Originally, I thought about using raw hemp stick which is the long, tough, coarse fiber of the cannabis plant, used to make cordage.
I through a bunch into my crude plaster test mould and added point shoe shellac and came up with a promising potential. But the feedback I go was the hemp looked a bit messy all tangled. The problem was the messy tangles were what gave the hemp it’s strength.
I wanted to layer the hemp up in one direction and then cross the direction. I layered up the hemp wet and let it dry around the one side of the last. However, this whilst potential beautiful and a bit subversive was propbematic in the sense that the fibres even if place and proper moulds were hard to control. Gravity pull these fibres down in clumps. I tried holding it with PU glue but I was worried this would interfere with the resin application.
I also tried with dry hemp resined but found whilst strong it could thin in areas and these areas were weak.
I revisited the information and realised I missed the matte suppliers of hemp. These are the mattes Werner Aisslinger used with his hemp chair. The company J. DITTRICH & SÖHNE sent me a selection of hemp mattes, some pre preg with the acrodur. This meant the mattes only needed to be moistened once delivered, however these mattes usually come with moisture still in and waterproof sealed.
So we created a rig to test the material of clay and ply
Then clapped the material through and pressed around the last
The result was a surprisingly strong form
The design is to use the hemp shrouded around the felt sock
But this was just the start. This matte is a combination of hemp and kenaf another natural fibre. So I tested the 100% hemp and it moulded really nice.
See I want to mould in this way so working with the material is a challenge. J. DITTRICH & SÖHNE the material supply have been great, a designers dream. These people are so helpful. They contacted BASAF the acrodur suppliers and sought further advice for me. I emailed images of my test and they were not put off by the fact I am trying to recreate compression moulding and resin transfer moulding in a workshop, non industrial environment. They picked up that my wall thickness should be less on the upper so suggested I use the 600 gsm weigh sheets but realised I will need thicker in the heel area and double checked I could fuse the two sheets together via heat and compression. They suggested with the consultation of BASAF to use a glove iron the heat thus curing the acrodur whilst on the form.
So the mould is for compression and once open and the material still around the last and the heel, insole blank I can run the iron over it. Brilliant! They are so cleaver!
Then once pat cured I can further cure in the oven at anywhere over 160-200 degrees. The lower the tempature the longer curing time.
But that is not all…They recognised I will need to potentially add binder to stiffen the heel areas of stress and I can either spray or brush on the acrodur BEFORE it cures in stress areas.
In my test using the flash oven I realised two things…if any water is still in the fabric the binder bubbles and becomes brittle. It really is using the sensitivity of a chef in these workshop conditions.
Thing I realised in this process were that for some reason people respond more to the 100% hemp moulding. The kenaf hemp combo is apparently 90% with a 10% polyester fibre. I am not sure if it is that 10% which is somewhat of a deterrent, or the 100% of a natural material which seduces us with it’s elegance or if the thinness of the material moulded over the last is so seductive, but something is happening which makes this material notable for a passer by.