Coydon Wallham

Various things I'm not sure how to implement:
Floor insulation. For the stratification bell, I'd like to put down insulative cob on the wooden floor. I have horticultural perlite plus a number of wine and beer bottles (a nearby restaurant might supply some liquor bottles if they would be any better). The more bottles that can be used the better, since they would otherwise be headed for recycling and are much easier to deal with than perlite/cob mixture.

Any experience with incorporating bottles to insulate like this? Are they efficient? What kind of spacing would they require between the floor or each other?

When it comes to the brick walls of the strat chamber, could they go on the cob/perlite mixture, or would they need regular cob? How thick?

Not sure if there's enough context in these to convey the whole concept, but here's the building footprint and the working elements of the RMH with strat chamber:

When I bought materials from Open Your Eyes Bedding (through a link here at Permies) for my hemp sand/latex bed, I had her toss in a kitchen sponge kit. It's some hemp fibre you stuff into the provided pouch sewn from upcycled wool.

It works like a rag rather than an aggressive scrubber. I do my dishes at an outdoor wash station. I think I started using it this spring, maybe last year some time. She says it needs special care to last, but I've left mine variously sitting in dishwater for days, or on the table without wringing, all year. Constant UV exposure. It still looks and works as good as new.

The only negative shade I see is that, like a sponge, it isn't easy to get into irregular surfaces. Perhaps altering the fill could improve this. I use brushes for that kind of stuff. The "eco friendly" ones (please excuse the Amazon link) have undergone the same outdoor treatment for at least three years here. The soft tip is key to those brushes as the usual nylon 'bottle brush' usually has a metal tip that does nothing but scratch up the bottom of an actual bottle. For hard core scrubbing I have an old nylon brush on a handle that was bought long before I knew things were made with materials of variable merit, but hey, it is still in use at least.

The key hidden architect of kitchen maintenance is to appreciate the wonders of cast iron- anything I can't scrape off with careful application of a metal spatula becomes either seasoning or part of the next meal...

Glenn Herbert wrote:I think thick internal columns would count as ISA, but thin isolated brick struts would not because they would quickly get saturated with heat and stop absorbing more.

My RMH project is documented here.

So it looks like the transition from your riser to the bell is simply the bottom of the cook surface with no other restrictions?

Glenn Herbert wrote:Yes it is. I took complete photos of my inspection last fall, and have intended to add a description to this thread. I'll work on it in the next couple of days. It has kept me warm all winter (including the long cold March) on about 7/8 of a cord of wood.

It's sure been a crazy decade. Still think you might post an update? Inquiring minds want to know...

Could mention be made in the comments which videos are being added as time goes on? As a subscriber to the thread, we only see that something has been edited, but no indication on specific changes...

Thank you for your efforts on this, I've already found one new to me video that is invaluable to my current projects...

Glenn Herbert wrote:My 8" J-tube has the whole riser inside the bell cavity, and works great. The combustion core is all insulated well.

My bell has a similar ISA to the 6" BBR spec, and extracts enough but not too much heat so that the exhaust stovepipe is hot to the touch but bearable for a while early in a burn, for a few seconds after an hour or more of burning.

I have found that my 8" J-tube draws strongly with a 6" metal chimney, even at startup.

Are there pictures or diagrams posted on it?

I think I miscalculated the ISA on my theoretical bench above, just on the math, but reviewing what has been written in various places am not even clear on the principle. I think @Peter van den Berg wrote something on his site that any interior walls/columns (except for the firebox) will count against ISA totals, but read elsewhere that they wouldn't...?

I'm probing the interwebs for all the arcane secrets behind this dark art of the hybrid RMH and one prominent set of questions is begging to be addressed in my mind:

A) Does the burn tunnel/barrel need to be in a separate area and ducted into the stratification "bell" bench?

B) Can one large bench simply be made to match ISA requirements and the firebox positioned within the footprint such that the bench is level with the top of the feed tube?

C) Can the bottom of the barrel simply empty into the stratification chamber without a manifold collecting and directing the falling gasses?

I'm picturing all of the BBR designs that have the box inserted into the bell, while wondering if the J-tube would struggle to get hot with the cooler (but still much warmer than ambient) air from the bottom of the bell around it...

Stephen B. Thomas wrote:I figured that my current favorite wood joint would be perfect here: a draw bore. You put the two pieces together, then drill a hole straight through them both. Finally, you add a dowel rod in the hole you've made.



Looking back, I think that drilling completely through both pieces of material was a mistake. To add the dowel rod snugly into this hole, we had to stick another dowel rod in the bottom to hold-in-place the dowel rod that would be used for the joint. Next time, we'll try to have at least some material remaining at the bottom.

From the description, sounds like you used a straight bore. For a draw bore, instead of drilling through both pieces at once, drill only though the outer one (mortise). Then insert the 'tenon' and mark where the hole is. Drill the hole in the tenon separately, offset toward the shoulder by a fraction of an inch. Then pound in a tapered dowel (long enough that the non-tapered part is longer than the mortise is wide) to fasten them together, pounding the dowel all the way through and sawing off the tapered end where it protrudes. Should be less work than wedging a peg, with a longer lasting, snug join.