MikeG2 wrote:...
Having built up the layers on the flat sides, will overlapping the fibreglass from the top onto the sides produce an invisible join, or do I have to treat this differently?
using staggered/graduated layers as you go over the top edge and down the side when carefully faired the seam wont be seen by anyone butt you a/o a composit boat builder
and it will create a corner that is stronger than you can imagine
AND there will be no avenue for water intrusion!!!
here's an article that may help
http://www.ptwatercraft.com/glassing_edges_corners.pdf
if you've ever done any dry wall taping & bedding you will remember how the tape was smoothed way out from the actual seam by wiping mud away from the seam and when it dried block sanding it
when you go over a corner it is virtually the same you just use thickened epoxy for a fast fairing job that gets painted (thickened epoxy takes on the color of the thickening agent) or un-thickened epoxy for natural finished projects and simply block sand the excess smooth/flat appearing
sw