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Hey guys, I am new to the group. I purchased a retired firehouse recently and have already moved my family into it. I have the rough out already made for the RMH heater exhaust and really need to get cracking on building it. It's very cold out and we are relying on electric space heaters ATM.

I would need help with a few things:

Have we determined the right dimensions that I should be shooting for for burn chamber, insulated stack height, etc. for the 6 inch builds? I could really use some help! So many sources pointing to different numbers...

Also, what is the best source in the Seattle area for flue pipe and 55 gallon barrels? Hoping to start my build this weekend and to be done by Christmas!

Thanks,
Adam

Welcome Adam, nice to have another Washingtonian here!

First, flue pipe and barrels. Barrels should be easy, my preferred source is my local Pettit location. I imagine they have a spot near you too. They will usually give them to me, but some might sell them. Otherwise, scrap yards, truck service places, shipping places, and so on. Drive around industrial areas and keep your eyes open, you will eventually find someone with way too many. As for flue pipe, recycled can be hard to find, but I've had good luck at construction companies. Go to their yard where they keep materials and vehicles and ask if they have any old HVAC ducting, or again, just drive around and keep your eyes open. If you are in a hurry, it can seem impossible to find. If you have time, it seems to come to you on it's own. Good luck on that one. Oh, if you have buddies who do construction, especially remodels, ask them if you can come help them demo and get the heating ducts.

As for dimensions, my 8" core casting video will give you pretty good dimensions. Just scale down the square sections to be 5.3" sq. and you'll have a great core. Same overall length, same height of feed and riser stubs. Riser height will be the same, roughly 31" from top of core.

Keep us posted on how it goes man, nothing makes me happier than seeing a new build come to life!

Welcome Adam, ditto on all Matt said. I might urge you to go for an 8" system if you can but I guess that all depends on what kind of exhaust limitations you might have. If you're going to go for the 6" system, for sure just follow Matt's video. I was pretty confused when I started looking at these things too. There's so many people just making these things out of brick and dirt, and everybody will tell you something different about what is right.

I have some issues with my 6" heating my home due to Illinois climate, but as far as performance goes- it runs like a dream.

I would like to add my welcome as well Adam. Glad to have you with us. You will find that this site will be a wealth of information for your build. My only opinion about building a 6" unit vs an 8" unit comes from these pages, I have no personal experience myself. From what Manny has experienced with his 6" heater I would definitely go for the 8". If because of your warmer climate you find that the 8" seems too large, what's the worst that can happen? You have to fire it Less, that is the only " Down " side I can see. But if the 6" has trouble heating your space, well, that is a major disaster. It might help is we knew how many sq ft of area you have to heat, and how much you need to increase to temperatures. Maybe a 6" unit will be more than enough for your needs, Having said that, I would still go for the 8", more power, more heat .

Thanks everyone for all the replies. I am getting started by buying supplies this weekend. I am planning to build next weekend. We have a baby coming in a month and I need to get the place heated.

I don't think I will have time to scavange for used stuff, so I am open to buying things if necessary. I am only heating 900 sq ft. and it's all in one room. I have already roughed out the 6inch vent, so i doubt i will be going to an 8inch at this point.

I am worried about riser height as this is going to be built following the model that you see here in belgium:

http://www.flickr.com/photos/71355476@N00/4149423745

Given that the 'cook top' needs to end up at counter height i think i will need a shorter riser. Is that okay?

Matt, when you say the square sections what do you mean? Any chance you could use paint and label this drawing with dimensions?



Thanks,
Adam

No problem Adam, here's the numbers.



As for riser height, for sure that's going to be an issue. The taller the better, and shorter can be problematic. That said, I've built some outdoor systems with as short as 36" risers(core+24"), and they seemed to work okay. If you are trying to get real counter height, and that's including top gap, core thickness and insulation under the core, and top material thickness, you are probably going to run into problems. That's not for sure, it just might work, but you are really messing with one of the main elements in a functional rocket burner by not giving it enough time in the riser. I'd seriously reconsider that plan if I were you and needed heat. I know aesthetically it's hard to accept a taller cooking surface, but I'd say rough it in at full height and try it out for a bit before you commit to something experimental in the house. You can experiment with lower counter height burners and modify this one later if you come up with a good solution.

My other solution would be starting at lower than floor level... This would be very expensive, but possible.... The exhaust would then have to raise in elevation quickly off the back... would that mess things up?

No, that would be fine, however, it will be a pain in the butt to light/clean/fuel down on your knees reaching down in the feed hole. Personally, I think it would be far preferable to cook up a little higher than we are used to rather than crawl around on the floor to stay warm. I dunno though, I do see the attraction of a nice cook top.

Yes. You are probably right. I'll start with a taller cooktop and work down if I can.

For the heat riser core i was thinking of using a 6 inch steel pipe. How large should the next wall be? Is there a specific thickness of insulation needed in the riser or is it the more the better? I have Ianto's book, but it seems that folks have been "going against the grain" on some of this stuff and I am not sure what the current community wisdom is...