Crazed Perspex

JackFrobisher

JackFrobisher

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Anyone know how bad crazing can be allowed to get before it becomes a risk? Sounds a bit like I'm looking for a reason to ignore it but I'm thinking do I replace it before or after the summer cruise. There could be problems if I make a mess of it before we go, with the attendant risks of not having a watertight hatch. If I leave it until afterwards ...
 
Well, a boat I sail on (28 year old Impala) had a very crazed forehatch (500x500mm approx), so that you actually couldn't see through it anymore. A cocked up gybe coupled with a slightly clumsy 16 stone foredeck man meant he put his foot and a spinnaker pole end through it.
I dont think this would have happened to the cabin windows as the unsupported area is much less on most boats.
However, it must surely be good practice not to have windows that can be caved in easily, unless you dont go out in that sort of weather?
I can see your point though, as its expensive, my cabin windows were replaced at about 15 years old and it cost me about 300 quid for Makrolon. My mates forehatch was about 90 quid for a cut piece, so he bought a new hatch from Houdini.
 
Hi, I have just reglazed my cabin windows and forehatch with polycarbonate, I bought it from a local plastics specialist, 12mm for the hatch and 6mm for the windows, twice as much as I needed, all for 50 pounds. I tried bending he old piece of perspex and it just shattered (it was crazed, but you could see through it ok). Polycarbonate is unbreakable, (police riot shields are made from 3mm), I tried with an offcut and it bent, but wouldn't snap. Perspex is harder, more scratch resistant than polycarbonate, but is more brittle and will break. The polycarbonate that I got is called 'Palsun' and has a UV reistant coating. There are many different brand names for Perspex (acrylic) and polycarbonate.

Peter
 
When I bought Traigh the survey specified replacing forehatch & windows before going to sea.
My insurance company accepted that I could do a delivery trip home if I carried some pre cut ply covers ready to bolt in place in case of failure.
Could you do something similiar for your summer cruise?
 
Crazed hatches are very common and usually the crazing is on the surface only in reasonable quality hatches. Our previous boat a W33 ketch built in 1978 still had the original hatches when we sold her 4 years ago, they were crazed but the crazing was only in the outer surface and not into the considerable thickness of material below, that crazing was present when we bought her 14 years earlier! The boat passed the buyers survey with flying colours (he sent me a copy of it) and I discovered recently she has been sold again, again passing survey. Hatches often craze within a couple of years of new so I wouldn't be too paranoid but it is yours to call, have a really close look and decide.
 
My windows were leaking and crazed and 10mm thick but only spanning 200mm maximum.

I took one off and polished it. This improved the appearance quite a bit. /forums/images/graemlins/cool.gif

In taking the other side off it broke in half all too easily /forums/images/graemlins/frown.gif

This made it necessary to replace that side so a new piece of acrylic was required which should match the exisiting. This was not to be had presumably colours had changed over twenty five years. This meant renewing both sides with new material. The other side broke equally easily whilst removing it.

The new material was acrylic as before but very much stronger. Offcuts flexed in a similar way to the crazed material did not break. Crazed acrylic should be replaced. On a hatch required to take foot traffic or to maintain seaworthiness I wouldn't think twice about replacing it.
 
I replaced all my Perspex windows in my E32 - all 18 of them.
They were comprehensively crazed and (probably) 28 years old. Those that were bolted trough were no problem to remove. Those that had been sealed with Sealastic or similar, were very diffucult to remove with the most agressive techiques, and frankly would have stood up to anything that the sea would have thrown at them, and were remarkably resistant to breaking.
As another poster has indicated - go on the cruise, but dont use plywood blanks, use clear offcuts of Perspex or polycarbonate as blanks and Sikaflex or Sealastic them to the existing sheets, to provide extra protection and peace of mind, and the bonus that you will have daylight where it was designed to go. At the end of the season strip away the lot using the old as templates for the new
 
I have been told that there is a firm that advertises in the "boat windows" section of PBO that will cut and supply my Snapdragon windows with tinted perspex resistant to crazing for around £40.

I have yet to check it out as I still have more urgent things to do. I can't remember the name of the company, but they are based on the Whitehall Ind Est. at Colchester, Essex.. Worth a shot, they might do mail order?
 
Hi

We've got a new product kit arriving from the US within a week or so, designed to restore crazed panels as you describe. I'll email the PDF of the data sheet to you if you could send a pm with your email addres.

Adrian

www.cleanandshiny.co.uk
 
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