Portlight Glass

[Extemporaneous]

Originally Posted by Benjamaphone

and by using the best cast acrylic, your ports won't need to be reglazed for at least 15 years which is at least very comparable with glass.

And so what exact brand is the "best cast acrylic"?

Thanks,
Extemp.

[s/v Jedi]

Ah, I just learned and researched that ;-) It's Acrylite GP sheet (that's the cell cast quality) and you buy that clear and after mounting you put the "silver" PolyGard on the outside.

My bookmarks:

http://www.cyro.com/methacrylates/us...sheetstandard/

PolyGard | Film Pacific

cheers,
Nick.

[roverhi]

"With a good installation and by using the best cast acrylic, your ports won't need to be reglazed for at least 15 years which is at least very comparable with glass."

The fixed glass main cabin windows are over 40 years old. The plastic sandwich has begun to deteriorate around the edges but overall, the glass is still clear. I might just get by with them for another 40 years. Don't think you'll find any plastic that will last half as long as the fixed glass windows have. The opening port glass all have one crack but are still water tight. The frames are actually the problems with these ports. The aluminum is badly corroded in places and several dogs have broken so I'll be replacing when I pain the deck this year. Got a deal on some Vetus ports with plastic lenses but they will hopefully outlast my ownership.

[GordMay]

Some cast acrylic brand names:
Acrylite, Hesa-Glas, Lucite L, Lucite Utran, Plexiglas®, Poly II, Poly 76, Poly 84, Shinkolite A, USS Acrylic Sheet

[osirissail]

- - I use plain old plexiglass for major pilothouse windows and Lexan for hatches where strength is needed. The are both very cost effective and available products. The exotic plastics are not very available to "little/small" quantity users. You need to buy whole sheets or large quantities and with the prices being 10X higher it is not practical.
- - Weight is also a major problem with large pieces of laminated glass along with problem of sealing and holding the units in the frames. Then add the normal flexing of a boat underway in the ocean and only dimensionally small pieces of laminated glass are practical.
- - Plastics on the other hand, have one horrible problem and that is the "crazing" as a result of the Sun's UV. I used 4 full sheets of Plexiglass for my pilot house and after only 5 years the crazing was noticeable. After 8 years it is continuous across the whole sheets and I will have to replace them soon. Lexan is worse about crazing - just look at other people's hatches. Exotic plastics get around this by applying a hard coating on the outer surface of the sheet - but you are talking 10X the price (in 1999 when I purchased my stuff) for the same lifespan before yellowing. Actually the crazing wipes out the window before yellowing ever gets seriously started.

[Extemporaneous]

Originally Posted by s/v Jedi

Ah, I just learned and researched that ;-) It's Acrylite GP sheet (that's the cell cast quality) and you buy that clear and after mounting you put the "silver" PolyGard on the outside.

My bookmarks:

Methacrylates - ACRYLITE GP Sheet (cell cast)

PolyGard | Film Pacific

cheers,
Nick.

Thanks Nick, I'll have a look.
fyi This is for my Pilothouse windows.
Do you have film installed on your cast acrylic now or is that something that your planning?

Are there others of you out there that have used window film and what was/is your experience so far?
How long has it been on and how is it standing up?

Thanks,
Extemp.

[Extemporaneous]

Originally Posted by Extemporaneous

Do you have film installed on your cast acrylic now or is that something that your planning?
Extemp.

If you don't have this installed yet, this looks like a similar product.
Hanita Window Film Division Introduces New High Performance Films for Plastic Glazing

Regards,
Extemp.

[osirissail]

- - Unless you are in very northern latitudes I hesitate to install any "after market" films on windows. From the link by Extemporaneous ->>>>> “Developing films suitable for application to polycarbonate proved to be quite a challenge, since regular window film adhesive forms blisters and bubbles when applied to plastic substrates,”<<<<< I would hate to be at sea with pilot house windows filled with blisters and bubbles and then have to laboriously remove the film when in so out of the way harbor. If you have the money you can buy high end polycarb plastics which has a factory installed coating.

[Extemporaneous]

Originally Posted by osirissail

- - Unless you are in very northern latitudes I hesitate to install any "after market" films on windows. From the link by Extemporaneous ->>>>> “Developing films suitable for application to polycarbonate proved to be quite a challenge, since regular window film adhesive forms blisters and bubbles when applied to plastic substrates,”<<<<< I would hate to be at sea with pilot house windows filled with blisters and bubbles and then have to laboriously remove the film when in so out of the way harbor. If you have the money you can buy high end polycarb plastics which has a factory installed coating.

Yes, I would hate that too, hence the questions and caution.
It appears that this product (along with the one Nick linked to) is specifically for Acrylic (PMMA) and Polycarbonate installations and the words you quote are proper warning NOT to use films for glass on PMMA or PC.
The reading/questions/research continues.

Thanks,
Extemp.

[Benjamaphone]

I agree. If you're using cell cast, you shouldn't have to worry much about crazing/fogging for at least 10 years even at the equator. Adding films and coatings yourself is just asking for trouble...

[mikereed100]

Extemp,

I feel your pain. I have been trying to decide what to use for my pilothouse windows for several years now and am still ambivalent. I have gathered information from vendors, professionals and several internet forums during this time and the overwhelming consensus seems to be that glass/arcrylic is very strong/dangerously frail, is extremely expensive/dirt cheap is easy/impossible to work with and will last a lifetime/single season. All depending on the expert source.

My conclusion is that either would be fine assuming the glass is tempered and laminated and the acrylic is high quality cast. The self-applied coatings for acrylic are intriguing in that you are blocking the UV before it penetrates the plastic, theoreticly decreasing heat and UV damage in the plastic and possibly extending it's life and decreasing thermal expansion. If I recall, Polyguard offers an 8 year guarantee and claims the adhesive is easily removed without damaging the acrylic. I too would be interested to see how it plays out in the real world. I once applied cheap tint from Pep Boys to my car windows and they looked great for years until the car expired. What can I say?

Mike

[s/v Jedi]

I have Lexan XL10 for the pilothouse windows and that is just a big waste of money in the tropics. Think 2 years. The polymer coating I wiped on since last restoration holds up better than the original coating (I used RejectX if that's the correct name... from the CorrosionX manufacturer.)

So, I tried to get Lexan MR10 at 1/2" thickness, gray tinted. I found that I could get it at 40-sheet minimum order. I have found better sources recently (well, Gord did ;-). This stuff is extremely expensive.

I have seen Plexiglass lasting much longer but I have also seen it grazed. My feeling is that tropical UV will deal with it well within 10 years but when Benjamaphone writes it will keep good, I'm all up in confusion again ;-) Maybe the cast quality is that much better?

About the color: I did find that gray tinted makes so much difference compared to clear with the inside temperature that there is no choice: we must have tinted.

That is why I am moving towards cast acrylic, 1/2" thick, clear and a film on the outside. The film can be removed and replaced and another member used it and posted pictures in another thread. Time will tell and I bought some time with the last restoration of our Lexan.

cheers,
Nick.

[Extemporaneous]

Originally Posted by Benjamaphone

I agree. If you're using cell cast, you shouldn't have to worry much about crazing/fogging for at least 10 years even at the equator.
Adding films and coatings yourself is just asking for trouble...

If crazing/fogging was the only consideration, you might be right. If though I can add a film that will reduce glare, reflect heat instead of allowing it through and may even contribute to longer life, I'm in!
So far as asking to trouble, I ask for it everyday and usually when trouble comes it is because I was ill prepared and didn't do my research.

Regards,
Extemp.

[Extemporaneous]

Originally Posted by mikereed100

Extemp,

I feel your pain. I have been trying to decide what to use for my pilothouse windows for several years now and am still ambivalent. I have gathered information from vendors, professionals and several internet forums during this time and the overwhelming consensus seems to be that glass/arcrylic is very strong/dangerously frail, is extremely expensive/dirt cheap is easy/impossible to work with and will last a lifetime/single season. All depending on the expert source.

My conclusion is that either would be fine assuming the glass is tempered and laminated and the acrylic is high quality cast. The self-applied coatings for acrylic are intriguing in that you are blocking the UV before it penetrates the plastic, theoreticly decreasing heat and UV damage in the plastic and possibly extending it's life and decreasing thermal expansion. If I recall, Polyguard offers an 8 year guarantee and claims the adhesive is easily removed without damaging the acrylic. I too would be interested to see how it plays out in the real world. I once applied cheap tint from Pep Boys to my car windows and they looked great for years until the car expired. What can I say?

Mike

I don't KNOW (just a user) if it's true, but this is what I have come to believe and how I plan to go forward.

• Lexan IS stronger then Cast Acrylic (for a few years until UV take its toll).
• I also see NO value in a very strong piece of Lexan sitting inside my Pilothouse (in one piece) on the floor because it is able to flex so much that it came through the opening.
• Lexan is softer (and way more flexible) and crazes more quickly then Cast Acylic.
• Tempered/Laminated could be a good way to go but it's heavy and can break unexpectedly, it's expensive and VERY expensive if you have to custom bend/curve/shape the plate glass, then have it tempered/laminated.
• Cast Acrylic is the way to go.
• Films laminated to glass or plastic, done right with the right produce and be VERY useful.

Now I may not be right, but with what I have read it's what I understand.
But this wouldn't be the first thing that I have misunderstood.

Regards,
Extemp.

[Extemporaneous]

Originally Posted by s/v Jedi

About the color: I did find that gray tinted makes so much difference compared to clear with the inside temperature that there is no choice: we must have tinted.

That is why I am moving towards cast acrylic, 1/2" thick, clear and a film on the outside. The film can be removed and replaced and another member used it and posted pictures in another thread. Time will tell and I bought some time with the last restoration of our Lexan.

cheers,
Nick.

Ya, that's sounding right to me. Just wish that the Bronze films had as high of reflective qualities as some of the others. I think I read that the Bronze is better optically in certain conditions and doesn't change the appearance of the colors one see's through it (and I like Bronze).

Thanks,
Extemp.