UK oven build - help with fire cement

[samcoombes85]

Hey

A brilliant forum, currently building my first Pompeii oven.

Can you help with the fire cement? I purchased Vitcas Fire Cement, but now have three tubs and am unsure if this is the correct product for the job? It is more like tile adhesive / putty, and I am just not sure if it is going to do the job.

What else could I use? I only really have three options;

I have this: Vitcas Premium Fire Cement

But could have got one of these:

Vitcas Heatproof Mortar

Refractory Morset

Should I trust the fire cement will go off eventually? Three days on and it's still quite soft and I cannot see the top roof bricks staying in, rather just drop out when I remove the ply.

Thanks for any advice :-)

[jms]

Re: UK oven build - help with fire cement

I got similar stuff for my build. Its really not the best thing for pizza oven building. If you had enough time and patience then maybe it could work, but it would be far easier to make up some homebrew mortar (fine sand, cement, hydrated lime, dry fireclay). If you are using firebricks then a 3:1:1:1 mix is standard. Put your unopened firecement tubs on ebay/gumtree.

[samcoombes85]

Re: UK oven build - help with fire cement

Thanks for that, I think I will.

Would the Refractory Morset be better? I could exchange what I have for that.

Thanks again

[jms]

Re: UK oven build - help with fire cement

Generally none of the premixed wet mortars are very good for building a pizza oven. They are designed for things like fireplaces or kilns where they don't have wide mortar gaps or get much hotter than an oven would.

[samcoombes85]

Re: UK oven build - help with fire cement

Problem is I am struggling with dry fireclay and lime locally.

Will builders merchants do it in a big bag?

[jms]

Re: UK oven build - help with fire cement

Hydrated Lime should be stocked at pretty much any builders merchants. It usually comes in 25kg bags but they are huge because it is very light. My local Jewsons had it. I used about 3/5 of a 25kg bag for my 32" oven.

Fireclay; 25KG Bag of Fire Clay to make Refractory Furnace Kiln | eBay Places like Jewsons can usually order it in on request too, or if you have a local kiln supply company they will probably have some.

[samcoombes85]

Re: UK oven build - help with fire cement

Fantastic. Thank you.

[samcoombes85]

Re: UK oven build - help with fire cement

This stuff is just up the road from me, is it the same thing?

http://item.mobileweb.ebay.co.uk/vie...d=271289055216

[cobblerdave]

Re: UK oven build - help with fire cement

Gudday
The fireclay is just there to improve the workability of the mortar. It's not absolutely required
You could not use any at all a squit of dish washing liquid to make the mortar plastic
Use bricklayers sand which has a clay content.
Source bricklayers clay , bagged in powder form.
Use powdered clay from a pottery supply.


Regards dave

[samcoombes85]

Re: UK oven build - help with fire cement

Thanks Dave.

So I could use a mix of soft sand, lime and normal cement? I've got febmix for the workability....

[cobblerdave]

Re: UK oven build - help with fire cement

Gudday
Sounds like a good plan to me.
Remember Hydrated Lime could be called Builders Lime not agricultural Lime
Regards dave

[UtahBeehiver]

Re: UK oven build - help with fire cement

Contact Bookemdano, his is a UK builder and he could help you material sources.

[samcoombes85]

Re: UK oven build - help with fire cement

Thanks guys for all your advice.

I need to get on with it this week whilst there is a break in the weather, and the soft sand / hydraulic lime / portland cement is an easy option.

I'll mix this 2:1:1 unless anyone tells me different?

This forum is fab :-)

Here is my build so far, the bit on the right is my bbq, and the space under is my wood store.

I'm new to all this so bear with me!

[david s]

Re: UK oven build - help with fire cement

I could be wrong, but by the look of your photos the dome is sitting directly on your supporting slab. While your floor looks adequately insulated your dome is not. You will lose a substantial amount of heat via conduction into your supporting slab. It may not be too late to remove the first course and insulate under them.

[samcoombes85]

Re: UK oven build - help with fire cement

Thanks - I did a lot of asking around and was told this would be ok (the entire dome will be covered with 4" vermicultie and rendered).

I've actually built a bit more than in these pictures, so it would be a real pain now to have to remove them.

Will it really loose that much through the bricks into the floor?