Refinishing Rudder and Cuddy Doors: Epoxy, Varnish, or Both?

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Refinishing Rudder and Cuddy Doors: Epoxy, Varnish, or Both?

Postby pboulanger » Tue Apr 11, 2017 9:14 pm

Hello,

I've recently inherited a 17' O'Day Daysailer II that's in decent shape but needs some work to get it looking great for this season. Aside from some spider cracking in the gelcoat and a small 4" chunk missing from the floor of the cabin, the boat is structurally in decent shape.

One of my intended projects is to refinish the rudder and tiller which is structurally in good shape but all the varnish is worn off and is starting to show some fatigue on the leading edge. I've seen conflicting reports online and in videos - do I need to epoxy with something like WS 105, or use a marine varnish like spar varnish, or do I first epoxy one coat and then put varnish on top of that? The boat will be in the (salt) water all season, but the rudder pulls out in will stay in the cabin when not sailing.

Also, the boat recently had a new set of doors made for the cuddy, which are completely unfinished. Do those need just a varnish, or epoxy and varnish?

Finally, any tips for doing this sort of work?

Thanks!!
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Re: Refinishing Rudder and Cuddy Doors: Epoxy, Varnish, or B

Postby GreenLake » Wed Apr 12, 2017 11:46 am

You have three basic choices.

1) use some kind of oil that doesn't get hard. this will not be very durable, but reapplication is dead simple. great choice for things like wooden coamings that have edges where other finishes might split/rub off. does require you to be out there with a brush at least once a season

2) use some kind of varnish. needs to be flexible, so it can handle the way the wood works due to temperature or moisture. unlike an oil, you can get a glossy coat, if that's a look you are interested in. will last a bit longer, but touch ups are more difficult and involve sanding, perhaps removal of previous coats. The varnish is not completely watertight, but will allow water vapor to travel in (and out).

3) use epoxy to seal the wood, then a clear coat as UV protection. epoxy will seal the wood, no water gets in or out. no water getting in means the wood will no longer swell from being in moist air and shrink when it dries. this makes it possible to use a less elastic coating on it, for example a PU, which will give excellent scratch resistance. If there's any place water can seep into your wood (cracks, fasteners) there's no way for it to get out again and if the UV protection fails, the epoxy will fail, at which point it will be a bear to remove. otherwise, will last several seasons.

For a rudder blade, if you do want to use epoxy, you need to add extra protection against failure of the coating. The usual way to do that is to add a layer of glass cloth when you seal the wood (the thinnest cloth you can find should be fine). Correctly embedded in the epoxy, the cloth will become invisible; it will not detract from the appearance of the wood grain, but make the coating deeper, for an extra lustrous look. (Especially if your outer coat is a high gloss PU or varnish). The effect of the glass is that it will make your rudder more resistant against scrapes. An additional technique is to cut off the lower forward corner and glue it back on using epoxy. That's the spot that gets damaged most often. The glue line will prevent any water from being sucked into the rest of the rudder should the coating fail on the tip (say, due to a grounding). You need to be careful to seal the hole for the rudder pivot with epoxy, preferably a penetrating epoxy (not WS-105, but System Three X-1 or the like).

I have used epoxy plus PU on my wooden thwarts and also on the coamings. The result for the thwarts was super; absolutely no maintenance for a number of seasons. I've just recently touched up a few dings using penetrating epoxy and given them a new layer of PU. (I prefer semigloss, which is a bit more forgiving).

The coamings have a tendency to get damaged at the top edge, so I had to touch up every now and then and finally sand off the entire length of the edge and restore the coating after a few seasons. That spot would benefit from a bit of embedded fiberglass, but I don't see a reasonable way of applying it that isn't super labor intensive. Perhaps if done when I first sealed them.

For your cuddy doors, you would need to pay attention to fittings (making sure all holes are sealed) as well as perhaps adding a glass layer in places likely to get damaged.

If you keep your boat exposed to the sun in a high UV area, a clear finish may not give you enough protection, so either use one of the other methods, or opt for colored deck paint for your doors.
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Re: Refinishing Rudder and Cuddy Doors: Epoxy, Varnish, or B

Postby pboulanger » Wed Apr 12, 2017 7:56 pm

Thank you so much for the incredibly helpful and thorough response! My boat will be the water all season, so I'll likely choose a darker varnish for the doors to help protect against UV.

Just to confirm, did you mean Three Systems S-1 for the penetrating epoxy? Can't seem to find anything called X-1.

A somewhat related follow up: for refinishing the tiller, would you follow the same process, perhaps without the fiberglassing since it will (likely) not be taking any impact? Or, if you would still suggest fiberglassing, do you have any suggestion for laying and epoxying glass on a rounded edge? Actually, any advice on dealing with the rounded edge of the rudder would be helpful, too. Thank you!
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Re: Refinishing Rudder and Cuddy Doors: Epoxy, Varnish, or B

Postby GreenLake » Thu Apr 13, 2017 12:26 am

pboulanger wrote:Just to confirm, did you mean Three Systems S-1 for the penetrating epoxy? Can't seem to find anything called X-1.


It's SystemsThree and yes, I do mean the S-1 (why I keep thinking X, I don't know, it's not the first time).

pboulanger wrote:A somewhat related follow up: for refinishing the tiller, would you follow the same process, perhaps without the fiberglassing since it will (likely) not be taking any impact? Or, if you would still suggest fiberglassing, do you have any suggestion for laying and epoxying glass on a rounded edge? Actually, any advice on dealing with the rounded edge of the rudder would be helpful, too.


I would not bother with trying to add glass to the tiller, but on mine, I keep nicking the tip, and it's easy to press it into the coaming; there's a limiter on the rudder, but the lever arm is so long, it's possible to make the tiller touch the coaming anyway. I sometimes just tape a length of electrical tape in places like that. e.g. on the underside of the tiller, that allows things to glide better and is a bit sacrificial.

For sheathing the rudder, the technique is to set the blade with the rounded front end pointing up and then to drape a single sheet over both sides. The two halves will meet in a V at the trailing edge of the rudder, and you just glue them together there. (After they have cured, you cut off the excess). If the rudder doesn't have a nice sharp V shape, you can use the glass to help form one, but then you need to inject epoxy into any voids afterwards. If your rudder has a proper foil shape, the two halves will follow it, and meet in a shallow V (or actually, more a Y shape). Afterwards, you cut off the excess (the stem of the Y) and then make sure you grind the trailing edge so it forms a 1/8" edge, angled slightly asymmetrically, perhaps at 75 degrees instead of 90. (Will prevent flutter.)

If you have not used fiberglass before, it's not really hard, but a bit finicky and trying it on a small sample is strongly recommended; that will quickly give you a feel for how this works and you'll learn best how to get any air bubbles out, etc. While the glass will become invisible, any trapped air will not, so you need to make sure you are not working so vigorously as to form bubbles and foam with the epoxy!

PS: if you ever wanted to cover a spar or pole in fiberglass, the best way is to wrap it in spiral form with strips, like you would bandage something. It shouldn't be necessary for the tiller, but I did that, for example, when coating a bamboo spinnaker pole.
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