Polycarbonate/Acrylic for bimini?

[Kelpie]

My combined solar arch and bimini is now up and running, and comprises a stainless steel tube frame with two large rigid solar panels mounted to either side. Between them is a large gap of around 1700*1200.
For just now, I've slung a piece of fabric underneath to fill in the gap and provide shade. This works perfectly, until it rains!
The long term solution is to have a rigid panel in the middle. I did toy with making something with an opening to give better access to the boom, but I've managed a few weeks without that now, so I think I can get by with a fixed panel.
I'd like the centre panel to slightly overlap the solar panel frames, creating a continuous rainproof roof over the cockpit.

I'm leaning towards polycarbonate for this. It would have to be heavily tinted to do the job of course. I can only find it in clear, so I was thinking of adding a tinted film to it, which would have the added advantage of providing a replaceable scratch protection layer. I could also change the tint if I didn't like the colour etc. I really like the idea of being able to see the sails, and polycarbonate looks light, tough, and easy to work with.

Any thoughts? Should I use acrylic instead? What should I use for the tint? Will I end up needing it too heavily tinted to see anything through it? And where can I source suitable sheeting in Spain??

 

[coopec]

I've only used acrylic (perspex) for my rain-guards and I used that because it cost nothing. I preferred Lexan (polycarbonate) as it is less brittle. However I am interested in what you are doing as I plan to build a semi-rigid dodger and I'm sure I'll use tinted Lexan. Here are a few links which I found interesting

https://plasticwarehouse.com.au/product/grey-tint-polycarbonate-sheet-makrolon-uv2/

https://www.dicksmith.com.au/da/buy...XNeJ8iyGAyb9GZD6P5Cx7_MDJHuX7GCBoC7XUQAvD_BwE

Which is cheaper acrylic or polycarbonate?
One of the biggest differences between acrylic and polycarbonate is the cost. Polycarbonate sheets can cost on average about 35% more than acrylic.

Polycarbonate offers much more resilience than acrylic, making it ideal for highly demanding applications like bullet-resistant windows. Acrylic has a high gloss finish and is more transparent, making it ideal for display cases. Acrylic is also easier to crack, while polycarbonate is easier to scratch

 

[Neeves]

Acrily comes in many colours and shades, from solid black through to a very light tint.

An option is to have a light tint but with covers through which you can see but can roll back or remove completely. If you are concerned about the strength of acrylic you can go for a thicker panel - but they then become surprisingly (or not surprisingly) heavy. The windows for our saloon are a medium tint but 10mm thick which we have covered with a see through cover using press studs - we can see out - though not really at night. Our primary concern is keeping the sun off the acrylic (and trying to keep the saloon and whole interior cool - so a different application. You can source acrylic hinges if you want to have a flip, out, window/hatch.

Also consider you are adding windage and weight to the stern.

Jonathan

 

[Kelpie]

Thanks. I think UV resistance will be a bit factor, where acrylic appears to have the edge. But a suitable tinted film over polycarbonate ought to also work, I think.

The existing structure has two 18kg rigid solar panels on it. A sheet of 3mm clear plastic big enough to fill the remaining space would be about 7kg, so not really a noticeable extra. I'm not sure what the frame itself weighs, it's 25mm tubing and at a guess I would say another 20kg total.

Is there any difference in stiffness between the two materials? The sheeting will be fully supported around the perimeter and have a slight curve athwartships. Gut feeling is that 3mm should do, and I could always add a batten to take out any sag.

 

[geem]

My combined solar arch and bimini is now up and running, and comprises a stainless steel tube frame with two large rigid solar panels mounted to either side. Between them is a large gap of around 1700*1200.
For just now, I've slung a piece of fabric underneath to fill in the gap and provide shade. This works perfectly, until it rains!
The long term solution is to have a rigid panel in the middle. I did toy with making something with an opening to give better access to the boom, but I've managed a few weeks without that now, so I think I can get by with a fixed panel.
I'd like the centre panel to slightly overlap the solar panel frames, creating a continuous rainproof roof over the cockpit.

I'm leaning towards polycarbonate for this. It would have to be heavily tinted to do the job of course. I can only find it in clear, so I was thinking of adding a tinted film to it, which would have the added advantage of providing a replaceable scratch protection layer. I could also change the tint if I didn't like the colour etc. I really like the idea of being able to see the sails, and polycarbonate looks light, tough, and easy to work with.

Any thoughts? Should I use acrylic instead? What should I use for the tint? Will I end up needing it too heavily tinted to see anything through it? And where can I source suitable sheeting in Spain??

How about some solar panels to fill the gap?

 

[Kelpie]

How about some solar panels to fill the gap?

That was my original plan, but they'll get bugger all sunlight under the boom, they'll weigh a lot more, and tbh I'm not sure I need it. I've got 720w already installed with another 200w to put on the coachroof when I get round to it. Meets my needs most of the time, including electric cooking.