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Surface scratch repair on outrigger canoe OC1

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I have sustained deep scratches on the sides of my Hurricane OC 1 canoe , and although it has not holed the hull, it has caused exposure of the black hull under the paintwork. Which resin and polyurethane paint should I use for the repair?

It is an older canoe (around 2007-2009 model).

1 Answer

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Liza:

The canoe is made with epoxy resin, and should be repaired with epoxy.  Some people will repair using polyester, or bondo, which might work, but it isn’t a good idea.  Polyester doesn’t stick to epoxy laminates very well, and may separate later.  The canoes are painted using automotive refinish polyurethanes.  Your canoe was made using PPG Deltron paint, we have also used Dupont Imron in the past.  Awlgrip is also an excellent paint.  All of these paints are expensive, and require several components – activator, paint, and thinner.  Expect to spend about $100 if you choose to go that route.

Personally I have a utilitarian attitude to canoes.  While some people care very deeply about the appearance of the canoe, I prefer to spend more time paddling, and less time waxing and polishing.  If you are like me, or your canoe is already scratched up, you can just use good hardware store spray paint.  It sounds bad, I know, but it works, and is quick and cheap.

Either way the repair should begin with carefully masking the canoe around the repair areas.  This will save time later and is worth spending the time to do a good job.  Next, sand the area around the damage to feather the edges.  The epoxy will bond better to sanded paint and carbon, so sand a little bit beyond where the epoxy filler will be used.

The epoxy should be mixed precisely.  Wrong mixing ratios will result in uncured resin.  Stir longer than you have patience for.  Add filler to thicken the resin.  Aerosil is good for small areas, but will be hard to sand so you want to be clean with your squeegee or putty knife.  Large areas over a repair are better done with a filler like microcell, or microballons.  This will be much easier to sand, by is likely to have pinholes that need to be filled afterwards.  You can mix in some of both to balance the advantages and disadvantages of both.  Aerosil gives the mixture body and will reduce the tendency for the mixture to sag.  It doesn’t add volume, and results in a dense filler that is hard to sand, but is strong and not porous.  Microballons will make a light mix, that can self-level if wet enough( think honey), but will also sag.  If you add too much (peanut butter) it will not sag, but will have pinholes when it’s sanded.  If you add a little aerosol to a wet microballon mix you can get really nice results.  A lot of this is experience, so you might mix the resin, and pour about half in the cup where you mix the filler to be able to add a bit more resin to the batch if you need to.

Once the scratches have been filled and sanded you’ll need to paint.  Unless you go with the hardware store spray can, you need someone with the right equipment and experience to do it.  It’s not a simple process.

If you go with the spray can, just mask it off, and fire away.  Try to keep it thinner along the edges, and do several thin coats, waiting between coats for it to dry to the touch.  If there are small pinholes, you can drag with a squeegee immediately after the first couple of coats to fill them.  Remove the mask as soon as you are done, peeling the tape towards the wet paint to keep it from pulling strands of wet paint onto the unpainted areas.

It you want to you can sand the edges and polish, but sometimes it can cause more problems than good to do so.

Michael

Your Answer

Category: Tags: asked October 17, 2013

1 Answer

0

Liza:

The canoe is made with epoxy resin, and should be repaired with epoxy.  Some people will repair using polyester, or bondo, which might work, but it isn’t a good idea.  Polyester doesn’t stick to epoxy laminates very well, and may separate later.  The canoes are painted using automotive refinish polyurethanes.  Your canoe was made using PPG Deltron paint, we have also used Dupont Imron in the past.  Awlgrip is also an excellent paint.  All of these paints are expensive, and require several components – activator, paint, and thinner.  Expect to spend about $100 if you choose to go that route.

Personally I have a utilitarian attitude to canoes.  While some people care very deeply about the appearance of the canoe, I prefer to spend more time paddling, and less time waxing and polishing.  If you are like me, or your canoe is already scratched up, you can just use good hardware store spray paint.  It sounds bad, I know, but it works, and is quick and cheap.

Either way the repair should begin with carefully masking the canoe around the repair areas.  This will save time later and is worth spending the time to do a good job.  Next, sand the area around the damage to feather the edges.  The epoxy will bond better to sanded paint and carbon, so sand a little bit beyond where the epoxy filler will be used.

The epoxy should be mixed precisely.  Wrong mixing ratios will result in uncured resin.  Stir longer than you have patience for.  Add filler to thicken the resin.  Aerosil is good for small areas, but will be hard to sand so you want to be clean with your squeegee or putty knife.  Large areas over a repair are better done with a filler like microcell, or microballons.  This will be much easier to sand, by is likely to have pinholes that need to be filled afterwards.  You can mix in some of both to balance the advantages and disadvantages of both.  Aerosil gives the mixture body and will reduce the tendency for the mixture to sag.  It doesn’t add volume, and results in a dense filler that is hard to sand, but is strong and not porous.  Microballons will make a light mix, that can self-level if wet enough( think honey), but will also sag.  If you add too much (peanut butter) it will not sag, but will have pinholes when it’s sanded.  If you add a little aerosol to a wet microballon mix you can get really nice results.  A lot of this is experience, so you might mix the resin, and pour about half in the cup where you mix the filler to be able to add a bit more resin to the batch if you need to.

Once the scratches have been filled and sanded you’ll need to paint.  Unless you go with the hardware store spray can, you need someone with the right equipment and experience to do it.  It’s not a simple process.

If you go with the spray can, just mask it off, and fire away.  Try to keep it thinner along the edges, and do several thin coats, waiting between coats for it to dry to the touch.  If there are small pinholes, you can drag with a squeegee immediately after the first couple of coats to fill them.  Remove the mask as soon as you are done, peeling the tape towards the wet paint to keep it from pulling strands of wet paint onto the unpainted areas.

It you want to you can sand the edges and polish, but sometimes it can cause more problems than good to do so.

Michael