Brick bell on J tube RMH AND how do you do maintenance on the burn chamber and heat riser?

The subject sums up what I am hoping to understand.  I see articles and videos of people rebuilding their riser/burn chamber on a variety of heaters.  That concerns me if I go the route of a brick bell.  Can someone show me how you built a brick mass above a burn chamber and how you clean it out and replace it if needed without destroying the whole heater?

I'm leaning toward a steel drum bell because of these concerns.

Thanks, Tim

Hi Tim;
Depending on the materials and care of construction and use/abuse it can be many years before a J-Tube would need a rebuild.
By using a sand clay mortar it makes any disassembly fast and easy.
You could access your riser in 30 minutes or less, even enclosed by a brick bell.
Barrels with a removable lid are handy for inspection.

Building your first RMH is a daunting experience... Until you start...
By the time you have finished, you will understand just how easy it is.
Opening your RMH up for repairs/improvements is really no big deal after you are an accomplished builder/owner/operator...

Tim,

I would recommend building the core from the best materials. Burning wood is more challenging for refractory ceramics than burning coal or gas, because of alkaline slag that is eroding bricks.
Zirconium coatings may protect the bricks against slagging.
I saw some website with comparison of two masonry heaters needing maintenance. The one built with lower rating bricks needed serious repairs. The other one with Pilot DP bricks lasted 20 years not affected too much. Operating temperature of rocket cores is higher.
I would assume that min 40% Al2O3 bricks should last at least 20-30 years. With coating probably more. High alumina bricks may be even better choice.

Building lower, but wider bell will require less material removal for maintenance.
Of course it will only help when the bell is simple. If it has more ornate brickwork then the removal and reassembly will take longer.

Yasin Gach has solved the problem of maintenance by having the masonry bell with steel removable top.

Yasin Heaters

I always advocate for including a removable access panel in a brick bell, both for regular inspection/maintenance and to give some instant heat when the space is cold. In a traditional RMH the barrel gives instant heat; with a brick bell, especially a double skinned one, you have only slow delayed heat unless you have a metal panel. A metal top can do the job, though its radiant heat would be directed at the ceiling rather than the occupied zone of the room.