Repairing Gel-Coat Damages - It can be Done!

Wednesday, 20 September 2006
This article comes from Point 65N Kayaks from Sweden.

gel-coat_repair_1.jpg Gel-coat is the material which is used to create the glossy colored finish on the hull and deck. It is also the first material that is applied to the form, when building the kayak. Apart from generating the beautiful glossy finish on the kayak, the gel-coat’s function is to protect the fiberglass laminate - the boat’s main material – from moisture.

Accidental damages to the gel-coat should therefore be repaired as soon as possible to prevent structural weakness sustained over time by moisture creeping into the fibreglass laminate.

It is easy to repair the gel-cot, and if you use the right procedures and materials, the repair will be impossible to detect afterwards.

gel-coat_repair_2.jpgYou will need the following materials to repair your kayak:
1. Acetone
2. Sanding block
3. Wet sandpaper of the following thicknesses: 400, 600, 800, 1000 and 1200. (If you are unsure, your local hardware store or marine supply store will be able to guide you.)
4. Thin brush
5. A sharp knife
6. Polishing paste (such as Autosol chrome polish)
7. White Gel-coat putty/filler (such as plastic padding)
- A small spatula
- Clean rags
- A bowl of water
- An hour of your time

gel-coat_repair_3.jpg Start out by making sure that the damaged area is clean and dry. Scrape away any possible dirt from the edges with a sharp knife, sanding machine with a sharp edge or scalpell.
Clean the damged area with acetone on a clean rag. This will both clean and dry out the last moisture from the damaged area, and improves the conditions to attach the new gel-coat to the surface.

Mix the gel-coat according to the product instructions. On rule that applies to polyester products is that the more hardener is used the quicker it will harden. A normal ratio is 3%. Brush the gel-coat on the damaged area. Be sure to apply the gel-coat especially well to the edges of the damage.

gel-coat_repair_5.jpg Apply the bulk of the gel-coat with the spatula and let it harden. The damage is now sufficiently repaired to be able to use the kayak again, but if you want the damage to be invisible, you will need to continue with the instructions below.

When the gel-coat has hardened, it is time to polish the repaired area. Start out by using the No. 400 wet sanding paper on the sanding block. Use plenty of water when sanding and rinse repeatadly to prevent the sanding paper from clogging up. With the 400 paper you’ll sand away the surplus material and shape the right form. You will now know if you have used enough gel-coat to repair the damage. If nor you will have to dry out the area, clean it with acetone and start over. WARNING – the gel-coat is only 1-2mm thick on the kayak, so it is easy to sand through to the fibreglass if you are not careful.

gel-coat_repair_6.jpg If you are satisfied with the form you will now change to the finer sandpaper without using the block. Start out with the courser paper (600) and work your way through to the finest (1200). Remember to use plenty of water at all times. At this stage you’ll only have to sand sparingly.

Now that you’re finished with the sanding it is time to polish the area to it’s former glory. Use a polishing machine or brute handpower together with polishing paste. Wash and dry.

At this point the initial damage should be repaired and impossible to distinguish from the rest of the kayak.

David Johnston

David Johnston

David Johnston has been introducing people to the sport of sea kayaking for the past 15 years. He is a senior instructor trainer with Paddle Canada and teaches for several paddling schools in Ontario, Canada. Full Bio.

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