CS17 Glassing

[Tom Williams]

I spent today glassing the hull of my CS17. I use 6 oz. flat weave cloth and everything went well! I've got two coats of epoxy on the cloth and I believe one more will "fill it up". It was easier than I expected. I've used about 1.5 quarts of epoxy including a coat before the glass went on.

Note: My friend Rick helped out and confirmed his plans to order some B&B plans soon. I'm glad he volunteered ... it would have been tough doing this job single handed. Attached are a couple of shots.

Tom

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[Gordy Hill]

Tom

I did the same with my CS17 and among other advantages I found that it made it much easier to put on a really good finish.

If I were to do it again, from where you are I'd add graphite to the next coat of epoxy. When you sand all the high and low spots will become apparent.

Then, you might consider doing below the waterline with a couple more coats with the graphite and sand and polish it. The finish you'll get is amazing and the color goes much deeper than paint, so small dings and scratches don't show.

Gordy

[Guest]

Wait here a minute, you are in shirt sleeves in Michigan?? :wink: Nice work, but one question, what type of wood are you using?

[Tom Williams]

Thanks for the tip Gordy -- Did you paint over the graphite/ epoxy mix?

I just finished my third coat of epoxy, It's neat to see reflections on the hull! I'm really amazed at the fairness of the hull. I was expecting more bumps and waves. I guess its a tribute to the quality of the Okume plywood (and the great design of course). As you can see in the pictures, I really didn't have to do much filling.

Yea Oyster. The sun was out and the temperature was over 30F yesterday ... time for short sleeves. Another 10 degrees and the shorts come out!

Tom

[Gordy Hill]

Good question Tom.

I did my centerboard and rudder blade with the graphite and was really impressed with the finish, so much so that I think I'd do my next boat with it. However, I like the idea of a black boat.

Although it doesn't take much graphite to treat the epoxy it sure sounds like a good idea to do a test with paint on it.

[Howard]

When glassing the bottom, do you tape the keel and chine seams first?

Either way, it looks like you did a short overlap of the cloth edges at the keel and let the cloth drape to the gunnels and then cut it to fit.

I'm to the point of filleting and taping the inside seams on my Spindrift, but I have the glass cloth and have the epoxy, so I was planning to glass the bottom and sides too. I've just never glassed anything bigger than a rudder before.

The graphite you speak of is simply an epoxy additive? Other than color, does it have a function?

Howard

[Tim TITAN]

The graphite leaves a VERY hard durable finish. Jet black, rock solid, and very slippery, which are its main advantages. It's mostly used on centerboards from what I've heard. It does not protect the epoxy from UV though, so it's only good for areas that are not in direct sunlight like the centerboard. It's not really much of an advantage to use anywhere else on the boat. I hear that paints do not stick to it very well at all, which makes sense given the hard slippery surface, but with paint you wouldn't have that slick surface which is one of the main advantages of applying the graphite to begin with. I am leaning more and more towards a black hull on my CS20, and I was going to mix more cabosil into the fairing epoxy on the hull along the keel to add more strength/durability against scrapes(from beaching) going through to the glass. I thought about graphite for this area, but I want the entire hull protected from the sun and paint won't stick to graphite well. I'm doing my centerboard in graphite, but I'm thinking a rudder or centerboard is easily replaced. A hull is not, so why risk it? Not a whole lot of sun hits the keel, but after many years on the trailer I would imagine the sun would have some impact on the epoxy. Also, with the white cabosil along the keel I will be able to easily see any scratches through the black paint and hopefully fix them before they get too deep and the glass or wood gets wet. I've fixed boats that got water damage like that, and its a mess. Good luck and let us know what you decide to do. your boat is looking good.

[Tim TITAN]

oh, by the way, yes the graphite is just an epoxy additive powder, similar to cabosil or microballoons, but black of course. It's a little more pricey, but you don't usually have to use as much graphite in the epoxy as you would with other fillers. West System sells good graphite powder and is readily available from most suppliers, but other suppliers might have generic graphite powder for less money if you look around and need more than just a coffee can size. From my experience graphite powder is a little more messy too. The powder doesn't like to come off things, so wear gloves and try not to touch much unless you want black handprints everywhere. :wink:

[Tom Williams]

Answering Howard's question.

When glassing the bottom, do you tape the keel and chine seams first?

Either way, it looks like you did a short overlap of the cloth edges at the keel and let the cloth drape to the gunnels and then cut it to fit.

Yes, I did tape the chines with 10 oz tape. It probably wasn't necessary but I figured it would add some extra protection in an area that prone to bumps and bangs. I didn't tape the keel. It has two layers of 6 oz. cloth overlaping and, it will have the keel protecting it as well. The bow forward of the keel got the 10 oz. tape plus the 6 oz. of cloth overlapped (22 oz. altogether!).

I did allow the cloth to overhang the sheer. After wetting out, I cut it about 1/8" short of the sheer. It will eventually be covered with the rub rail so I wasn't too worried about trying to get it flush.

Tom

[Howard]

Thanks for the reply. The glass cloth procedure makes sense.

As for the graphite powder, this is but one example of how confusing working with all these products can be. They sell the stuff for the reasons stated....to create a smooth slick finish, yet we also know that epoxy won't last long exposed to UV rays unless it's coated with something. So the slick finish of the epoxy coat appears to be moot, except as a base for what is to follow. It's the finish of the coating that matters. If a smooth and fair base is what you are after, seems to me that using a fairing compound makes more sense than graphite. Again, such contradictions are confusing.

Howard

[Kidd]

Does anyone make a paint or similar finishing coating with graphite or what would happen if you added the graphite powder to the paint you finished the boat with? I know the paint would have to be black, but this way you would have the graphite in the last coating and UV protection. Only thing is, would it work?

[Gordy Hill]

Ok guys,

I'm not an expert on this graphite stuff. I've used it on my centreboard and rudder blade and love it . If I were building now I'd also use it on the inside of the centerboard trunk.

It wouldn't do for the deck for obvious reasons, however, if you used it on the bottom of your boat it would look nice and give a hard slick finish. True, it would not be UV resistant and I'm sure you would notice some chalking in about ten or twelve years or so.

What makes it so nice is when I sanded it down to 600 grit my rudder blade was ultra slick and looked like carbon fiber. It was exposed to the sun quite a bit and I noticed no effect.

You could also buff it out with compound and have an awesome finish.

Who knows, maybe it would make your boat slide more easily onto the trailer.

I wonder how powdered copper would work.............

[Gordy Hill]

Hey!

Wouldn't a coat of car wax take care of the UV thing????

[Frank Hagan]

Hey!

Wouldn't a coat of car wax take care of the UV thing????

Don't think so ... usually you have to have something opaque in the coating to make it protect the substrate from UV. Cetol, with its high percentage of solids, works. But clear varnish doesn't work so well ... the UV penetrates through the coating. There are things that are not affected as much by UV, but that doesn't mean they protect what's under them.

In the tropics and similar areas, like southern California or Florida, System Three estimates that unprotected epoxy will break down in 6 months. I don't know how much UV is really going to get to the bottom of a boat, though! I suspect if its just on the bottom, it would last a long time "in the shade".

I seem to remember one of the Weekender builders using graphite on the bottom of his boat, up to the boot stripe like you would use bottom paint. I would worry about the UV on the deck and sides (topsides) of the hull, as well as the problem of "print through" of the glass fabric in hot areas (a common problem, where with dark colors, the texture of the glass fabric can be seen).

[Tim TITAN]

one more thing I forgot to mention. The graphite is much harder to sand. I don't recommend using graphite for the entire hull, but if you wanted to, I would fair the entire hull in perfect with normal fairing compound(much easier to sand) and then try and coat the hull with a nice even layer of graphite. That should save a lot of time and hastle. With a black hull or any other dark color, any ripples or imperfections in the hull will stand out like a sore thumb, so make sure the hull is perfect. I would consider putting down a layer of plastic over the wet graphite and using a roller or squeegee(spelling?) to get all of the high spots out of the graphite. You might have to perfect that idea, but I think it would save a lot of time/sanding. The plastic should come off easily after the epoxy/graphite is cured.

[P Doug (WA)]

Speaking of graphite, whatever happened to Adla and the boat she was building. If I remember she used graphite on the bottom.

[Guest]

Well, Doomsday here. I think many are making a lot out of adding graphite to a hull bottom, with the thought that it is better in the long term. Epoxy resins, by itself, is not structual. Adding graphite to epoxy keeping with the consistancy of coating and flowing out does not really add enough of body to stiffen the resin to the point that its a lot more resistant to damages. The lack of uv protection, and the surface still needs to be fair, does not fit my criteria for a good finish coat, long term.

Sanding is a big problem, when adding enough to make it tough enough to keep from flaking and cracking. Down the road, if you keep the boat, you will still like to refinish the boat. The labor will be worse, still requiring fairing to be done. A great alternative is still the 2000 series of Interlux Interprotect system. This gives you a heavy duty protective sealant, and can receive regular paints and offer a good base to recoat the boat later down the road. Keep in mind, this stuff is easy to recoat, without sanding, working in a certain time frame, depending on the ambient temperature. but will harden to a steel coating, almost, if left to cure. I normally coat it with a two part primer while in the green stage, and then it makes life easier to prepare it for any topcoat of your heart's desire.

[Tom Williams]

I wanted to correct an earlier mistake I made at the start of this post. I stated I had use 1.5 quarts of epoxy after two coats over the glass. That was actually just the resin. With the hardner included, It was just over 1/2 gallon.

Since then, I have: put on a third coat of epoxy, epoxied on the keel, sanded the hull and just applied the forth (and final) coat of epoxy. I'm ready for a break! In all, I used just over a gallon of epoxy. I figure the glass (6 lbs) and the extra epoxy it consumed (~1/2 gallon) added about 10 - 12 lbs to the boat. I think the extra protection is worth the weight.

I'm going to paint with marine grade enamal. I was thinking Sunday afternoon (~ 4 days from now) would be adequate time for the epoxy to fully cure. Anybody have any thoughts on that?

Tom

[Guest]

My personal opinion, two weeks. I bet you can find something else to cut and fit while waiting for curing time to reach its max. Please accept this as my own thoughts. Quick question, are you using any primers, fairing in low places, checked for low spots that will show under the gloss, any pinholes maybe not noted in the coatings and recoatings by the resin................

[ricardo]

I'm posting this one because I found the ruined t-shirt in the depths of my closet...

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