How to Have Sexy Windows !?

[Tnflakbait]

http://www.cruisersforum.com/gallery...p?i=2999&c=501


Use dow 739 it works great and is REAL easy to work. Cleans up easy. doesn't leak

[schoonerdog]

george, after doing all of the above, which did you find worked best?

[Sunspot Baby]

Remembering that I gave up on saving the old windows, I tapped a wood chisel under the edge and pried. Every few inches the old Plexiglas, which had become quite brittle, would break. Thus I removed chucks at a time.

Be careful with the chisel and don’t dig into your gel coat. I have a couple of small areas that I repaired on the second window. Not a big deal since I didn’t have to worry about color match since it would be covered by the black Sika primer anyway.

Wear safety glasses or goggles. When the plexi breaks, it does so vigorously and some sharp pieces fly off. Not a problem if they hit skin, but I wouldn’t want a one in my eye.

I posted a couple of photos so you can see how it is going at New Page 1

George

[skipperaris]

Good work George and excellent illustrated account of how you did it.
Any idea if Lexan can be persuaded to bend and hold its shape with heating?

[GordMay]

Thermo-forming Lexan isn't easy.
To bend lexan (polycarbonate) and plexiglass (acrylic polyacrylate) your piece should be clamped firmly to a strong, stable surface, preferably indoors. Some recommend pre-heating in an oven, to reduce “torch time”.
Once you have clamped the piece begin to heat the panel, with a propane torch or high-capacity heat gun, along the line where you intend to have it bend. DON'T put the heater too close for too long, as this will cause the plastics to get cloudy, or even bubble up.
You'll know when the plastic is ready to bend, simply by applying pressure to the free end of your work piece.
Large pieces will require the help of a partner who can apply even pressure along the entire length of the bend, while you heat the plastic, keeping a uniform and consistent source of heat applied until you have achieved the desired bend. Thicker pieces require heating on both sides.
Lexan does not exhibit a sharp melting point, but softens gradually over a wide temperature range - beginning at about 300 degrees F (150 C), to melting at about 420 degrees F (215 C).

[Sunspot Baby]

I found the lexan to be pretty flexible. You can see how much my windows curnved and my wife was on the outside pressing it with just hand pressure as we drilled and inserted screws. I think if you could hold it firmly in place unil the Sika cured, it would hold it fine. The trhough bolts in my application made it easy.

George

[Maddog]

I had this posted in another thread. It is more appropiate here.I How it helps.

Let me jump in. I am researching this process now. The key piece of info the article leaves out is which tape to use.

I have been in contact with 3m and here is what they recomend. I am lifting from the email they sent me:

"You are exactly right, 3M™ VHB™ Tape 5952 industrial tape 45 mil gray closed-cell acrylic foam carrier. Conformable. Good adhesion to many powder coated surfaces and plastics will work on your application. Another alternative is the 3M™ VHB™ Tape 4941."

It has taken me about a month of causal looking and searching to find the right tape. I will be using the VHB 5952 with Lexan windows. Another key piece of info is from the spec sheets. The thicker the tape the more it is able to conpensate from thermal expansion, which Lexan is prone to. The VHB tape also works as a weather seal backing up the silicon. I was a little concerned about no mechanical attachments on these ports, till I read that this tape is used in construction to attach glazing and metal panels to the sides of buildings with no mechanical attachments. If it can hold a 4x8 sheet of metal in a high temp, high wind enviroment 15 stories above the heads of innocent pedistrians on the sidewalk below. I think it can handle my 18"x36" deadlights.

I have the broucher for this tape as a pdf, but it is too large to upload. Go to 3m.com/vhb and you should be able to find it.

I will be doing mine towards the end of this season. I'll post pics of the process at that time.

[TaoJones]

Below, I offer two additional sources for valuable information on the subject of windows on boats.

Boat Windows - How to Repair Window Leaks : Boats and Yachts Maintenance, Repairs and Troubleshooting

Boat Window Leaks and Design Faults - Leaky, Leaking Windows : Buying a Boat or Yacht

The home page from which those articles come is:

Yacht Survey Online: David Pascoe, Marine Surveyor

It is a great source of information on many things nautical.

TaoJones

[Gulfcoastbreeze]

Sexy windows don't open. I hope you have air conditioning.

[Sunspot Baby]

The sexy windows are dead lights, for ventilation we have port lights. No we don't have AC on Sunspot Baby.

[mikereed100]

I checked out Mr Pascoe's article on fixing leaks and this is what he had to say about Lexan:

"Tinted Lexan against a black surface: This is a combination that will never stop leaking in Florida or the Gulf coast simply because the black absorbs too much heat from the sun and the rate of expansion is too high to permit a seal. The only solution is DON'T USE BLACK MATERIALS"

Most of the lexan windows I have seen recently were installed with black tape or black Sikaflex as described here. Is he saying we need to use white Sikaflex or put a bit of white paint over the glued part of the window? Is he saying we shouldn't use tinted Lexam? Is he FOS?

[bigwhyte]

i have been a glazer for 10 years what u want to use is auto windshild polyurethane it is availabe at any glass shop . u need a good cocking gun and primers and it will be in there till u r read to cut it out then u might need some help getting it out if u wat to chage them but will never leak

[Sunspot Baby]

Bigwhite, have you used the windshield polyurethane with Lexan on fiberglass? The difference in coeffecient of thermal expansion is considerable.

Mikereed, black is more UV resistant. I think that is why so many use it. Sika's 295UV and 209 primer are both black for just that reason. Sika recommends a 3/16 spcer between window and deck house, to give plenty of room for flex. If you put the two surfaces too close together, the sealant can't flex enough, it will shear and a leak will result. I built 3/16 spacers from Sika for my application.

I have no idea how long the work I am doing will last since it is a project in progress. But, the top line boats use Sika in new construction, they have a ton of information on use and application on their web site and the engineer I talked to was very helpful. I get the feeling they know their sh*t.

George

[seafox]

Did my windows in Sika 295uv over a year ago. Used the expensive primers etc and no leaks yet......touch wood.

[Alan Wheeler]

The primer is expensive yet essential. It's better to buy once, cry once on this job. I have just fixed my pilot house hatch for the second time because I refused to pay the $118 dollars for the 125ml of that Sika primer the retailer was charging. I thought, nah that sika is damn good stuff, I can get away with out the primer. But alas, no I didn't.