Is joining important for batchbox of insulative firebricks?

[wrekinwanderer]

Hi there,

I know lots of you guys are making insulative casts for your batchboxes, and I'm really looking forward to trialing a donkey style mud batchbox when I find somewhere to put the ash other than in the veggies, but here I'm thinking of using high spec insulative firebrick in an upcoming build. I'm just trying to figure out the best way of joining the bricks together.

Would using regular fire cement cause too much thermal bridging at the joins, or do you think it would be okay either by itself or with extra insulation outboard of the batchbox?

Or better to join the bricks by routing out a tongue and groove?

Or is there some ridiculously high temperature sealant that could be used?

What do you reckon?

Mike

[matthewwalker]

I'd probably just smear the joints with plaster or cob once the whole thing was stacked. Better yet, just cover it all with cob. Done and done.

[morticcio]

The burn tunnel and riser on my J tube rocket was made using insulated firebrick. I did same as Matt suggested, using clay slip to butt them together then covered them in cob. When it came to dismantling the stove the bricks were stuck together well enough. Not as permanent as cement or mortar but I wanted to re-use the IFBs.

[satamax]

The ones i have salvaged from calcium stills, in a company i worked for, had a sort of layer, may be 5mm, or less. Of something which looked the same collor. May be a smidge darker. Cream collor i'd say. That's all i know. The joints were thin tho, that's for sure.

[doggy1969bc]

From what I've seen ,just dip them in fireclay slurie and stack them . The clay will hold them together