The sun shined today! The baby dragon took a nap.

Finally the sun shined today !  Was so nice I let my new shop dragon take a nap.   And then I pulled its convertible top off and had a look inside.

A lot blacker in there than before … a thin light coating of ash. All told it looked just like I left it....


While I had the top down I built a second column nearby the first one.  More mass, more ISA. Hoping to hold more heat in longer.


Took about 2 hrs with the wet clay before  exhaust gas temperature was up to 240F …  I guess a growth spurt will be happening this summer.

The ceramic blanket I used to seal between the barrel and the brick / hardy board top is working flawlessly!  Not one soot mark on any of it!  

With my new column I over estimate my ISA to now be 88-89'.  An 8" batch box is suggested to run 95'... My 8" J tube is doing rather well!

Nice job!  Dump bags of vermiculite or perlite into all open areas?

Michael Moreken wrote:Nice job!  Dump bags of vermiculite or perlite into all open areas?

I am sure what you think Tom would achieve by filling with perlite or vermiculite.  They not not add much mass and as an insulator they don't absorb much energy/heat.  Also he might end up not absorbing as much heat into his mass if it is partially insulated from the hot gas.  If I misunderstood your reasoning, please correct me and enlighten me.  Thanks.

Hi Mike;
The outlet for the exhaust is on the floor. Filling the bottom with anything would block it:)
The entire brick bell is built on an insulated section of my slab, that heat is staying rite there.

Guess you could instead add the clay mixture where you want to add mass for conduction.

Hi Mike,

What Tom is attempting to achieve is to maximize surface area to absorb heat.  If you simply add more mass without sculpting it to increase surface area as well as providing a path to the mass so it can heat up you will simply lose heat as the new hot gas coming in from the fire, displaces the existing gas in the bell.

This is why Tom has stacks of block and brick in the bell with lots of edges sticking out into the gas stream.

It is a balancing act to get as much heat out of the gas and into the mass as possible before the gas goes out the flue and up the chimney for ever taking the latent heat with it.

Sincerely,

Ralph

Tom, what temperature does your bell reach?

Hi Graham;
Depends where I check it.    External brick temps are 225+ near the core, below the barrel.   Average external brick temps are running 150-175F,   The barrel is 880F on top and 400-500F on the sides. Roof is 200+

What I consider to be a problem is, my mid stream exhaust is running as much as 325F at head high on the chimney. I would like to see this number around 250 F max.

My plan for this summer is to go taller with the walls and try to give it an arched domed brick roof.

Tom, I guess it's too hot then to use water as mass storage inside the bell.  What about outside near the bell?



I've always hankered after these solar tubes but never had a floor that could sustain their weight.

http://www.solar-components.com/TUBES.HTM

Hey Graham!    Those tubes are way cool !  My wife pointed out that we would need to sterilize our water, its gravity artesian  and very alive...  would be tinted (algie) green in no time...


Back to my stove. Water is not an option. That RMH is the only heat, in an uninsulated shop in northern Montana. If I leave town to go to work …. frozen water out there by the second day.

A taller bell with a cool arched roof is my answer, or possably a secondary barrel bell like Max sugested.

thomas rubino wrote: or possably a secondary barrel bell like Max sugested.

That would be a quick fix for this winter.

You plonk a barrel above your little stub of bricks, with the tube entering it a smidge. Remove one of two lengths of that black pipe, use two elbows to move the tube to the side, from where it is now, and do a plunger tube in that barrel. Make two brick legs for the barrel, and cover it with bricks or pavers.





That's an afternoon job May be well prepared, two hours and you're done.