Thats nice to know.
Rindert
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Here is more then I ever dreamed of knowing about it. It goes under various names from wikipedia:
Autoclaved aerated concrete is also known by various other names, including autoclaved cellular concrete (ACC), autoclaved concrete, cellular concrete, porous concrete, Aircrete, Thermalite, Hebel, Aercon, Starken, Gasbeton, Airbeton, Durox, Siporex (silicon pore expansion), Suporex, H+H and Ytong.
I kind of have an issue with some of these because AirCrete as I know it, isn’t autoclaved.
Ytong patented it in 1924 in Sweden. The formula has been radon free since the 70s. The alum powder Ytong was using contained traces of uranium.
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I’m going to try to duplicate this guy’s results. If that works I’ll try a foundry furnace. If that goes well I’ll make a gasifier that way.
Rindert
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Gasifier update- Tuesday.
well 4 days of wind and rain has kept me indoors. Yesterday I emptied the feed hopper and discovered
The first issue: bridging. The central nozzle with its 5 separate ceramic outlets is like a big grabby hand that grasps my lumpy charcoal and wont let it fall into the combustion area. Solution- better grading of my fuel stock- Ill make a trommel. It will be so useful for mixing mushroom substrate, garden compost, sieving wood chips. Today Im smacking charcoal lumps on a ply wood board with a shovel like Whack a Mole while I look for free things to make trommel from.
Second issue: Low fan volume. the outlet flare pipe has barely a breath of airflow so Ive removed the pot scourer primary filter shoved up inside the exit from the ash chamber. Also I investigated the wiring and found the second hand on/off switch had extremely high resistance. Rewired to eliminate switch and tripled the air flow. Still not stunning, but after grading my charcoal I expect airflow though the pot to be better as well. Ill be back outside when the weather perks up.
Eventually- Ill need a wood chunker so Ive been looking at the rotary slicing rim type and the rotating machete type- both seem good. Im on the look out for a Subaru or Nissan rear diff head. they are a 3.9:1 ratio and really strong. being IRS -they have stub axles and flanges suitable for mounting cutting implements straight on to, and sturdy mounts to bolt directly to a frame. If I lock the diff head by welding up the spider gears, both sides will turn in unison and I can have a branch chunker on one side and a threaded splitting cone on the other. I have a 6.5hp Lifan engine and a compressor double vee belt 400mm pulley in my useful box… grammar edit!
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Hi Stuie , a quick make shift way of reducing the size of my charcoal is as i take the charcoal out of the fire in a saucepan i carry them out side to a 25litre drum and tip the charcoal in and then tamp it down with a 90x90 about 400 long and its allows me to get way more into the drum almost twice as much and then i carry it down to where my garden shredder/mulcher is , i have that on a 12/24 wheel chair motor with a gear box that turns nice and slow and reduces down to no bigger than about 16mm , always see these types of shredder mulchers on market place real cheap .
Dave
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the wheelchair motor sounds fun- they do have ridiculous torque but I cant go faffing about with my ‘timeshare’ chipper. Its not all mine- I just have a share in it- 2 other guys with money abuse it then bring it to me to sharpen and maintain. then I ‘test’ my work with it on my branches then return it. Ill try removing one blade off it and see how big my chips are- that could give me feedstock that is perfect char size. - Can anyone advise me on that?
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Hi Stuie you don’t want to use a chipper blade , what you want is a chipper mulcher/shredder the type with hammers, its the frame that the hammers are attached too that crush and push the charcoal through the 1 inch screen if i can find a photo of mine i will upload it in a few .
Dave
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This is a short video i took last year before i stripped it down to clean it up as its been sat out side in all weathers for 12 years crushing away .
I took the lid off and reversed the direction to show the frame the hammers sit on that does the work as it doesn’t spin fast enough to throw the hammers out , when the lid is on you can fill it u and it will go through a 25 litre tub in less that 2 mins .
Dave
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through the 1 inch screen if i can find a photo of mine i will upload it in a few .
Im in the middle of making a rotary 1" trommel screen right now.
Whats the negative in making chips of a larger size? then retort those and have a nice uniform char size?
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I am unsure about charcoaling small chips they can tend to pack in to the retort tightly and not fully cook is what i have found , if you can get larger chunks that would work fine , i also have a normal chipper shredder with a side chute to do the branches up too around 3 inches in dia ,I played with the gap as best i could and managed to make really nice sized chunks to run on my wood gasifier , this is how they look when i cut length’s of wood in 1 inch width and feed it into the chipper , they feed into the power labs wood gasifier nicely.
Dave
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yes- thats what I was meaning. Im not sure what the shrinkage is when charred so have to play around a bit. Im excited about building a chunker. There is great YouTube channel called Dangerous Homemade Firewood Machines. Thats where the most exciting chunkers are found. Years back I made a really dangerous slasher mower for the ATV, ground driven by an Escort Diff. you couldnt ever stop it not even for transporting. It was nuts. had two landrover leafspring blades.
I think the weather is clearing up here- I will get that charcoal back in the hopper tomorrow and try a flare up on dusk
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Oh and I figured using Matt Ryder’s flare off plumbed fuel drum system. but the open top tilted and constantly fed char maker might suit small chip sizes? Im just trying avoid upsetting my loved one as my property is really cramped and my processing area is just 6m from the lounge doors. Ana is a clean freak.
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@bsoutherland does that method in a forced induction TLUD. He says it works very well for him.
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Since it’s moving so slow it’s really less the hammers and more the bars and grate doing the crushing work, right?
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Cody the hammers don’t come into play at all its just the the rotor its self that does the crushing and pushing of charcoal through the grill , the more feedstock on top the more it pushes through the grill .
Dave
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The knives/flatbars hanging from the rotor, they are there only to clear the grill?
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No they are there fitted as they are the hammers that would normally smash the garden waste that’s put in to the hopper if the rotor was spinning at its normall speed the hammers would fly out , due to the rotor only turning around 120 rpm @24V , there was no need for me to dismantle them at the time over 12 years ago and they have sat in there ever since .
Dave
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I don’t think it will work for a foundry without an additional refractory coating. The melting point of sodium silicate is 1088 °C (1990 °F). Aircrete will probably work for the portland style foundries because air is an insulator. But you need something with like aluminum oxide for a refractory coating.
that being said, it looked like the original formula for aircrete, during the sintering process they were using an alum which might leave aluminum oxide on the outside of the brick.
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When I make charcoal in my TLUD total volume is reduced by 1/3-1/2.
Rindert
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Thursday was second light up day.
After attending to bridging in my fuel hopper- poorly graded char. I removed a primary filter- scrunched up steel pot scrubber shoved into my primary gas pick up pipe.
These two actions tripled my airflow and improved combustion. My second light up was much faster coming up to heat, I got a gas flame in 6 minutes. But it was still a very poor color, very orange.
Already- Matt- Thrive Offgrid has watched my video and suggested that I have too much nozzle area resulting in a low velocity of air. That’s an easy fix. Ill make another nozzle with just 3 outlets instead of 5 and Ill give it another burn. I also have an inline 6amp blower on it’s way from Chiinaaa. That should pull the air through more aggressively and I can then fit a variable resistor to control fan speed
Thanks to everyone here who is encouraging and helping me to achieve this. You guys rock!
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