Nice job and great description! Joel
On Wednesday, December 2, 2015, Gary Russell via CnC-List < cnc-list@cnc-list.com> wrote: > Grr! Still trying to get link to work. > > Try this link: > > https://drive.google.com/drive/folders/0BwQRSP2fYIFmemxYOGlVcHNUNVk > > Gary > > ~~~~~~~_/)~~~~~~ > > > On Wed, Dec 2, 2015 at 8:57 PM, Gary Russell <captnga...@gmail.com > <javascript:_e(%7B%7D,'cvml','captnga...@gmail.com');>> wrote: > >> Oops! Try this link: >> >> >> https://drive.google.com/folderview?id=0BwQRSP2fYIFmemxYOGlVcHNUNVk&usp=sharing >> >> Gary >> S/V High Maintenance >> '90 C&C 37 Plus >> East Greenwich, RI, USA >> >> ~~~~~~~_/)~~~~~~ >> >> >> On Wed, Dec 2, 2015 at 8:47 PM, Gary Russell via CnC-List < >> cnc-list@cnc-list.com >> <javascript:_e(%7B%7D,'cvml','cnc-list@cnc-list.com');>> wrote: >> >>> For those who were following my post on bonded windows on High >>> Maintenance, I have an update and many thoughts on the project enumerated >>> below. I have successfully installed two windows on the starboard side and >>> replaced the acrylic on all the hatches and can say that the project has >>> been very successful. I have terminated my project at this point as the >>> temperatures are now too low for the VHB tape which requires a temperature >>> of greater than 60 degrees F for application. Here are my observations: >>> >>> >>> >>> #1. Plexus is evil stuff and should not be allowed on a boat. It is >>> too hard and tenacious a bond. Because fiberglass and acrylic have such a >>> different expansion coefficient, fracture of the acrylic is assured. >>> Removing the stuff is impossible without destroying the gel coat >>> underneath. I tried a sharp blade between the fiberglass and the acrylic >>> and all I managed to do was rip up the gel coat. >>> >>> >>> >>> #2. Before removing the windows, make a template out of some thin >>> plywood (or other material) because the window will (no doubt) come out in >>> pieces and you will have nothing as a reference for making the new windows. >>> >>> >>> >>> #3. I finally was successful removing the acrylic with a 5/8” router >>> bit set to a depth equal to the thickness of the acrylic plus the thickness >>> of the Plexus. I actually used a Roto-Zip instead of a router as it had a >>> smaller footprint and was easier to handle. I free-handed the router to >>> cut through the acrylic and into the Plexus. It’s risky but effective. >>> Don’t cut all the way around the perimeter, but leave tabs to support the >>> window. Otherwise, the window will sink under the weight of the router and >>> you will cut into the gel coat. You can break out the tabs later. >>> >>> >>> >>> #4. Once the windows were out, I used West System epoxy thickened with >>> low density filler to repair any damage to the gel coat. Fortunately, all >>> my gel coat damage was limited to the area under the windows. Once the >>> windows are out and the damage is repaired, the rest is fun and easy. >>> >>> >>> >>> #5. I cut the new window out of 3/8” Plexiglas using a pattern router >>> bit (sometimes called a Formica trimmer). I used masking tape folded in >>> half lengthwise to stick the new Plexiglas to the old window (or >>> template). I ran the tape at right angles to insure that they wouldn’t >>> slide in either direction with respect to each other. It does a very nice >>> job and is quite easy. I then used a 1/8” round off router bit on the >>> outside edge of the new window for cosmetic reasons and a 45 degree chamfer >>> bit on the inside edge to make room for the Dow Corning 795 silicone. >>> >>> >>> >>> #6. I installed the 3M VHB 4991 tape on the coach roof and masked >>> around where I wanted the window to go. This would help me locate the >>> window and provide the masking for the Dow Corning 795 silicone to follow. >>> I also masked the edge of the new window for the same reason. >>> >>> >>> >>> #7. Now cones the tricky part. You only get one shot with the VHB >>> tape, because once it is down, it is not coming up. I tried adhering two >>> small pieces of acrylic to each other with about two square inches of VHB >>> tape, and I can assure you, you won’t pull them apart. VHB is amazing >>> stuff. As a guide, I mounted two small wooden blocks to the masking take >>> below the window with a small piece of VHB tape. By attaching it to the >>> masking tape, I was sure I could get it back off. Actually, VHB doesn’t >>> stick very well to masking tape anyway. I also stuck a small wooden block >>> to the masking tape at one end of the window as well. This allowed me to >>> set the window on the two bottom block and then slide it over to the end >>> block before pushing the window into place. By all means, make several >>> trial runs with the film still on the VHB tape before removing the film. >>> Once the film is off you are committed. I pushed the window in place and >>> it looked perfect. Then it is simply a matter of squirting the Dow Corning >>> stuff into the gap and smoothing it out with a finger. As soon as the >>> silicon is smoothed out, you can remove the masking tape and pour yourself >>> a stiff one, while you admire the fine job you have done. >>> >>> >>> >>> #8. There was concern expressed that the VHB tape would be visible >>> through the window, and it was suggested that the window should be painted >>> with Krylon Fusion Black. Actually, the VHB tape is the same color as the >>> Plexus which is not visible, so the VHB won’t be visible either. No paint >>> is necessary. I used the darker shade of grey Plexiglas and can say that >>> it look spectacular. The darker shade really “pops” and the contrast is >>> particularly attractive (in my humble opinion). The darker color makes it >>> difficult to see into the boat, but has a minimal effect when looking out. >>> The VHB is not visible at all. >>> >>> >>> >>> #9. There was also concern expressed concerning whether the curvature >>> of the coach roof would cause a flexing force to peel the VHB tape. I can >>> say that the radius of curvature is very large (>20 feet) and the forces >>> are thus very small. 3/8” acrylic over those lengths is quite flexible. I >>> see no problem at all. >>> >>> >>> >>> #9. I have posted some pictures on Google Drive and I think you can >>> view them at: >>> >>> >>> >>> >>> https://drive.google.com/folderview?id=0BwQRSP2fYIFmemxYOGlVcHNUNVk&usp=sharing >>> >>> >>> >>> I am new to posting pictures, so if you have trouble seeing them, email >>> me and we can get it fixed. I will add more pictures as they become >>> available. >>> >>> >>> >>> #10. Needless to say, I am thrilled with the outcome so far. I have >>> also re-glazed the hatches using the Boatworks video and they came out >>> spectacular as well. The only difference I made from their recommendations >>> is that I bedded the acrylic in butyl tape instead of the Dow Corning 795 >>> because it was much easier to get a uniform bead and that was the way it >>> was done from the factory. I still filled the gap around the windows with >>> the Dow Corning 795. Boatworks is right, the Dow Corning 795 is nice stuff. >>> >>> >>> >>> #11. If I have left anything out or you have any questions about this >>> post, just give me a shout. >>> >>> >>> >>> Gary >>> >>> S/V High Maintenance >>> >>> ’90 C&C 37 Plus >>> >>> East Greenwich, RI, USA >>> ~~~~~~~_/)~~~~~~ >>> >>> >>> _______________________________________________ >>> >>> Email address: >>> CnC-List@cnc-list.com >>> <javascript:_e(%7B%7D,'cvml','CnC-List@cnc-list.com');> >>> 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 >>> >>> >>> >> > -- Joel 301 541 8551
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