My thanks to the several responses to my problems with ripples when
using injection wax in an RTV mold. You were all correct in
diagnosing the problem: not enough heat. My problem was that I was
letting the mold sit with the wax copy inside far too long, so that
the mold was never really warmed up when injecting. Tonight I tried
making one copy after another, as soon as the wax in the sprue tip
looked solid, and it worked great.