I am building a 21 ft open launch, chapelle's fisherman's launch "boatbuilding" pg 393.
I will nail each strip (cedar) , ocasionally nail to the ribs and, fiber glass the inside and out three multi dimensional coats because plan to trailer the boat.
I am wondering what the opinion of the group is concerning putting a layer of epoxy between each strip. Should I epoxy each strip? Should a different glue be used or none at all.
Thanks
Epoxy will make a stronger boat, as would a good waterproof glue. I am having great luck with the new Titebond III, which is a lot cheaper than epoxy, easier to use and way easier to clean up. Plus, it sands and takes stain if you care. This stuff sets up in 20-40 minutes, and is hard overnight. You can keep on a'strippin' with glue, but epoxy tends to slow you down with the mess and the longer cure time. No question, however, that you need to seal and glass the exterior surfaces of your hull (yes, that means insides too) with epoxy, following the instructions (good source for this is the Goudgeon Brothers' book for West System epoxy). JR
ReplyDeleteDoes the class and epoxy sealer get around the manufacturers disclaimer about continuous submersion or use below the waterline? I would assume so, but just asking.
ReplyDeleteUnderstand, this is just opinion, based on comments read elsewhere: One of the books told me that the more layers of epoxy on the exterior, the more water resistance. This was in weight context: the more layers of epoxy = more weight, always assuming this is a bad thing. I don't remember the words, but the context implied that if you have a boat that will spend most of its life out of water (like the pieces of furniture we cedarstrip canoe makers call canoes and kayaks), then one sealer coat, one glas coat and one filler coat is enough. If it's going to be in water longer, add more coats, and if it lives ther for a long time, maybe six or more layers, plus additional glas in the buildup. It stands to reason that the more you attempt to seal the boat's exterior, the fewer opportunities there will be for exposed glas fibers, pinholes, bubbles and suchlike to let moisture into the core. Once there, the moisture will follow the pores of the wood and all kind of ruckus results. Bottom line (and what I believe as a strip-builder) is that if you have a good argument for lightness (portages, single-person loading, personal preference) then fewer coats of epoxy is better but I don't advocate less than three exterior, two interior. But in honesty, I am old enough to prefer to trailer my boats, so I don't mind the extra coat or two. If I could afford a slip and a bigger boat, it would be three or four coats of glass with seven or more coats of epoxy, and she'd be a beauty under sail.
ReplyDeleteJR, you said it... That was a perfect summing up of how I would deal with glassing any boat. I am not sure if there is such a thing as a clear gel-coat finish. Is this something that would work in place of traditional glassing? I have left a stripped rowboat in the water for several weeks on end and have never seen any adverse effects on the structure or finish. This was in fresh water, I don't have any experience with saltwater. Andy
ReplyDeleteHey andy, There is clear Gel-Coat... Just take a close look at any metal flake embeded bass boat. The first shot in the mold is clear gel. Not sure the process in reverse is worth the trouble of sanding and buffing. A good two part epoxy/poly product with UV protection is going to have as good if not better abrasion resistance. -Kruez-
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