Well you must mix up a better batch of epoxy that I ever have. Also my recollection is that I have read in some marine publication that the bond between epoxy and gelcoat is not a secure one. Can't say that I recall where I read that exactly. The previous owner of my boat drilled a few holes and filled them with epoxy. Gelcoat stuck to that for awhile. I removed a spinnaker pole holder and filled those holes with epoxy as well and ditto for the failure of those bonds in time.

I mixed my batches of epoxy as per the West System's instructions. All of the epoxy that I have covered with gelcoat was cured and sanded before the application of the gelcoat, but I have no idea at this point what the ratio of resin to catalyst was, since that was a number of years ago. The epoxied areas were very small in relation to the areas to which I applied the gelcoat. If it works for you, that's cool, but my few experiences with gelcoat to epoxy bonds have not been 100% positive.

The reason that I use gelcoat is that my boat has, as did all Ariels, a gelcoat skin on top of the fiberglass deck molding. I applied a new coat of gelcoat in several areas where the original coat was worn or where holes had been drilled and filled, or where stress or impact cracks were evident. I like gelcoat. It's pretty stuff if you apply it correctly, and it looks and lasts better than LPU. As to epoxy being a safe product to use, the safety of all marine products in my opinion is a matter of mythology, unless of course you are applying steamed white rice to nori, in which case only the raw fish that you apply afterwards is potentially toxic.