JDW: Gelcoat Repair
Here is the recap of the Video on Gelcoat Repair.
1) The first step in Gelcoat Repair is to feather out the edge of the repair area. It is important to use a sanding block: Do Not sand with just your hand as it will cause uneven sanding. Use a heavy grit (80).
2) Once you’ve finished sanding, wipe off any excess particles wih a tack cloth. Now you’re ready to fill the repair.
3) For this demonstration, we used autobody putty. Hardener needs to be added to the putty before it is applied. There are several different kinds of Hardener.
4) A red hardener makes it easier to see if it’s been mixed well with the putty. However, if the surface and gelcoat are a light color, the red can show through. Conversely, white won’t be visable, but this makes it more difficult to tell if it’s properly mixed.
5) Apply the putty using a putty knife or spreader. The thinner you put it on, the less sanding you need to do. Then you let it dry (approx. 5 minutes).
6) When the putty is dry, remove the excess by sanding (120 grit, remember to use a block). The putty should stick to the repair area, but not the outer surface.
7) The patch area will be greater than the actual scratch, because you will need to fill in where you have sanded as well as the scratch.
8) Before you apply gelcoat, clean the area by wiping it down with acetone. Then you need to add catalyst to the gelcoat (2% minimum). You can measure by using cap-fulls. One cap-full is 3-4 cc. This means that 4 cap-fulls are needed for a full quart of gelcoat. Apply the gelcoat nice and heavy. Do the first coat right on the scratch and then with each additional coat, work your way out.
When you’re done applying gelcoat, you’re ready to and it down. This time you’ll want to do a wet sand. Every so often, clean off the excess.
Now you’re ready to buff. Begin with a rough rubbing compound and use a variable speed buffer. Continue as needed, using gradually finer compounds.
All of these Materials and Tools are available at 