This is my first ever instructable, so we will see how we go!
I was in a predicament, that I had several small crushing marks, a couple of bits of pitting, and some grazed parts on the exterior and interior of my Rowing carbon fibre/honeycomb mould, and I did not want to pay the $500++ it would have cost me to get it repaired by a proper boat repair company.
You can see an example of the crushing/areas that were damaged on the interior, and I had accidentally run over some rocks on the bow, and there was some damage on the bow of the boat (unfortunately I don't have any pics of the bow in its damaged state).
Tools you will require:
Sandpaper (600grit, 1200 grit, and 2000 grit)
Something to smooth the surface as much as you can, i.e. a soft plastic card, or a lollipop stick)
Epoxy Fairing Compound
Large working space / well ventilated
2-pac spray paint in the correct colour. Get the paint company to put it in a spray can, and add a hardener, you won't need much, A 100ml can is more than enough for covering more than 1/3 of the boat
Step 1: Rub It Back
So the first thing you are going to need to do is to get all of your surface areas ready for fixing.
As you can see in the photo, you will need to rub the area back lightly with the 600 grit sandpaper, and work up to the 2000 grit paper, ensure that the area is sanded back smooth, and back the carbon fibre layer. You will also need to do an area about 1/2 an inch around the 'wound' to ensure that the paint sticks.
Ensure that you clean up all of the areas that require fixing afterwards using a vacuum cleaner and a rag with metho or something similar on it.
Step 2: Getting Messy!
Now is the time to get messy.
You will need to grab out the two parts of the fairing compound, and mix a very small amount together. I used about a coke bottle lid's worth of the two compounds put together, and this was more than I required.
I mixed them together on the back of a piece of used sandpaper, and applied the mixed compound to the open wound. You can try to smooth it out as best as you can (this will make some of the following steps easier).
I found it easier to use a larger amount on half a lollipop stick, and ran it over the wound on the boat. I then scraped the popsicle stick on its side over the wound to make it as smooth as possible to ease my efforts later in the process.
Leave it now for at least 72 hours in a dry area (doesn't have to be too warm) to cure, and go off. The instructions on the fairing compound will tell you how long to cure it for (each brand is different).
Step 3: Smooth It Over
Once the compound has cured, you will need to sand it back to be completely smooth, and flush with the rest of the boat. Make sure it is absolutley smooth to the touch. You will want to use the 2000 grit sandpaper to do this, but again, depending on how good your initial smoothing over was with the popsicle stick, you might need to use one of the lower grit sandpapers to smooth it over first.
It should feel as smooth as a babies bottom when you are done!
Step 4: Paint It
Mask up or tape over the bits you don't want to paint, and ensure that you don't paint the bits that you have not sanded back. As weight has a vital role to play in your boats speed, you will want to ensure that you do several coats of very light spray paint, allowing the paint to dry between coats, otherwise you will get a dripping down the side of your boat.
If you have over sprayed, you can always rub the paint back with the 2000 grit sandpaper, and re spray until you have as smooth a finish as you want.
I apologise that I do not have any photos of the finished boat, but when I can take some, I will post them up.