Fiberglassing the exterior of the Coaming
After installing the riser, I glassed the outside, reinforcing the coaming and securely attaching it to the deck. The riser was initially installed using hot-melt glue which is not particularly strong. It is used because it is quick. The strength comes from the layers of fiberglass installed here.
I start by masking off the deck about 1" from the riser. This masking tape will be used later to clean up the edge of the glass. I then cut several strips of bias-cut glass. This bias tape is useful because it distorts easily which allows it to conform to the curves and form to the angle between the deck and hull. I cut enough 4" wide strips to go all the way around the cockpit once and then set of 2" wide to do the same.
The 4" wide strips go down first extending from the top of the riser strips down onto the deck and overlapping the masking tape. Before applying the tape, I brush on some resin. This resin will help hold the glass in tape as I lay it around the coaming.
I am careful not to pull on the tape as this will stretch it and make it narrower.
The cloth is seated in place with gentle dabs of the brush. Stroking the bias tape will stretch and bunch it up.
I wet out the pieces one at a time and then overlap the ends about 1/2" until I've gone all the way around. This I applied the narrower strip. This one extends from the top down on to the deck about 1/2". I want two full layers at the sharp angle but want to be able to feather it out smooth on the deck.
After the resin has set up to the point that it is a stiffened but not yet rubbery, I use a utility knife to trim off the glass just inside the masking tape. I apply just enough pressure to cut through the fresh cloth. This does not take much pressure, just a light touch. Peeling up the tape removes the cut-off fiberglass.