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View Full Version : Fiberglass epoxying - is cloth neccessary?



Andy M
01-29-2004, 12:03 AM
Help!

I am new to this forum but what I've seen (read "read") I like.

My brief history, I am a pretty good woodworker, own a fair selection of power and hand tools and have successfully built one stripper canoe. I used the Hiawatha plans from "Canoecraft" by Moores and Mohr.

I am currently in the process of building a sloop-rigged beach boat that I can use on my local lakes with an occasional trip to Wisconsin Point on Lake Superior. (Miles of shallow water and pristine beach). I have it framed and am just fitting in the chines. My intention is to use 1/4" AC exterior plywood for the hull covering.

My question is this - can I use the two part epoxies (I have West system product on hand) without using fiberglass cloth (i.e. "painting" the hull with the epoxy resin). I see and read stuff on the "net" that seems to indicate this is a common practice if you want to paint a plywood hull, but no one gets specific. Am I way off base? I am thinking of just using cloth on the plywood seams.

I would appreciate any advice.

Andy

shawnkfl
02-05-2004, 09:17 PM
Andy...how ironic. you just helped me out for a strip built canoe. If you're ever in the market for a boat building partner.....

Anyway, I built a ply 8' sailing pram and a 14' ply canoe. both of which only had fiberglass tape on the seams. 4" wide for both. On the pram I coated (painted) the hull with 2 coats of epoxy and painted it. On the canoe I used two coats of epoxy and left it. Both are great and have no delamination at all. I take my pram all over the gulf coast (close to shore of course) and drag it up beaches and small mangrove islands....no sign of wear yet. In a plywood design it mainly comes down to two things. The design of the craft and the use it's going to see. Some designers highly recommend a full 'glass hull, others want 6" above the waterline and still others just want the seams. I'll try to post a pic of my "tough" little pram when it was complete if I can figure out how to do it. Hope this helps even a little.

quietjim
10-01-2004, 06:08 PM
Very nice pram...what plans did you use?

Noah's
03-27-2005, 10:05 PM
To fiberglass or not to fiberglass?
Plywood construction using frames, battens and chine?s does not need fiberglass,
as the framing keeps the boat together, but may be desirable on the outside for abrasion resistance when beaching , docks etc
Stitch and glue obviously needs fiberglass as well as some designs that use frames but no battens.
Cedar strip construction needs fiberglass on inside and out because the cedar is only a core and will crack easily on impact.

Andy M
03-27-2005, 11:41 PM
Thanks Shawnkfl:

Since my original post I have gone ahead and built the hull. I epoxied 4" strips of fiberglass (6 oz) along all of the seams. The frame has hard chines and the plywood panels are screwed every 5-6" into the frames and chines. The entire outside hull was sanded and marine primed.

My florist/greenhouse business has kept me busy and so the project has been at kind of a standstill since last summer. We are going to be moving the business to a new location and so I need to get the hull on a trailer as it currently resides in one of my greenhouses. I am in a rush now to get the interior filleted(?) for strength before I move it.

Once the filleting is done I can prime and paint the interior and add the deck and finish work.

I have also obtained a 25 foot spruce pole for a mast from a neighbor's front yard. The tree has been dead on the stump for 2 years and is well-seasoned. I cut and peeled it last fall and have allowed it to season further outdoors since then. My intention is to use my hand power planer and hand planers to dimension it.

If I can figure out how to attach pictures I will post my progress.

Thanks again, Andy M

pipefitter
01-24-2006, 01:43 AM
Some plywoods such as pine or Douglas Fir will check through the paint if not glassed.I use the lightest cloth for a veil on D-Fir to stop it from checking without adding too much weight.It gives the best base for a much more stable finish.