Builders' Forum Archives
Re: Painting/epoxy hull
Posted by LeeG on Apr 24, 2006
any unprotected epoxy needs a UV barrier, wether it has graphite or aluminum in it. Kayaks are picked up and exposed to the sunlight,,bottom paints on boats aren't.
Any epoxy layer above the glass that is providing ablative protection has to be thick to be useful, whether it's just epoxy, epoxy/graphite, epoxy/aluminum, tinted epoxy fill coats covered in paint, etc.
Look up the one ocean kayaks website epoxy test. You'll get an interesting revelation. Thin coat of epoxy above the glass provides less long term weathering resistance than a thick layer of epoxy above the glass. To say nothing of protection against scrapes into the glass.
The best thing you can do for the bottom for cosmetic durability is three fill coats, sanded down, plus four-five coats of varnish. You could put on an opaque layer of tinted epoxy that will still have to be sanded/refinished as the epoxy degrades over time. If you wanted more durability than three fill coats on 6oz glass then you should be looking at more glass instead of more fill coats since the glass will provide more ablative/impact resistance than just epoxy. A thin coat of epoxy with some kind of additive will have different characteristics than plain epoxy but not anywhere as significant as another layer of light glass. If you wanted to get tricky buying three yards of 3.25oz fine weave e-glass and applying it only on the bottom panels could take the place of two fill coats with MUCH more ablative/impact resistance than two fill coats. My two cents is to just lay on more fill coats, extra ones on the chines, and a wear strip like what's on the A.Hawk will be more useful in the long run. Putting on epoxy that has those tinted fillers will pretty much commit you to using them from then on as the risk of removing them will require sanding down to the glass to take them off.
In Response to: Painting/epoxy hull by Eric on Apr 23, 2006