aloapiddThe secret to sealing fiberglass parts: cotton swabs, apparently!
I heard of this trick a year or two ago but this is the first part I've had the chance to use it on. Just put a small mount of CA glue on a cotton swab and use it to apply it to the edge. If you want a really nice finish, sand with some fine sandpaper between coats once it dries.
Even without sanding, the finish is quite smooth with only a few rough spots.