03/05/2019 at 18:41 •
I spent last night dialing settings for the 3D printer, and was finally able to extrude my first multi-layer object. There's still a lot of improvements to be made, but this is a huge step forward! The final part is light and flexible, and so strong you can't pull it apart or break it no matter how hard you try.
This was made with #5 polypropylene plastic, which used to be trash food containers, which were washed and shredded with the Precious Plastic shredder into fine flakes, and then fed directly into the print head.
The next step is to see what kind of low-resolution objects I can make with this. I'm also interested in trying to make a part with 100% infill to see how solid an object I can make. Stay tuned!
10/22/2018 at 13:49 •
The metabolizer is made up of at least 7 distinct sub-systems- the Hearth, the Turbine, The Shredder, The Printer, the Gasometer, and the Generator. Like the organs in your body, and the cells inside the organs in your body, and the organelles inside the cells inside your body, the individual machines that make up the metabolizer all have unique chemical roles to play, and while they can each be considered as distinct systems, they are also dependent on the other machines in the system in order to complete the metabolic process, and so they can also be considered as part of a larger system.
All living things are best described as processes rather than things- life is, by definition, a thing that is constantly happening. And all lifeforms, even the simplest ones we know of, can be described in terms of their sub-systems, things like hearts and cells and mitochondria, and those things can also generally be described in terms of their sub-systems, like ventricles and organelles, and all of those things can all be described in terms of what they take in and what they put out- they are all processes. This may seem kind of obvious, but it’s an important distinction to make, because our language categorizes most of these things as 'nouns', when really they are verbs.
This concept of things as processes nested within larger processes, is called a “holon". A holon is any thing that can be accurately described as BOTH an individual thing, like a heart, AND also as a component of some larger whole, like a human. A lot of people that I talk to have never heard the term ‘Holon’, but when I tell them what it means, they often have an immediate recognition of the concept. Anyone who’s spent any time looking around this world knows that nature functions in this way, even if we don’t have widely-used words to describe it (yet).
When we're trying to talk about complex systems, it’s important that we make this distinction, because it’s a fundamental part of of how complex systems work. Some things are things that are actually things, like a pile of rocks, or a gallon of water, and some things are better described as processes within a system, like an engine, or a human. A generator and a human can both be described in terms of how much fuel they consume, how much O2 they inhale, how much CO2 and H20 they exhale, and how much work they produce.
This is not very different from what the Mitochondria in your body are doing (that is- the cells inside your cells inside your organs inside your body). Mitchondria play a pretty specific chemical role- as we all learned in high school, “The mitochondria is the powerhouse of the cell”. Mitochondria take in a complex hydrocarbon- in this case glucose (C6H12O6), and react it with Oxygen to produce CO2, H20, and energy, stored in a highly refined, and easy to access from- ATP.
Chemically speaking, there’s no fundamental difference between what a Mitochondrion does in a cell, and what the metabolizer does in my backyard- it takes in complex hydrocarbons, like sugar or polyethylene, and breaks them down by reacting them with Oxygen from the air to create H2O, CO2, and a refined, readily available form of energy. In cells, that refined energy is ATP. ATP is Adenosine Tri-Phosphate- it’s a simple molecule with a 3-phosphorus “tail”. Breaking the third phosphorus molecule off this tails is easy to do and releases a relatively large amount of energy. ATP is the energy that powers all of the chemical processes inside the cell. In the Metabolizer, electricity plays the same role as ATP does in a cell- it’s a highly refined and readily available form of energy that can easily and efficiently power the rest of the system.
In both cases, the energy released from those hydrocarbon bonds is ultimately solar power. All life on Earth, with fascinating but negligible exceptions, is powered by sunlight in one form or another- wind, rain, sun, food, biomass, and fossil fuels are all just flows and storages of solar power. Photosynthesizing organisms build chemical bonds from sunlight, water, and CO2, and everything else breaks them down again. It is the fundamental metabolic relationship that powers life on Earth- build up and break down, production and respiration.
The other half of this reaction is photosynthesis. In plant cells, photosynthesis takes place inside chloroplasts, which use solar energy to vibrate the chemical matrix of chlorophyll in such a way that it catalyzes the production of sugars- some of the simplest hydrocarbons. This is a fundamentally and necessarily reciprocal process- break-down cannot occur without build-up.
Many organisms, like plants and algae, contain BOTH chloroplasts AND mitochondria within their cells, which makes them “photo-autotrophs”- which means they are capable of feeding themselves directly from sunlight- making them independent, autonomous, basically micro-biospheres. Many other organisms, and most notably humans, ONLY have mitochondria within their cells. They are not photo-autotrophs. They are “heterotrophs”- the energy they need to live must come from outside of themselves.
This is why it’s so important to think (and communicate) in terms of holons and processes instead of arbitrary labels like "species". If you think of humans in terms of chemical processes, you quickly see that humans cannot, and do not exist by themselves, in exactly the same way that your heart doesn’t exist without your body.
Humans do not exist without an ecosystem, made up of a wide range of different species of plants, bacteria, animals, and fungi. By ourselves, we are just an incomplete chemical reaction- breakdown with no build-up. In order to exist, we need each other, and we need a diverse web of other, non-human organisms that have chemical superpowers that we don’t- like turning sunshine into food or decomposing our poo into fertilizer.
The metabolizer, as it currently exists, is basically a meta-mecha-mitochondrion (meta-chondria?). It's still a heterotroph- it requires food, and that food is the chemical bonds embodied in trash and waste biomass. But in the future, isn’t it fairly easy to imagine the system evolving to incorporate new systems, like open-source hydroponic grow towers, algae photo-bioreactors, or water-filtering reed beds, that can perform photosynthesis?
And if it did, the Metabolizer would become a photo-autotroph- capable of sustaining itself (and it’s endosymbiotic human operators) directly from sunshine and other locally available flows of solar energy, without ecological damage.
My dream for this project, ultimately, is to get there- I believe that there should be a globally-available open-source library of disruptively-useful, easily-replicable, small-scale, low-cost, open-source, ecologically-regenerative infrastructure components that enable people anywhere in the world to easily build autonomous, decentralized, autotrophic communities that can provide for as many universal human needs as possible- like clean air, pure water, nutritious food, comfortable shelter, abundant energy, workable material, and useful information, and do it from shine alone, forever, for free.
That’s a big goal. Bigger than me, bigger than you. I don’t know how to do it, I’m not saying I know how to do it, and I’m not saying you should care. But what I am saying that I believe that goal it is possible, and it seems to me to be a difficult and worthwhile goal. The Open Hardware challenge challenged me "Choose a challenge facing the world today and design the best plan possible for the boldest solution you can envision.“
Well, this is the boldest solution I can envision. What I would love more than anything else, is to be able to easily share designs like this with other folks around the world, and work to together to make disruptively useful information as available as possible to as many people as possible as quickly as possible.
In 1961, Buckminster Fuller proposed the idea of a “World Game”- which he envisioned as a mass mobilization of people and resources on the same scale as a world war, but with the goal of trying to “Make the world work for 100% of humanity in the shortest possible time through spontaneous cooperation, without ecological damage or disadvantage of anyone.”
I couldn't have said it better myself. Game on!
10/21/2018 at 00:17 •
Just had a major "EUREKA!" moment! CLEAN PORTABLE 120V/60HZ POWER ON DEMAND FROM TRASH GAS! One thing that's been bugging me as the deadline for the Hackaday Prize approaches is that the reactor part of the system is very simple to build and requires almost no specialized skills- not even welding or cutting. It can be built entirely out of readily available parts that you can get on Amazon or at any hardware store (detailed BOM coming soon). I did that on purpose, because I wanted this project to be as easy to replicate as possible. But the engine/shredder/generator I built, while a neat proof-of-concept and technically what I had hoped to build, is super-janky, highly technical, and would be very difficult for others to replicate since it's all custom parts and custom attachments.
Powering the shredder with electricity is much easier to do than direct engine power, and it lets you easily reverse the motor if it gets jammed. It may not be quite as powerful or efficient as direct engine power, but the gains don't really make up for the added difficulty to build. It's also WAY quieter, which is important if you want to be able to actually talk to people.
So as a last experiment before the deadline, I took a chance and bought a Harbor Freight "Predator" generator for $550 (including the 1-year unconditional replacement policy, of course) to see if I could get it to run on trash gas. I took off the side access panel, and the cover to the air filter, and removed the foam filter that came with it and replaced it with another piece of foam I had- so I could put it all back together and return it if it didn't work.
I copied the shape of the air filter cover, and used my girlfriend's Glowforge to cut out the parts in clear and black acrylic. The Glowforge has a "trace" function that makes making simple parts like this super easy- no CAD! I had to play around with the air-fuel mixture, and promptly ran out of gas (you can see the barrel emptying in the vid), but I was able to get it to run with enough speed to produce clean, 120V/60Hz house power, which is huge!
While there is still a lot of testing to do (total wattage output, long term wear...) this a major step forward! This means that even if you bought all of the parts of the system new on Amazon Prime, which is the most expensive way you could do it, it would all still come in at under $2000 for everything (not including the Shredder ($600-$1200) or 3D printer (>$500)), and it would let you produce around a kilowatt of clean AC power from any reasonably dry biomass- woodchips, pellets, grass clippings, dog poo, cardboard, paper, even the Amazon packaging all the parts came in... AND it produces hot water in the process!
10/19/2018 at 23:06 •
The Metabolizer doesn't require perfectly dry material to make fuel, and in fact I've run it with some pretty seriously wet woodchips, with no problem. However, being able to remove all of the water from incoming material before it enters the reactor to be thermally decomposed would have several distinct benefits.
First of all, if you know the material is completely dry, you get a better sense of how much actual biomass you're loading in by weight, which lets you figure out how much energy you put in, versus how much energy you get out, and that lets you calculate the overall efficiency of your system.
Second of all, it ensures that the liquids that distill out aren't watered down, which means there is less refining to do, and less liquid to deal with.
Third of all, if you could remove the water in such a way that you were able to recover it, then the system would actually produce clean water, would be super neat since humans need water to live.
So I've been looking into ways to dry out the material before it goes into the metabolizer, that isn't too insanely energy intensive. A simple dehumidifier inside a closed container is remarkably viable considering you get quite a lot of very-nearly-drinkable water out, but it's still a bit too power hungry for my liking, and it requires an extra bit of specialized equipment that is prone to breaking.
So the most intriguing option I've found is using desiccants, specifically, "zeolite" desiccants, which are a particularly fascinating material and so I wanted to do a log about them.
Zeolites are a class of naturally-occurring alumino-silicate clays (although man-made zeolites also exist), that just happens to have a particular molecular structure that gives them some very interesting properties.
Zeolite means "Boiling Stone" in Latin, because when zeolite is heated to around 300-600F (depending on the type) it expels a large amount of steam- seemingly from nowhere. The reason this happens is that the crystalline structure of Zeolite acts sort of like a cage for water molecules. Water molecules are attracted by the inter-molecular forces inside the zeolites, and at room temperature water molecules migrate into the crystal matrix and just kinda get stuck there. This is called "adsorption".
There are over 50 types of zeolites, but the kind I'm looking at, 3A (which refers to their pore size- 3 angstroms across), can adsorb roughly 20% of their dry weight in water. For this reason, they are often used in industry as desiccants. They're also widely used in chemistry as "molecular sieves" since only very simple, very small molecules can enter (and get stuck in) their crystal matrix, and everything else just passes between the pellets. So they're often used to selectively remove gases such as water vapor, hydrogen sulfide, and carbon dioxide from gas streams.
Zeolites will absorb water from air until they are saturated- and all you have to do put them in the same air-tight container with a wet material, and they will suck the moisture out of the material. Once they are saturated, they can be completely regenerated by heating them up to their recovery temperature. The heat causes the crystal lattice to expand, which eventually allows adsorbed water to escape (which is almost pure water, and easy to capture and condense).
But the most intriguing part of this thermodynamic cycle (to me, currently) is that it acts as a near-infinitely regenerative heat battery. When you heat up zeolites to their recovery temperature (which is on the lower end of the same ball park as the pyrolysis temperature of biomass- temps the metabolizer can easily reach) they start releasing water vapor, and that takes energy away from the system- it's an endothermic reaction. You have to keep adding heat to the system, but it won't get any hotter until all the water is released. You spend heat energy in order to recover the zeolite, and that makes it more efficient than using a vapor-compression dehumidifier, since you don't have to refine the fuel heat into electricity.
When dry zeolite begins to hydrate, it heats up- it's an exothermic reaction. Like....really hot. Nearly the same amount of energy is released in the hydration phase as went into the dehydration phase. And this heat actually needs to be dissipated somehow in order for the zeolite to be an effective desiccant, since the hotter it is, the less effectively it can retain water.
I've only just started experimenting with this, but my hunch/hope/suspicion is that I can fill a keg with zeolite pellets, just like I do with wood chips, use heat from charcoal to recover the water from it, potentially recover that water for later use, and then use the keg full of dry zeolite to dry kegs full of biomass. Most raw wood chips have a water content of around 20%. Zeolites have a water capacity of roughly 20%.
A 5 gallon keg full of dry zeolite (which would cost around $100) should be in the right ballpark to suck very nearly all the moisture out of a 5 gallon keg of wet biomass. If you put the kegs side by side, and insulated them, as the zeolite keg heats up from the heat of adsorption, the biomass in the other keg would warm up via conduction, causing the air inside to warm up as well. Warm air can carry more moisture, and that warm wet air would migrate due to the pressure gradient to the zeolite, accelerating hydration, and increasing the heat, until the material is completely desiccated. If that's the case, the zeolite kegs could be used as a sort of "load dump" and heat battery, that has the additional benefit of recovering clean water.
Right now, I only have about a pound of zeolite to test with, but I'm really intrigued by the possibility of such a simple, stable, heat-driven desiccation system!
10/18/2018 at 18:23 •
I decided to re-design the turbine at the last minute, since the parametric design was a little too complicated to do on the timeline I need to do it in. I still want to try it out, but it'll have to wait for later. But in the process of designing something light and cheap and easy to make, I hit on a much simpler, and apparently effective design!
This design only uses a single sheet of coroplast- around $12 in material. I twisted the parts in sketchup, and then made cross-sections for the top and bottom, and cut out the parts on my partner's Glowforge (she makes laser-cut jewelry for a living).
I had originally thought that I would sort of sew the top and bottom plate together with wire, but that ended up being pretty tedious, and after play around with the parts a bit, also turned out to be unnecessary. I ended up not using the bottom plate at all, and just used the slotted one. The cuts are accurate enough, and the coroplast is flexible enough, that I could just slide the turbine vanes through the slots, and they would stay press-fit in there.
This had not been my intention, but what ended up happening is that since the coroplast vanes are twisted and under slight tension, when you align them in a circular array, they end up creating a sort of reciprocal "tensegrity" effect, where they are all pushing out against each other, which makes the turbine remarkably strong and sturdy for it's weight (less than 1lb). I dropped it from about 7 feet twice by accident while figuring out how to mount it, and it was fine- it just kind of bounced.
I used a gear I had laser cut for a failed prototype earlier in the project, and wedged it into the top of the center tube. This was an inelegant hack, but worked surprisingly well. I'm using a NEMA17 stepper motor as the central bearing- since I need a bearing anyway, and the stepper will produce a bit of power. The neat part about doing it this way is that the power is produced on the rotating part of the turbine, not on the fixed pole.
This lets me hook the stepper motor up to some copper "fairy light" style LED strings, and wrap them around the turbine. When the turbine spins fast enough, the LEDs light up and strobe directly from the low-voltage AC power produced by the stepper- visualizing power output with light. The RPMs required for this to happen are still higher than I would like, but it does happen, and that also makes it kind of special, like an achievement to be unlocked.
I'm hoping that when the gas mantles are on (did I mention I got the gas mantles running on trash-gas), the hot air will push out the top of the lamp and out through the lower vanes, causing the turbine to spin- eventually fast enough to light up the LEDs. If that works, then the effect will be that as the Metabolizer heats up and starts producing gas, the gas mantles will start to glow brighter and brighter, the turbine will start to spin, and then the lights on the turbine will begin to fade on, a swirl of strobing points of light that get brighter as the turbine spins faster- hopefully to dramatic effect...
10/13/2018 at 20:13 •
In the process of learning how to recycle plastic, I've learned a TON about what plastic actually is, how it's made, what it's made of, and why the different types have the particular (sometimes peculiar) properties that they do.
It's not only fascinating, it's really empowering! For my whole life, plastic has been a material that I have had zero control over. I couldn't make it, I couldn't work with it, and I didn't get to decide what gets made out of it. When I started this journey, basically all I knew about plastic was what most people "know" about plastic:
1) It's made out of oil, and oil is both running out AND killing the world, and you should feel bad about that.
2) It can't be burned, and if it is, it produces a poisonous smoke, and you should feel bad about that.
3) It doesn't decompose, EVER, and it's piling up in the oceans and killing the world, and you should feel bad about that.
4) It's everywhere, it's in everything, and is extremely difficult not to use, and you should feel bad about that. Especially straws.
5) It's made out of toxic chemicals and is probably leaching poison into our water bottle right now, and you should feel bad about that, and probably buy a new water bottle.
Our society's relationship with plastic sums up the feeling I get from our entire industrial economy- Nebulously terrifying, clearly unsustainable, manufactured by a corporate system that is entirely outside of my control, but also still definitely MY FAULT for the fact that it's killing the world.
It's a lot easier to be afraid of things we don't understand, and most people don't really understand plastic. That's why I think the term "Precious Plastic" is so brilliant. In two words it reframes our assumptions about plastic, and refers to it as the precious, abundant, disruptively useful meta-material that it really is.
And of course, all that being said, plastic CAN INDEED be toxic and dangerous. But that's exactly why understanding how, why, and when plastic is toxic is so important- because plastic is far more benign that people often think that it is. When you understand a material, it empowers you to be reasonably cautious about it and to take appropriate safety measures, instead of just being generally afraid of it. Fire is dangerously hot, but it's really, really easy to take the proper precautions to have a fire and not burn yourself. Plastic is the same way. It can be dangerous, but it's fairly easy to avoid danger if you know what to look out for.
SO! This post is going go over all the very-specific ways plastics can be dangerous, so you can take reasonable precautions. It's is accurate to the best of my knowledge, but the best of my knowledge is constantly changing- so revisions, additions, and factual corrections are always welcome. Now, let's revisit over those 5 things people "know" about plastic that I mentioned earlier..
1) Plastic is made out of oil, and oil is both running out AND killing the world, and you should feel bad about that.
So to address this, let's start with something a little more basic- what even is plastic? There are many different types of plastics, and they all have different chemical and physical properties. However, all plastics are polymers, which just means that they are long, repeating molecular chains of a base-molecule, called a monomer. Poly-ethylene, for example, is just a long repeating chain (polymer) of the ethylene monomer.
But where did that ethylene come from in the first place? Most people know that most plastics are made from oil, but are a little sketchy on exactly how. So here's a quick recap- crude oil is ancient organic material, mostly plants (basically fossilized sunshine), that were not fully decomposed by animals, fungi, and bacteria before being buried deep underground by sedimentation and/or plate tectonics, which cooked the material under heat and pressure in such a way that the organic molecules making up the proteins and DNA and tissues of the formerly-living organic material sort of agglomerated into large, more-complex organic molecules (to put it overly-simply, this happens because Carbon is really f*cking sticky, molecularly speaking, and that's part of why we're here having this conversation at all).
"Crude oil" is just a catch-all term for oil as it comes out of the ground- which is just a mixture of hydrocarbons (with a few other bits in there too, sulfur, nitrogen, oxygen, although in much smaller amounts). That's why crude oil can have "flavors" like "light" and "sweet". The lighter the crude is, the smaller the hydrocarbon molecules it contains are, on average, and that makes it clearer and less viscous. The "sweeter" crude is, the less sulfur and other compounds it contains, making it easier to refine into gasoline. Saudi Crude oil is particularly light and sweet.
Fractional Distillation, which is a primary process in refining (sorting) crude oil into it's molecular fractions, is a very simple process in theory, and only slightly less simple in practice. Crude oil is heated up in a furnace without oxygen, and the heat causes the big molecules to break apart into smaller molecules, which boil off into a gaseous smoke, and that smoke escapes up a distillation column, which cools the gas and causes different hydrocarbons of different molecular weights (sizes) to condense out of the gas stream into liquids. The heavier molecules distill out first, at higher temps, they smaller molecules distill out at lower temps.
The gas left over is used to power the refinery. If this process sounds familiar, it's because this is exactly what the Metabolizer does, just with trash and biomass as the hydrocarbon source instead of crude oil.
Ethylene, and other small hydrocarbons used to manufacture plastics, are typically made from steam-cracking oil and gas into smaller components, and then distilling/sorting them by type.
That's how plastics relate to oil. TL;DR- Crude oil is broken down into small molecular bits with heat, condensed and sorted by molecular weight, refined into single monomers, just as ethylene, and then catalyzed into long chains. Onto the next one!
2) Plastic can't be burned, and if it is, it produces a poisonous smoke, and you should feel bad about that.
It's true that all plastics can be toxic if burned- particularly if burned on an open fire, which leads to uneven, low-heat burning. This causes the polymers to break apart, but not ALL THE WAY apart, creating smaller hydrocarbons, some of which can be toxic.
All plastics are composed primarily of the elements Hydrogen and Carbon. Most of the common plastics, including ABS, PS, PP, LDPE, and HDPE contain ONLY Hydrogen and Carbon. If burned on an open fire, they can create molecularly toxic compounds, such as benzene:
Compounds like benzene are carcinogenic and generally mess with your body, because they are they look and sometimes act like things your body uses all the time, for example, seratonin, which has a benzene backbone:
But contact with these compounds can be avoided by either burning plastic in a reactor that gets so hot that everything is burned off, and/or condenses these compounds and reflows them back into the reactor where they are burned up completely and add energy to the system. If you burned these kinds of plastics ALLLLL the way down, you'll get a flammable mixture of Carbon Monoxide and Hydrogen, often called Syngas, which is an odorless, colorless, flammable gas- when ignited, the Hydrogen reacts with Oxygen in the air to produce Water Vapor (H20) and Carbon Monoxide reacts with Oxygen to produce Carbon Dioxide (CO2)- both of which are 100% non-toxic bioavailable compounds that the biosphere knows how to process.
Carbon Monoxide can be toxic if it is breathed in large quantities- it binds to the Hemoglobin in your blood, but doesn't let go the way that Oxygen does. Fascinating side note: Did you know that the Hemoglobin in your blood that carry oxygen to your cells and the Chlorophyll in plants that acts as a photo-catalyst for sunlight, are very-nearly identical molecules? The only fundamental difference is that Chlorophyll has a Magnesium atom at it's core, and Hemoglobin have an Iron atom at it's core.
Anyway, if you breath too much CO, it will prevent your blood from carrying oxygen. However, this is easily avoided by using CO sensors when working with syngas, working in a well ventilated area - the same as you would with a Charcoal BBQ. If done properly, with the proper precautions and safety measures, plastics like ABS, PS, PP, LDPE, and HDPE- that is, the vast majority of all waste plastics- can all be chemically reduced to CO2 and Water Vapor, releasing a large amount of energy in the process.
There are some plastics you need to be more careful with, as some plastics have other elements incorporated into their structure in addition to Hydrogen and Carbon. For example, PET (polyethylene terephthalate) and Polycarbonate, both have some Oxygen in there too. Other, less common plastics, also contain other, more exotic and potentially-harmful elements as well. Teflon (PTFE- Polytetrafluoroethylene), for example, is a "Fluoropolymer" and contains the element Fluorine. The most notable/common example in the waste stream is PVC (#3, Poly-vinyl Chloride), which contains the element Chlorine.
PVC is nearly chemically identical to Polyethylene, but it has a single Chlorine molecule in the place of one of the Hydrogen atoms. When PVC is burned, the Hydrogen and Chlorine are released, and they recombine into Hydrochloric Acid- which is dangerous and highly corrosive. Burning PVC It can also produce Dioxins, which are also toxic. It's best to just avoid ever burning PVC- which is easy to do, as things made of it are fairly easy to identify. The easy approach is to just never burn waste if you aren't sure what it is.
PVC wastes can be repurposed or recast into new shapes or building blocks, without releasing HCl. And bubbling a gas containing HCl through water containing Sodium Hydroxide (NaOH, AKA Lye, which is a widely available component of wood-ash) causes the HCl to react with the NaOH to produce NaCl (AKA table salt) and Water (H20). So while burning PVC is not a good idea and outside the scope of this project (for now), it's quite feasible, even on a small scale, to design systems that can entirely scrub it from the waste stream.
3) Plastic doesn't decompose, EVER, and it's piling up in the oceans and killing the world, and you should feel bad about that.
It's true that plastics in nature take a long time (1000s of years, potentially) to decompose, and when they do, they often just break apart into other, smaller, still-toxic compounds. But that doesn't mean that plastic is forever, which is what most people think. We just need to help it along, and a great way to start is to stop throwing it in the oceans. If we had a real viable strategy to collect, recycle, decompose, and process plastics, we could use them in a renewable way, benefitting from their useful qualities, and designing systems that entirely avoid or manage their negative qualities.
The catch is- that's on us. We made the plastic, and very few living things can break it down again (yet), so it's our responsibility to be smart about how we use them, and what we do when we're done with them.
4) Plastic is everywhere, it's in everything, and it's extremely difficult not to use, and you should feel bad about that. Especially straws.
While single-use plastic is poor way to use plastic, it's not necessarily the problem. The problem is an industrial infrastructure that invests heavily in (and profits heavily from) the production of plastics, and puts little to no effort into creating viable systems to actually recover and recycle them in a real way (not in a sort, palletize, and ship them to china kind of way). If we have a process in place for actually dealing with plastics, then we don't have to feel bad about using them. And having to do that, to treating plastic as a precious material, often changes the ways that we choose to use them.
5) Plastic is made out of toxic chemicals and is probably leaching poison into your water bottle right now, and you should feel bad about that, and probably buy a new water bottle.
The whole thing about water bottles leaching BPA comes from water bottles that are made out of Polycarbonate (AKA PC, Lexan, Makrolon), which is polymer made up partially of the monomer Bisphenol A:
Bisphenol A has an organic structure that is similar enough to Estradiol - a human hormone produced by the endocrine system- that it can disrupt normal functioning of cells. But Bisphenol A is present ONLY in Polycarbonate, which is a comparatively uncommon plastic in the waste stream, and is only really a problem if you're drinking out of it. The simple solution here is- don't drink out of it! There are plenty of other materials to drink out of (I like stainless steel) and that way we can save polycarbonate for the things it's really good at, like stopping bullets or building greenhouses (or building bullet-proof greenhouses...)
Be cautious, be smart, be prepared, but don't be afraid of plastics. Like other dangerous things that we interact with every day, like cars, stoves, or the Internet, they can be used in a way minimizes or eliminates their negative potential. All it requires is care, a willingness to learn, and a belief that we can learn to understand problems and design solutions to deal with them.
Plastics aren't bad, and humans aren't bad for making them. Plastics are complicated, and humans have, to-date, been too careless with them. But it's worth noting that all the plastics that we know and use today have only been around for 100 years or less. I think we can be forgiven for not knowing how to deal with them until just now, IF we start learning how to deal with them, right now.
10/09/2018 at 15:59 •
Nathaniel and I met up at CTRL+H last night and hacked on the printer for nearly 5 hours. We successfully "printed" our first "objects" directly from shredded trash flakes, and we learned a lot in the process. One of the most promising things we learned is that coroplast sheet can indeed be used as a build plate. For a printer of this size, making a heated bed like a typical printer has is a daunting and expensive design challenge. But without a heated bed, how do you get your first layer to stick?
I knew that Polypropylene is very self-adhesive, and my hunch/hope was that maybe I could just lay down a sheet of cheap Polypropylene coroplast and that the molten PP would adhere to that, because they're the same material. That way you could just slide in a piece every time you print, and then cut off your object (and then shred up the scrap and print with it, of course). That part worked out quite well- the PP adhered much more strongly to the coroplast than it did to the wood underneath. That means that a heated bed upgrade isn't necessary- putting the cost to replicate this setup at under $500, using almost entirely 3D printable, laser cuttable, or widely available parts.
We decided to try and print out the Hackaday logo [based on this model from Thingiverse], and this the result of our first attempt. It's more of an "ckaday" logo, but it was an encouraging first shot. Nathaniel adjusted the ratio of extrusion to speed, and we tried again. One of the challenges of this kind of printing is that the extrusion is non-linear. It's not moving a spool of solid filament, it's building forward pressure in the extrusion barrel, and so there's a 3-5 second delay between when the auger starts pushing and when the plastic actually starts coming out of the nozzle. Luckily Nathaniel speaks robot quite fluently, and after a bit of arguing, we got this:
Not bad! Not, you know, great either, but pretty damn good for our second try. Next steps are to rebuild the extruder to be little sturdier (it was wobbling back and forth a little when extruding), mount the thermistors more securely (one of them got pinched and wouldn't read) and build an actual wiring harness and material feed. But all in all, I'm really happy with this test, and I am confident that this approach can produce useful (if not-very-detailed) objects.
10/08/2018 at 18:32 •
I had intended to just fire up the new setup to test to make sure my seals and connections weren't leaking (or if they are, where), and it ended up working so well I was able to fire up the engine! Still a very basic test, with no intermediate gas storage, but very promising!
The last major step to demonstrating a working prototype is connecting the engine to the gear box, and the gear box to the shredder! From there, there are a million upgrades and re-builds I still want to do, but I'm trying to focus on getting a tangible proof-of-concept running in time for the Hackaday Prize deadline! Onward!
10/04/2018 at 17:09 •
I've been doing these logs sequentially, but today I wanted to do a throwback to highlight some work we did back in February, right before I pitched the Metabolizer to Hackaday in the Open Hardware Challenge. This project has been a huge learning process for me- lot of parts of it are right outside my skillset.
I'm a designer/inventor by nature, the kind of person who needs to understand how things work. So I'm really good at understanding what's possible with currently-available tech, but I rarely have the actual technical skills required to make it happen.
Luckily, I have very talented friends, who have helped me immensely on this project, and since I can't pay them anything for their help I want to make sure I at least give them proper credit!
These are my friends Darcy (Hackaday user DRC3P0) and Matty (Hackaday user softjitter) assembling the MPCNC. Darcy works at the FabLab at Portland Community College, and so she help me print all the parts required to build the MPCNC, and Matty helped us get it moving. They are both rad and very accomplished makers, and you should check out their work!
I had never worked with any kind of CNC machine before, although I've been aware of them and had friends with access to them for years. Without Darcy and Matty's help, I wouldn't have known where to start!
Here's a funny picture of Darcy. Sorry Darcy. You're great.
10/03/2018 at 18:11 •
Dallas and I hacked on this parametric wind turbine design again last night, and made some real progress! The model now auto-generates flattened array of individual layers, and adds number tags, so they can be turned into individual cut-files required for CNC fabrication. I really want to make a turbine that is as tall as the patio heater is (I'm a sucker for symmetry, I'll admit). That's about 7 feet, or 84 inches. At 5 layers per inch, that's 420 layers of 4mm (3/16") coroplast. By my estimates, that would require around 20 sheets of coroplast, which go for about $11/sheet. So a couple hundred dollars, if using virgin material. But coroplast is also easy to find in the waste stream in the form of lawn signs (and there will be lots available come November 6th...) So if I can "recover" a few of those, that should bring down the cost significantly.
This is my most-current design on Shape diver. You can play around with it too! Check out the live parametric model here! Unfortunately, shapediver doesn't let you download the file, or the cut-files, which would be really epic, but it does at least give you a taste of the power of parametric design, without all the expensive hardware and difficult to learn software. And I'm uploading the Grasshopper definition file to the Files section, so even if you don't have Rhino/Grasshopper yourself, you can find the parameters you like on shape diver, and then send the values and the open .gh file to someone who does, and they can compile the cut-files for you. And of course I will also post the cut files for the version I end up building either way.
But I really like the idea of letting people play around with the parameters of this design. This will not be an efficient wind turbine, and efficiency is not my top priority at this point. But I think it's cool that people could tweak the design to suit their preferences and then test their results against mine, and together we could find more-and-more efficient versions moving forward. It's sort of a microcosm of how I hope this whole project could be improved systematically over time by a community of folks, like the Precious Plastic machines have been.
But if that's gonna happen, I've got a lot to do in the next 3 weeks!