speccing glass for panel in bottom of hull

dylanwinter

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I am seriously considering putting a small glass panel in the bottom of the duck punt

about 8 inches x 12

I am going to put bilge runners along either side to protect it

what sort of glass do I need

I want it to be scratch resistant

failure of glass upon hitting a rock is not the end of the world as I will be able to step out of the boat

the ply it will be let into is to be 6mm

Dylan
 

andy59

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I would use laminated glass for that Dylan , you can crack it with a hammer blow but not break it unless you have several goes at it . So if something does crack it you will see the damage before there is any danger of sinking .
 

fergie_mac66

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for laminate , ask in a big glass merchants they will cut it for you, not too dear . I have used it in a few doors in place of toughened . They cut it with a glass cutter and a Stanley /razor for the plastic in the middle.You will be better with 8 mm(or even 12mm) than 6mm it cracks surprisingly easily. Toughened not an option if it breaks it will break into crumbs.
 
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what sort of glass do I need

Toughened glass, not laminated. It's a lot stronger than laminated.
Think of Pyrex and how much tougher that is than an ordinary glass bowl.

Remember when you install it that it's the edges that are vulnerable. Protect the edges and you'll find that you can stand on it.
 
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fergie_mac66

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He's already said that it doesn't matter if it breaks as he'll just step out. However, the laminated will break long before the toughened.

agree with that but depends on thickness and the plastic core in some types are amazingly tough and would get him home across 5 meters of tide . so you pays you money
toughened has to be ordered to size and then sent away for the process and costs a lot more
 

dylanwinter

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laminated it is then

agree with that but depends on thickness and the plastic core in some types are amazingly tough and would get him home across 5 meters of tide . so you pays you money
toughened has to be ordered to size and then sent away for the process and costs a lot more

how big and how thick if I go for the laminated bandit glass
 
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agree with that but depends on thickness and the plastic core in some types are amazingly tough and would get him home across 5 meters of tide . so you pays you money
toughened has to be ordered to size and then sent away for the process and costs a lot more

It's true that it takes longer to get made up, but the difference in price is trivial. The first site with prices that I found was http://www.christieglass.com/products.php
6.4mm laminated is £45.10 sq m.; 6mm toughened is £56.10 sq m. Not much in it really, particularly as Dylan only wants a small piece.
This supplier has a minimum order or .25 sq m. so, if I were Dylan, I would be inclined to get 2 or 3 pieces, whichever type he goes for.

If he goes for laminated though, he'll be replacing it regularly. If he goes for toughened, which is four or five times stronger than laminated, he'll only be replacing it when it is eventually too scratched for his photography.

To be nit-picky he may want to think about the optics. Light transmission of laminated isn't as good as toughened. Toughened may have more distortion than laminated. I don't think I would want to be looking through toughened glass whilst wearing polarised sun glasses though with water on one side that may not be a problem....I just don't know.

But, drop a camera, an oar or lunchtime thermos flask on laminated and it may well break. Do so with toughened and it won't (well! :rolleyes:) break.

Over to Dylan! :)
 

Greenheart

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Always thought a clear panel in the bottom of a dinghy could be lots of fun, durability permitting. And depending on water clarity!

I always imagined using two identically-sized removable panels, one glass, the other marine ply; so when the water-window won't be needed, the tough substitute can fill in, and pulling out on shingle/concrete slips needn't risk damage.

Will you be cutting further holes to house recessed lights? Vital in my plan, for nocturnal observation of tomorrow's lunch. (Or do shellfish sleep at night?) :D
 

fergie_mac66

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how big and how thick if I go for the laminated bandit glass

12 mm/ 11.5 but 8 mm would do as your only looking at a small piece ... But is a guess really your not going to be hitting rocks of Cromer ooo err !.

ring your local biggish glass firm up tomo ask what they have got in laminated and compare cost of 8/12 see what offcuts they have .
 
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