I saw this as my only time to really test the compostability of my foam and so first thing i did was take 4 of my samples, all with different strength and compression levels and buried them in a dorment compost. These were by foams before:
I will revisit them in two weeks to see what the difference is like.
I revisited an earlier concept and made a model to help me decide which sole i will use.
Between my two soles i decided to go ahead with the voronoi speackled sole from my final design presentation as it gave me more room to work with.
The sole form works best for creating a shell where the tailor made voronoi structure can fill in. I am also able to use the cells individually to change for the best overall function, Such as; using the larger cells in the center of the heel and forefoot as these will absorb most impact, they also reduce wear from traction as appose to smaller pieces, I can remove the cells in the arch to help with flexibility, I can speckle the cells around the heel and forefoot to represent the dispersion of the force while walking, and i am also able to utilise the top row of empty cells along the edge for stitching the upper onto.
Next I needed to work out how this will be printed, i ran a test to see what it would be like printing with no support and separating the tread from the shell.
This worked a lot better than trying to print in one go, a few tweaks were made by increasing the height of the tread so it pushed through and held better. To glue the tread on i simply used superglue and thought once the foam was poured in this will also help keep everything together.
The foam shows well through the open cells on the sole, I could remove more around the edges for a more speckled gradient.
Pouring the foam last does make the join look cleaner from the inside but the fabric does cover some of the voronoi cells from the outside, stopping the foam from showing through well.
The two layers of fabric helped with comfort and also the look of the upper, it doesn’t crease up as much.
Out of curiosity I then weighed the shoe against an Allbirds woollen sneaker. My shoe weighed 245g and the Allbirds weighed 234g. Although the Allbirds is a size 11 compared to my size 6 but too only be 11g heavier is a promising sign as this weight would get lighter with a 3D print infill amongst the foam.
I revisited the first 3D printed sole I modelled and applied some of the skills I learnt from grasshopper to make a shell with closed areas that would make contact with the ground. When printing I set it to build support but this proved problematic as it made a thin layer of TPU across the entire sole, when I tried to remove this it left a rough torn texture across the sole.
Continuing with the print, I wanted to test how the foam would look if I was to sew and attach the upper before pouring the foam in.
To sew the upper I wanted to using two layers of fabric so I used a stretchy cotton blend with the hand woven fabric I made earlier in the paper. These are the cuts and stitches I would be making:
The red line show where a cut would be made and folded over before sewing, this would give strength to the lacing holes. I also used the 3D prints of the heel and toe cup to insert in between the two layers to help with support.
Then using the leftover nylon I stitched the upper to the sole by hand.
Next I made a large batch of bio foam to pour into the 3 concept soles. Two of these used flour that I flattened along with masking tape to contain the foam and the last used just masking tape.
Pouring the foam after attaching the upper was a lot more difficult as the fabric would hang over the entrance and some got covered in foam, once set I was able to peel it all off but was still an annoyance. It was also more difficult to get an even lever as I had to tilt the shoe to get the foam to flow to the front but some would slow down and set and cause a lump in the middle of the forefoot.
Now that I had another concept sole to work with I cut and stitched on a new upper. For this model i used one of the thinner 3D print details on the fabric. I used a white canvas to see how the colours looked compared to the red and blacks.
To get the pattern I roughly followed an existing upper and then wrapped it around a model foot, marked any area that needed extra fabric and cut it out. I sewed all the edges over and used nylon to stitch the upper to the edges of the sole.
Collected the ingredients and made a batch of foam, for this batch I tested adding pigment for coloured foams. For this concept I added black. I also tested different methods of containing the foam, as the pieces are separated i needed something to stop the foam from covering the parts completely. For this i tested using bluetack and flour.
The flour worked well but left a lumpy texture on the underside, this could be better if i took more time to smooth the flour out.
The bluetack worked to begin with but as it heats up from handling it becomes more difficult to get out.
The black foam was successful although it made cleaning up quite difficult and I end up cracking one of bowls from trying to rub off blag pigment. It is an option to consider if the off white doesn’t look so nice with the 3D print filament colour.
In my mind I still have one other concept to test out. This is using the voronoi sole shape and extending the pieces on the edge to run up the side of the sole and join to the fabric. This means the sole doesn’t have a solid edge and is able to move and bend easily without and restriction. I modelled and printed this concept…
Printed out of PLA plastic so there is no flexibility just because this is cheaper as this model is noticeably heavier. I do like this concept as it is less flimsy and i would be able to print stitching holes along the top edge of each piece and even add a small groove so that once the thread is pulled tight it can sit flush.
The black has a nice shine to it and i think it will contrast well against the off white of the bio foam.