Alembic Club: Apply POLESTER RESIN to fretless fingerboard to reduce string abrasion?
HG Thor Epoxy Fretless
Epoxy Coating a Fretless Bass - Strange Guitarworks
Mitchell Feldmann, PhD on Twitter: "I have been playing fretless guitar (home modified with epoxy resin) for about 2 weeks, and today I played one of my fretted guitars and the frets