How to Repair Epoxy on a Sailboat Keel

How to Repair Epoxy on a Sailboat Keel
Repairing damaged epoxy on the keel of your sailboat isn't that much different than a similar repair on the side of the hull, except that on the keel, differences in color won't be as noticeable if you use paint instead of mixing and applying a gel coat finish. The keel isn't likely to suffer color deterioration from exposure to ultra-violet radiation from the sun, which is known to damage gel coat, paint and other boat-coloring methods, simply because the keel is underwater.

Instructions

Difficulty: Moderately Challenging

Things You’ll Need:
  • Mild dish detergent Water Acetone Palm sander 220-grit sandpaper Epoxy resin Epoxy hardener Paint mixing stick Disposable container or bowl Disposable paint brush Paint scraper Long sleeve shirt Respirator Safety glasses Gloves
  • Mild dish detergent
  • Water
  • Acetone
  • Palm sander
  • 220-grit sandpaper
  • Epoxy resin
  • Epoxy hardener
  • Paint mixing stick
  • Disposable container or bowl
  • Disposable paint brush
  • Paint scraper
  • Long sleeve shirt
  • Respirator
  • Safety glasses
  • Gloves
Step 1
Clean the damaged area, first with mild dish detergent and water, then with acetone and a clean rag. Your goal here is removal of any foreign matter, dirt or grease from the damaged site and the area around the damage.
Step 2
Remove any loose material on the damaged area of the keel, with a palm sander and dry 220-grit sandpaper. This grade of sandpaper is very fine, but damaged gel coat and fiberglass will disappear very quickly. Sand the edges of the damaged area to a more or less smooth state. Wash the area down with acetone.
Step 3
Mix the epoxy resin and hardener, and the epoxy filler, with a paint mixing stick, in an old bowl or other disposable container. Some "epoxy repair kits" have pre-measured amounts of resin and hardener in packages; all you have to do is mix the contents. If you don't opt for a kit, follow the instructions on the resin.
Step 4
Paint the epoxy/filler mix into the damaged area with a disposable paint brush or paint scraper, as if you're troweling mortar: work it into the damaged area, and pile it on until it's slightly "humped up" above the surface of the keel. Allow the epoxy to cure for at least 24 hours; the "hump" will disappear.
Step 5
Sand the repaired area lightly with 220-grit sandpaper, by hand, to polish the surface (and level it, if necessary), preparatory to painting or the application of gel coat. The palm sander might seem easier, but could get out of hand quickly.

Tips & Warnings

 
Since your keel will be in the water almost 100 percent of the time, unexposed to air or sunlight, paint is recommended for a finish coat.
 
Since your keel will be in the water almost 100 percent of the time, unexposed to air or sunlight, paint is recommended for a finish coat.
 
When you're working epoxy or gel coat, whether applying it or taking it off, wear long sleeves, a respirator, safety glasses, gloves and all other personal protective equipment recommended by the manufacturers of the products you use.
 
When you're working epoxy or gel coat, whether applying it or taking it off, wear long sleeves, a respirator, safety glasses, gloves and all other personal protective equipment recommended by the manufacturers of the products you use.

Article Written By Will Charpentier

Will Charpentier is a writer who specializes in boating and maritime subjects. A retired ship captain, Charpentier holds a doctorate in applied ocean science and engineering. He is also a certified marine technician and the author of a popular text on writing local history.

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