Wednesday, 20 June 2012

48hrs later

Wow I've been itching to get at the PDMS for the past two days and tonight I finally got to play with it.

Firstly what was I thinking with my two pieces or perspex hinge thing, yes I needed to bend the silicone to pull on the rods but up is as good as down. I could have used a single piece. That is what comes with doing things on the fly and being seduced by "clever" ideas.

As expected the rods did come out and to be honest as expected it did take a bit of a toll on the silicone, I think a primer should probably be used to keep it well stuck to the perspex and apparently they are available. There were also a few bits of silicone pulled into the channels by the rods so if something like this method were to be used the other ends should be encapsulated in silicone.

Now it is free of plastercine (never again will I use that for this process) I have stuck it in the oven at about 70C to ensure it is as cured as it can be. Then I need to sort out the manifolds and see how it responds to negative pressure, then I'll mix up some solution that is index matched. Glycerol and water can be used it seems but may be too viscous, other stuff can be added to boost the index too. I've got a recipe for something with the index of PDMS and the viscosity of blood and I guess that would do OK.

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