world of trouble and expense with using castable. Even using it for the vent top has caused trouble for builders.

Just my opinion, others may disagree.

[DrakeRemoray]

Re: Casting?

Even using it for the vent top has caused trouble for builders.

I love my cast vent...but it cause me some heartburn when it broke in casting...

[edschmidt]

Re: Casting?

I dont know if its the refractory or not but it looks like you had quite a few air pockets, Also what is the thickness, the refractory I used was specified as min. 2"

[DrakeRemoray]

Re: Casting?

Hey Ed,

I used "Insulcast", a castable insulating refractory concrete from a company called pryor giggey. It looked a lot like the perlcrete, but it is supposed to be strong structurally up to 1800 deg f.

I have discussed this before, and I am not sure it is the right choice of materials, as I also used it for a lintel, and it chips when my tools knock into it...but it is in it's second year now and still standing. The vent walls are 2" thick. I just was not as careful as I could have been about the vent. You can read about this in my oven thread starting here:

http://www.fornobravo.com/forum/f8/d....html#post3641

Drake

[edschmidt]

Re: Casting?

Im glad its working well, But I think what the problem is is that you used an insulating product which generally contains copious amounts of air. I have a couple of kilns and you can easily make a deep scratch with your fingernail.

[DrakeRemoray]

Re: Casting?

Ed, I concur. I love the vent design, beacuse no smoke escapes the front of the oven at all, so no black stains on my oven. However, I would use a different, refractory-type castable if I did it again. I had trouble locating a refractory castable locally and they guys who sold it to me said this would be strong enough, and it is...but....it still is a weak point in my design...
Drake

[aferaci]

Re: Casting?

I know most people here in the US shy away from casting...presumably because of the expensive nature of premixed stuff.....But has anyone thought about mixing their own castable refractory mix themself out of calcium aluminate cement and sand as described at this site?
? Castable for a Bread or Pizza Oven

Doing it this way would be far cheaper if you cast the dome at a 2" thickness....Any thoughts or has anyone tried this recipe?