vic008 17 Posted May 31, 2019 Share Posted May 31, 2019 With the wet weather, having to reseal perspex windows. Best sealant please? Quote Link to post Share on other sites
Island Time 1,226 Posted May 31, 2019 Share Posted May 31, 2019 If your going to use sealant, quilosa ms35 from the glue guru. Awesome stuff, works great. Quote Link to post Share on other sites
ScarecrowR31 8 Posted June 1, 2019 Share Posted June 1, 2019 Yep use 795 and VHB. Avoid screw/fastenings if possible (Thermal expansion). Discussion may need a little more focus on how attached ie external,rebate,frame and if perspex or lexan. Quote Link to post Share on other sites
idlerboat 116 Posted June 1, 2019 Share Posted June 1, 2019 As above.... VHB tape. .. Test your tape first or use 3M. Dont use the thin stuff...you need flex. and a low modulus scilicone. If you use scilicone then tape/mask a boarder onto your windows that lines up where the scilicone will be. Gently rough up the area with 360 grit ...(Careful to keep it only where the paint will be) Paint that area with a scilicone based exhaust paint. This painted area is called a frit. You will see that it is on all fixed windows on cars . Its purpose is to protect the tape and scilicone from uv degradation. Somewhere on the net is a several page article I wrote about 14 years ago on window installation with step by step pics....but I cant find it. . My windows have never leaked or look like doing so in the future... they have done many thousands of miles Quote Link to post Share on other sites
Freedom GBE 27 Posted June 1, 2019 Share Posted June 1, 2019 Yep use 795 and VHB. Avoid screw/fastenings if possible (Thermal expansion). Discussion may need a little more focus on how attached ie external,rebate,frame and if perspex or lexan. Our perspex windows leaked from day one, no screws. I have now added machine screws, hopefully that will fix it. If it doesnt, the windows may have to be replaced with fiberglass with a clear resin. Can you put a dark tint in a resin that will still allow light to come through? Quote Link to post Share on other sites
MartinRF 53 Posted June 1, 2019 Share Posted June 1, 2019 Buthyl rubber sealant has work fine for me. Applied in 1986, still no leaks in 2019. I don't know what brand name but this looks right: https://www.ebay.com/sch/i.html?LH_CAds=&_ex_kw=&_fpos=&_fspt=1&_mPrRngCbx=1&_nkw=butyl+rubber+sealant&_sacat=&_sadis=&_sop=12&_udhi=&_udlo=&_fosrp=1 This stuff neither cures nor dries out. It is still soft and sticky. /Martin Quote Link to post Share on other sites
Zozza 293 Posted June 1, 2019 Share Posted June 1, 2019 Like Martin, I used Butyl tape, but a particular brand called "Bed It". Apparently, not all butyl is the same. I also used this particular butyl for most of my deck fittings. The key is to counter sink / chamfer your drill holes. Here is an in depth article about how to use it: https://marinehowto.com/bed-it-tape/ Quote Link to post Share on other sites
Vorpal Blade 89 Posted June 2, 2019 Share Posted June 2, 2019 Our perspex windows leaked from day one, no screws. I have now added machine screws, hopefully that will fix it. If it doesnt, the windows may have to be replaced with fiberglass with a clear resin. Can you put a dark tint in a resin that will still allow light to come through? Why bother doing that, glass it up and put a big window shaped sticker on the cabin side. Never leak. Quote Link to post Share on other sites
Island Time 1,226 Posted June 2, 2019 Share Posted June 2, 2019 Properly installed acrylic windows don't leak. Mechanical fasteners are no longer needed with modern modified silicon adhesives. In fact, its the lack of flexibility in the mechanical fasteners that CAUSE most of the leaks. There is quite a bit of difference in the thermal expansion rates of GRP and the acrylic materials, and the adhesion and flexibility of the correct adhesive is essential to a good result. Quilosa MS35 is awsome. Quote Link to post Share on other sites
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