Saturday, November 28, 2015

The Nose Job

A few months ago, my favorite windsurf board needed cosmetic surgery:
I had gotten a bit confused while having fun. I forgot that I was not a wave sailor. I also forgot that I do neither loops nor Grubbies. But when a lovely little wave presented itself, I tried to jump of the lip so that I'd land back on the wave. Which must have looked like a bad Grubby or loop attempt. At least so I think - I got thrown around, and the mast landed on the nosed of the board.

That was not the first (or second or third or ...) time the mast hit the nose. Nor was it the hardest crash. But the damage was much worse than ever before, with a big crack that went from the top to the bottom of the board. The main difference to previous crashes? My poor board was not wearing any protection! For three years before that, it had worn plastic protection where it mattered - on the nose. With double-density foam! That had not kept the nose from being hurt. In fact, I had it repaired twice at Fox in Buxton. The repair guy there stated that all the nose protector  did was making the repair more expensive, since he had to remove it and replace it. So the second time, I told him to leave it off.

Well, wrong he was. With the nose protector, the nose needed two repairs over 5 years. Both times, the damage was not nearly as bad as this time around. I was actually able to temporarily fix the board with ding stick, and keep using it until our next trip to Hatteras. But without the nose protector, the nose lasted only a couple of months, and the damage was much more severe than ever before.

I love my Skate 110 dearly, but it was showing signs of age and heavy use. The area under the foot pads was starting to get soft - damage that, according to the experts, was not worth fixing. So I figured - if the board is almost dead, maybe it is the perfect board to practice board repairs on!

I had never done any board repairs, other than using a bit of ding stick for small holes. This one clearly needed much more serious work, including some new fiberglass. Back when the concept of "pin tails" and "fully retractable daggerboards" was new and exciting, I had built a windsurf board. Not quite on my own - the university that I attended actually offered a course "Build your own windsurf board". A long time ago, but I remembered that working with fiberglass and epoxy was not that hard.

I started asking a few questions on the iWindsurf  forum, and got a number of useful tips. So I went ahead and bought a bunch of supplies:
  • West System epoxy resin, slow hardener, metering pumps, and filler from the local West Marine store
  • Fiberglass from Fiberglasssupply.com
  • Polyurethane pour foam from a couple of different suppliers (since the first one I got did not work)
  • Sandpaper, gloves, dust masks, and masking tape from the local hardware stores
  • Epoxy mixing sticks from amazon.com
  • Cups for mixing the epoxy from the local grocery store
  • Spray paint from a local car store
The electric tools I used for the project were:
  • A battery-operated Dremel tool (ca. $30 from Amazon)
  • An electric sander
I decided to do the fix in two parts, starting from the top of the board. I used the Dremel tool with a disc wheel blade to cut through the fiberglass and the PVC foam underneath, and removed some of the damaged foam underneath:
My original plan had been to fill the hole with polyurethane pour foam, and then glass it over. However, when I mixed some of the foam to get an idea how to work with it, it did not polymerize. The foam I had gotten said the mix had to be 1:1 by weight. I did not have an accurate scale, but I figured that mixing by volume should also work (many other PU pour foams suggest to mix by volume). Maybe that was the problem? I bought a scale with 0.1 g accuracy, and tried again a few days later, but still nothing happened. Obviously, the pour foam was bad (I later got a refund for it).

The local West Marine store had pour foam, but they wanted almost $200 for something that I could get for less than $50 online. I ordered from a different supplier through Amazon (for easy returns), but since the chemicals have to be shipped via ground, waiting for it to arrive would have added another one-week wait to the repair. Since it was the middle of the best surfing time of the year, I developed another plan.

My idea was to use epoxy to fill the hole. To reduce both the weight and the heat produced during polymerization, I added a lot of filler to the epoxy. I also added a lot of styrofoam bubbles that I made from pieces of packing material. I was concerned about things getting to hot, so I first let everything polymerize in a cup. Everything looked good:
So I made another batch and filled up the hole. Everything looked fine at first:
But a few minutes later, bubbles started forming, and I knew I was in trouble:
When I opened up the other side of the board a while later, this is what I saw:
The heat from the polymerization had melted a lot of the styrofoam, and produced a big hole! I had overlooked one thing in my test: in a cup, the heat from the polymerization can easily escape in all directions. But in the board, the epoxy is surrounded at most sides by styrofoam, which traps the heat! That starts a bit of a chain reaction: with no way for the heat to escape, things keep getting hotter, which makes the polymerization go faster, which makes things even hotter... until it's hot enough for the styrofoam to melt, and air bubbles form.

Alas, the pour foam still would not arrive for a few days that I did not want to wait. So I started again with my epoxy-filler-styrofoam ball mix, but with two important modifications: 1. I made it even thicker (to "peanut butter" consistency), and 2. I added only small layers, instead of trying to fill the entire hole in one turn. I carefully watched for any bubbles, but did not see any. After about 4 or 5 layers, I had finally filled in the entire hole.

Sanding things down was pretty easy, since I had used so much filler. I started with the electric sander, but switch to manual sanding pretty quickly, since I had better control that way. On the top, I had to fill in the air bubbles with some epoxy-filler mix, and then sand again. Putting on three layers of glass was pretty easy:
After sanding down the glass, I sealed the region with a layer of epoxy without filler:
At this point, you can actually see a small area from a previous repair. One more careful round of sanding, and the area was ready for painting:
Here's what the bottom looked liked after painting it:
Not bad, I thought! I took the board out for a test session, and it behaved just like it always had. But when I inspected it closely back home, I noticed that there where bubbles coming out! Not in the region that I had fixed, but right next it, in the region that had been repaired before (or close to it). 

So the tools came back out. I cut out another section to make sure that the damage was limited, filled it, and glassed it over again. You can see the second section in this image:
This was a small repair, with much less drama than the first one. Good practice! Here's an image of the top after the final round of painting:
One concern I had about the repair was that the area I had repaired was now harder than the surrounding area. It would probably be more resistant than the original, but a hard hit with the mast could now break out the entire area! But as much fun as the repair was, I had no desire to repeat it any time soon, anyway, so new protection was in order. I bought a Dakine EVA traction pad at the local windsurf store, cut it up, and taped the pieces onto the new nose. The most endangered area is now protected by an inch of EVA. In a hard crash, the EVA will absorb some of the energy by deforming, and distribute the rest of the energy over a much larger area - not too different from an air bag in a car! On the sides of the nose, the EVA is thinner, but both impact angles and leverage are not as bad there. In really bad crashes, the nose may still take damage, but it is now nicely protected from most mast hits and catapults. 

I spent about $250 on all the things I bought for the repair project. I used only a small fraction of most things (like epoxy and fiberglass) for this repair, so I can do many more repairs at no additional cost (I actually did another small repair a couple of months later, when Kiri Thode's board got damaged on his flight from Bonaire). I have used the board more than 30 times since the repair, and it sails just like it did before the damage, so it was definitely worth doing. I thought it was a fun project, too - and I now know that I can easily repair any similar nose damage in the future. With Nina working on Vulcans and Flakas, that might come in handy sooner rather than later!

3 comments:

  1. BTW, you can get dual-density nose protectors from NSI in the gorge for about $30:
    https://www.northshoreinc.com/store/pc/showsearchresults.asp?pageStyle=H&resultCnt=9&keyword=nose+protector&submit=

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    1. Brian, I had the NSI nose protectors on the board for years; Nina still has it on her Skate 100. They definitely help, but I think that the traction pads may work even better. The thick section of the traction pad is a bit harder to compress than the NSI foam; I think it will absorb more energy, and distribute the shock better.

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