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Post by dirtdevil on Jun 24, 2019 10:20:47 GMT -8
Hi. I just joined this site and I have a question. I am building a RMH in an aquaponic greenhouse and I am planing to use a six inch stove pipe with a ten inch galvanized duct over it and filled between with perlite and refractory cement. There is not enough headroom in the greenhouse to set the heat riser in place and then slip a three foot high 55 gal drum over it. I see no reason why the heat riser cannot be built in two sections and stacked but I wanted to check and see if anyone sees a problem with this. Hope this isn't a dumb question.
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Post by martyn on Jun 24, 2019 10:57:15 GMT -8
No problem stacking up sections as long as they mate together nicely but have you though about using the 5min riser method?
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Post by dirtdevil on Jun 24, 2019 14:35:45 GMT -8
Don't know what it is but I'd like to.
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Post by martyn on Jun 24, 2019 21:03:52 GMT -8
The so called 5 minute riser is a piece of ceramic fibre wool cut to the right size and pushed inside a metal tube.
The method is relatively cheap and only takes 5 mins to construct!
This would mean there is not metal exposed to direct flame and due to the insulating properties of ceramic fibre, the riser will be very effective and long lasting.
Sorry that this forum photo stash is full but I am sure you can google up a picture.
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Post by Vortex on Jun 25, 2019 0:52:55 GMT -8
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Post by dirtdevil on Jun 25, 2019 4:31:38 GMT -8
That looks pretty interesting. I don't know much about these things. I bought a Rocket Mass Heater Builders Guide from Amazon. That's about the extent of my knowledge. I think I found this site from looking up information about building heat risers. I've looked though quite a few threads since I recently joined here. Haven't found much about people heating greenhouses. This is an experiment for me. The greenhouse is only ten wide and twenty long. It it works out I'll be going bigger. thank's for the information.
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Post by travis on Jun 25, 2019 6:44:20 GMT -8
I have minimal experience but would recommend at least a six in batch box or 8 inch j tube as the core to have quicker heat up times.
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Post by drooster on Jun 25, 2019 13:03:35 GMT -8
... I bought a Rocket Mass Heater Builders Guide from Amazon. ... ...and it recommended a steel riser? I second the advice to make a ceramic-wool lined steel riser instead. (Protect yourself though) |
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Post by wiscojames on Jun 25, 2019 13:13:32 GMT -8
The OP didn't say he was thinking of using a steel riser, but a fireclay-perlite riser with a stovepipe liner. That'd be OK with the understanding that the stovepipe liner would eventually burn out. I've used a Sonotube liner for that purpose. The fireclay-perlite risers work well, and are durable if made right. They are heavy, though.
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Post by gadget on Jun 25, 2019 15:09:29 GMT -8
... I bought a Rocket Mass Heater Builders Guide from Amazon. ... ...and it recommended a steel riser? I second the advice to make a ceramic-wool lined steel riser instead. (Protect yourself though) We should call it the "5 min/wear a mask riser". I always cringe thinking of the unsuspecting new comers working with ceramic fibers and not knowing to protect their lungs |
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Post by dirtdevil on Jun 25, 2019 16:05:52 GMT -8
Yes, I was aware that the inner liner would burn away. Most of the builds in the book I have use a fire brick riser with insulation wrapped around the outside. Fire brick is expensive. I have already laid up the burn tunnel up to where the heat riser will start with fire brick I already have on hand. I have cut the base barrel for a manifold and fitted it around the fire brick. I have the perlite and half a bag of refractory cement on hand. I have the stove pipe and duct already but I am going to look into the ceramic wool. I have some knowledge of working with high temps because I am a hobby blacksmith and do some metal casting. I'm not familiar with a batch heater. I'll have to look that up. Very cautious about what I breath. I appreciate the input.
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Post by dirtdevil on Jun 27, 2019 16:02:09 GMT -8
Having spent some time looking through the the site and reading threads I have decided that the recommendation for the Ceramic Fiber heat riser is the way to go. Looking for a place to buy it I find most listed as 2300 F and a few as 2400 F One was 3000F My question is if the 2300 F blanket is sufficient? Also is a one inch layer enough or do you need to double it?
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Post by matthewwalker on Jun 28, 2019 5:42:35 GMT -8
A single layer of the 2300F rated material will be sufficient.
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