Neil, You need to address this question to Stan Susman aka PaintBoy. We are fortunate to have Stan as the resident Interlux coating Guru! It's a full service kinda thing. He can steer you in the right direction. He will probably chime in here any minute now.... GO GO. "Air Powered" ex-"LB/GF!" M-17 # 316a 'that ain't bad gelcoat -it's "patina"! Team Geezer Racing.....Old and in the Way