Whilst we get everything up and running here on the website, we've decided to document our own experience so that it can be used to help create the website material as we progress through the various stages of the project. It will also help us test the viability of the project and iron out any bugs or issues we may come across.
The first part of the project and an aspect with a large impact on your perception of plastic is undertaking the Trashbin Challenge. Basically all plastic waste is retained and set aside for a period of a month. The waste can then be recycled using the processes outlined in the project. The actual period could be shorter or longer but for anyone undertaking the challenge at home a month seems to be about the right amount of time.
So here we are 1 week in.
We are starting off at the beginning - the collection stage. We've basically decided to seperate all plastic waste from our recycling and retain it
This is what one weeks worth of plastic waste from our household looks like...
The plastic tub and bag were just being used to store the waste, but as you can see they are already full. I guess this is probably typical, not only of our family but also many others. We have two kids in our household and everything that you buy seems to come in some form of plastic packaging. So this probably represents average plastic usage by an average family.
We've decided not to try and alter any habits initially as we are interested to see how much plastic waste we end up with at the end of the month. Then we will look into strategies to cut down on single use plastics. For the remaining waste that we generate we will look into methods by which we can re-use / re-purpose or re-cycle
To be clear, we always 'recycle', but this only amounts to putting recyclables into our yellow bin (recycling bins are yellow in our council ward). When you find out that only a small percentage of this segregated plastic waste actually gets made into other products it makes you realise that there have got to be better alternatives, which is partially where this project comes from.
The Tech Stuff
Whilst we have been busy collecting and washing used food packaging, we have also been getting together the necessary equipment to allow us to process the plastic. We've been very busy with the 3D printer printing out the parts to make a larger format 3D printer that can carry a printer head capable of processing pellets. This has taken some 90 hours of printing. We are now just waiting on the remainder of the components to arrive before assembly can commence.
The biggest challenge at the moment is the creation of the granulator or 'shredder' as they are sometimes known. Precious plastic have a good open source design that is suitable for this project, but the unit is fairly expensive to build. So currently I'm creating an alternate design that can be created with simple bench tools from cheaper material. The trade-off with this cheaper design is that it will take more time to build, but that could help to make this project more accessible. Of course, the option to get the parts laser cut is also still there.
Blade design is a critical aspect of the shredder, not only the shape of the blades but the amount of overlap the blades have, the number and location of the fixed blades and the phasing of the blades relative to each other. The shredder needs to produce a consistent sub 5mm granule / shred for the extruder to have any chance of working accurately.
The extruder screw design is also another critical aspect of the project and one that will make a big difference to the accuracy of the printer output. Whilst many DIY designs use simple auger drills, these are not entirely the same as a plastics extruder screw which has a tapered feed profile - increasing pressure as it transports plastic to the nozzle. Our aim is to produce accurate repeatable results and so this may require manufacture of a similar screw.
The plan is to have both the shredder and printer operational by the time that our initial month of plastics collection has ended so that we can flow into that aspect of the project. Fingers crossed. :)
Until next week...