Duco cement and the wood glues are the easiest glues to sand. The finish resin epoxies are next. 'Regular' epoxies seem a little rubbery and load sandpaper quicker. Polyester resins are very hard (but I don't use them to assemble airframe parts) and are better if mixed with microballoons. CA's are just plain 'hard' and in no way do I want them on a surface that needs to be finished sanded. I have no experience with the new foaming adhesives and such. Elmer's or Titebond wood glue is so inexpensive. I buy it by the 1/2 gallon and use a small glue bottle that I refill as needed. It is one of those little Elmer's school sized bottles that has a nice fine tip. Makes accurate placement of glue a breeze and it doesn't clog.