Acrylite vs Lucite Acrylic Lens for hatch

[mrybas]

I'm replacing the original Polycarbonate lens in my Bomar hatches with acrylic. I saw that Acrylite was recommended on another thread. Is Acrylite any better for hatches than Lucite. The place that sells Acrylte said it would be 3-4 weeks to have them cut it to shape, while the Lucite shop will cut it today.

[oceanscapt]

When I replaced my hatch lenses I used smoked Lexan, having read somewhere that the Lexan was more durable and stronger than plexiglass. So I'm interested in how this thread goes.

[sailingdog]

I would point out that Acrylic is a far better material for hatches for several reasons: First, it is far more UV resistant; Second, it is far more scratch resistant; Third, it does not foreshorten under impact, which means the hatches are likely to stay sealed properly for much longer.

Acrylite and Lucite are both tradenames for Acrylic, as is Plexiglas, and I doubt that there is a significant difference, provided all the materials are CAST acrylic.

I'd point out that the majority of all production hatches are glazed with ACRYLIC, with the exception of one line of Bomar hatches. The Bomar hatches in question have re-inforcing bars crossing the hatch to support the polycarbonate lens and prevent them from distorting under impact enough to break the seal.

[mitiempo]

Lexan scratches easily and doesn't stand up to UV as well as plexiglass. In the thickness of a hatch plexiglass is plenty strong enough. Most major hatch manufacturers use plexiglass for these reasons.

[deniseO30]

mrybas, do you have a plastics supplier in our area?

[ulferlingsson]

In my previous boat the previous owner had installed a home-made polycarbonate (PC) hatch, as well as PC windows that overlapped the fiberglass for strength. The idea was that everything should survive a 360, something that is all too common during a storm at sea (why every small sea-going sailboat should be designed to survive it). PC is the material of bulletproof "glass" in banks and armoured cars. PC is more impact resistant than acrylic (PMMA), but less scratch resistant. In both cases you need to get a grade that is made for outdoor use, so it survives the UV rays. If not, it gets hazy quickly (why do I know?...). On the other hand, I didn't mind having windows that let light through but which nobody could see through. That way I could remove the curtains...

[killarney_sailor]

The polycarbonate used by Bomar is much thinner than the acrylic used in most hatches and the hatch is designed for this thickness (or thinness). If you used acrylic here it would stick up a lot all round. Similarly if the hatch was designed for acrylic you would need much thicker poly which would be immensely strong but quite costly (the thinner poly and thicker acrylic are similar in price).

Go with whatever was in the hatch originally

[mrybas]

Originally Posted by deniseO30

mrybas, do you have a plastics supplier in our area?

There is a place on Byberry Rd called Everything Plastic. I was going to have them cut new 1/4'' Acrylic.

killarney_sailor- The orignal lens was 3/16'' polycarbonate. I was planning on replacing with 1/4'' acrylic. Do you think this is a bad idea? I don't think 1/16'' higher would cause a problem. What thickness are most acrylic lens used in hatches?

[killarney_sailor]

I have replaced the plastic in acrylic hatches but not for some years, but it was much thicker than the polycarbonate that I replaced in the current Bomar hatches. Do you have the intermediate supports in these hatches? Without them I can't imagine that 1/4" would be strong enough. I don't think 1/16" would matter though.

We had to redo the glazing on our two larger hatches since the adhesive suggested by someone at Defender was not up to the task. We used a Sikaflex product designed for plastic but it required a primer that was an obscene price like $60 for 250 ml and once opened had no shelf life at all. We only used about half of the can and pitched the rest - did a good job though.

[mrybas]

Originally Posted by killarney_sailor

I have replaced the plastic in acrylic hatches but not for some years, but it was much thicker than the polycarbonate that I replaced in the current Bomar hatches. Do you have the intermediate supports in these hatches? Without them I can't imagine that 1/4" would be strong enough. I don't think 1/16" would matter though.

We had to redo the glazing on our two larger hatches since the adhesive suggested by someone at Defender was not up to the task. We used a Sikaflex product designed for plastic but it required a primer that was an obscene price like $60 for 250 ml and once opened had no shelf life at all. We only used about half of the can and pitched the rest - did a good job though.

My hatches have 3 cross support bars (if you look closely at the pic in the first post you can see them behind the tinted polycarbonate). I bought GE ultraglaze to bed the lens with. I was planning on prepping the new acrylic lens with alcohol and acetone for the frame...