Ballast Glue

What do you guys use to hold ballast in place outside? I’ve heard that some people use diluted white glue, but wouldn’t the rain wash it away?

Check out this thread, http://cs.trains.com/trccs/forums/t/159524.aspx

In English it is called “Gravel Glue” and we have a rather long discussion with phone numbers, names of vendors and much more.