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Tranona

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Crazing is quite common and you should be able to improve them by using one of the cleaners sold for car headlights, although some swear by toothpaste. However it us unlikely you will be able to get them back to new and if it bother you the perspex can be replaced.

Thread on the same subject running here forums.ybw.com/threads/crazed-port-lights-and-hatches-any-fix-other-than-replacement.608913/ with far more detail on the options. As you can see a common problem
 

stu9000

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On car headlights,,,

I use an orbital sander with around 2000 to 3000 grit wet sand paper (spray with washing up liquid).
Mask everything off so you dont go through the bodywork paint
White goop will go everywhere but it washes off easily.
Keep sanding and spraying, clearing the sanding pad regularly.
The glass is a little cloudy at this point.
Farecla G10 polishing compound on a red green, or black soft polishing sponge, still using the random orbital sander, will clear the misting and bring your headlight, or deck hatch, back to life (not deep cracks obs).
 

vyv_cox

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On car headlights,,,

I use an orbital sander with around 2000 to 3000 grit wet sand paper (spray with washing up liquid).
Mask everything off so you dont go through the bodywork paint
White goop will go everywhere but it washes off easily.
Keep sanding and spraying, clearing the sanding pad regularly.
The glass is a little cloudy at this point.
Farecla G10 polishing compound on a red green, or black soft polishing sponge, still using the random orbital sander, will clear the misting and bring your headlight, or deck hatch, back to life (not deep cracks obs).
More technical progress! 👎
The headlights on my 2007 motorhome were in a very poor state in 2020. I could have abraded them back to clear I guess but I needed to modify them for right hand driving (deflector stickers are OK for the MOT equivalent in France) so instead I simply replaced them. After only three years one of them is going cloudy.
I own a 1948 MG TC. As far as I know the lenses are original but perfectly clear.
 

Aja

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My understanding is that car headlights are made from polycarbonate and that lewmar type deck hatches are made from acrylic.

Two different materials that may or may not respond to abrasive polishing.
 

Aja

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More technical progress! 👎
The headlights on my 2007 motorhome were in a very poor state in 2020. I could have abraded them back to clear I guess but I needed to modify them for right hand driving (deflector stickers are OK for the MOT equivalent in France) so instead I simply replaced them. After only three years one of them is going cloudy.
I own a 1948 MG TC. As far as I know the lenses are original but perfectly clear.
1948 MG TC may have acrylic lenses. Quite popular at the time (think canopies on fighter aircraft)

There was a change from acrylic to polycarb as polycarb is considered safer in an accident. Polycarbon will not shatter when hit unlike acrylic.

That your headlamps went cloudy indicates polycarb as that is one of the materials tendencies.
 

Plum

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1948 MG TC may have acrylic lenses. Quite popular at the time (think canopies on fighter aircraft)

There was a change from acrylic to polycarb as polycarb is considered safer in an accident. Polycarbon will not shatter when hit unlike acrylic.

That your headlamps went cloudy indicates polycarb as that is one of the materials tendencies.
Post in thread 'Crazed port lights and hatches, Any fix other than replacement?' Crazed port lights and hatches, Any fix other than replacement?

Post in thread 'Perspex Washboards - any recommendations?' Perspex Washboards - any recommendations?
 

vyv_cox

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1948 MG TC may have acrylic lenses. Quite popular at the time (think canopies on fighter aircraft)

There was a change from acrylic to polycarb as polycarb is considered safer in an accident. Polycarbon will not shatter when hit unlike acrylic.

That your headlamps went cloudy indicates polycarb as that is one of the materials tendencies.
I would have said it was glass but both lights have grilles over them so not easy to tell. Quite happy to accept they are acrylic though.
 

Aja

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Post in thread 'Crazed port lights and hatches, Any fix other than replacement?' Crazed port lights and hatches, Any fix other than replacement?
To get a good UV protected polycarb would certainly be at a premium to an acrylic panel, Perspex is guaranteed for 10 years as are the best polycarb such as Lexan or Palsun but you would pay a 10% uplift. Acrylic comes in many more colours/tints

Can't see the fascination with the expense of polycarb when most boats are still being supplied from new with acrylic hatches.

I would probably consider it if living aboard and doing ocean crossings, but getting a boat coded doesn't require polycarb hatches.
 
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