Thank you Byron! This is exactly the kind of info I was looking for.
I see from your posts that rockets are the main reason you post.
What are you using for your burn chamber?
Are the insulating bricks tough enough?
Are you using the roll of insulation around your riser?
I haven't dealt with Harbison-Walker, but insulating bricks are not at all tough, rather fragile and somewhat crumbly (usually). They are perfect for a heat riser which will never see abrasion, and full bricks are plenty of insulation by themselves for a riser. (Electric kilns are commonly built of just 2 1/2" thick insulating firebrick with a stainless steel wrapper.)
Hard firebrick would work excellently for a durable feed tube and burn tunnel.
The ceramic fiber blanket would be good for wrapping the burn tunnel to insulate it.
Location: Upstate NY, zone 5
posted 2 years ago
The fireclay can be mixed with perlite (barely enough clay to stick the perlite granules together) to make heat risers which are better shaped (round) and much cheaper than insulating firebrick. It is also a good mortar as a thin soupy mix to build the brick core with.
Location: US, East Tennessee, north of Knoxville
posted 2 years ago
Hey William, what ya planning on building, j-tube or batch-box?
Yeah, as Glenn mentioned, best not to use IFB in the firebox's heavy wear areas where it will be subjected to cleaning tools and stuffing wood in the stove etc. IFB is very insulating, light in weight, and low density.
Wood fired heat is relied upon as my only heating source. I spared no expense in building my indoor RMH, needing a system built tough for as close to zero chance of breaking down in mid heating season as possible. A system that would give Methuselah a run for his money, so to speak:)
Construction is standard fire brick (9.0 x 4.5 x 2.5, dense, aka 7 lbs. per brick) for the Peter van den Berg batch-box combustion unit (6" system size) along with some standard fire brick "splits", cut to form the firebox's Vee floor.
The heat riser is constructed solely from 2600° F. IFB, stacked on edge for a 2.5" riser wall thickness, all mortared together (1:1, fire clay to masons sand). Totally self supporting, very rugged, long lasting, and quick to build. No added insulation is needed, the IFB do a fine job all by themselves.
The brick layout I followed is similar to that pictured on Peter van den Berg's site, with the exception of the Vee floor brick arrangement:
I used the ceramic wool blanket to insulate the batch-box combustion unit. Then everything is encased in regular brick, the non-holed kind of solid brick many homes and commercial buildings are "faced" with. The whole thing, thermal mass bench and all, is encased in that brick, kind of "Russian stove" style.
Thanks for your replies.
I intend to a build batch box or three.
A J-tube can't compete in performance or convenience.
I think water cooling the feed tube might allow one to burn long lengths of fuel without risking reverse draft, butthat is an idea that is utterly unproven.
I have been looking for affordable castible refractory, going in the direction of homemade mixes,but now that I have found a source of insulating bricks,an all brick build seemd like the easier way.
For a variety of reasons I need to keep the dragon outside and bring the heat inside. Because of that ,I want to get the most out of every load,and I am not worried about overheating the house.
So I plan for an 8" batch box.
I intend to place it at the rear of my house,just outside my window,and circulate air through the mass, which will be insulated.
Warmed air will be directed into the return air duct of my conventional hvac system,cold air will be drawn from my basement.
Before any of that ,I want to build a much smaller batch box to go in the chicken coop/greenhouse.
I don't have a lot of room for mass in the coop but I have run corrugated pipes throughout the foundation,and I hope to use them to store heat, sunnyjohn style.
After I get heat to coop and home,there is a shop to be built and heated,a bread oven,grills,forges,kilns and maybe some other things to be built.
But first things first. I need to parse out which materials I need as I settle on build.