Prepping hull to repaint

Thread starter #1
Greetings everyone,I'm new to the forum. I picked up a 1985 Sunfish over the weekend so my wife can get back to sailing here in Naples Fl. I would like to give it a new coat of paint on the hull and then the deck. The boat is in good condition and has been stored inside. My question is,in order to prep for new paint what number sandpaper do you suggest I start with then progress to. I have a palm sander that I'll be using for this project. I appreciate your input and patience in advance as this will be a new area for me.
 
#3
If you really do want to paint it, there are lots of people who have done it here. Search the threads and you will get a LOT of information! :) Does it really need to be repainted though? If you don't do it right, it can end up looking a lot worse than when you started. If the gelcoat is just a little faded or chalky, you could get away with some fine sanding and be in the water a lot faster. I worked on a 1972 boat and used a mouse sander. With a light touch, I worked my way from 200 grit down to 1600 then finally used a scotchbrite pad on the sander. Took the better part of an afternoon, but the boat looks pretty good. Not as good as new or a new paint job, but good enough, and had it back out on the lake two days later!
 

Webfoot1

Active Member
#4
Here are the Marine TopCoat Directions. . .

BARE FIBERGLASS - The entire surface, regardless of age, must be thoroughly washed with a fiberglass cleaner to remove all traces of mold release agents and wax. Sand the gel coat with 80-120 grit sandpaper to create a dull, frosty appearance. Remove sanding dust and residue. If the surface is in excellent condition, proceed with application of the Topside Paint. Rough surfaces or imperfections should be repaired. Fill all nicks and gouges with a fiberglass repair compound. Allow to harden and then sand smooth. Remove sanding dust. Follow with a coat of Marine Coatings Primer for Wood & Fiberglass to smooth the surface and provide a uniform base for the finish coat. Sand smooth and remove sanding dust. Proceed with application of the first coat of Topside Paint

I'd try hand sanding if you've never done it before.
 

beldar boathead

Well-Known Member
#5
Can you post pictures? I would not paint if the hull and deck are good.
I second Charles. Any by you saying “prep for new paint” it sounds like you think it has old paint on it. From the factory they have no paint. They are covered with gelcoat, a fairly durable low maintainance finish. Paint is not as durable Or as low maintenance. I’d avoid painting if possible.
 

L&VW

Well-Known Member
#6
Here are the Marine TopCoat Directions. . .

BARE FIBERGLASS - The entire surface, regardless of age, must be thoroughly washed with a fiberglass cleaner to remove all traces of mold release agents and wax. Sand the gel coat with 80-120 grit sandpaper to create a dull, frosty appearance. Remove sanding dust and residue. If the surface is in excellent condition, proceed with application of the Topside Paint. Rough surfaces or imperfections should be repaired. Fill all nicks and gouges with a fiberglass repair compound. Allow to harden and then sand smooth. Remove sanding dust. Follow with a coat of Marine Coatings Primer for Wood & Fiberglass to smooth the surface and provide a uniform base for the finish coat. Sand smooth and remove sanding dust. Proceed with application of the first coat of Topside Paint. I'd try hand sanding if you've never done it before.
Read the manufacturers' precautions on "Topside" paint. :oops:

One I used (@ $20/quart) said not to immerse for longer than 2 hours. Sure enough, the hull developed 1-inch blisters when left moored overnight. :( In my case, "Topside" really meant "Topside". :confused:

As for the deck, I've found that any color other than white reduces eye strain. (And maybe affects cataracts as eyes age).

.
 

leob1

New Member
#7
Due to some necessary fiberglass repairs that I had to fix, I had to paint my boat, top and bottom. After using glass cloth and resin to fix the holes, I smoothed them over with Bondo, then sanded that smooth with 80 grit, then 100. Then I filled the patches with glazing compound, it's a fine filler, I also filled all the shallow scratches and gouges I could find. This take a few applications to get smooth, sanding between with 100.
After I was satisfied(aka I got tired of doing it) I prepped the entire hull by sanding, from 80 grit(light pressure), through 100, 120, 150. Wiping with denatured alcohol between grits, and after the final round of sanding.
Then the first coat was Rustoleum Wood and Fiberglass primer, using a roller and brush, a light sanding with 150, and filling any scratches I missed, the a second coat of the primer. Then I top coated with Rustoleum Topside paint. Two coats of Oyster White for the bottom, and at least three coats of Navy Blue for the top. It took more coats to cover the light primer with the dark top coat than I expected, but a little goes a long way, and it's a small boat. Light sanding between coats, of course.
The end result was OK, not fine art. But I'd rather be sailing than painting. The TopSide paint is for use above the water line , my boat lives on a trailer most of the time, so I havent had any issues from it being in the water. It does seem to scratch easy, so the lighter primer shows through the dark color, lots of little nick and scratches from use. But again I rather mess it up from use than re-painting it. I give a new coat every other year, to cover the nicks, etc. A quick sand, then spot the nicks and scratches, then a quick coat of the hole thing.
Maybe one day I'll get ambitious, sand it all off and paint it with something more durable, but probably not.
One piece of advise, a random orbit sander will do a quicker job than a palm sander.
Good Luck.
 

beldar boathead

Well-Known Member
#8
Read the manufacturers' precautions on "Topside" paint. :oops:

One I used (@ $20/quart) said not to immerse for longer than 2 hours. Sure enough, the hull developed 1-inch blisters when left moored overnight. :( In my case, "Topside" really meant "Topside". :confused:

As for the deck, I've found that any color other than white reduces eye strain. (And maybe affects cataracts as eyes age).

.
Agree that pures white is BRIGHT in the sun! I'd personally recommend a reasonably light shade of paint for the deck, as a dark color gets HOT HOT HOT in the sun!
 

signal charlie

Well-Known Member
Staff member
#9
120 grit. If you have chunky stuff and you are good with the sander you can go down to 60. Find the color of paint you like and stick to that same family for primer, thinner, fairing compound and paint.

And have fun with the paint job!

Standing by for questions.

IMG_6678.JPG
 

L&VW

Well-Known Member
#10
Agree that pure white is BRIGHT in the sun! I'd personally recommend a reasonably light shade of paint for the deck, as a dark color gets HOT HOT HOT in the sun!
I've just discovered that Lovebugs, (which are out for the month of May) are attracted to the color white. So here I am yesterday, sailing along, carrying about ten pounds of Lovebugs on white deck and white sail! :confused:

.
 
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