Gerry Parent

Rocky Massengale wrote:J tube Dims appear to be good ?

Just now looking at your core dimensions.

Top gap (space between top of heat riser and barrel) could be made more spacious as this is where ash tends to build up.
Instead of raising the barrel height, I'd just lower the heat riser height by at least 1.5" since its already slightly taller than needed.
3" has been found to be a minimum for top gap in a J tube, a bit more if you can manage it.

In regards to the height of your feed tube being 14" tall.
It is recommended not to have any wood sticking out of the feed tube (mostly for safety reasons) so if your wood is cut 16" long, you may consider a shorter fuel supply. You don't want to raise the height of the feed tube too much either as it can lead to it being a competing chimney and also make it that much harder to be able to reach in to scoop out ash.

Burn tunnel could be made shorter.
Closer to 24" is preferred. The heat riser doesn't  have to be in the center of the barrel so it can be moved a tad closer to feed tube.

Your update to the exhaust exit looks much better. Depending on your space and layout preferences, you could also have it exit straight out the top of the jut-out you've created eliminating the 90 degree pipe bend.    

Rocky Massengale wrote:I have also removed the 180 and incorporated a Sump and approximately a 3" elevation change to bottom of Chimney 90 so that the Sump is not to deep. Your thoughts ?

From your picture, the opening to the exhaust looks cramped to me. The transition from the bell to the vertical pipe needs to be large enough as not to restrict the gas flow. A funnel shape is ideal.

Rocky Massengale wrote:Do these seem to be in line with criteria required for an optimum functioning RMH ?

From my understanding, the tube within the bell is only necessary for longer runs (or bends) where the heat has a harder time getting to the other end of the bench and heating it unevenly. Otherwise, its just another thing that can clog up with ash and in your case, no real way of cleaning it properly.
The exhaust exit on the bottom of the bell could also be a problem in this same manner. Eliminating the extra 180 degree turn and just have it come straight up from the bell would be better.

Rocky Massengale wrote:Does this dimension include all partition sizes as well such as top, walls and floor of bell as well ?

Yes, however the floor is never included into the ISA calculations.

Rocky Massengale wrote:is that a square foot dimension for bell size, calculated, but will the cubic foot of space also be important or should it be limited to attain a particular stratification in the bell? By the dimensions shown the square foot dim is only 18'6" but the dimension shown for a 6" system requires 57' which is almost 4 times the size shown seems rather large compared to what i see in videos and pictures ? Please explain

The chart Peter gives on his website were intended to accommodate a batch box build, not a J tube core, so the numbers may not be exactly the same for both (although it is a good starting point).

Not sure where you got 18'6" from as it is not the total ISA of your bell - That's approximately just the roof ISA. Add another 4 walls and there's your explanation.
I see in a later post you have also updated the size of your bell and have said it is roughly in line with the recommended chart which appears correct.

Although bells can be pretty much any size or shape, bends, restrictions and obstacles will impede the natural flow and stratification may suffer. Your rectangular bell is simple and should have no issues. If floor surface area is in limited supply, columns can add to ISA and also help to support the bench top.

Rocky Massengale wrote:Thank you,
After Looking at some of the calculations from Peter, do the stratification chambers require a certain amount of cubic footage to work most proficiently or will the cooled gases find their way out not matter what size the chamber is ?

I would say both of your statements are true however, without a certain amount of heat going up the chimney, draft will be compromised leading to all kinds of problems. So yes, it is important to size your bell correctly unless you like breathing smoke.

Substitute Thomas Reardon for today's Thomas Rubino and we now have his origin story.
Keep up the sharing and educating my friend!

Yes indeed Mark, I think it looks great too.....what a great Christmas present you gave to yourselves.
I like the way you arched ceiling of the firebox and the interesting way you supported the superwool on the roof of the bell.
May it keep you both warm for years to come.

Just noticed my watch settings for this forum were turned off..... my favourite forum too!
Anyways......Cedric the stove turned out beautiful !!!
You have my whole basket of apples as a virtual gift.
I liked the way you created corner posts as guides for the bricks without the need for levels as much.
May it keep you and all its inhabitants warm for years to come.

Peter van den Berg wrote:This is the lining on the inside of the bell. This is where the greatest thermal load is expected in the bell, hence the extra protection. As a hindsight, it could have been one brick higher....

Splendid Peter! Thank you for documenting this build so that it can be a bookmark for future builders to reference...... and a delight for us that have worked on a similar contraption with the same enthusiasm.
Question: Curious why the ceiling of the bell had regular bricks instead of firebricks, especially right above the riser exhaust port?
Also, I noticed a latch on the door which appears to do something for the air inlet flapper. Is it to lock the flapper closed when the fire is out?