By-products of the cotton industry in Benin. © Caroline Grellier
In Benin, the Potemat laboratory brings together participative approach, DIY and maker spirit around the project of upcycling by-products of the cotton industry.
Cotonou, correspondence (text and photos)
Following the field survey, each of the fourteen by-products identified in the production and transformation phases in the cotton industry was carefully labelled and put away…in a recycled mayonnaise jar, at the Center for the promotion of local materials (Potemat), a research laboratory at the Abomey-Calavi university (UAC) where I am an intern.
Yes, indeed, here, numerous collection, cleaning and reselling chains are in place. Including the mayonnaise jar! You can buy this glass jar with a functional format, light blue or dark blue top, €1.80 for 14 jars at Dantopka market, the great market of Cotonou (one of the biggest in west Africa). I found these same jars on the lab bench of the Abomey-Calavi university applied chemistry laboratory, very frequently used by the researchers for their experiences.
We know need to imagine materials from these fourteen by-products. In order to do so, I organized three co-creation workshops, the objective of which was to lead to a maximum of material ideas and experimentation protocols. Architects, mechanical engineering students, PhD students in materials, a teacher-researcher, an agricultural mechanics manager, a representative from the cotton industry, and draftsmen thus worked together at the Abomey-Calavi engineering school (EPAC).
On the workshop menu, the first exercise was a brainstorming where they manipulated the samples, expressed their intuitions and reached an agreement on the recognized features of the substance, its alleged features, the reference projects that echo this substance. As a result, they got a board of Post-its.
The second exercise consisted in filling in a material idea-index card, working in pairs. Having read a fiction story, written according to the needs noted during the field study, participants had to find solutions to the problem with an appropriate material answer. In order to make this work easier, I designed index cards that detailed the process: draw a diagram of the material (its shape, its dimensions, its description); give it a name; list its ingredients like a recipe; glue machine stickers / tool stickers in order to communicate the transformation stages from waste to material; finally, write down result intuitions, characterization tests to carry out, remarks, etc. The idea-index card tool worked rather well: sixteen index cards were completed with a whole raft of concepts to develop and test!
Off to the metal recycling market
In order to make these material samples and test them, we now need machine tools. On the program: a tile press turned into a thermo-press, a crusher to adapt to cotton stems and a low-cost defibrillating machine to clean and stretch cotton fiber waste.
Once the plans were approved, we went to purchase the equipment at the metal recycling market in the Akpakpa Midombo district. An impressive site. From dawn to dusk, rickshaws roam neighborhoods to collect the metal people want to get rid of. The parts are then transported to this type of workshop-market where they find a second life through being cut, pounded, melted, soldered to make stair railings, door hinges, etc.
Sitting on the floor, under a wood and sheet metal shelter, very young apprentices handle the mallet with disconcerting dexterity and a certain amount of experience. The market resonates, deafening noise, you can barely hear what is being said. You can find anything here, nothing seems impossible. We located the tubulars we need for the defibrillating machine axles, and also a slab that we had cut out of the least rusty meter door. Unbeatable negotiated price. Back at Potemat, we will start on the production that I will carefully document through a tutorial made of drawings.
And a little medium in the glue
I concurrently took a closer interest in starch paste waste, collected during our visit to the textile factory in Lokossa. With a teacher-researcher colleague we started manipulations aiming to find out the starch content present in the paste residue, determine its gluing power and better understanding its potential to become a medium in our future materials.
Next step: several days of observation and exchanging views in a village of cotton farmers in order to approve the proposals outlined during the workshops, and if possible, organize this same workshop with them, onsite. The more the project makes progress, the more it seems relevant that the production of construction materials should take place as near as possible to the field, by the villagers. Might as well work in collaboration with the main people involved!
See the previous columns of a material maker