need help winding toroidal transformer
I'd like to know how to wind a torodial transformer with a toroid that I just happen to have. I would like it to work at 60Hz at 120 volts (US mains) and have an output of 36volt centertap (18-0-18) or maybe a little less (I'm building an op-amp powersuppply that gets regulated to +-12volts) and as many amps as possible (well, safely).
The toroid I have is painted a light green with a blue ring on one side. it is 1.25" outerdiameter, 0.75"innerdiameter. It's 0.5" thick.
It looks like the bottom left toroid in the picture below, just bigger and no wire.
I do not know what gauges to use, how many windings (well, I know the ratio), how many amps it can deliver, how I should wind it, etc.