Firebrick mortar in first bell

I am about to start building a 6 inch j tube system with bells in my basement soon. I'm just trying to figure out how to join my firebricks for the first bell. I can use just clay to join then but that is very fragile. I want to have my bricks be very stable if bumped. Is the Portland lime perlite sand fireclay mix good to use for joining bricks in a high temp area such as the first bell? In the second bell I plan on using maybe regular bricks and regular mortar but is this mix ok for joining bricks or just for making castings?

Also I'm still looking for a recipe to make the casting of the top of my bells. Is this recipe also good for this purpose?

Or can someone recommend a top plate to use for covering the tops of my bells? I do want a masonry top and not steel. I would just mortar bricks together and then top the bell with my bricks but I can't find a high temp mortar to use which is why I want to check if that recipe is ok to use.

Thanks

Dave M. Do you have a workshop or home office or a rec room in your basement, If not a strictly conventional 6'' j-bend Rocket Mass Heater RMH
Probably Will Not work well for you ! Placing any RMH in a remote location where you can not run it by ear will degrade your ability to give it the
attention it deserves ! The rmh can only serve you as well as you serve it !

There is also the increased possibility of smoke back, made worse by running a Clothes Drier with an outdoor exhaust*, or the exhaust fans in your
bathroom,or in the range hood over your cooking stove! To understand this and the way that your house breaths releasing hot moist air from the top
of your house and drawing in cold air at the bottom, you will need to Google Stack Effect, And Whole House Stack Effect !

There is a adaptation of the j-bend RMH that allows for the batch loading of your RMH will a full charge or Batch of wood still super dry and split fine.
While this does decrease the total amount of time needed to tend to a RMH, a good part of the RMHs super efficiencies are do to paying close
attention to its burn, if it is located within the heart of the home this tending becomes sound driven, with no more thought taken than it takes to
adjust your reading glasses .

I think that you will get more than one negative comment on using any kind of Portland type cement anywhere near your RMHs combustion
core or the 1st barrel,as Portland cement fails at temperatures well below the Temps found in the Burn Tunnel and Heat Riser, possibly also
within the 1st bell !

Just fireclay and sand will make a superior mortar for your firebricks ! If using fire brick to create your Heat Riser The easiest way to insulate the
Heat Riser is with Rockwool !

Perlite is used with just enough clay slip to be able to make small snowballs of clay perlite that pop apart when pinch between finger and thumb
Perlight and clay slip mixed to gather is the insulate material that stops you from setting your floor or walls on fire, is tamped into place and
covered with Cob !

This is where I ask if you have been to rocketstoves.com to download your PDF Copy of Rocket Mass Heaters, if not you are overdue !

For the Craft! Think like Fire! Flow like Gas! Don't be the Marshmallow! Your comments and questions are solicited and Welcome Big AL

I was aware about the whole house draft but figured since it didn't hinder my wood stove I would be OK but either way I can work around the dryer and exhaust vents.

Also for the sand and fireclay mix does it need to be fired really hot to get high strength? Is it comparable to heat stop? I tried with clay and it seems very brittle but maybe it never got hot enough.

One more thing, I have all my firewood cut to about 30" so I don't think I will have to fiddle with it too too often. But still either way I have a finished basement so won't mind spending time down there in the cold winter anyway.

Dave M. : Depending on the physical characteristics of YOUR clay and Any other materials trapped in it All Clay expands when heated and contracts when cooling, the
Clay acts as the ''glue'', and the Sharp or builders Sand retards the expansion…!

Some clay as it comes out of the ground has a perfect ''mix'' of Clay and Sand to make a perfect Mortar or a Cob when fired ! Its all different and ALL needs to be test
fired.

Because two or more pieces of firewood setting in the Feed tube can in-channel air between them, acting as little chimneys -this can make Your feed tube with 30''
wood in it taller than your Heat Riser, making a competing chimney -instant smoke back

To use 30'' fuel wood requires that the Heat Riser be 3Xs as long or 90''* plus the heat riser to barrel gap you are now set up to radiate most of your heat directly to
the ceiling. Also 30'' logs are hard to split Fine enough to give you the efficiencies your RMH can deliver. . ! For the Craft ! Big AL

* the Ratios Feed tube 1X, Burn tunnel 2X, and Heat riser 3X can not be fiddled much -with out smoke back And your basement local is also not ideal!

These are issues for you to address to the best of your abilities, with the materials you have, or can get, however to be properly informed you need more information
than what your fellow members can give you in dribbles and squirts! You need to drink from the hose ! PLEASE, Get ''The Book'' A.L.

Al

A couple things. I did read the book. It was very helpful but I still have many questions even after researching for months and months. Mostly because I just haven't built the actual stove yet so I will gain a ton of knowledge when it goes hands on.

Also as far as feed tube and dimensions, I found it was 1:2:4 I didn't think it was 1:2:3
So if feed tube is one foot deep then burn tunnel is 2 feed and heat riser is 4 feet. No?

And my fire wood, I though the heat riser is in proportion to the burn tunnel and feed tube, not the fuel. Do I have it wrong?

One or thing, the basement. Do you forsee an issue because of the need to be near the stove and you feel it won't be attended to in the basement enough or are there other factors about the basement you feel will arise?

Thanks

Dave M. : It totally depends where you measure from, The Book is the final authority go with what it says !

While you did not give a depth for your Feed Tube, your RMH works best with several pieces of very dry fine split wood,Again several sticks WILL simply
by their close proximity to each other form air channels what effectively increases the Height of your Feed Tube, this will make it a competing chimney
Stack Effect !

As a minimum every piece of wood you are planning on feeding your RMH with should be split so that there is more wood surface exposed than bark
surface remaining. Starting your fires with wood split thinner than that -without bark! With 30'' long pieces, splitting that fine is a lot of work, with splitting
maul and wedges

Opening a window anywhere up stairs ,but especially a 2nd floor window, and even sometimes just having a well ventilated attic will compete with the
RMH chimney

An open window 24'' by 30'' can make a better Chimney than your 6'' or8'' chimney, The more vertical distance between the RMH that you hope to put
in Your basement and that window the better the open window can act as a Chimney outlet ! Whole House Stack Effect

Stack Effect and Whole House Stack Effect are not just intellectual concepts, you have to understand them so well you could explain them clearly to your
Grandmother !

A rocket stove in the basement should heat that space very well, and your upstairs floors will be warmer, but in effect what you are doing is adding to
your total living space and increasing the heat load, As you have it planned now- next spring you will be saying Damn, I surely didn't see the fuel savings
everyone told me I would see with a new RMH !

One of Three things will happen, ether your finished basement will become the new heart of the house with everyone gathered there! You will become a
basement dwelling Troglodyte, " Where's Dave…?'' , Downstairs tending his damn wood stove, or trying to continue to live life like before, with every trip
to the basement an interruption in your day Quickly growing into a drudges task, you will find reasons to ignore !

Your RMH can only serve you as well as you serve it ! For the Crafts ! Big AL