Oysters are a vital organism in maintaining the global health of the planet and waterways. As natural filters, they actively remove toxins from the water. They are also a sustainable and healthy source of protein. As a hyper-sustainable source of protein that produces chemically interesting waste during the harvesting process, I wanted to explore if and how the shells which are thrown away by restaurants could be diverted from landfills and turned into something useful. This is an active investigation and the page will be updated with new updates as they happen.

Oystercrete

One of the materials I wanted to know if I could create is concrete purely from oyster shells. The shells are composed of the same raw material as concrete—limestone. Knowing that concrete production is environmentally taxing in a few main ways like: quarrying and transporting limestone and converting limestone into lime (the key ingredient in concrete), I wanted to explore a few different approaches to reduce the carbon dioxide output of this oyster-based concrete to something more net-zero (while also cleaning the water before its made). Being in an architecture program, I witness first-hand how much concrete is wasted on projects that get discarded at the end of term, creating a massive environmental footprint but also an opportunity for to create a material for craft, design, and prototyping purposes while reducing waste. Given their naturally smaller size I assumed I could fire the shells at a lower temperature and still achieve the same output. The initial test mirrored the traditional concrete production and worked perfectly.

test 1//Fall 2021

The preliminary test of oystercrete was created for my biomaterails class at GSAPP. These tests were not controlled and lacked thorough research and a developed recipe; however, they showed promise if the ratio of ingredients were correct. The initial oystercrete tests produced some very pretty and irridescent samples that were too fragile. If this material were to be used for architectural model making and home decor objects it needed a bit more strength.

test 2//Summer 2022

After I finished my class I began researching more about natural plasters and concrete production. I thought about the different components of concrete, what is used in traditional concrete, and what could be used in mine. Two scenarios framed my thinking, one of a world where shellfish forms the bulk of residents dietary protein; and the other more similar to our current world that utilizes non-local materials to create something sustainable but not necessarily ocean-specific. Concrete is a mix of quicklime, fine aggregate, coarse aggregate, and water. My quicklime is made out of oystershells, for fine aggregate I considered many things but decided on diatomaceous earth because it was most similar to sand as it is also silica, and for course aggregate I considered many different things in these tests I used recycled glass, spent oystercrete from previous tests, and unfired crushed oyster shells. I wanted to mirror some of the similar processes used in traditional concrete production, which is how I decided on these coarse aggregates. Additionally, I decided on diatomaceous earth as is it made from algae and therefor another thing made from something living in water, so it felt poetic and very practical. Furthermore, the harvesting of sand is very environmentally degrading and this is a more sustainable and ethical option. I am recording all of my thoughts and results in Notion. However, is a quick excerpt of my findings and formula results thus far. I am further clarifying that these samples were produced after testing the oysterchina so I did not follow my exact recipe in hydrating the oysterlime. I plan to redo these tests properly in the coming weeks, as all these tests were rather weak, broke easily, and not uniform in construction. Each sample dried for about 5 days.

Oysterchina

Pulling from my fascination with ceramics and speculating about what the world could look like if our daily diets were more seafood-centric. If somehow our diets gradually shifted to consume more seafood, specifically shellfish, the amounts of that would be produced would intense and provide a valuable source of raw materials. I started to think about how their shells could be substituted in as the bone in bone china. Given that oyster shells are chemically more akin to limestone rather than bones, I knew it wouldn't be an exact substitute was curious to see what it looked like and how it functions as a clay body. I've run a few different tests most of which resulted in the production of quicklime (a key component of bone china). However, I wanted to know what you can make with the shells at lower firing temperatures to bypass the need for other additives. I am still working on getting the consistency just right but until then please enjoy these renderings of the pots I plan to make!

test 1//Summer 2022

I thought about the formulation of oysterchina for many months. I had the idea for oysterchina over a year ago, after learning about the production of bone china. I've never actually made clay from scratch before so I knew there would be a learning curve but I eventually I had to stop thinking and just start trying. There are a few differences between the core ingredients in bones and oyster shells; bone are a mix of calcium and phosphorus but oyster shells are nearly entirely calcium. In clay, phosphorus is one of the few elements that acts as a glass former, which provides bone china with its translucency. There are a few other elements that act as glass formers in pottery, including boron, which for constraints out of my hands I used instead of phosphorus. I came up with 3 recipes to start with just to see how things would react chemically given that I am using a strong base (quick lime), a weak acid (boric acid), potash, and kaolin clay. In an effort to simplify things, I started with traditional bone china ratios which is 25% kaolin, 25% feldspar material (in this case potash), and 50% bone ash. I made small 100g samples for each recipe, which in this case ended up being 3 different recipes. The first test is the traditional ratio but for the bone ash I tried to mirror the ratio of calcium to phosphorus in bones, subbing boron for phosphorus. I knew doing this probably wouldn't work given there are many differences between boron and phosphorus most importantly the bonding and mass of these elements with calcium, but it was good starting point simply because it just let me start. I then created 3 different variations from this initial formula which focused mostly on changing the ratio between boron and calcium. I was not a good scientist when testing these out because I abandoned by recipes after the second test and just started freestyling (test 1a). While being fun to depart from the recipes, I should have followed my own instructions because after further thought and actually applying more chemistry knowledge I think a better recipe might lie in one of the formulas I did not make. Although departing from the recipes allowed me to come to this conclusion more concretely. I also think that I should do a little bit more chemistry given that I have to use a specific set of ingredients that I had not originally considered.

It was pretty easy to create a clay consistency to my surprise. However, I never actually got around to hydrating my quicklime to create a more stable ingrediant, something I plan to do in the second round of resting. I think this is critical as the quicklime reacted a lot with the water and less so with the boric acid. The clay heated up a lot which I hoped it wouldn't given that I tried to over hydrate the quicklime by creating an aqueous solution instead that was something like a slurry. This however, created something that changed the actual amount of calcium in the final clay body as water also has a mass. Out of the three tests the second one was the best and only successful one, I have yet to fire it so time will tell if it actually works. Test 2 was the only solid one after a 5 day drying period. The other two tests were powdered when I returned. I plan to make a few more pieces using this formula as well as some more samples of other recipes including a properly hydrated batch using the same ratios from the initial recipes. I created a variation of the first recipe that I thought would be the most successful because it was the most clay like but it actually did not survive the 5 day drying period. There are many variables of the project that could change which could produce dramatically different results, the ratio between all of five ingredients as well as the firing temp meaning there are at least 700 different recipes. I will probably not try all of these because I am currently doing this as a fun side project and I have other responsibilities but I will keep toying the recipe until I get something that is throwable on a wheel as well as castable as slip as well as printable on ceramic 3D printer. I know there is a recipe for oyster shell filament for 3D printers (standard and ceramic), but again that is not what I want to make. I plan to test 2 other recipes for a total of 5 recipes to first see how they feel, how they air dry, and how they fire.