You need exactly the right size pilot hole for self-tapping screws. Trial and error has led me to two sizes that work reliably. #10 screws need 11/64 pilot hole, 1/4" fasteners need a 1/4" pilot hole. I know that sounds very strange, but try it on some scrap glass and see how it works.
Jim Watts Paradigm Shift C&C 35 Mk III Victoria, BC On 26 February 2015 at 10:30, Martin DeYoung via CnC-List < [email protected]> wrote: > Steve, > > > > Epoxy (West’s or others) provides a superior secondary bond over > polyester. West Systems is often used by DIY boat owners because of their > very helpful instructions and guide on their web site and the availability > through retailers. > > > > Also, polyester based resins and fillers absorb moisture faster than > epoxies. (Our company uses both in aerospace and mil-spec components that > are tested for suitability in a wide range of exposures.) > > > > For short term repairs polyester based fillers and resins will work fine. > Over 10+ years epoxy based resins and fillers will provide a better bond > and resist water intrusion/absorption better. > > > > Both need to be protected from UV. > > > > Martin DeYoung > > Calypso > > 1971 C&C 43 > > Seattle > > > [image: Description: Description: cid:D1BF9853-22F7-47FB-86F2-4115CE0BAF2F] > > > > *From:* CnC-List [mailto:[email protected]] *On Behalf Of *Steve > Thomas via CnC-List > *Sent:* Thursday, February 26, 2015 10:15 AM > *To:* Josh Muckley; [email protected] > *Subject:* Re: Stus-List Need Recommendation for Tool to remove balsa > core from drilled hole - resins etc > > > > I bought a used Natty dodger for my boat and am faced with the same task > for the 30+ holes to install the Lift-the-Dot® fasteners that it requires > to fasten the canvass to the deck. > > I did try to counter sink holes in the gelcoat and screw into the top > fiberglass layer underneath, but that turned out to be a disaster. > > I have done lots of through bolting for various things over the years > without difficulty, but this was my first experience trying to use self > tapping fasteners (look like wood screws) in the deck and it was not a > positive experience. The gelcoat is very thick in places, and in spite of > my attempts to counter sink the gelcoat, often as not the screw chips out a > huge flake. Removing the canvas female fastener from the deck mounted pins > can take some force, and the screws pull out of the thin top layer of fiber > glass. So I concluded after several failures that I need to stop what I was > doing and use the drill and fill procedure. Then came winter. > > > > In all of these discussions about drilling and filling over the years, > everyone defaults to using West System epoxy resin to fill the areas > needing reinforcement. > > What is it about this product that makes it so superior? > > Why not use a polyester resin? - at least gelcoat will stick to it. > > Like most of us older guys I had experience with automotive body fillers > in my younger years. > > They are all polyester. What is wrong with using that? > > > > Some of the Lift-the-Dot® fasteners are difficult to release and I don't > know how to fix them. I have been thinking about changing over to the > flat, 1/4 turn fasteners that are commonly used now. Is it a practical > solution? Has anyone tried this? > > > > Spring project. > > > > Steve Thomas > > C&C27 MKIII > > > > _______________________________________________ > > Email address: > [email protected] > To change your list preferences, including unsubscribing -- go to the > bottom of page at: > http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com > > >
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