rural
New Member
Posts: 38
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Post by rural on May 7, 2015 7:55:10 GMT -8
While reviewing an as-built drawing for one of Ernie and Erica's rocket mass heaters, I noticed that they were using firebrick splits for the heat riser, which makes perfect sense. Thinking about the stove's core, I realized that firebrick splits could be used for a lot more than just the riser. As an experiment, I'd be tempted to use splits for the whole core, even laying them flat over the throat, just to see what would happen. In practise, I'd probably use full firebrick above the throat.
This would cut the cost of firebrick in a stove by a fair bit and would allow the core to heat up more quickly.
Any thoughts as to why one would/wouldn't want to do this?
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Post by Daryl on May 7, 2015 8:27:03 GMT -8
A helpful hint for those of us way out in the boonies...ACE Hardware sells the splits/wood stove liners. I haven't had a problem with them in my ovens.
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Post by satamax on May 7, 2015 11:44:42 GMT -8
Rural, check this video for example. www.youtube.com/watch?v=7RyvsZD1_CUI use thoses too And i think from now on, my future batch cores will be split firebricks surounded by air entrained concrete.
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rural
New Member
Posts: 38
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Post by rural on May 7, 2015 15:50:33 GMT -8
Ya, I'm sold on using splits for the riser, but why not make the bulk of the core out of splits? That way you only have to heat up half the material before hitting insulation. I could see issues over the throat and perhaps where the gases shoot out of the throat and hit the wall on the back of the heat riser, but maybe splits are actually advantageous even in those areas.
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Post by satamax on May 7, 2015 18:53:04 GMT -8
I think the trick with all bricks, would be to use theses dry stacked, and attached somehow. I use fence wire (well actualy wire made to attach rebar) In Web4deb's video, he uses angle iron. I'm kind of actively searching a chimney's insert, which i would transform into a batch, by dry lining it with either splits of full bricks, may be even insulative ones. Since my beginings in rockets, i have that aim, to make metal forms filled with refractories, to hold them. This way, the lining is "easy" to replace, and metal doesn't suffer too much from the heat. Lately i also have that obsession with lining air entrained concrete with firebrick splits.
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Post by Robert on May 12, 2015 1:12:22 GMT -8
Hmm. I did one core from splits as well... but... when i build the heaters for client i want to be sure they will last ages (well 20years at least). With splits i would be afraid that eventually they will break... what is interesting ... when i speak with the technicians and experienced stove builders they adress a firebrick as an insulating material rather then accumulating... and especially when the firebrick is porous and softer, not this heavy dense compacted once...
i would be interested what Benoit thinks. He is also a very experienced stovemason from france... any others pro builders here?
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rural
New Member
Posts: 38
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Post by rural on May 29, 2015 17:49:07 GMT -8
Satamax, what are those tubular bits in your picture above? They look really interesting, but I doubt they are available here.
Anyways, thanks for the discussion. I received a bunch of firebrick and firebrick splits and hope to do some experimenting over the summer. (For the last couple of years, my interest in rocket stoves peaked late in the fall, as temperatures dropped to the point that outdoor masonry became impossible.)
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Post by satamax on May 29, 2015 23:55:20 GMT -8
Rural, where are you located? I guess in the us. My be your best bet would be to check if schiedel products are available near you. Mine are landini refractory tubes. Rated 400C° continuous, 1000C° peak. They usualy crack once, and that's it. May be there: Superiorclay or Sandkuhl. donkey32.proboards.com/post/10643/threaddonkey32.proboards.com/post/10637/threadAvoid the stuff which is too red. Usualy clay with chamotte (grog) in there; is pinkish or yellowish. If you are elsewhere, check in that thread, there's a few supliers who look promissing.
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rural
New Member
Posts: 38
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Post by rural on May 30, 2015 6:56:20 GMT -8
Satamax, I'm in Alberta, Canada. I've only just plugged into a supplier for firebrick, clay flues, and castable refractory. Hopefully, I can find someone who carries some of the manufacturers you've noted. Thanks for that.
But I have to admit, I lean towards natural building materials. It's just a lean though.
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gjh42
Junior Member
Posts: 61
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Post by gjh42 on Jul 20, 2015 13:19:31 GMT -8
Don't try using splits to save money; all the sources I have seen price them about the same as full bricks. If shipping is an issue, they would be cheaper to ship. If you want the durability of firebrick on all interior surfaces, splits would indeed reduce the mass to be heated.
"they adress a firebrick as an insulating material rather then accumulating... and especially when the firebrick is porous and softer, not this heavy dense compacted once... "
Yes, soft porous firebrick is highly insulating. It is used in kilns which fire above 2000 F for hours or days.
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