Builders' Forum Archives
Re: fiberglassing the hul
Posted by don foote on Jun 10, 2006
I hope to build one of the shearwaters soon myself but, alas, not for a while yet.
While I am not familiar with the "3 layers of fiberglass" called for in your boat, I can tell you that the first coat of epoxy will be very bumpy. You DON'T have to sand this coat, IF your second coat is applied before the first coat sets up and is hardened. The second coat will fill most of the weave (depending upon thickness of coat, with the third finishing things off, other than a few touch ups, perhaps. Between the second and third, you will find through sanding that the pattern of the weave will disappear as you sand. This is due to the weave being filled with epoxy but the texture of the weave "printing through" the layers of epoxy above it. There is a good visual of this somewhere - in the shop tips, perhaps.
What I would encourage you to do is be light on the sanding and spread out any sanding efforts along the length of the boat, rather than focussing on one spot. this will result in a final surface that is more consistent without dimples created by focussed sanding. After your first coat, keep following coats thin to allow a more consistent coat tht will require less sanding later - don't worry, there will be planty enough of it. It' surprising, too, how much weight a hick coat of epoxy can add to a hull.
If you get to your third coat of epoxy, and sand after curing and it STILL has some areas that show the texture of the weave, or feel bumpy, do a follow up coat in those areas, or, as some have suggested, go on to the next step of primer/paint or varnish and let these finish layers fill in the last little bit of the weave. Three layers of epoxy gives you the waterproof barrier you are looking for. Anything beyond that is simply extra weight.
My (amateur) 2 cents.
It's pouring here in Vermont so I'm looking for some solace here on-line while many others are frolicking at Okoume - fest... thanks for posting pics, Laszlo, so the rest of us who couldn't, or simply didn't, go to Okoumefest could feel like a part of the activities....
In Response to: fiberglassing the hull by Bob Lippold on Jun 10, 2006