dark spots on gelcoat

Thread starter #1
I have dark dots on my faded vanilla gel coat of my 70 sunfish. I'm trying to whiten it up and remove the dots. I've tried bleach, toilet bowl cleaner and wet sanding with 220 on a DA (random orbital) sander. Somewhere under there is bright white color. Should go to a lower grit or is there something better?
Pic attached is dots and fading on the right and where a sticker was on the left.
 

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mixmkr

Active Member
#2
400 grit can buff out.....lower you will leave scratches...like from your 220 grit. I'm afraid you might have to live with it as the gelcoat has faded at different rates (behind a sticker, graphics, etc), and for the most part you have done all you really can without sanding thru the gelcoat.
 

beldar boathead

Well-Known Member
#3
400 grit can buff out.....lower you will leave scratches...like from your 220 grit. I'm afraid you might have to live with it as the gelcoat has faded at different rates (behind a sticker, graphics, etc), and for the most part you have done all you really can without sanding thru the gelcoat.
I agree. The boat is 48 years old and has spent a lot of time in the elements and is unlikely to ever look like new again. Someone may have another option, but I strongly suspect that the white is stained, faded and discolored throughout. Not much can be made to look new after 48 years of use. I would not paint it, as that just becomes another maintenance item if it gets scratched, detaches, etc.
 

mixmkr

Active Member
#4
Put some new graphics over the areas if you can. You'll never see it then. This happens a lot as boats change ownership.
 
#6
3-M makes a fiberglass restorer product. It is basically a rubbing compound with some wax. It works well on oxidized and stained gelcoat. Might be worth a try.

Also, try some CLR. It is a plumbing product that removes calcium, lime and rust and sometimes removes stains that bleach doesn't remove. Also, there is a product called FSR (Fiberglass stain remover) It's expensive but a little tub will last for years.

Alan Glos
 

mixmkr

Active Member
#7
I actually went thru a quart of 3m restorer today....waxing a Hunter 35 hullsides. Good stuff but won't "whiten" gelcoat.
There's is this stuff called "Zing".... it is basically muriatic acid and I've used it on stained waterlines (the white stripes , etc...). You CAN'T touch the stuff, but if it doesn't clean up stains and such, nothing will. Bleach works actually pretty good and gives you an indication. Soft Scrub with bleach works wonders, but strips any waxing off. "Tidy Bowl"...similar to probably what you've tried cleans up stubborn waterlines on boats. Wet sanding is typically the last step, hopefully with nothing more aggressive than #400 grit. If that doesn't get it, the next step is a quality paint. Gelcoat doesn't have an indefinite lifespan, especially darker colors which fade/oxidize much faster. (Look at those blue waterline strips in the hulls of older boats.) They'll buff out and maybe last a couple months, tops. Realize there isn't a "hidden" layer down underneath, just waiting to come to the surface and bring back the original color in all its' glory. My '69 Sunfish shines like the dickens...but the original color is long gone. That said....a REALLY good gelcoat color matcher ( I don't do too bad myself) can do a respray and fade the edges in.... cover it all in a clear coat. That's what you're looking at. The "snake oils" are just that....respray to an edge, fade it, cover it or go sailing.
 
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