Heat resistant mortar - hydraulic or ceramic drying??

[aureole]

Re: Heat resistant mortar - hydraulic or ceramic drying??

Ah,

I've got an option b given to me, I've been recommended/suggested: air-drying mortar on the inside of the bricks, followed by some very fine refractory concrete on the outside. The concrete I'm getting has a very fine ballast/aggregrate inside. If this is a stupid idea, I've got the backup plan of 75kg of fireclay on the way. Not sure what I'll do with all the spare refractory stuff!

Quite an interesting conversation with the guy from Midlands refractories: he essentially told me I was completely mad to try this (although he conceded the Romans definitely knew what they were doing, and if ovens survived the volcano at Pompeii, they must've got something right!). He suggested the air-drying stuff is used (very, very thin) because you don't want any joints between refractory bricks.

Interesting stuff, I'm hoping the refractory concrete/cement I get is pretty close to refmix (I'll check the label when it arrives).

[atdabch]

Re: Heat resistant mortar - hydraulic or ceramic drying??

be carefull of the pre-mixed mortars...the ones i found are not water-proof when dry...constant rain and wetness will break them down

[asudavew]

Re: Heat resistant mortar - hydraulic or ceramic drying??

Frances finished his build a while ago !

Yeah SHE finished a long time ago!

[Frances]

Re: Heat resistant mortar - hydraulic or ceramic drying??

Hehe, yep definately still female the last time I looked...

Sorry I didn't answer earlier, but we were away for a couple of weeks. Sounds like the mortar I used wasn't the same as what you're talking about at all. Mine was a dry sandlike powder which needed to be mixed with water before use.

Here's another thread where I go on about it at length , and so far it seems to be working just fine! (further long term testing is being undertaken as we speak)

http://www.fornobravo.com/forum/f8/h...clay-2783.html

Oh yes, dvonk has since built an oven with the same sort of product.

[aureole]

Re: Heat resistant mortar - hydraulic or ceramic drying??

Hehe, yep definately still female the last time I looked...

Ooops. Sorry about that

It's a funny thing... I've got two options: the fireclay mortar or the superplastic. My current plan is to butter the bricks finely with the superplastic, then use very fine castable concrete mix in the wedges (provided it's workable enough to do that). I'm going to have a play with the materials to check it'll bond well enough and fill the voids.

Anyone have a clue about plasticising compounds at high heats? Is it okay to add them and/or PVA to a high-heat mortar?