Fire cement

[leetheldc]

Hi all I've been doing a lot of reading before I start my Pompeii oven here in hull england uk and all these dry fire cement products are only to be used for a max joint of 5ml as the Pompeii is a dome and outside of the dome the joints are at least 10ml min because of the tilt how did anybody get round this?

[UtahBeehiver]

Re: Fire cement

Home brew mortar is used quite a bit 3:1:1:1, Sand, Portland, Lime, Fire Clay. Also Bookendano is a UK builder and he can help with where you can resource materials.

[leetheldc]

Re: Fire cement

Hi Utah yes I've read about the home brew but I read that it does not last as long as the pre mix that for forno bravo sell or victas sell where I am in england I'm just worried about the joint size on the outside of the dome as no refractory cement I've seen can be used for that joint size

[stonecutter]

Re: Fire cement

It will last plenty long enough for an occasional use oven.

[UtahBeehiver]

Re: Fire cement

and a lot less expensive...........too.

[cobblerdave]

Re: Fire cement

G'day
Your building a wood fired oven not a kiln. Your oven will not get a 1/3 of the temps that most of the furnace cement is designed for anyway. I recon you doing yourself a favour as homebrew mortar is a hell of a lot easier to work with than refractory cement. It sticks to the brick better you can squish it down and do small adjustment to the brick without losing bond. You can't do that with refractory cement.
Regards dave

[leetheldc]

Re: Fire cement

Good points there dave I just always go to the extreme in what ever I do but think you have made the decision for me if it's easier to work with and it's going save me about ?180 and will better for bigger joints like the outside of a pompeii

[leetheldc]

Re: Fire cement

Iam hoping for 20 years or so out of my oven would the home brew last this long I don't want to do it half harted ?

[Niro]

Re: Fire cement

Hi all, I'm building an outdoor 40" Pompeii oven and I'm about to start setting the doom as soon as I find the right mortar.
My local supplier suggested that I should use premixed mortar named "Unibond" that is manufactured by Unistara an Italian company.
After I bought the wet premixed mortar I found that the Pompeii building guide mention this

"Finally, makes sure that you do not use a wet, premixed fireplace mortar with water-soluble binder. There are a number of mortar brands designed for in-door fireplace installation, where the mortar does not cure to a fully-cured, waterproof state. This is the wrong product for pizza oven installation."

I tried to search online whether this product is water-soluble binder, without any luck.
My questions are: Does this mortar has water-soluble binder.or
can this mortar be used for an outdoor oven? or this is the mortar that's the guide warn me about?
Thanks Niro

[cobblerdave]

Re: Fire cement

Gday
There is an oven built in the late 50s by a Greek family near where I live. It was unused when I saw it about 10 yrs ago. I couldn't tell you how it was constructed then but the hearth bricks were worn thin at the entrance so I reckoned it had seen a bit of use. So I recon mine should last as long as I can still cut wood I hope.
The hardest ingredient to get for the homebrew mortar is the fireclay. The refractory properties of the fireclay are not needed. You can substitute by using brickies sand which contains clay anyway. Or you can use powdered clay.
Its what gives the mix the stickness and workability that makes it easy to use for mugg bricklayers. Too much of a good thing is still to much so don't overdose it or it can lead to cracking.
Regards dave

[leetheldc]

Re: Fire cement

I've today been advised by a kiln supply company that for a lasting pizza oven mortar he would recommend grog and fondue cement @ 5 to 1 you can purchase grog at the grain size of builders sand up to the grain of sharp sand what's peoples thoughts on this

[UtahBeehiver]

Re: Fire cement

Isn't grog just ground up firebrick? If you do a search on the forum you will find several builders who use the fines from brick cutting in the "home brew".

[leetheldc]

Re: Fire cement

I also forgot to mention he strongly advised against builders sand as there are too many unknown particles that could shrink crack or blow

[leetheldc]

Re: Fire cement

Yes ground up fire brick to a sand consistency mixed with fondue cement makes for the perfect 2 dry part mortar the more you think about it. It's basically a sand and cement that can take the temp needed at all times unlike Portland and building sand

[leetheldc]

Re: Fire cement

But how pliable it is I don't know think I might make an order and see how it works