Can I safely epoxy Teak on gelcoat?

Rather than use epoxy have you given any thought to using an adhesive like Sika.There are a number of really great flexible adhesive products on the market now.I used Sika for teak decks on my yacht around six years ago and it is still working fine.You can caulk the gaps with the same product and then just give a light sand to finish...works a treat.