Robert Crose

I'm going through the same deal. My heater is slated to be a twin to yours. I'm now thinking about what Erica said. So because of the theory sounding good, I'm thinking about cutting my riser off at about 2" and building the rest o the riser out of refractory brick. Say about 28" tall, same as you have in the picture.

So now after even more reading I'm thinking hybrid. Steel 5" square feed and burn chamber with a riser of only 2" going up inside a refractory brick riser of the same size, 26-28 more inches. Would insulate better affording greater rocketing inside and then falling of gasses and heat outside. Any thoughts? Instead of building it "on the tank", I'd build it on the bottom of the tank then slide the tank over the top of everything and weld the two back together.

Thanks for everyone's help. The flue will be 6" black stove pipe. Otherwise the remainder will be 1/4 inch thick 5" square tube. I'm now slightly concerned about the insulation on the riser.
I originally was going to wrap it in a high-temp batting with a stainless wire wrap to hold it in place.
So now I'm thinking about a sheet metal enclosure outside the riser in place of the batting then filled with
Refractory cement. Any thoughts on that? The feed tube and flue will both have clean outs.

Anyone able to assist with a tech question regarding rocket stoves?
Here's my dilemma. This will be a small heater for my shop. Hopefully the first of many for my home and others. My heater is an old 100# propane cylinder. The intake and horizontal burn chamber is 4x6 heavy gauge steel tube, the vertical insulated chimney (if you will) is 5" square tube stock. The issue is that I want to use 3" insulated pellet stove pipe for the flue or exhaust.
Do you feel the size difference, other than the CFM being lower on the smaller pipe, would somehow inhibit the functionality of the stove? I understand the air velocity will not be as great but this particular unit will be for periodic and power outage use.
Or am I over thinking this whole thing; just build the damn stove?
Help?