watch the video
sorry you will get it if you watch the video
you do not need to make the hole bigger. the smaller the better
with a one inch hole you dont really need a backer. but if you want even a piece of duct tape on the inside would do.
if the glass is 3/8, grind out about 4 to 5 inches in taper so the inner edge where the hole is a knife edge. the taper will go from very thin to just taking off the gel coat. then you will need about 8 to 10 layers of glass ( 7 oz ) the fist layer is the full size of the taper ie about 10 inches. thats the one inch hole plus 4.5 inches each side. cut each smaller piece of glass about 1/2 inch smaller. so the first circle is 10 inches, the second 9.5, third 9 inches etc.
spread some plastic ( trash bags work ) out on a table, mix the epoxy. put the smallest piece of glass on the plastic, pour on a little epoxy and work it in with a squeegee, put the next bigger layer of glass centered on the first. add a little more epoxy and work it in. keep going until you put all layers of glass with epoxy all centered, smallest to largest. take a little epoxy and mix with collidal silica and brush that around on the hull where the taper is. this epoxy layer fills any grinding grooves so the glass will not have to. then pick up the plastic with the glass and resin on it. place it over the hole so the last and largest layer is against the hull, and make sure its centered. then use a squeegee to work the glass to the hull, do not remove the plastic bag yet. work out as much resin and air as you can, then let it cure over night.
the next day, pull the plastic and see how close you are to a level surface. if you need you can add some more glass to build it up. when its close ie around 1/8 inch to level let it all cure. then mix some epoxy and light weight filler to a thick paste and spread it out. then sand smooth when cured.
you can use gel coat to cover this to protect it from then the sun.
Last edited by scottyt; 08-04-2009 at 08:10 PM.