Jeff Ballantyne wrote:Hey everyone,
So heres my rocket stove. its been in the works for a while now, tweaking and tweaking... heres a video describing it and some temperatures!
one of my main questions is, if I used landscaping brick, other than fire brick, what things might I experience as far as burning and efficiency and stuff?
Please check out my video though and leave some feedback!
My rocket stove design
Heres the temps
Rocket stove temperatures
I had looked at a few of your videos, but still haven't got a clear picture in my head of how you are connecting the pipes and the firebox and all.
I'm on a slow internet connection, so a diagram or photos of the whole setup would be far more useful than video, if you have time.
Regarding your landscaping brick question:
Regular building brick, especially the older stuff that sometimes turns up from a demolition of an old chimney, can work just great. I like the stuff that is not as hard as
concrete; it can be used as 'sidewalk chalk' as a quick test to identify it. If it scratches the concrete, or just leaves a weird white line or no line, it's hard-fired clay or concrete pavers rather than old-style common brick.
Landscaping brick is often made with Portland cement these days, tinted red, rather than from actual clay. Portland cement tends to turn back into powder at the temperatures in a rocket firebox; we don't use it anywhere inside the combustion areas. Old brick found in the garden could be anything; try the sidewalk chalk test above.
The differences to combustion have more to do with density:
If you use an insulative or 'light' brick like foamy kiln brick, you get to hotter temperatures faster, sometimes too hot (we have melted perlite embedded in refractory insulation, indicating over 2400 F was reached). This is better for cookstoves and other briefly-used
heaters
If you use a denser brick or fire brick, you take longer to heat up to working temps, but then the brick itself can help stabilize those temps, and serve as heat storage between fuelings. This is better for long-burn or daily-use heaters. You would need insulation around the outside of the dense brick, so it's some extra material but the double-layers can lead to better seals too.
You want to keep the burn between 1000 and 2000 F for the cleanest, most efficient combustion of
wood and wood gases. This means the brick itself doesn't need to get hotter than 1800 F if you really dial it in. Some spots usually get a bit hotter, though. Common building brick handles up to about 2000 F, fire brick usually 2400 to 2800 F depending on type.
Hope that helps,
yours,
Erica W
