ACP or plastic hull painting suggestions

Jun 8, 2004
10,024
-na -NA Anywhere USA
Moderators: This will appear in Ask A Hunter Owner, Smaller Boats and Day Sailors as I have talked with Al Fooks to make sure this information is distributed to those who wish to bottom paint the ACP or plastic hulls by Hunter.

One respondent advised his hull was painted Petit's Vivid anti fouling paint with a tye coat. Petit is a division of Kop-Coat Marine Corp.. Customer and Technical Support is 800-221-4446. I was advised to call 973-776-8253, Frank Legalman (?). I left several messages and never got a response.

However, I was able to find ssome notes. First, these are plastic hulls and many of the anti fouling paints will react with the plastic hulls; therefore, you have to be very careful. Further, ACETONE or any other surface preparation chemical shoud not be used as it may attach the plastic hulls. The first step to adding anti fouling paint is to scuff-sand the bottom surface of the boat at and below the waterline. Next wipe down the entire area with denatured alcohol constantly using clean rags to remove wax and dust from sanding. Finally paint the boat with Interlux Fiberglass BottomKote Act. It is recommended Interlux's gray white color as does not attract the heat build up on the hull like darker colors do. If leaving the boat in the water, it is suggested the centerboard and centerboard trunk be painted if needed.

On the Hunter 216, it was suggested that the centerboard and trunk housing be should be painted. You can either hoist the boat up and drop the centerboard or remove the centerboard from the boat topsides. To remove from the topsides, there are 8 screws in the cockpit securing the frame which will need to be removed. Using a hoist carfully raise the complete centerboard cartridge from the boat. Remember the centerboard is made of solid lead so it is heavy and extra caution is recommended when taking that out either way. Originally the lead centerboard was primed with a primer which if I recall, Interlux 2000 or 2001.

I hope this information will help all ACP built boat owners.

Dave Condon
 
Oct 22, 2014
20,989
CAL 35 Cruiser #21 moored EVERETT WA
@ggrizzard
The answer your query.. Advanced Composite Process (ACP) by Hunter and later from fiberglass by Nickels and WindRider.
ACP is a laminate consisting of a foam core, an inner fiberglass skin, and a 1/8" outer plastic skin.

according to Wiki.
 
Apr 16, 2017
841
Federation NCC-1701 Riverside
The part that is not mentioned is a thin adhesive between the foam and plastic that disintegrates with thermal expansion causing delamination.

ASA Plastic, adhesive, foam, fiberglass.

Dont forget the plywood between the foam and plastic for bedding areas.

Its important to separate paint for topside vs paint for anti-fouling.

Topside paint requires an acetone like substance adhesive promoter. This will create a long-lasting bond.

Antifouling is temporary and ideally should be removed easily, like artwork renovation.

Surface prep for ACP is different for antifouling versus topside paint. For topside paint the plastic layer needs to be sanded and faired to 320, even wetsanded to 400 before spraying. This creates a very beautiful finish at very close range. If rolling on paint then 220 is probably as high as needed as the orange peel will be the issue.

Rustoleom has a plastic primer that creates a layer that once applied allows almost any non specialty paint to be applied. Once any paint is applied you can use other non specialty paints. The most important layer is the one in direct contact with the plastic.

You really could just fare the bottom if needed and then spray some any pink spray paint that says "bonds to plastic". Then roll any antifouling on top of that.

It really depends on the quality desired for bottom painting.

If painting the hull for trailerling to cover up dock rash and beaching repairs i suggest using rustoleum plastic primer and put some non white dye in it. Or use a pink spray can.

When faring the orange peel you'll know to ease up when you see the primer color.

If spraying with a paint that already has adhesion promoters just start with a perfect surface at 320 and add about 3-4 light layers of spray. Followed up with a 2500 wet sand or clay bar to get rid of "overspray dust" if you are picky
 
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