Gel Coat is a no-brainer imho. I went to West Marine and got gel coat and insteuctions on prep and coating. The coat i used was painted on with a brush and due to the gels thickness....the brushstrokes disappear and its a perfectly glossy smooth coat. about as diy as it gets and is good for another 20years in beating sun. Oem and relatively easy diy project. Prep was simply sanding the old gelcoat off (mine was 40year old orig which was failry baked dry and already almost completely flaked off)without going into the fibreglass too mich so something like a 200grit). Then simply address any fibreglass gouges with a sandable filler) and paint on the gelcoat. i did 2-3coats in areas where the coat thinned out due to gravity on corners humps where gel would run down if painted too thick initially) since this was my first go around- and i learned from mistakes-id strongly suggest painting it on thinner vs thicker-and then follow flash times and paint on 3-4thin coats vs 2 thicker as i did...for more even coverage as the gel tends to droop if too thick.)
On the inside of the top i later shot some lizard skin ceramic -1gallon- and then applied an SOR headliner once the Lizard skin was dry. The Lizard skin interior and Gelcoat exterior is noticeably better than my 80series with just the lizard skin interior roof/painted exterior as far as heat reduction on a blazing California day. So the Gelcoats UV and glossyness adds to some heat shedding.
heres a 10footer shot today- already 4years old and looks oem-i purposely didnt do the outer lip with gelcoat to keep some patina transition to the roof. (i was afraid the roof would look too new for my patina cruiser paint- but by leaving the outer roof lip it keeps a nice transition surface rust)
in the second pic- you can see the color of the 40s gelcoat in relation to the oem cruiser cygnus white in the fzj55behind the 40. pretty darn close to cygnus.
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