Take a small (4.5" using a 36 grit sanding disk) grinder and clean all the glass within a couple of inches of the hole. Then using the same tool taper the hole so that it remains about an inch on the outside but the width of the hole tapers out to about 2 inches. <br /><br />The inside area is almost preped. Next go to the outside and hand sand an area around the existing hole usin 36 grip paper. Only sand out from the hole about a quarter to a half inch and just make sure its throughly roughed up so new material is exposed, but no more. Finish by washing down the cleaned areas, inside and outside, with acetone.<br /><br />Mask the outside area leaving only a working area a couple of inches larger than the outside hole. Don't bother masking the inside.<br /><br />Now the patch. Cut a patch of glass matt that is about a quarter inch larger than your hole. Wet it out using expoxy and a fast set hardner. Just mix up a thimble full because you are only going to put on this one piece for now. Wet the patch and put it over the hole on the outside. Using plain old Duct tape hold it flat and in place while it sets.<br /><br />Once its set pull the tape off and head inside the boat. Mix up epoxy and paint the hole and all the tapered area using a small soft disposable paint brush (maybe three quarter inch wide). You should have preprepared a bunch of disks of glass matt or cloth in progressively larger diameters from the 1" of the actual hole to about an inch wider than the tapered part. Most hull sides are around a quarter to three eights inch thick so it will probably take about 6 or 7 patch sections. Lay each one up, the painted epoxy will hold the first one and every other one will hold too. Using your brush just paint enough epoxy (this should be mixed with a medium or slow set hardner) on to wet out the patch and then get the next one and do the same. What you are going to build up, in about 10 minutes, is the complete patch. Make sure you don't allow any air bubbles. Don't lay on the epoxy too heavy, let the glass build the hole up. If your surface is actually vertical you will have to do this build up in steps. Just don't build up so much at one time that it droops. Your last patch section will probably be a rectangle around 4" square.<br /><br />With that done go to the outside and mix up a paste of epoxy and West Systems #404 High Density filler. Using a plastic paddle, like the ones you would use to apply automotive body-putty, that has been mixed to the consistancy of about peanut butter, just skim a coat over to fill any voids. After that sets up finish it as you would any other repair.<br /><br />If you do this in the driveway you should probably figure this for a full saturday, but that doesn't include the finishing.<br /><br />ThomVW
