If you have a used Powerboat or Sailboat, boat gelcoat repairs are really easy to do, especially if your hull color is white. There are small tubes of gelcoat repair for those small cracks which you just spread over. But if you have a bigger/deeper crack, scrape, or gouge some from possibly bringing up that anchor on your yacht or boat, this may be the way for a quick repair.1) Clean the area of any loose material and use some acetone to strip away any wax residue by adding it to a clean rag. If you have a sizeable crack, make sure the ends of the cracks are rounded out so they don't keep going. Tape off the area with blue masking tape.
2) On a deep crack, scrape, or gouge, pick up some body putty (bondo) on Yacht Authority.com Marine Supply or your local marine store. I would get a white colored one so another color does not bleed thru.
3) Follow the instructions on the mixing of the hardener and when ready apply to the crack, scrape, or gouge making sure you push it in good, so not to leave an air bubble underneath. For big or long areas, you may want to use a putty knife to get it on evenly. Clean off any excess around the repair...(you can always retape)
4) After the putty hardens (20 minutes or so if mixed right) take some light sandpaper (220-320) and lightly sand off the putty so it is just below the original gelcoat surface...just a touch! It should look pretty juicy (good) at this point. The crack/scrape/gouge is gone and you see just a color difference where the putty is...but all looks even.
5) You can pick up some white gel coat here on Yacht Authority.com Marine Supply or at a marine store, make sure you get the hardener. You can also pick up a spray set-up about $10.00...comes with a spray top and a jar it screws on to. Get a couple of brushes just large enough to cover the area. If you have a real wide area, you may want to spray the gelcoat on.
6) Now wipe your repair clean and use a lightly moistened rag with acetone. Re-tape as necessary. Mix the hardener with the gelcoat as per instructions on the can and apply with the brush. Don't worry if there is a little too much. Just make sure it looks pretty smooth. Don't like what you did, wipe it off and use the moistened rag with acetone and start again. You'll get it right...you probably have a few areas to repair, and you'll get better as you go.
7) If spraying, have your blue tape further away and of course paper it off for overspray. Put your gelcoat mix in the jar and add some acetone to thin it out a little so it comes thru the spray nozzle. Apply with a back and forth motion, stopping the spray and starting it again on each stroke. Put a nice few coats on for good coverage.
8) Once good and dry, use wet and dry sand paper (220-320-400 grit) and lightly sand. Take your time...there's no rush. First smooth out the high spots and always keeping the sandpaper wet. You'll feel when you're taking off a lot. Do a little and look. If it looks good enough, it is. Your powerboat or sailboat will look so much better. As you become better and more relaxed at it, you'll find your work coming out mint...or really juicy (really good). The spray jobs will need much less sanding to look good.
9) As you sand, use lighter and lighter sandpaper till you get to 400 grit. At this grit the gel coat will be smooth where you just have to wax or use a little bit of white compound first then wax it up!
There are some variables, like using a tint to match the color of your used boat or used yacht closer from the standard white out of the can. Hint; A touch of blue makes the white whiter...gray, black, yellow, tints gets you the darker/faded whites. Make sure you read all instructions and cautions of the different products. You can do so many repairs with what you purchased because you're using so little of it to do the repair...and Why Knot?
