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Post by patamos on Oct 31, 2020 11:27:07 GMT -8
Ya clay is such an interesting material. And then there are so many different types of clay. For many years i used lincoln fire clay in my light coloured finish plasters, and as mortar in fairly hot sections of heaters. But compared to the brown clay that comes out of the ground where i live Lincoln is way less sticky and more crumbly.
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Post by patamos on Oct 29, 2020 17:00:20 GMT -8
Hi Trev, I have been running my stove a couple of weeks now. My bench as I was thought when building is too big. Originally the flue temps were only 50 C. At these temps the stove would form a rams horn vortex but after a short time the air control needed careful management. Still it was testament to your design that it worked at all in these conditions when sometimes the outside temps were in the high teens. It seemed to run best with no exit port then. Since I have blocked off nearly 2/3 of the bench and flue temps now peak at around 75 C it now runs with the exit port. I shall block off a little more of the bench to boost the temps further and was also thinking of making a couple of hinged insulated covers for the hot plate. I have noticed on windy days the flames in the afterburner flux or corkscrew in and out, maybe an anti-downdraft cowl will help? There is no room for a draught regulator. One of my best runs was on a calm dry day where with my umbrella cowl was taken off ( highest flue temp). Delighted with it and thanks. James. Cork, i'd be surprised if the issue was bench ISA. I've built a few of the old school vortex fireboxes with waaay more ISA than Trev has in his home unit. (Although it has mostly been with bells chambers) Perhaps a permanent 10% bypass straight to the chimney (or something like that) will help get more heat thru the bench. just a thought
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Post by patamos on Oct 28, 2020 20:54:13 GMT -8
Thank you Peter and Trev for sharing this thread. I have been following it with great interest. Although i do not have a testo or condar PM analyser, and therefore cannot contribute to the empirical findings... I am inclined to wonder what effect different shapes of post-port stumbling blocks, baffles, etc... might have on gas mixing dynamics at various amplitudes of combustion. For the most part we have been experimenting with corbell-like impediments that span the width of the upper shoebox/chamber. But what if the shapes are different? On one of my recent experiments i carved a number of cylindrical shaped columns (about 1" diameter) out of an insulated firebrick and placed it hanging down from the roof above (just down stream of) the throat. The objective was to create paths of micro turbulence during early and late stages of the burn cycle, when the vortex is not yet formed and/or no longer optimized. During full burn more of the flame and gasses flow under the cylindrical features than into and through them. So another type of baffle, perhaps a bit further down stream may be of better use for that. Just a thought.
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Post by patamos on Oct 25, 2020 9:39:25 GMT -8
"it is always good to let them soak in the barrel (about 60% full of water) for a day or two" yeah i did this a week ago in a glass jar to check the sand & organic content of a new vein of clay we dug up - it's almost all clay 5cm & about 3 mm of sand Ya then best to figure out how much silt. swooshing a bit between your teeth can be an indicator. A bit of grit okay. Lots of grit may be a problem...
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Post by patamos on Oct 13, 2020 20:01:34 GMT -8
Thanks Guys My drill in harness in barrel set up has served me well for many years now. I just took pictures for someone asking about it so i will see about posting them soon. Yes it can mix anything from dry clay to sludge to hard clumps. ALthough with the latter it is always good to let them soak in the barrel (about 60% full of water) for a day or two. Mike, i tend to build with old clay bricks and fiber-less cob mortar. Then a layer overlapping sheets of 4.5oz fiberglass mesh (often used in EIFS concrete mortar application) over the outer surfaces. This gives a durable yet resilient structure that IMHO is better than double wall (refractory core with separate brick/stone facing) or single wall (old school clay brick and mortar). It would most accurately be described as 'double-skin' but this term is commonly used interchangeably for double wall masonry heaters. I've built a lot of cobb and light clay houses/cabins/studios... but not so many pure cob heaters. Somethings about the old clay-bricks, the feel, the versatility in shapes and volumes impels me to keep working with them. That said, I also tend to follow some sound advice from long-time builder Lars Hellbro: 'Above 500c use firebrick. Once below 500c any clay brick will do'. And also from Norbert Senf: 'Refractory materials lining the first 4 or 5 feet downstream from the fire chamber. After that any clay brick.' So the question then is: What areas of the heater are going to experience over 500c under the craziest over-firing scenarios (eg winter earthquake or ice-storm... running 24 - 7...)? Tall narrow ones will accumulate more concentrated heat than long stretched out benches...
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Post by patamos on Sept 26, 2020 12:26:28 GMT -8
I'm thinking of using dogwood , its abundant here & straw is available free or cheap - a big bale , you know one of those monster things costs 5 € In the UK Hazel was traditionally used & it grows here a few miles away but i'm keen to just use what's around me , experiment , fail and learn , work things out.I made a small amount of slip to cast the top slab of my oven , broke it up by hand so any tips would be welcome . I don't have a cement mixer , i do all my mixing by hand as most of our construction is dry wall stone or timber but i'm not a primitive ! For larger volumes of light clay there are a few ways to mix. I have an old mortar mixer that modified paddles/blades this works for shorter length fibre such as wood chips, hemp hurds and any plant stalks under 2" long. For longer straw/fibre better to use a tumbler for smaller volumes i sometimes mix (shortfibre) in a horse feed bucket with a drill and egg-beater bit. to mix light clay without machinery have 3 people face towards each other with pitchforks and take turns 'tossing the salad' For mixing clay slip I have a good drill and harness set up in a barrel. I will post pictures soon.
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Post by patamos on Sept 23, 2020 18:24:40 GMT -8
Ya bamboo sticks are great for that. or most any green branches will do.
for the daub i like to mix thick clay slip with chopped straw. So easy to work with, and the straw is becoming easier to find in compressed bags at farmer supply stores. (it is sold as stall bedding for livestock in barns)
You could also just stud frame it and then infill with light-clay (see amosclayworks.ca website). Most any fibre will do in the mix.
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Post by patamos on Sept 23, 2020 10:42:19 GMT -8
ha. I think most anything is better than concrete! I remember reading that Thomas Edison came up with a house building system back in the early 1900s that was almost entirely concrete, poured into forms. The formwork moulds were complex, made to look like elaborate arts and crafts style of that era. But the overall cost was very low. He wanted to mass produce homes for low income families. However, NOBODY wanted to live in them. Something about the feel (energy) is just not good. Give me clay wood and stone any day
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Post by patamos on Sept 19, 2020 11:44:06 GMT -8
Ya man,
Clay and wood are kindred. So many people around here (west coast canada) suffer from moldy houses made of synthetic garbage... And when i tell them how these ancient techniques involving clay and fibre offer a simple durable mold-free solution... they shake their heads in disbelief It is usually only people such as yourself who have personally experienced such dwellings who have an inkling of what is possible.
kinda the same situation with rockets and masonry heaters...
Thanks for sharing your perspective
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Post by patamos on Sept 16, 2020 20:54:07 GMT -8
Thank you both for the feedback Ya, i love working with clay. So calming and grounding to have my hands in it. A few years back my neighbour was digging out truckloads of sticky brown stuff. I paid a dump-truck driver (my other neighbour) $90 for 3 full loads = About 30 yards worth. Everyone was happy with the deal. I've lost count of how many earthen floors, wall plasters and masonnry heaters i have since built with it, and i'm still barely halfway through the pile!!
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Post by patamos on Sept 15, 2020 19:02:52 GMT -8
Hi Folks, Been a while... Great to see this awesome forum still humming along... Just thought i'd say hi and share a bit about some of the ways i have been getting muddy lately. amosclayworks.ca/
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Post by patamos on Apr 8, 2020 11:01:36 GMT -8
One thought would be to widen your port at its existing height, then add 1 or 2 or 3 insulated firebricks above that to gradually narrow it. Staggering/corbelling the bricks to make a mini heat riser will evoke some pressure gradients, turbulence and possibly better mixing of gasses in the taller throat. This is a technique often used in larger masonry heater firebox exit ports/throats. If you place the bricks loose you can play around with configurations to get it dialed. And you should at least be able to get a concentrated blast of heat under the cook top my 2 c
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Post by patamos on Mar 23, 2020 9:42:47 GMT -8
If you build the masonry stove and find that it cooks/bakes okay, but otherwise gives off too much heat into the room too soon... you can always add a layer or two of clay plaster with a high ratio of shredded horse manure. I like to gather the pucks in summer when they are dry, then run them through a leaf shredder, then sift the loose fibres through a 1/8" (2mm) screen to remove the harder chunkies.
This fibre mixed with a good fire-clay is a very good insulative material in hotter regions as well. The fibre burns out, but the clay remains in place. That said, 'lincoln fire clay' is not all that good for this application. I am fortunate to have local ground clay that works much better. So you will have to test...
my 2c
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Post by patamos on Mar 15, 2020 10:04:02 GMT -8
Matt cooked on/in the one in his house all the time. If your intention is a combination of year-round cooking and seasonal mass heating that is a very good design. For summer cooking you might want to divert hot gasses straight up the flue pipe and harvest heat for hot water system off that eg. spiral of copper coils tied into a vented hot water tank. You can also get flues with water jackets. but i cannot speak to the durability of that approach... my 2c
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Post by patamos on Mar 12, 2020 9:58:31 GMT -8
Congratulations on the arrival of your daughter And good to hear your stove is performing well. An exsulated house is ideal for radiant mass heating applications. The whole interior becomes the heat absorbing, storing and sharing medium... Happy firing !!
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