"marine" glass?

[Daydream believer]

That stuff never stasys truly clear for long and scratches too easily.

If it is a situation where scratching may occur then toughened glass could be a problem. As stated earlier one only has the penetrate the very thin outer layer which is in tension & the whole pane shatters into tiny pieces. I certainly believe that laminated glass is the way to go. I have never used laminated with one layer of toughened . I suppose one has to decide where it will go. If it goes inside will it give strength protection? If it goes outside, it is liable to shattering from an impact chip. Laminating need not be an issue, if the edges are properly sealed, I would suggest a chat with the people at the Glass & Glazing Federation. I used to discuss various problems (About glass, not the wife, or the warts ) with them & they would always be willing to advise.

 

[pandos]

Scratching on toughened is not very likely and you won't break the outer layer very easily, (just think of the side windows in your car)

I think if you go laminated just ordinary glass in 6.4 would perfect it's what I have fitted for I6 years in my hull lights , and I would have chosen that at a time when I had just stopped working at security creens and high end houses with compex glazed panels etc.

It may be expensive to get laminated cut in circles, but it will depend on the supplier.

The originals had been perspex and they were scratched and sun damaged, the difference in light transfer was immediate and pleasing.

I regularly sail with these underwater and no issues so far.

In the windscreen Hallberg Rassey fitted toughened and I replaced one pane (which had been demolished by a loose mainsheet pulley swinging from the boom in a storm) with locally sourced toughened. That was about 10 years ago and so far no problems.

 

[AntarcticPilot]

Like others, I can't imagine why the original supplier thought there was special marine glass. Sure, basic soda glass like cheap drinking glasses isn't suitable (look at what happens to them in a dishwasher)- but we're talking about glass that can be toughened, which is an entirely different kettle of fish. Of course, we could specify borosilicate glass or silica glass for ultimate chemical resistance, but I'm quite sure that toughened or laminated glass would be amply strong enough and resistant to chemical weathering from salt water. After all, it wouldn't be much use in car windscreens if it couldn't stand a bit of salt!

It might be worth looking at the surface hardness of the glass. Even borosilicate glass scratches over time in the kitchen environment. But you're unlikely to wash windows in the same sink as steel cutlery!

 

[rotrax]

To be a little pedantic, before the QE2 had ever carried any passengers it was alongside at the Ocean Terminal in Southampton.

My fathers firm, Aygee Glass and Glazing, had provided most of the decorative internal glass and mirrors plus all of the Pilkington's Patent 'Amourcast' glass for the portlights. These were two inches thick.

Armourcast is still a trademark but the Pilkington Patent has long expired.

Mum, Dad, First Mate and I had a trip around this impressive vessel in the spring of 1968, before it was in service.

The benifit of such glass in the lower portlights was explained to us, both by the Guide and Dad, who knew his onions when it came to glass and its properties.

So, for SERIOUS use in the North Atlantic, perhaps there is a marine glass............................

 

[Rappey]

You could go mad and get toughened laminated

Is there such a thing ? There are laminated and toughened double glazed units where one pain is tough, other laminated but a toughened piece of laminated ?

 

[geem]

Another alternative might be laminated glass as that won't shatter.

In rooflights over shopping centres and in high rise buildings in London bomb spec glass is toughened then laminated. It's pricey but you would never worry about you glass?

 

[Zing]

To be a little pedantic, before the QE2 had ever carried any passengers it was alongside at the Ocean Terminal in Southampton.

My fathers firm, Aygee Glass and Glazing, had provided most of the decorative internal glass and mirrors plus all of the Pilkington's Patent 'Amourcast' glass for the portlights. These were two inches thick.

Armourcast is still a trademark but the Pilkington Patent has long expired.

Mum, Dad, First Mate and I had a trip around this impressive vessel in the spring of 1968, before it was in service.

The benifit of such glass in the lower portlights was explained to us, both by the Guide and Dad, who knew his onions when it came to glass and its properties.

So, for SERIOUS use in the North Atlantic, perhaps there is a marine glass............................

Just curious, do you know what type of glass was used on the Titanic portholes? They are all unbroken still.

 

[rotrax]

Just curious, do you know what type of glass was used on the Titanic portholes? They are all unbroken still.

I'll just nip down and have a look.........................................

Seriously though, I expect the Titanic had simple cast glass portlights. 2 inch thick glass is very strong even when not heat treated.
It is, of course, annealed slowly to stop internal/external tempreture change causing it to shatter.

You can walk over the clear glass panel in the Spinnaker Tower. There is nothing except the harbour water underneath.

 

[Rappey]

Spinnaker towers glass is 3 layers making up 60mm and rated to over 1800 kg.
I would guess it's 40mm laminated and 20mm toughened.

 

[pandos]

Is there such a thing ? There are laminated and toughened double glazed units where one pain is tough, other laminated but a toughened piece of laminated ?

Yes you take two panes of toughened and stick them face to face them....

The glue is just a clear resin type of stuff that is injected into the gap and it spreads like magic.

You may recall the atempted theft of jewels from the dome some years ago. The glass cabinets (like many jewelers windows) were made from laminated toughened. The thieves brought along Hilti nail guns, these fire steel nails into concrete and steel.

The laminated toughened glass cases crumbled when pierced with the nails.

 

[steveinnice]

"bullet proof"glass will not always stop a projectile but will slow it down enough so it's velocity is not lethal.thats why some are rated ,for example: XX caliber at XX metres per second. for 3 impacts

 

[V1701]

The windows in my wheelhouse were supplied by Seaglaze, they are kite marked. Might be worth a call. No problems with them but they were already fitted when I bought the boat so I don't know anything about the properties of the glass...