lexan or plexi?

[deniseO30]

this winter I plan to replace the old lexan with new. I've heard that plexiglas is ok too. good, bad? thanks in advance

[sevseasail]

there was a thread a while back discussing the properties of both.
Look Here http://www.sailnet.com/forums/showth...ght=plexiglass

Hope this helps.

[sailingdog]

Lexan is less UV resistant but far stronger. If the original ports were lexan, I would replace them with lexan... If you plan on sailing the boat is rough conditions and/or heavy seas, the Lexan can take far more abuse than the Plexiglass.

[Omatako]

Is there any reason in a flat-glass situation why there isn't more use made of ordinary automotive laminated flat glass? It'll last forever with no crazing or UV damage, can be had in a range of tints and is pretty damn strong. Even when it is broken it represents no danger to anyone around it.

I am thinking of a solid dodger for my boat with laminated glass windows.

Any thoughts?

Andre

[sailingdog]

Laminated glass, unless it is made with tempered glass is much more dangerous than Plexiglass or Lexan, as it will break and can leave sharp splinters and pieces.. Tempered glass is relatively safe, but not often available laminated. However, I think Lexan is still the preferred material IMHO.

[Omatako]

SD
Side windows on motor vehicles ("door glass") are tempered. These fragment into little pieces when broken.

But . . 200 zillion cars world-wide are fitted with laminated glass screens front and back which to my knowledge are not tempered. They do not fragment but are held together by the laminate medium. They are not seen as a danger to the user.

I'll do some research but I'm sure that all the really expensive launches and superyachts built here in NZ use glass. (Maybe there is a message in that statement?)

Andre

[sailingdog]

Andre-

Have you ever hit a windshield... it does break, and yes, most of the glass gets retained by the lamination, which is in the center of the laminate usually. However, small, very sharp shards can break off, and hitting the glass or rubbing against it can leave you seriously cut.

The rear windshields on most cars, at least in the USA, are just tempered glass, not laminated glass.

There is a newer, more expensive type of laminated glass used in some higher end cars, which has three layers of laminating film, and prevents any glass from escaping during breakage, and protects the occupants from the glass edges.

[HatterasJack]

Replaced both portlight and hatch with plexi. Worked great, Cut by Creakside Glass Pemberton NJ perfect fit, perfect price. Lexan was very expensive and figured that with as little as I venture off shore beyond 25 miles I could replace them three times as often when they get fouled for the cost of lexan. Two years now and they look great!!. Jack

[MidLandOne]

Denise, I would be interested to know who the manufacture of your hatches is because as far as I know none of the quality hatch and portlight manufacturers such as Lewmar use Lexan (polycarbonate) - acrylic (eg plexiglass) is used. That because of the lack of rigidity of polycarbonate (which among other things may lead to sealing problems), its softness making it less resistant to scratching and its unreliable UV performance.

With respect to the use of glass which has been mentioned, marine glass is always tempered (toughened) glass and if laminated glass is used it is laminates of temperered glass not of annealed glass. One of the main reasons, apart from the requirement not to break into sharp pieces already mentioned, is that laminated annealed glass is, contrary to popular belief, normally slightly weaker than the equivalent thickness of annealed as it is made up of two thinner sheets of lesser total thickness (but it, of course, maintains some strength once broken due to the interlayer). Tempered glass is around 5 or 6 times stronger and the finished panes should come with a fused stamp in one corner stating the relevant standard for marine glass in the country of manufacture.

Superyachts have been mentioned - again where glass is used it is always tempered or laminates of tempered. Similarly, when glass is used, for coded vessels and any properly built pleasure ones.

Worth noting that tinted glass not be used in any windows used for navigation and all codes require that to be so.

[RickLaPaz]

Here's a shot of my new neighbor in Mexico. Boat is a 53' Waterline Yachts, Canadian built out of steel in '00. Auto glass with mirror reflective was used, according to the owner. Hell of a boat......