Possible to use glass instead of plexy for hatch?

[bradfordharley]

I am in the middle of replacing mine, and the recommendation from my manufacturer is CAST (I originally mis-stated extruded) acrylic. It seems to be a commodity, and you may have a better time asking it by product rather than a brand name.

[nortonscove]

I replaced a cracked hatch couple years ago. Went to an auto glass supplier that also did a bunch of specialty stuff. They took the old piece and matched it with something equally as good or better. Offered levels of shade and or colour. They also drilled all the holes to match the old one and charged me 40 bucks Canadian. Not too bad if I might say.

[Cadence]

If all you can get is glass use safety glass. Tempered glass shatters into chards.

[riki]

Hello folks, thank you very much for all the ideas and suggestions.
So, with your indications and help i got an idea and, as time is enemy, i ended up ordering from a local the glass for the 2 hatches i have to replace.
They are 2 Lewmars from the 90s that have a sliding arm to hold open the hatch so weight should not be an issue. And being relatively small (32x32cm) i think that they should be quite sturdy. Obviously i ordered in 8mm......sadly not laminated because also in this case they had to order and, unfortunatelly, i know from previous experience that when it comes to orders you have to put long waiting time.
I will see how it will work out. My intention is to fix the glass to the aluminium frame with sikaflex creating a proper sealing under and around the glass. Should do well, what do you think? Anyways i don't exclude to get anyways the plexy so if something is not convincing i'll have it on the way and meantime I have my hatches closed.
The glass will be worked all around not to leave cutting edges. It's the first time i am doing this work so.......learning experience anyways.
Cheers and thanx again for the support.

[riki]

By the way, i am talking about the 2 hatches on the main windows behind the mast

[Cheechako]

Originally Posted by riki

Hi,
as title: i am having trouble to find an 8mm plexy sheet to replace my hatches lens, so i was wondering if i can use 8mm glass instead. It's a 32x32cm hatch,
Opinions?
Cheers.

I suppose you could, good portlites are glass. But stepping on hard or a dropped large block or spinnaker pole may break glass easier...

[AndyEss]

I understand the problems of replacement parts. I hope the glass you finally obtained was at least tempered or wire reinforced security type.
Regular glass (unlaminated, untempered, or non-wire reinforced) breaks in long, deadly shards.
Stepping on the hatch lens, breaking through, and lacerating a leg may result in a bloody even fatal wound.
If you went with plain glass replacement lenses, you might consider some sort of tensile reinforcement on the inner side, like a clear, tough, packaging tape.
I’d also replace those hatch lenses with proper safety glazing ASAP.
Personally, if I couldn’t find acceptable glazing for openings that might be stood on, I’d temporarily replace with plywood before non-safety glass.

[noelex 77]

Originally Posted by riki

Obviously i ordered in 8mm......sadly not laminated because also in this case they had to order and, unfortunatelly, i know from previous experience that when it comes to orders you have to put long waiting time.

The only two options to consider are tempered (sometimes called hardened) or laminated glass. It cannot be ordinary untreated “household” glass. Tempering is a heat (or occasionally chemical) process that is done after the glass has been cut and shaped.

Glass and aluminium are materials that are fussy about the right glue and surface preparation. The glue also has to be UV stable, as glass (unlike most plastics) will not block this. So do a search for the right products. These should not be difficult to find, as many household windows have glass glued to an aluminium frame.

[bcboomer]

Hopefully you are getting tempered safety glass. It shatters into squarish bits that are not likely to cut anyone.

[dennismenace111]

Here in South Florida where we are exposed to the threat of hurricanes every summer, a laminated impact resistant window glass has been developed! You can hit it with a hammer, it will scratch but not shatter and will maintain it's strength! Downside is that its very heavy! Two lanes of glass with a clear vinyl layer sandwiched between the glass!

Regular glass is too brittle.... Movement in the hatch in a seaway would damage regular glass!

[Cadence]

Originally Posted by noelex 77

The only two options to consider are tempered (sometimes called hardened) or laminated glass. It cannot be ordinary untreated “household” glass.

Glass and aluminium are materials that are fussy about the right glue and surface preparation. The glue also has to be UV stable, as glass (unlike most plastics) will not block this. So do a search for the right products. These should not be difficult to find, as many household windows have glass glued to an aluminium frame.

Tempered or safety glass are two different things. Yep. houses have plain old window glass which has no place on a boat along with tempered..

[noelex 77]

Originally Posted by Cadence

Tempered or safety glass are two different things. Yep. houses have plain old window glass which has no place on a boat.

I think the term “safety glass” is an overall term that encompasses tempered, laminated, laminated and tempered (some glass has both treatments) as well as the old “wire glass”, to distinguish this from ordinary “household” or float glass.

For marine use there are pros and cons of the different options, but ordinary “household” or float glass is never suitable.

[mikereed100]

You should be fine using glass in that size and thickness. Have it tempered, if you can. That will increase the strength 4-5x and, if by some miracle it should break, it will not break in shards. The best solution, as mentioned by others, is laminated and tempered but may be difficult to find and is probably overkill for those small hatches. Sika 295uv will work for bonding, but you will need to buy the expensive primer. My favorite is Dow 795, an architectural silicone used to bond windows in skyscrapers It is cheap, easy to use, does not require primer and has 50% elongation to allow for expansion and contraction of the glass, although this should not be of much concern in your application. Whatever you use, be sure to use a silicone remover before bonding. Scraping and sanding will not suffice. You will get a good bond for a year or two, but it will eventually fail and you will have to redo it. Also, don't mash it down into the frame, but leave a space, say 1/8", between the glass and aluminum to allow for movement (remember that 50% elongation).

[Mike Banks]

Not unless you want a serious injury at sea.

It is theoretically possible to use glass--just not 8 mm. It would have to be much heavier than that, laminated and tempered. Far too expensive and heavy to be practical.

I use f glass for bigger areas than that as deck house clear light, and they are 8mm tempered marine glass with a filter factor of about 2 and UV and IR absorption panes--but there is an additional hatch between the deck house interior and the vessel companionway below decks. The breaking of such a pane would be bad--but not catastrophic as would a collapsed hatch on a deck in a storm situation.

It is not the waves likely to cause damage to such a hatch as a stupid accident--like someone stepping on it while carrying a heavy load.

[Cadence]

Originally Posted by noelex 77

I think the term “safety glass” is an overall term that encompasses tempered, laminated, laminated and tempered (some glass has both treatments) as well as the old “wire glass”, to distinguish this from ordinary “household” or float glass.

For marine use there are pros and cons of the different options, but ordinary “household” or float glass is never suitable.

I always took safety glass to be that which is used in car windshields that have a film between two glass plates, They used temped in read windows. I had one rear become chards with and air tight VW and a barometric change.