Curved rooflights

[dhar]

We have owned a 1991 Beneteau Oceanis 393 for about 6yrs it has been a very good boat for us but being an older boat maintenance is always an issue,one of which is the Curved perspex Cabin rooflights,l think l have attached a picture,they are very crazed and l would like to replace them,the flat windows l can do ok but have no experience at trying to curve 10mm perspex.We live in a small coastal town with very limited industrial works,just wondering if anyone has had a go at fabricating these window panels.Would a heat gun over a shaped mould work for that thickness of perpex.???

[billknny]

Panels with broad sweeping curves like this are usually bent in an oven over a mold. Gives much better control over temperature than the localized heating from a heat gun. Of course, thats a bit bigger then your average home oven.

With care, and time, you can bend it with a heat gun, but it will show a lot more distortion than a factory bent panel. You'll learn a lot about how to do it here:

https://www.plexiglas.com/export/sit...ing-manual.pdf

When ever I see these curved windows on a boat I know the designer was more concerned with showroom appeal than actual real world longevity. Plastic windows last MAYBE 20 years. before they become too murky to see through. Less if they get a lot of sun exposure. I wonder if the thought even occurred to them?

[Checkswrecks]

Being nearly 7/16" thick means the acrylic will be so stiff and solid it will need a form to be bent on. Especially if you want the left and right sides to be symmetric.

[er9]

you cant do those without an industrial oven. the entire piece of plexi has to be heated up evenly to around 380 degrees. once its uniformly soft it can be draped over a mold.

dont waste your time with a heatgun. you would be wasting your money. 10mm plexi will burn on the surface long before you could ever possibly get it hot enough to form. that and the size and shape would make it near impossible.

it is possible to make simple plywood ovens lined with aluminum foil and heat them with two or three heatguns if your handy and want to save some money but, there is a learning curve.

I quoted making a set of those windows at around $1500 for two just to give you some price point to work with if you went to a shop that specializes in this. no installation or removal just making the windows.

[Jim Cate]

Have you checked with Bene directly? Perhaps they can supply them. And from my limited experience, you will have one hell of a time making those bits and having them fit well enough to get good seals and to have decent optics. Not an easy job for pros, near impossible to DIY.

If you do try to do it, a heat gun will never give even enough heating. One friend did a biggish hatch in a local vendor's pizza oven (after hours, and he held the anchovies). Another option for heating is a bank of a few infra red heating bulbs... with enough of them you can perhaps get uniform heating over the whole panel.

However you apply the heat, you will need very carefully made forms to drape the hot plexi over, one for each side. Not a trivial project at all!

Good luck with it.

Jim