Dynel or just a coat of epoxy and a quick keel question...

[Art Read]

I've just finished installing the Sapelle plywood "cover" for the small trunk cabin at the forward end of my cockpit coaming. Fastened with bronze screws into the Mahogany coamings and the cabin beams you see being "roughed in" in the photo below. The plywood end grain will be sealed well and covered with varnished Mahogany half oval "trim" pieces. The screw holes through the ply will all be sealed and bunged. I'm planning on a simple painted finish for the top surface of the plywood. Perhaps Kirby's Classic "Sand"? I wonder what the best "prep" for the raw plywood would be? Canvas over white lead and Irish felt would "look" right, but I worry about mildew up here in the Northwest and suspect that with the ply, Dynel over epoxy might be a good substitute? But I also wonder if perhaps a couple of good coats of epoxy alone wouldn't work just as well for such a small area. What purpose does the Dynel serve other than providing some extra strength, a nice canvas-like texture and perhaps better leak and abrasion prevention? I'm not sure any of those factors will be an issue for this application. Thoughts?

While I'm thinking about getting one more bottle of googe, how well would some thickened epoxy work for filling and fairing the few, smallish "voids" remaining in my ballast keel now that I've "smoothed" the rough casting. I suppose I could just melt up some of the scrap lead I just cut off it to fill 'em, but I'm not really too concerned about any weight differences, just getting a nice surface for the anti-fouling. Epoxy would be a lot less "hassle". Also, is there any treatment or special "primer" for the raw lead that I should know about or can I just put the bottom paint on straight? Seems a little "silly" somehow to cover a solid hunk of lead with red lead "primer"!

http://www.imagestation.com/picture/sraid21/p6160b6f097116509be6b3edc4674ac78/fdb12197.jpg

[ 07-07-2002, 02:22 PM: Message edited by: Art Read ]

[Todd Bradshaw]

Boy that's a pretty boat. I had a conversation with one of the guys at Gougeon Brothers once when I was getting to fair the fin and bulb on my Starboat (cast iron) and they suggested that epoxy would work fine. I sanded it, coated it and slathered a mix of resin and microspheres into the little pits and hollows. Once it hardened, I sanded it to shape and painted it.The last time I saw the boat, it was doing fine. For lead, they suggested sanding right before applying the resin to get the base coat on before the metal started to oxidize and then to do basically the same procedure.

[True Love]

Art,

She's just looking fantastic! Do you have a link to a picture album of the building process?

I'm anxious to know how she sails - is there a tentative launch date? Lastly, can you float her off the trailor to launch her?

[paul oman]

from the quality of your work, we should be asking you the questions!

We sell epoxies (www.epoxyproducts.com). Use just use thickened epoxy to fair the keel. If the keel metal is exposed I would paint the entire keel with epoxy to seal and protect it from corrosion etc.

regards

paul

[DougWilde]

Back to the original question, it depends.

If the cabin top is subject to dropped objects, to dings, then cover with Dynel or Xynel. That plywood is awful soft. As far as letting the natural weave of the cloth show through...Dynel is a pretty open weave that distorts easily and gets "hairy" when soaked with epoxy. I found it best to coat, sand, coat, fair with microballons and coat one last time. Then the surface can take nearly any (normal) abuse).

Doug Wilde

[Art Read]

Thanks folks. I guess maybe I'm just being optimistic about all the inevetiable "dings" on that plywood. Anybody know offhand if Dynel is available locally here in Seattle? I didn't see it in Jamestown's catolog. Fiberlay maybe?

I see why the raw lead might want "cleaning up" before applying paint or epoxy after watching it change from a bright, shiny finish after machining it to a kind of dull sheen a few hours later, but "corrosion"? Lead corrodes?

As for the "launch date", "Oyster" got it pretty close with his quess about about "when the leaves turn" on another post here... I'm planning on keeping her in the water year round, if possible, so I'll just use a travelift to launch her right from the cradle for the annual haulout. The plans say she can be trailered "with diffuculty". I do know of at least one other that lives on a trailer, but she was strip planked. The link to my "photo-journal of the project is here:

http://www.imagestation.com/album/pictures.html?id=4292219521&show_all=1&start=1

[Ed Harrow]

Art, what a beauty... A heart stopper for certain, every new picture saves me a couple of beats for future use... Nice work.

Dynel is sold only (I believe) by Defender, located in RI. I can get you more details if you can't find anything.

The keel-bolt pockets in Phoenix were filled with epoxy, and it took an air chisel to make any real progress at removal. Seems like that (epoxy) would be fine.

[Buddy Sharpton]

Pretty boat you have going there. I have done both projects you are talking about and feel qualified thereby to offer suggestions.
I built a similar, but removable, "hatch" to cover the forward three feet of the 5 1/2 foot wide co0ckpit of my 15'Marsh Cat. I used a two layer sandwich of four mm Okuome plywood so I could eliminate springback and lock in the curve, about 6" in five feet, on a removable part. I sealed both sides with epoxy, the underside with 207 WESt hardner and varnish.The cabin top side as I did the decks, to Joel White's spec with Dynel. Great stuff!. You can mail order it from Defender at about 7 bucks per 60" wide yard. It's benefit , besides looking like painted canvas, is its impact resistance is greater than glass. While the fabric is lighter than fiberglass, its thicker and takes more, about three coats, of epoxy to sufficiently fill its deep weave "pockets". I think it evens out as to overall weight, but having a thicker layer of epoxy, gets more impact resistance. I painted mine with Interlus 414 primer and three coats of Brightside Buff with a little polymeric non skid additive to boot. Used a varnisssed mahogany half round "eyebrow" trim below the rounded off plywood edge Well. well pleased with the lot and recommend it highly.
As to the keel filling, if you're doing a bunch of fairing, as in a race boat finish, using the WEST 407 filler is easy to sand and fair and will hold up immersed. For just a few spots, any kind of Cabosil on hand, even talc powder, will do but apply smmothly as you can because it's a bear to sand.

[Tonyr]

For what it's worth, I am finding that no matter how much I coat rotary cut marine ply with epoxy (and paint, of course), it still checks after a season of hot sun exposure. The only way to stop it seems to be to add a layer of some sort of fabric, and fill the weave with epoxy before painting. Solid and/or laminated wood does not have this problem, nor, I suspect, would sliced-veneer-faced ply.

Regards, Tony.

[Chris Coose]

Art,
How about the epoxy idea and if it does not work out you could go to the dynel.
I did decks on my cat boat in dynel and WEST in 1988. I laid the cloth into wet WEST and followed with another coat - wet in wet. There was one spot that I kind of double coated, as I recall, and the extra WEST smoothed the dynel "fur" and made that area a bit slicker under foot than I like.
I've painted the deck 4 or 5 times since then with regular one part epoxy paint and I still have a safe surface.
It is still stuck good and no maintenance to speak of.
Where you won't be dancing on that small deck, I wonder if I'd want a slick or an abrasive surface.
Did you get my note on that blue color? If not, I simply cut Teal Blue with white until I liked it.

[Todd Bradshaw]

I suppose the advantages of sheathing it would be abrasion resistance (to a limited extent - though you'd probably have to run over rocks with the deck to see any difference between sheathing and just resin coating) impact resistance (in case you drop something like a winch handle on it)and the ability of the sheathing to completely remove any possibility of that "rotary cut look" that sometimes shows up on plywood from certain angles even after careful finishing. Strength-wise, you're making half a sandwich, which doesn't do much.

On such a small chunk, I doubt you will see any real advantage using Dynel or Xynole, shipped all the way across the country over a readily available piece of 6 oz. or 7.5 oz. fiberglass cloth which will lay down easily with no fuzz. I would be inclined to either fill it completely (if you want a smooth, glossy finish - though I would expect to still see some telegraphing of the weave) or not fill it at all if you want the canvas look. I'd squeegee it carefully, make sure it was down tight and completely saturated, let it dry, wash it and paint it. With a little work, it's possible to get a very even looking surface with the squeegee. Partially filling with another coat or two or a filler blend is harder to get even. Any of these fabrics are actually stronger and have more ability to deform without damage without the filler, which is just unsupported (or poorly supported) resin and screws-up the fiber-to-resin ratio.