Rudder delamination repair

[DannyS]

Last Fall I removed the rudder and brought it home to repair some delamination. I'm about two thirds through the fiberglassing and fairing process. One side is complete, the other side is close to being done. My question is what should I use to protect the new glass? The guys at my local West Marine suggested Interlux InterProtect 2000E, http://www.yachtpaint.com/usa/default.asp Anyone have any experience with this product? I was thinking of painting on a layer of Gelcoat to the new glass but was worried about being able to see the buildup area. Should I plan to coat the entire rudder? I assume I'd have to sand the rudder down to gelcoat to re-gelcoat. In our area we use VC17 bottom paint (Lake Superior-cold water!) I don't have much experience with gelcoat so any insight would be appreciated.

 

[sailingdog]

Did you build it with epoxy resin or polyester/vinylester resin? If it is epoxy, then it really shouldn't need a barrier coating or protection from water intrusion, since epoxy is basically nearly impermeable to water, unlike polyester and to some degree vinylester resins. If you're really worried, fair the rudder, then apply a few coats of interprotect 2000E, alternating colors, so that you can see if you've accidentally sanded through the barrier coating in the future.

 

[DannyS]

I used West System epoxy. Since the rest of the rudder (as well as the bottom of the boat) has been coated with VC17 up to the point where I re-laminated the new glass, could I just paint on a few layers of VC17? I guess what I'm asking is if epoxy is basically impermeable, is the VC17 enough to protect the rudder? Where I sail, the water is so cold and it being fresh water, the boats come out in the fall looking like they did when they went in in the spring. We don't get growth so I'm not so concerned about that, I just don't want to go through this project again anytime soon.

 

[Ross]

The epoxy is enough to protect the rudder, the VC17 is gilding the lily.

 

[sailingdog]

I wouldn't call VC17 gilding the lily, since some sort of bottom paint is probably a good idea on the rudder.

Gilding the lily usually indicates that it would be an unnecessary step or treatment... which coating the rudder with VC17 is not.

 

[DannyS]

Well, you guys have shortened my project considerably! Without a gelcoat or InterProtect step, my rudder should be done by the end of the weekend. Thanks guys!
BTW, VC17 costs enough that the rudder may as well be gilded!

 

[jibes138]

Danny,
I replaced my rudder a couple years ago and the reason you might want to go with the Interprotect is it is supposed to be a good base for paint adhesion. I'm sure if you sand off the surface of the epoxy and prep it you could get a good adhesion but each time I've done what you are suggesting, like I west epoxied my lead keel since paint wasn't sticking and I wanted to make sure the lead wasn't oxidizing (not much sticks to metal oxides) then a couple coats of interprotect for paint adhesion. Worked good so far., I coated the new rudder with interprotect this year and then several coats of WHITE bottom paint. White paint will keep it cooler when hauled and sitting in the sun so less chance of delamination again. Another option is make a cover for the rudder when it is hauled to keep it out of the sun.
Just a few thoughts.
Dave

 

[sailingdog]

I'd agree that Interprotect 2000E makes a very good primer for raw fiberglass.

If you're not going to use Interprotect, do make sure to give the rudder a good final coat of epoxy to seal it. If you've sanded the fiberglass in the fairing process...the glass fibers exposed by the sanding process can "wick" water into the laminate unless it is sealed completely.

Also, I'd point out that Jibes's point about painting the rudder a light color is very important for an epoxy construction rudder. Epoxy begins to distort at a fairly low temperature. If it is painted a dark color and the boat is hauled out, the sunlight on the bottom paint could easily raise the temperature enough for that to occur. This is true of all epoxy-resin laminates, and a good reason why many hand-built boats are only painted in lighter colors.

 

[DannyS]

Rats! You guys are ruining my shortcut to the finish. Oh well, what's one more step in this project. I just laid my last pieces of glass today, final fairing tomorrow or Sunday, paint next week, back on the boat next weekend (after I replace the cutlass bearing). Good ideas about the light color paint on the rudder, I've heard others say the same thing. I just wish the VC17 came in white. Perhaps I'll just shrinkwrap the rudder with white from now on.
Thanks guys!