Best castable refractory for batchbox, throat, etc?

[ukdan]

I'm getting ready to mould my batchbox for my outdoor stove (similar to the peterburg design) but I'm not actually sure of the correct type of castable refractory.  I see three main choices.... dense, insulating, or "low cement". 

I understand that the low cement version is better for resisting chemical attacks in incinerators so probably not applicable to me so it's down to dense or insulating. Does anyone know if insulating refractory is hardwearing enough for a firebox?

[satamax]

UKdan, have you seen the green machine post?

Well, i've used insulating firebricks to line the oversized firebox of my horizontal rocket It's working lovely now, despite the restriction in the flue. May be an easier way would be to make a metal box lined with thoses. Cheap, fast, easily replaceable. Jmho.

[ukdan]

I have yes....interesting work and project

I considered firebricks but I just like the idea of casting something to my own desired shape...similar to the PvdB but with a few differences here and there. I just wondered what type of refractory people were going for; I can cast mould and cast it quicker than I could fab up a box, and line with cut bricks. Plus the castable seems to work out cheaper too.

[satamax]

Do you have refractory mapegrout in UK? Quite cheap to cast stuff with.

[ronyon]

Satamax, can you tell me more about Mapegrout? Not only does there seems to be more than on formulation, I would be interested in how you would uses it.

[satamax]

Well, by the book, the refractory mapegrout is suposed to whistand 1000C° continuous, à smidge low i'd say. But i think it can cope with more.

I mixed it with vermiculite to pour a six incher. And to hold the parts of the green horizontal batch thingy together. So far, it's holding.

[morticcio]

Sept 15, 2013 12:42:09 GMT -8 ukdan said:

Does anyone know if insulating refractory is hardwearing enough for a firebox?

My first batch box was cast using insulating refractory. It works well but isn't holding up as well as the one cast using dense refractory.
I'd use dense and then insulate using 25mm or 50mm superwool or perlite. You get the best of both then - hard wearing + high level of insulation with the added benefit of the"flywheel effect" a dense refractory gives you.