To capture the heat from the J-Stove, a secondary stove pipe connects into a separate mass, the pipe then exits the mass and rejoins the main J-Stove stove pipe to flow out the chimney. This is the mass form I designed and made. It will warm to a few hundred degrees durning a 40 minute burn of the J-Stove and radiate heat for 8 to 12 hours.
The side vent of the stove fits into the hole pictured below- the mass form is upside down and will have a welded metal platform to align it with the side vent.
I’m letting it cure into next week. There has been some small shrinkage/settling that will need another round of pouring- I may use a fast setting concrete to make a stronger platform for the mass, then I will remove the form. If all that is successful, I’m going to cut it down in size quite a bit. This is designed as the ideal form to have at the ranch that can fit into the back of the pickup, but it is too heavy to move without at least two more strong guys and a bit much for a 500 mile trip in the back of the little pickup. I’ll remove the bench and bevel an angle into the body of the mass, dropping around 100lbs. If all that works out, it will travel up to the ranch sometime this fall for installation and testing.