Sanding Gelcoat can be a daunting task!

In this article we will;

  1. Tell you when sanding is necessary
  2. Tell you the process.

When is it necessary to Sand Gelcoat?

  • When you gelcoat is oxidized, or faded. You should be able to look into the reflection of the gelcoat and see the hairs on your face. Now if you boat is slightly oxidized and still has a pretty good shine to it but its not flawless, compounding is all that is needed to bring the oxidation out. You won’t need to sand. Check out Restoring your shine for more info on this.
  • Sanding is necessary when there is absolutely no shine to the gelcoat or you have tried compounding and the finished look is not even. The picture to the left, you can get an idea that there is no reflection and the gelcoat is somewhat black.
  • Sometimes you can get deep scratches or marks that will come out with sanding.


The Process!

You can do this process using wet sandpaper and water or a sander and dry sandpaper. That is your preference. If done as followed, there wont be a difference.

  1. First step is to clean the surfaces that you will be working on. Not doing so, can cause the surface to become worse by sanding the dirt into the boat revealing more scratches. Pick a grit of sand paper to start with. This just depends on how bad the boat is. The pictures to the right is a 48 Fountain we worked on 2 weeks ago. I will go over what we did to that! We started off with 800 Grit sandpaper. Using a 5 inch Dewalt sander, we went over a 2 x 2 foot section. Go over the surface in even passes go over it 3-4 times. Make sure it is all evenly hit with the same amount of pressure.
  2. Hit the same 2 x 2 foot section with 1000 grit then 1500 grit the same way as explained above.
  3. You can go up to 2000 grit, on this job, we stopped at 1500 grit. Now wipe your surface clean of dust. You will need a buffer to compound out the scratches. The purpose of sanding is to take off a layer of gelcoat revealing a new scratched up surface. When the sanding is complete, you will need a good compound in order to get the scratches off the boat. If you pay for a good compound, one coat will take the scratches off. We use a 3m Material Finishing Compound. Works Awesome! Go over the 2 x 2 foot section that was sanded. Apply the compound to the boat and use a new wool pad to compound the scratches out.
  4. Then apply a good coat of wax, we used Collinite 925.
  5. If the above steps are followed and your technique is good, you will end up with the picture to the right. Notice the shine that is different from above.


In Conclusion

Sanding your gelcoat can be daunting if you don’t know what your doing. If you read through this article, you have a good idea of when you need to sand as well as how to do it. This will save you a lot of money if you do it over a professional as well as give you a great shine!

Now once you sand the boat and get the shine back, take a look at how to Maintain the shine so you don’t have to do this process again!

Good Luck!