I've made "sand pumps" All I did was place a large steel ball in the pipe
and welded a washer to the end where the ball can seat. A small rod is
welded across the pipe to limit ball travel. To use the sand pump you just
jog it up and down in the well pipe. The sand pump fills with sand and you
pull it up and pour it out. If your digging a well and you hit sand there
will be water there in most cases.