Stoves: firebricks: who knew?!

[Another John]

We got our first wood stove two years ago (exactly).

Noticing that the firebrick liners look a bit worn, I bought a sheet of firebrick material[1] and cut a spare set today, using the current set as templates.

I never realised that this stuff is so fragile! The only firebricks I'm familiar with were hefty things in the back of fireplaces: this stuff is completely different material.

I've put the current set back in the stove now, but two of them have cracks (not created by me moving them in and out). They're all also very knocked about simply from the process of chucking logs in the stove. Is this kind of life-time normal for stove liners?

Cheers John

[1] I had the chimney swept last week: the sweep told me that I could buy a sheet of firebrick material from the local stove shop, and also that I'd be able to get the local blacksmiths to replicate the baffle plate, when that becomes necessary.

[Dave Liquorice]

Probably is if you throw logs in rather than putting them in...

The proper fire brick liners in our similar age stove are in good condition. One has a corner cracked off but thats down below the grate rather than in the actual fire box so not particulary bothered about it. Broke when getting the things out as they are a damn tight fit, especially when they have two grains of ash behind 'em. B-(

Proper fire bricks are quite brittle so break easily but are quite hard so should take the occasional knock from a log, tongs or poker without damage.

Sheet fire brick material seems a bit of contradiction in terms to me. The only sheet fire stuff I can think of is relatively soft. Like the "asbestos" mats you have in chemistry labs at school.

[Another Dave]

I bought some vermiculite sheet a couple of years ago and made a complete set of firebricks. As you suggest I don't sling the logs onto the fire and everything is fine. The insulating properties of the vermiculite make the fire burn well too.

Another Dave

[Another John]

You're both right: I shouldn't be using the term "fire brick", because although these look like bricks, they are really liners. (Though I see that Esse call them bricks, looking at their spares site.) The stove is an Esse 301 SE btw.

And Yes AD, I think the material must be vermiculite. You cut it with a saw (and finish off the detail with sandpaper -- it's very soft!).

I was just surprised at how fragile this stuff is. I don't doubt that the original "bricks" will last for another year or two, even if cracked, since their role is not structural in any way.

And Dave Liq:

I'm not a chucker by nature, and this is a tiny stove so you can't really chuck stuff without danger of missing :-D However the heat of the thing prevents a gentle, refined placement, and encourages a swift "toss" [/this is getting a bit uncomfortable/] .... maybe I should dig out the massive fireproof glove we got, so that we can go for the refined placement. Another bit of paraphernalia!

John

[Tim Watts]

On Wednesday 13 November 2013 09:16 Another John wrote in uk.d-i-y:

Weird - my stove's firebricks are pretty heavy - and also slightly fragile once cooked in.

I had to change one last year... Definately not vermiculite.

[Scott M]

It's a refractory insulating material, not firebrick per se, more designed to go behind the firebrick proper to keep the heat in.

[dennis]

Are you confusing pearlite and vermiculite?

Vermiculite is a mica derived substance.

Pearlite is a volcanic rock.

[harryagain]

I think it is similar stuff to the tiles on the space shuttle.