I used 'Fastglas' resin that is for automotive fibreglass repairs, I think this is polyester.  It cost around £13 for possibly a litre and I bought some fibreglass tissue at the same time.  I put a couple of layers of tissue in the mould, painted them with mixed resin, put in the coils, filled with resin and then put on more tissue followed by the lid.

I had to very quick because it set in around 15 mins.

One year on it's still ok, but I have a feeling that it's slightly brittle stuff and I'm usually quite careful handling it, perhaps needlessly; it could be much stronger than I think.

You get what you pay for of course, and I didn't want to pay a lot, trying to make the turbine on a very tight budget.  The only other options I could find were buying large amounts of stuff or very high prices.