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Re: Rocket Mass Heater for my home

PostPosted: Mon Feb 09, 2015 4:36 am
by mannytheseacow
Woah! Great update! Albeit leading to several more questions.

Would love to see more details about making the door, and what do you use to get the plaster color? Is that just concrete pigment?

So when you're talking about air percentages, is that % of CSA of the riser, or firebox, or the calculated base? And what size stock did you end up with for air feed along the floor, as I'm sure it's a standard stock? And the primary air and the sheet flow at the door are the same?

It seems like it's a great system. Even though you're not measuring for it, with the reduced velocity you must be cutting the omnipotent PM2.5. I'm not sure it would make sense for me to convert my stove again since it works fine now, but maybe down the road I could add a bigger bench and it would make more sense. I'm really seeing the best application for me to be an oven (finally, one of my own). But this would still be a balance between playing and necessity.

Oh man, and that wood caddy/rolling seat is the bomb.

Re: Rocket Mass Heater for my home

PostPosted: Tue Feb 10, 2015 5:17 am
by matt walker
Door details are few, unless you ask specific questions which I'm happy to answer. I'm no fabricator! I told a friend I might as well have carved it from a single block of steel with an angle grinder for all the work I made for myself in the making of the thing.

To describe it simply, it's angle iron configured to create a channel that holds fiberglass rope. Then another piece of angle iron for the frame, that seats in the rope. The door profile looks like this:

LL___JJ

Air is % of riser CSA. Rectangle stock is 2.25" x 1.25" I.D. Primary air is roughly 2"sq. Sheet is just 4 1/4" holes.

Yeah, flow through the fire box and ash is greatly reduced, and ash disruption is probably a fraction of what it was before. PM is for sure way better with this type of burn.

I think the wood cart changed my life!

Re: Rocket Mass Heater for my home

PostPosted: Wed Feb 11, 2015 12:51 am
by mannytheseacow
Wow, that door is way more in-depth than I would have expected. I assume you fitted the window with angle iron too? Looks like you need a whole thread on how you made that door.... ;) Pretty cool, though. I would have just put a stack of bricks in front of it.

Re: Rocket Mass Heater for my home

PostPosted: Wed Feb 11, 2015 5:48 am
by matt walker
It was a pain. The window is just captured with some screws in the other angle. If you, or anyone else, would truly like to know how I built it, I'll make a video with some detail. But yeah, lots of fiddly details. It's one of the big downsides to my current set up compared to the J. To get this thing to run well, it needs a well sealed door. That's not true of a PvdB batch in my experience, but this one is relying on controlling the delivery of primary air fairly strictly.

Re: Rocket Mass Heater for my home

PostPosted: Wed Feb 11, 2015 4:05 pm
by mannytheseacow
Well, I'd love to see it as I'm interested, but realistically not going to make one. Or if I did find myself making one, I'd be using whatever is available to me and probably not what you have available anyway. But if you're ever bored....

Re: Rocket Mass Heater for my home

PostPosted: Wed Feb 11, 2015 8:56 pm
by ByronC
You did a jam up job on fabricating that door Matt. Very nice, and a knob for "dialing" in the burn too:->

The kitty ottoman / wood storage is really neat.

So when your yard was pretty much full of smoke, what do you figure caused that? Switching over to secondary air before the firebox was sufficiently warmed up? Or maybe using a different character of wood than normal that takes a bit more handholding to get it buring well?