Cut cloth, without serged edges, will always tend to fray. This could
be seen as an advantage, as it facilitates good feathering at the edges.
Preventing frayed edges:
Run a piece of 2” masking tape so that the inner edge of the tape is where you want to stop the glass. Lay down the cloth so that it runs at least an inch past the outer edge of the tape. Wet out the glass past the inner edge and about halfway across the tape. When the cure reaches the green state run a single
edge razor blade right down the inner edge of the tape. Pull off the tape and presto; you have a nice edge right where you cut the fiberglass
. If a little of the cloth lifts, press it back down.
Make certain any Acetone you use is “virgin” acetone, not recycled acetone. Virgin doesn’t contain any residual waxes or oils. Recycled acetone can damage virtually anything to which it is applied.