That all went well, with very little drama. I got a little bit of silver solder in the threads, but only a very little bit and it cleaned up after running the 10-40 die over it a couple of times. I decided at the last minute to make the cap for the needle valve out of steel instead of brass. I always scrub the brass parts I've soldered with a small wire brush to get rid of that pink color that forms on the brass but I couldn't get it all. Maybe I'll mix up a new batch of citric acid and give it a half hour soak to see if that helps.