james manning wrote:Hey Brian, I hope that works. There is a castable version of IFB (soft brick refractory) called Greenlite (they have different grades, the increasing number corresponds to tougher stuff) A monolithic interior should last longer and ship easier. I do wonder if this may end up being a more cost effective version than the Silicon Carbide? The advantage of the SiC is that is non-porous and more resistant as a whole to the erosion/abrasion of combustion gasses in regards to the flow (think wind erosion) and chemical attack (wood ash has a high alkali/alkaline content). When do you expect a prototype? I work with a company out of the Boston area that has a fast turnaround time... Have you thought about building it outside and running it nonstop (sleep depending) in order to ascertain lifecycle? A shared google sheet with all owners could allow an aggregation of data (spall, hot face wear, cracking) to be tracked over time to factor in the price of the riser vs life and factor that into the overall efficacy... How much does one cost?
james manning wrote:I don't think think the expense is in the casting. There shouldn't be any reason why the draft angles to make it in one or two pieces would get in the way. It's really about spreading the cost of setup, design, and tooling over enough units to bring that cost down. Additionally, my thoughts for SiC were that people use it in wood fired kilns over 2600 f for decades and they're still serviceable. That's why I'm curious to track life vs cost/ energy required to fabricate. My thoughts are that a SiC core insulated with ceramic fiber would out last an IFB core by an order of magnitude of thousands... My basis for this is that no one uses soft brick in anything wood-fired because the alkalis degrade it very quickly (wood firings typically go to over 2500 f and will stay there while accumulating caustic ash deposits for hours) while SiC lasts in these conditions for decades. That being said, if the short run time of a rocket stove limits exposure at temps that melt ash maybe it's not an issue, but then wouldn't said ash be a particulate concern?
james manning wrote:
P.P.s if the cost is less than 50 bucks count me in on your project.
Thyri Gullinvargr wrote:You mentioned something about doing a Kickstarter for this, if that paid for the tooling and mold how much would each core be? Do you know yet?
Thyri Gullinvargr wrote:It depends. Paul just ran a Kickstarter that was something like 1400% funded (goal was something like $6000 and final amount was over $80,000). A bunch of that went towards stretch goals, but I think that's because the whole point of the Kickstarter was to give people something they were asking for. You might find the Kickstarter podcasts he did after useful.
Part 1: https://permies.com/t/65954/kickstarter-part
Part 2: https://permies.com/t/65976/kickstarter-part
Part 3: https://permies.com/t/65992/kickstarter-part
The thing is is that if it's for something people really want and they know about the kickstarter you may get more than you're expecting. It could go anywhere from not getting funded to getting funded much more than you thought you would.
james manning wrote:I'm just curious as to the lifespan vs the cost of an IFB/ fiber core vs the lifespan vs cost of an SiC/ fiber core. For shits and giggles I've fired a soft brick next to a hard brick in a wood kiln a few years back... the soft brick eroded by half its volume in one firing, while the hard brick was slightly bigger from an accumulation of melted ash without having worn away or eroded. I am still interested in this project though and would be interested in helping track the life cycle and total run hours of any configuration as I believe that we will do more with data to push UL standards and bring this tech into the mainstream.
Dina Herrington wrote:Is it too late to get in on the group purchase? My only concern would be shipping to AZ
J.D. Ray wrote:More power to you, and good luck.
I'm very interested in buying a well-made ceramic core so long as it doesn't cost a huge amount of money. I have no idea what your expected production costs are, but (for me) two or three hundred bucks for a core and riser seems about the upper limit of what I could justify. The $36 riser linked above in the group-buy situation seemed almost inordinately cheap; I'd happily pay double that for a riser.
J.D. Ray wrote:Put as much as you can into video production. Hire a professional; they're worth every penny. And again, good luck. If there's anything on the analytic or technology front I can help with, PM me. Also, I do pretty well with SketchUp.
J.D. Ray wrote:Also, I do pretty well with SketchUp.
Matt Walker wrote:James, I launched my shippable core yesterday. I put an intro post in the RMH forum, it's here:
Brian James wrote:I posted a brief update on our progress at https://permies.com/t/69539/Shippable-cores-progress-report