Thats a good search term and source 8 didn’t know before.
After thinking about things and looking at prices, I found two 5 gallon pails of cement that I had stashed in the basement.
Well, I might be cement or it might be hot mud mix, basically plaster of paris.
I couldn’t remember or figure out which one it was, but figured either would do.
I mixed it 2 powder to 1 water to 2 damp sawdust and packed that into the cavities of my boiler.
The saw dust will just turn the carbon if the heat can get to it, or stay saw dust if not. Very interesting idea. Let’s us know how this works out.
Bob
You can find bentonite clay at well drilling supply places, or basement waterproofing. It gets sticky and prevents sand collapse in well drilling. Also from farm supply co-op it is used as a binder in making feed.
I tried sort of the same. It didnt work out well, to much mass. Mass is nice if the burner is inside the house, not for heating the water. Now, first the mass has to get heated and then the water or charcoal. If it cools down, it is the other way around, you loose the heat in your mass.
Better make it as light as you can and well isolated.?
I do a fair amount of experimenting with aircrete, foamcrete and different aggregates. I made some planting boxes out of cement mixed with the fines from my charcoal fuel production. They are two inch thick and seem to be holding up just fine exposed to the weather.
I just moved it into the green house and it was heavier than I anticipated.
It’s not a disaster as all the heat will heat the green house and none of the thermal mass/ insulation placed so far is in direct contact with the body of Tlud, or the flame path.
I’m going to want some rockwool to insulate the water tank , so I might use some around the “heat riser”.
That’s what I’m calling the short bit of Tlud chimney that stays inside the body of the boiler all the time.
The higher temperatures that will hopefully result from insulating in this area should quickly destroy the #10 can that is the original heat riser.
I’ve crafted a cast chimney from cheap Calcium aluminate cement and rock wool, that will hopefully last indefinitely.
The sides of this cast tube are roughly 3/4" thick, so they shouldn’t be a terrible heat sink if backed by decent insulation.
There will be a 3-4 " doughnut of relatively dense cast material right before the flame /exhaust reaches the inside of the water tank, but that doughnut is in direct contact with the bottom the tank, not a bad place for heat to accumulate.
I’m hoping to get this thing in place an operating inside the the greenhouse within a week, with the warmth encouraging me to do other projects in said green house.
I was think of insulating the voids in back wall of the green house with a mud and charcoal mix.
I’m considering Styrocrete, but I hate to think of how it will be disposed of after I’m gone.
It will at least be sequestered in the cement, but its still not a great outcome.
Charcrete or Charadobe could be a net boon to the earth.
Do you think it would serve well enough?
Would they be light enough for insulation around the boilers “heat riser”?
I’ve seen ratios of 1 to 5 or six cement to aggregate for light weight concrete.
What ratio do you use?
I make aircrete five gallons at a time. For that I use 10 lbs of cement and about 2/3 of a gallon of water. That would be the same if I mixed in perlite or other aggregate which I don’t normally do. When I made the char-crete I just made a slurry and mixed in the char until it seemed to be a good consistency but probably well more than one to five. The thing about concrete and it’s off shoots is to determine what you are using it for. Your average bag of quickcrete will give you between 3000 and 4000 PSI depending on how long you keep it damp while curing. A cubic yard of concrete weights 4000 Lbs and uses a little under 500 Lbs of cement to get around a 3500 psi rating. So that’s about an 8 to 1 ratio. The 1-2-3 ratio that most people use for home mix is way above that. The thing about styrocrete is that the styrofoam most people use is shipping packing. If you don’t use it for something durable it will just sit in a land fill. A much worse option environmentally.
Funny thing, I prefer Styrofoam in the landfill to in the soil.
I would also need to grind what I have, which means building something else.
Normally I love that, but right now I’m actually trying to get a project done, lol.
Those ratios are excellent.
I think I could lower the amount of cement I used for the sawdust-crete tremendously.
The only thing the I need the insulative 'cretes to hold up is their own structure, loose granular insulations like perlite are known to settle a lot.
I broke down and went to the big box for some cheap rock wool, only to find they didn’t have the 13 dollar bale at my local store.
Every other bale cost more than I wanted to pay, so I went home to sulk.
Instead of sulking, I just used what I had, with wild abandon.
The cast heat riser is now surrounded with a six inch doughnut of insulation consisting of various amounts of mud, sawdust and cement.
Once the fire drys it out I hope it the sawdust will slowly pyrolise while the mud/cement fires to a hard but fragile substance.
If that doesn’t happen, I’ll tear it out and start again.
I’ve moved on to getting a chimney and thimble set up.
I have a couple of 6" to 4" reducers laying around, I figured on running the 4" duct through the middle of some 6" and stuffing the space in between with the little bit of rock wool I do have
Insulator is air that is trapped between the fibers of the insulation to retain air, fill the empty space between the walls with pebbles 1-2 cm in size.
