Gelcoat repair (cracks, scratches, dullness)

A gelcoat finish can get damaged and (spider and hairline) cracks and scratches can occur. Fortunately, it is easy to repair and Polyestershoppen has all the necessary materials. In this article you can read how to fix gelcoat with simple, easy-to-follow instructions.

Not sure what materials you need? Please feel free to contact our specialized customer service team! 

Repairing minor gelcoat scratches 

Repairing minor gelcoat scratches is fairly simple. You can simply sand out the scratches and then polish the surface.

1. Start sanding with sandpaper grit 400-800 (wet on a sanding block) and sand as finely as possible (up to grit 2000).
2. After this, you can polish the remaining sanding scratches with coarse and fine polishing paste.
3. To optimally protect the repaired gelcoat layer and make it shine again, use Riwax RS10.

Repairing deep gelcoat scratches 

To repair deep gelcoat scratches you will have to be a little more thorough. However, this repair is still easy to perform. To do this, follow the steps below:

1. Grind out thin scratches with a multi-tool or similar tool. Wider scratches can be sanded first.
2. Mix polyester topcoat and the hardener and apply the mixture to the scratch with a putty knife or glue brush. It is preferable to apply a little more, because polyester topcoat does shrink.
3. Once cured, follow the instructions for repairing minor scratches as described above.

Deep scratches can also be filled with a gelcoat filler and coloured with pigment paste. Then follow the steps for finishing a scratch and the repair will be invisible.

Repairing dull or weathered gelcoat

Over time, the gelcoat of your boat can become dull due to ageing or UV light. If this is the case, you can make the gelcoat shine again with the steps below:

1. Polish the gelcoat with a coarse and medium polishing paste.
2. If this does not produce the desired result, it is advisable to sand a top layer of the gelcoat with fine-grain sandpaper on a sanding block. After this you can repeat the polishing operation. Don't sand off too much!

At Polyestershoppen.com you can buy polishing paste separately. This is especially useful if you need to polish larger surfaces. We also recommend using polshing cloths or a polisher in combination with the polishing paste.

Repairing gelcoat spider cracks

Cracking and grazing can be recognized by the numerous cracks in many directions in a gelcoat layer. This sometimes looks a bit like a mosaic pattern. Repairing crackle is easy if you follow the steps below:

1. Clean the gelcoat thoroughly with a high-pressure cleaner.
2. Sand the gelcoat with 180 grit sandpaper.
3. Degrease the surface and make it dust-free.
4. Coat the surface with diluted ZF Primer (can be diluted with thinner for ZF Primer).
5. After the ZF primer has hardened, you can sand lightly (280 grit) and top with Double Coat DD Paint.

Frequently asked questions

I didn't use the right colour, can I fix this?
Yes, you can grind out the wrong colour again and follow the steps again. 

I have sanded through the gelcoat, what can I do about this? 
You can fill that area with topcoat and carefully sand it smooth and finish it. 

Do you have another question? Or are you having trouble finding a solution and do you need advice? Please contact us!