Unfortunately my awesome idea for this week didn't quite turn out.
My idea was to make a rock-shaped lunchbox which would be lightweight but strong for carrying lunch. I also was interested in casting an irregular shape from nature to see how that worked out with the composite.
I found a great rock on a family hiking trip this weekend. It was a lunchbox-ish and also very rock-ish. I cleaned and dried it off and sprayed two layers of the 200 mold release. In retrospect, I should have COVERED the thing with vaseline and not bothered with the mold release because it totally didn't work!
The composite process was pretty straightforward and fun. I put a good amount of layers of linen on the rock.
I let it vacuum overnight just to be sure the resin had hardened and because I had several layers of linen.
Cutting it out of its bag.
I thought I'd be able to cut a parting line and split the composite off the rock. I started with an exacto but that was painstaking. Sam helped me use a dremel which cut through the composite really nicely. HOWEVER, even with a nice clean cut in the composite it would not budge from the rock. Oh woe!!!
In retrospect, I would try
vaseline on the rock
casting two sides of the rock separately and then laying up the composite material in that mold
Pip had the good idea of felting around the rock in two halves, then dipping the felt in resin and putting it back on the rock to vacuum. That idea would also get rid of the wrinkles around all the rock's irregular shapes.