So in my last blog i had told you about worries that the whole invisible sculpture thing was not going to work and because of this the Mike Nix and I had been working on a solution to make sculptures that are clear, but turn pink under UV light. Our plan was to add photochromic dye to the resin and see what happened. We were pretty sure that the solvent we had used was not the best but when we came int he next day disaster……
Both resins with the photochromic dye had set (more or less) in the visible spectrum, turing the resin purple. According to Mike (later on in the lab) this was interesting because the dyes work by flipping or changing shape (Bad explanation, sorry Mike)
The really really cool thing was the the set resin cast I had made which contained two different types of resins looked clear, until you put light under them, then a cloudy form appeared inside them. Its not perfect, but it proves that the idea of what i wanted to do is possible. Pretty exciting, but it can be improved.
After making the base for casting encasing a glass pear (that i got from a charity shop the day before) i headed up University of Leeds Chemistry department to meet Mike to do solvent tests on the resins. What we were trying to do was add metals into the resin to make them denser thus changing the refractive index of the resin. To do this however we need to dissolve the metal in a solvent making a metal solvent solution that can be added to the resin. We tried a few things out, but after a couple of goes found a solvent that would work.
So now to decide what metal to use. We had been using copper in these test, because it was available, but its also makes a blue solution, so its not idea. The obvious one is Lead. Its used in crystal and its clear in liquid form (i think). Its also cheep. On the down side its also really toxic. So in the end we went through the whole process. We considered others, but they were either too dangerous, too expensive, or not heavy enough. In the end we went with zink because its cheep and not too toxic, but its also not that heavy. Even so it should help to change the refractive index (and we also discovered that there is a difference in the index between the two resins i was already using.) By adding the metal to one of the resins i will make difference between there RI greater.