Emotionally, I can’t take this anymore. (Windows)

[Allied39]

Originally Posted by Don C L

Funny, I just came upon a thread on this yesterday, but now where is it... looking...
OK found from another forum that you should look into using GE Ultraglaze Glazing Sealant (GE SSG4000) You may have to order it from GE directly. It is used by Bomar for their windows and is used for windows on skyscrapers. Supposedly it is good for plastic too, but good to double check.
Still looking for the other thread about plastics for windows..

Ha, I could not remember the name ....yup, GE Ultraglaze. I have used it, 4 years in FL sun and doing great. Farco In Jacksonville actually had a rep drop a tube for me at their business. I like Farco.

I used the 795 after on another hatch and found I liked it a little better.
I don't think that sealant is your problem....as I am sure you are aware.

I dealt with thermal expansion over 6 ft with 1/4 thermal formed acrylic and the end solution was that it ended up in three pieces....problem solved.

Drilling and installing mechanical fixings however tempting will only bring other issues.....believe me. A clamp system.....maybe?

Remember if it was easy, any idiot could do it.

I always remember that Iam not the "average " idiot.....as far as idiots go, I am well above average!

Good luck.

[Squanderbucks]

You say polycarbonate. What type exactly. There is a large difference between plexiglas and Lexan. I have Lexan for my bridge as a windscreen and it is totally unsupported all along its top edge. Panels are ~38” wide. No warping or bowing. Here in south Florida and Bahamas.

How thick is your material?

[Chotu]

Originally Posted by Squanderbucks

You say polycarbonate. What type exactly. There is a large difference between plexiglas and Lexan. I have Lexan for my bridge as a windscreen and it is totally unsupported all along its top edge. Panels are ~38” wide. No warping or bowing. Here in south Florida and Bahamas.

How thick is your material?

1/4” Sabic Lexan, UV protected. The entire boat is that.

This sheet that’s collapsing under its own weight is mystery brand because there is no Lexan now. Covid.

[chris mac]

Originally Posted by scottydaum

I am speaking from the perspective of someone who was in the Sign Business for about 20 years and worked with a lot of different substrates that were required to be out on the elements 24/7.
The Polycarbonate I worked with was mostly LEXAN Brand. I also worked with different types of Acrylic (plexiglass) which is not as impact resistant than Lexan.
I THINK what I see is two issues.
1. The plastic looks pretty thin. Like maybe it cam e from one of the big box home supply stores. The stuff we use for signs, and what is in my boat is 1/4 inch thick. vs maybe 1/8 inch you would get at Big Box.
2. Expansion Ratio.....the expansion ratio of most plastic substrates is very high, meaning when heated by the sun it grows a lot more than you would think. I would think that the expansion ration of the plastic and the Fiberglass Rienforced Plastic would be nearly the same BUT you always need to make the window plastic much smaller than the hole it is filling.
It MUST have plenty of room on all it's sides to expand within the space it is filling.
If it is cut to fit too snuggly it will expand and bow out the way it is in the photo.
While the expansion ration of the Lexan, and the FRP may be the same, because of the difference in thickness, the thinner Lexan will heat or cool faster/slower than the surrounding FRP. The final expansions may be nearly the same but the time it takes to get there is different and causes problem.
The bedding/sealant/adheisive used to hold the plastic in place also need to remain flexible enough to adapt to the expansion without losing it's bond. Others will have better ideas of what product is better for that.
On my Tartan 30 the port lights (1/4 inch Lexan) are held in place by an inner and outer bezel which is bonded with butyl tape, and thru bolted. The wholes also need to be drilled oversized to allow for expansion.
I suggest you find a Plastic Supply House, or maybe even a local Electrical Sign Maker to source your plastic.That way you can access different thickness plastic, as well as folks who understand the material. You can also get plastic which is darker, or different colors.
One caution.....acrilic plastic, and polycarbonate are two different animals and different chemicals effect them differently causing premature brittleness, cracking, crazing, and frosting. Best of luck with you.

A slightly different background, but I installed vinyl siding for the last 20 years in canada.
Plastics definately expand and contract with temperature changes whether you allow for it or not. If it doesnt have room on the edges for it, thinner products will bow out. Thicker products may just push and destroy what is framing it in. Much like water inside a rock freezing.
I would look at simplifying the frame. Surface mount instead of confined.
For what it's worth, these frustrations are in my immediate future. We have 6 double compound windows needing replacement. I'm not looking forward to it

[rbrentp]

My longest windows were 68" by 18". I used the butyl tape 3/4" wide and the thicker of the two I think it was 3/16 maybe 1/8. I had room to apply the tape and leave a 3/8" gap from the tape to the edge. I used the Dow 795 to fill that gap and make a tapered seal out about 3/8". I put it on in the spring, splitting the temperature range it would experience. In the Florida heat, we have two years with no leaking or buckling. If you don't have screws then you need to get pressure on plexi along the tape for twenty-four hours, it needs that to stick well. Also, before applying I lightly sanded and wiped the surface really clean. Hope that helps.

[Chotu]

Seriously considering the Maine Cat Eisenglass route for just the problematic side windows. Glass replacements for the front windows.

It’s either that or all glass at this point.

Maine cat route plus insulating storm boards may be a good solution for the sides saving tremendous weight.

If the weather looks dicey, drop in the insulating storm boards. If it looks hot, drop in the insulating storm boards to keep the heat and sun out,, if it looks cold, drop in the insulating storm boards to prevent heat loss. If the neighbors looks sketch or are annoying, drop in the insulating storm boards.

Otherwise, Eisenglass on normal days and wide open with screens any time it’s nice out.

[Kd9truck]

What about Lexan? They may make a thin version, I think it’s lighter than glass.

[Cpt Mark]

1/4" for large windows??? In comparison my windows are very long but maybe 30" high and they are made from1/2" polycarbonate.

When I went to rebed mine I called Island Packet since they built the boat and asked what to use. They use SilPruf scs 2000. Talked to the manufacturer and they said they have been putting up large glass windows for 40 years with this product and they don't use fasteners.

In reading all of the posts and getting more information the question I have for you now is multipart.

Is this a factory built boat or a one off? If it's a factory built and they are still in business, call them. If it is not or they are out of business then how do you know the original windows were 1/4"? Some previous owner might have cheaped out the project.

[hpeer]

OK his may be the stupidest thing ever but I have an idea.

It can not see tuis stuff bowing because of gravity no latter how hot. One would think it would running up and down. It is the BOW that is so very odd. It is bowing either because of a manufacturing differential between sides OR because of a temperature differential between sides.

The windows are bowing out.
Suggest you take one of the those windows and flip it so the other side is exposed to the sun. Then let it bake.
Which way does the bow develop? Did it change?


The other possibility is that because of the material thickness the exposed side is getting hotter than the interior side and that is causing a differential bow. Again.c the thickness will make the matter worse.

Not sure how figuring this out would help you. But if I am correct the you need to find a way to equalize the temperatures inside and out or perhaps bend it slightly to the interiour.

[zstine]

I doubt it is just bending on it's own. I would bet that it is buckling under compression because the bottom and top edges have bottomed out in the channel you installed. I'm guessing heat expansion caused it to bottom out. Maybe you can just cut an 1/8 inch off the height of the window so they have more room to expand in the channel.

[Chotu]

Originally Posted by Kd9truck

What about Lexan? They may make a thin version, I think it’s lighter than glass.

Yes. I think that’s strataglass. It’s the better performance “Eisenglass “

[Chotu]

Originally Posted by zstine

I doubt it is just bending on it's own. I would bet that it is buckling under compression because the bottom and top edges have bottomed out in the channel you installed. I'm guessing heat expansion caused it to bottom out. Maybe you can just cut an 1/8 inch off the height of the window so they have more room to expand in the channel.

I’ll take your bet. $1000?

There’s lots of room in the channel. In fact, it was 1/8” from falling out after collapsing under its own weight in the sun.

[Chotu]

Originally Posted by hpeer

OK his may be the stupidest thing ever but I have an idea.

It can not see tuis stuff bowing because of gravity no latter how hot. One would think it would running up and down. It is the BOW that is so very odd. It is bowing either because of a manufacturing differential between sides OR because of a temperature differential between sides.

The windows are bowing out.
Suggest you take one of the those windows and flip it so the other side is exposed to the sun. Then let it bake.
Which way does the bow develop? Did it change?


The other possibility is that because of the material thickness the exposed side is getting hotter than the interior side and that is causing a differential bow. Again.c the thickness will make the matter worse.

Not sure how figuring this out would help you. But if I am correct the you need to find a way to equalize the temperatures inside and out or perhaps bend it slightly to the interiour.

That could very well be true.

BUT, it can only be used with the UV protected side out. Otherwise it’ll disintegrate in short order.

I think the short of it here is polycarbonate, while sometimes great in small doses, is quite a difficult house of cards to handle.

Drawbacks:

Massive thermal expansion
Is destroyed by mold etching into it
Will deteriorate rapidly if no UV protectant
Many chemicals attack it
Scratches easily
Temporary lifespan
Doesn’t take yo traditional tint films well

For these reasons, it’s “check mate”.

I lost to polycarbonate.

[Chotu]

Originally Posted by Cpt Mark

1/4" for large windows??? In comparison my windows are very long but maybe 30" high and they are made from1/2" polycarbonate.

When I went to rebed mine I called Island Packet since they built the boat and asked what to use. They use SilPruf scs 2000. Talked to the manufacturer and they said they have been putting up large glass windows for 40 years with this product and they don't use fasteners.

In reading all of the posts and getting more information the question I have for you now is multipart.

Is this a factory built boat or a one off? If it's a factory built and they are still in business, call them. If it is not or they are out of business then how do you know the original windows were 1/4"? Some previous owner might have cheaped out the project.

It’s a one off boat.

I did most certainly not cheap out. It was about $4000 for the Sabic UV protected Lexan I bought to do the windows initially, and they were great for a while.

If you were to read the thread, it’s all in there

Silpurf SCS 2000 is holding GLASS panels. A world of difference there

[Matt Johnson]

It's the thickness that's the issue. You're asking 1/4" polycarbonate to be rigid over large spans.... No production boat uses this thin for anything but glass*.

Matt

* That I know of.

Originally Posted by Chotu

1/4” Sabic Lexan, UV protected. The entire boat is that.

This sheet that’s collapsing under its own weight is mystery brand because there is no Lexan now. Covid.