Builders' Forum Archives
Posted by LeeG on Mar 11, 2006
The 4oz deck glass provides general deck durability and the sheer roundover where the deck and hull meet.
Wrapping it over and down the sides an inch+ appears to give some extra durability for that vertical top edge of the side panel but honestly any impact that 10oz of glass (6hull+4deck)is usefull for will be more than the 4 oz right at the sheer can handle. In other words it's the 4oz right at the roundover that matters, not the doubled up layer below it. For example in a conventional t-rescue when the kayak is dragged across your lap and rolled over it'll still be 4oz glass on the most exposed edge, not the doubled 10oz layer on the side that's providing durability. Likewise in a paddlefloat self-rescue when the paddle shaft rocks onto the deck and sheer with a large part of your weight it's the 4oz and not the doubled 10oz that will provide the protection. If a person really wanted to protect the sheer edge then layer on a 1" strip of 4oz OVER the edge would do it or go straight to 6oz deck glass and feather below the sheer. That's why you'll find 6oz deck glass as a common weight for strip boats and 4oz for light constructions.
As you mention you've already sanded the hull sides before putting the deck glass on, putting on a normal 1"+ wrapover (for taped deck/hull joints) requires feathering down the glass. It would require less overall sanding of glass and epoxy if you did most of the fairing when cutting off the excess glass and making the wrapover as small as necessary.
Unlike deck/hull joints that require internal taping the deck on the Chesapeake doesn't require glass to finish the deck/hull joint, so a wrapover isn't structurally necessary. If it's not necessary why bother unless you really like the idea of a 10oz "rub rail",,except the "rub rail" doesn't protect the most vulnerable edge during paddle whacks and rescues (paddle float self-rescue).
Here's what I've done on a couple kayaks,,it's the same kind of wrapover you'd do for adding a "football" of glass for the hull bottom where the wrapover feathers in just above the chine and isn't visible. Run some blue masking tape about 3/16" below the sheer roundover, then run some 2" plastic tape over that(helps pull the whole thing up with less tearing, and a little extra masking). Glass the deck squeegeing onto the tape. When it's partially cured come back with a straight razor and cut the glass at a shallow angle while pulling up the tape. When the wrapover is that narrow it allows for a shallow feathered edge since the blade handle can angle near the sheer. When done come back with a scraper to pick up bits of tape and finish the feathering.
After that put on a couple more fill coats on the sheer than you'd put on the deck since it's VERY easy to sand through an edge. Since the 4oz glass is there to provide some durabilitly to the sheer you'd want to have a thick fill coat BEFORE sanding it down.
This may feel as though you're cutting things close with the 4oz glass immediately fairing onto the 6oz sides with little wrapover but the same would happen wrapping the glass down the sides then going back with the ROS and feathering it in,,,making sure to not nick the 4oz edge.
I'm finishing varnishing a friends Ch17 where the deck glass was freehand cut and glass over the sides 1"-2" with ragged edges. Since he didn't go back and carefully feather down the glass but did a cursory sanding with fill coats and varnish on top of that any revarnishing that requires removing the old varnish(cracked,flaking) is requiring me to sand all that rough wrapover since the flaking varnish is below the high spots in the wrapover. Putting on more varnish will put it over weathered cracked varnish. Of course if the wrapover was neat it would be less of a problem,,but if there was no wrapover and just a thick fill coat then refinishing that involves taking ALL the varnish off would make the job easier.
yeah,yeah this sounds a tad obsessive but for the 1/2 square yard of 4oz cloth that comes from wrapping around the sheer for 1 1/2" you could put it under the aft deck and on the bottom panels in the aft compartment. If you intend on sanding down that 1"+ wrapover for a faired in edge why not cut it short so you don't have to do so much sanding? For folks comfortable with sanding with the ROS to feather edges this may seem like no big deal,,for others it's a challenge to not have the 80-100grit grind more into the adjacent hull glass or take off an edge accidentally, repeating the sand/coat/sand/coat/sand/coat/sand cycle excessively.
In Response to: question on deck glass by Joe Oliver on Mar 10, 2006
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