Originally Posted By Dryer
My first hammock rain fly was a plastic blue tarp.

I'm currently using a 2mil plastic drop cloth cut down to 8.5 ft square and pitched as a diamond. The loops (that the ridge line attaches to) and the guy lines are all held on with sheet bends. You just have to be sure to gather up enough material when tying the sheet bends so it's strong enough to take the tension. It's not the most durable, but it works well, and it only cost a few bucks (US).
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