This would work, but I doubt the OP would want to ignore a board which they just recently posted in. AFAIK, there is no other option for removing a topic you posted in from your "show new replies to your posts" list.
I sometimes follow up threads directly through my replies list linking directly to the thread (I just assume new replies would have been added after a while).
Piggy's notification bot is also a convenient way to keep up with threads.