So after casting my first core and trying to figure out a decent refractory mix and most likely failing , I had an idea. Most people like myself can get a hold of those firebricks. Assuming one could jenga together a clever pile of these might it not be possible to make a couple custom pieces that could be fit into this pile? A carved trip section or the ramp at the back of the burn tube etc. Could these parts be made to fit into a standard brick core thus making it somewhat better and cheap/easy to make?
That "kind'a" already exist in other areas of oven and kiln building. I am sure if someone came up with really good, functional design (I have a few proprietary work ups in CAD) we could get a brick manufacture to cast or shape parts that when assembled would fashion a rather nice RMH. I have spoke with a few brick manufactures that I have been friends with for years, and all say it is achievable. The challenge in getting into the cost of "production runs," liability for combustible furnishing/apparatus and related "depart of sad" kinda things.
Because of this, from a "professional or commercial" level, it is just easier and better to make custom units. I am sure as RMH technology becomes mainstream we could see "fire brick shippable core assemblies" and full build kits...Which I kind'a like the idea of...BUT...I am also afraid of this too!! When "business-industrial" thinkers start messing with an idea...profit/greed...start corrupting the process. If I had the capital I would do it as a 501C3 cooperative.
Hi James; There is a performance difference between a home built cast core and a firebrick core. The cast core will reach high temps faster than a firebrick core as it is highly insulated. The cast core,s issue is durability of the feed tube. Gentle loading and occasional patching with a cast core and it should last indefinitely... A dense firebrick core is very durable but it will soak up heat away from the riser until it heats up. Using a masonry blade on an angle grinder you can make up a brick for the burn tunnel roof with a "trip wire" carved in it. A swale tail at the back of the burn tunnel could be carved from a firebrick or cast with refractory, although I have noticed that ash will form a natural one rather quickly. Professionally made cast cores are currently available from dragonheaters, very nice looking units, very shippable , all features cast in , I can't afford one myself ,but for the product you receive ready to go it's worth looking into.
Our neighbors put a commercially made masonry heater kit together as the primary heat for their straw bale house. I believe it was from HeatKit in Canada. I saw all the parts when it was delivered. It didn't look any more complicated than a knockdown piece of furniture from Ikea.
I've linked to a schematic of how the parts are broken down. All they had to do was assemble the numbered pieces and then sheathe it with their chosen exterior finish. In their case, they chose local sandstone and it is gorgeous.
So the technology and marketing solutions exist in an allied industry.