- From letter to Practical Sailor I wanted to share my experience with sealing Lexan. I used half-inch Lexan MR10 to replace all porthole glass and all overheadMessage 1 of 4 , Jan 16, 2007View SourceFrom letter to Practical SailorI wanted to share my experience with sealing Lexan. I used half-inch Lexan MR10 to replace all porthole glass and all overhead hatch windows. I used Dow Corning 3145 RTV Mil-A-46146. It has very high mechanical strength, UV and high temperature resistance. I primed the MR10 with Dow Corning 1205 Primer. It does take the 3145 a week or so to cure thoroughly. After four years in Florida, Mexico, Guatemala, and Roatan, it's still sealing well.
The sealant and primer is available from most industrial supply houses. I use Ellsworth Adhesives, Germantown, Wisc. (800/888-0698, www.ellsworth.com). This product is used on aircraft where tensile strength and resistance to UV and heat are important. Most places I've used 3145 have both high UV exposure and high temperatures caused by strong tropical sun heating up exposed metal surfaces. This product isn't cheap (approximately $60 list per 10.5 oz tube). I've tried a lot of "marine" sealants and been disappointed with their short service life. The way I justify the price is that the cost of the labor to install a port hole, hatch, etc. far outweighs the sealant's cost. If this sealant lasts 10-15 years rather than three to four years, it has paid for itself several times over. There is also the safety issue of inconvenient leaks at sea. I recently purchased a case of 3145 on eBay for $17 a tube. Surface prep is important in getting a good seal. I use MEK first. Then light sanding, and finally a wipe with acetone. This is per the Dow Corning spec sheet. The 1205 primer is necessary on Lexan MR10 because of its very hard and smooth surface. MR10 has 20 times the impact resistance for the same thickness of tempered glass!
S/V Intrepid, Tayana 37
On 1/16/07, Bill Scanlon <Catalina30Ruby@...> wrote:Tim,There is a "kit" for fixing that .. Ahmet went through it last year and can offer some adviceI believe the kit comes from www.CatalinaDirect.comIf you can't find it e-mail me and I'll search for it.Congratulations again on your new Catalina 27, she seems to be a beauty!Bill ScanlonUSCG Master 50 GT Inland Waters
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Lic. # 1092926
1984 Catalina 30"Ruby"Std. Rig Hull# 3688Winthrop (Mass.) Yacht ClubNavigare necesse est, vivere non est necesse
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- How about 3M 4000 This high quality cosmetic adhesive/sealant cures to form a firm, rubbery, watertight seal. It has superior UV resistance and a very lowMessage 2 of 4 , Jan 16, 2007View SourceHow about 3M 4000
This high quality cosmetic adhesive/sealant cures to form a firm, rubbery, watertight seal. It has superior UV resistance and a very low odour. Highly flexible, resistant to weathering, salt water, and stresses caused by joint movement. Seals between mechanically fastened joints on wood, fiberglass, metal, and most plastics above or below the waterline.
SikaFlex UV Resistant Marine Adhesive & Sealant 295UV
Designed for bonding Acrylic and Polycarbonate materials makes this product ideal for installing and replacing frameless plastic windows, hatches, shower walls and more. Because of its excellent UV resistance Sikaflex®-295 UV is also ideal for sealing joints in areas of severe exposure. Becomes tack free in about 60 minutes.*Surface prep required.On 1/16/07, Tim <c2csailor@...> wrote:
After spending last weekend on the boat, I awoke to a partially wet
sleeping bag as the window in the cabin was dripping on me pretty
steadily. The catalina 27 I have doesn't have any window trim, but am
unsure if there is more to rebedding the window than removing 4 screws
and popping out the window after breaking the seal.
What type of caulk/bedding compound/adhesive should I use? I would hope
after doing it once the right way that I wouldn't have to mess with it
for a long long time. I don't plan on using 3M 5200 in the event I ever
have to remove the window in the future.
Unfortunately, this project can't wait till spring, so the next semi
decent day with no rain is when I plan on doing this. Thanks.
1985 Catalina 27