What the heck happened to my Lexan windows? And can it be fixed?

[valhalla360]

Originally Posted by chrisr

along with a couple of others, i question why not use glass ? all our windows (side & front) are glass and can handle anything we throw at them (well almost anything obviously...) and naturally are perfectly clear

Glass is nice for long term resistance to scratching and crazing.

But if the opening wasn't designed for a flat glass pane, it can be problematic to convert to glass. This is especially true if there is even minor curvature. This isn't like a toyota corrolla where they produce thousands of windshields to a form to match the curvature perfectly is already produced.

[canadianbeethov]

Dry sandpaper can work.. try it..

[er9]

Originally Posted by contrail

Is this a coincidence? Like the OP, I have a Leopard, although I think that is irrelevant. In 2018, I decided to replace the original windows, which were acrylic. I thought long and hard before I decided on a Polycarbonate. More expensive than acrylic, but, I thought, stronger and more durable, although it was explained to me that whilst acrylic polishing is relatively simple, on polycarbonate it is very hard to impossible. I noted that OEM stuff is almost always acrylic, but went forward with the polycarbonate. The windows turned out beautifully. About fifteen months later, I decided to Awgrip everything from the toerail on up. I explained to the painters, very experienced and good, about the windows and told them to be very carefully, because they could not be polished out, should not have lots of masking tape, etc, etc. Within a couple of weeks of the paint job's completion, exactly the same kind of crazing, described and shown in the OP's pictures, appeared, in a two inch band around the edge of all the four side windows. I was furious, as I expected it was a mistake by the painters; I am still inclined to think it was, but they told me how careful they had been, per my instructions, and I know them well. I tried to clean with a mild soap, but to no avail. It was the rainy season, and as we went through rains, those same streaks now appeared down the windows. I washed several times and nothing made any difference. The installer and the distributor looked very carefully but could offer no solution and both shook their heads and said the windows were ruined. The condition got worse and worse and the crazing spread more and more. My theory was that the painters must have used a solvent that, despite very frequent washing, still was present, and that each time it rained, a bit more was spread around. I know, it sounds absolutely crazy, but when I read the OP, saw lexan windows, the same crazing I had, and Awlgrip, I could not resist relating my experience.


The end result is that the windows got so unsightly that I replaced them last week. I think it will come to that. I was fortunate in that both the distributor and the installer, with both of whom I have done business before, basically discounted everything by about 25%, in sympathy. The whole thing, labour and materials, cost me about $3000 for the four side windows, which are now acrylic.



Now, here is the mystery. The two front windows were identical lexan, and the area around them was painted as well. But, being an older Leopard, they are protected, to some extent, from sun and rain (but not washing) by the louvers/steps on the front of the salon/galley, and they are undamaged! So, perhaps the stronger UV exposure on the side windows made everything worse.



I feel for the OP, having gone through almost exactly the same thing. And, I think it will come to new windows. Ouch. And I would love to hear some definitive cause, but we now have two almost exactly the same occurrences. By the way, I live on and sail my boat year round, in the BVI, so whilst the environment is the same as Grenada, I don't think the storage, or bird poop, etc, made a bit of difference.

i dont think it was your painters. MAYBE if they used masking tape on the windows and tried to clean off the tape residue with solvent but, i think chemicals were leaching from your awlgrip that washed over the surface of the windows and caused the crazing. thats what looks like whats happenig to the OP's windows as well. chemicals can leach from paints, sealers, caulking and resins for years.

Polycarb i think is more absorbent than acrylic. harsh chemicals and organic acids (bird poop) will soak into it ever so slightly. the damage can be done instantly but not show up until external factors (sun, heat, cold, cleaners etc...) stress the plastic to the point it gives in and crazes.

i agree with Jedi. I dont think you can buff that damage out. maybe some of it but the crazing looks pretty deep.

[apirate]

We’ve found that prism polish works best on windows.

[contrail]

Originally Posted by er9

i dont think it was your painters. MAYBE if they used masking tape on the windows and tried to clean off the tape residue with solvent but, i think chemicals were leaching from your awlgrip that washed over the surface of the windows and caused the crazing. thats what looks like whats happenig to the OP's windows as well. chemicals can leach from paints, sealers, caulking and resins for years.

Polycarb i think is more absorbent than acrylic. harsh chemicals and organic acids (bird poop) will soak into it ever so slightly. the damage can be done instantly but not show up until external factors (sun, heat, cold, cleaners etc...) stress the plastic to the point it gives in and crazes.

i agree with Jedi. I dont think you can buff that damage out. maybe some of it but the crazing looks pretty deep.

I agree, too. In my case, above, the crazing was very obviously deep and not really visible on the surface. That's why I eventually gave in and changed them......lesson learned, as I think it will be, sadly, for the OP.

[Chotu]

Originally Posted by apirate

We’ve found that prism polish works best on windows.

Attachment 225778

What material are these ports made from?

[s/v Jedi]

Originally Posted by apirate

We’ve found that prism polish works best on windows.

Attachment 225778

If that is acrylic, it will last for a while but when it’s polycarbonate, the UV protective film is now gone and it will be back to oxidized within months.

If have done this multiple times, starting with wet sanding 220 grit, all the way up to 2000 grit, then polishing. When done carefully, you get a near perfect result, but it simply won’t last.

We are flip-flopping between acrylic and laminated glass for replacement.

[StoneCrab]

If you want to try buffing out the windows, check out the products carried by aviation supply stores. Airplanes have their windows polished all the time. You can polish out many surface microcracks.
Its been a while since I used the aviation products, so my recommendations would be out of date.

A more local source would be your local automotive supply store. They sell kits for removing the haze and crazing on headlights. 3M has a kit with polishing sponges that you put on your drill. I did my truck headlights in about an hour for both. They went from yellow and dim to clear and bright.

I'll admit that I was a skeptic when I bought the kit but it worked out really well. On sale the kits run around $10. Full retail is around $25. Basically you sand the surface, progressing through finer grades of paper. Then you polish it with a compound. When you are done, it is clear.

3M Headlight Restoration Kit

[oldmansfolly]

Yeap, I would say that is bird crap. Mate it might polish out, maybe. A fine cutting polish even tooth paste could do the trick. Shame that it happened, the rest of the windows are fantastic.

[contrail]

I think a lot of people are missing the point that it's not at the surface, but deeper in, at least that is what happened to mine, and the OP's look identical.

[s/v Jedi]

Originally Posted by contrail

I think a lot of people are missing the point that it's not at the surface, but deeper in, at least that is what happened to mine, and the OP's look identical.

This happens often. The windows are installed with the UV coating in mind but the exposed edges are overlooked. When these are painted (1-part black polyurethane) this problem is eliminated. The light that enters the edge, is reflected back into the material every time it reaches the surface and does maximum damage as compared to light that passes through after entering from a surface area instead of the edge.

[CassidyNZ]

Originally Posted by s/v Jedi

We are flip-flopping between acrylic and laminated glass for replacement.

Yep, me too, except laminated glass cut to shape is expensive, generally quite thick (means bulkier frames) and much heavier. But it does look good and will out-live the rest of the boat.

So I guess it’s going to be acrylic (sigh).

[apirate]

Originally Posted by Chotu

What material are these ports made from?

These are Acrylic. It took all of 3 minutes to get the result you see after trying a whole slew of other products. So far, after 4 months it still looks great. It’s not perfect but did make a huge difference.

[a64pilot]

Glass is heavy, but will last decades, my windows are 33 years old and look new, plus glass is impervious to just about anything, get paint on it, scrape if off with a razor blade.
however if you go glass, do NOT go with tempered, tempered is designed to break into tiny pieces like gravel so you don’t have a large guillotine piece of glass, think shower door.
Go with laminated glass, a cars windshield is laminated so that when struck with an object that breaks the glass, the plastic layer laminated between two pieces of glass will keep the windshield in place.
All of the other windows in a car which are not required to keep the window in place are made from tempered glass.

Point being that in heavy weather it’s entirely possible to have the entire window knocked out if tempered, where if it’s laminated it will shatter, but it will most likely stay in place.
Drop a winch handle on tempered and the whole window explodes.

[chrisr]

Originally Posted by a64pilot

Drop a winch handle on tempered and the whole window explodes.

sounds like the voice of experience ? is there a story attached ?

cheers,