• Mobile App For Android Now Online!

    Download it here. The app is searchable in the Google Play Store under Sailboat Owners.

    Sorry iPhone/iPad users, we are still waiting on Apple. :(

    Click the X in the upper right corner to make this go away

crazy to cast own fixed portlights?

Jul 19, 2016
1
Beneteau 361 anywhere
Has anyone used clear, impact-resistant resin to cast their own replacement portlights? Really bummed at how easily I broke one on my Beneteau 361 (very light point loading). Naturally I'm concerned about safety and durability in all conditions, especially off shore. I'm reluctant to take a risk casting my own. At the same time, I can't help but wonder whether casting the replacement with quality clear epoxy resin (maybe West Systems?) and making it more thick is actually less risky even though it's not backed by a major brand. Interested in others' experience!
 

kito

.
Sep 13, 2012
2,011
1979 Hunter Cherubini 30 Clemmons
Can't you just use thicker acrylic and cut it to size?
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
You do know that ships have sunk because their hatches or portlights were lost and the boat down-flooded? Beyond that, epoxy resin has no UV resistance. As your acylic ports and hatches age, they lose strength. They, like so many other parts of your boat have a usable lifespan.
 
Last edited:
Mar 23, 2009
139
Rafiki 35 North East, MD
Epoxy resin will degrade from direct exposure to UV light, so it is not a good choice for replacing a portlight on your boat. Not to mention that even clear epoxy would never be as clear as the portlight you are replacing-- you would get light through it (at least for a while, before it started yellowing from the sun) but you wouldn't be able to see things clearly through it.

I would buy lexan or another high quality polycarbonate resin panel and cut it to size using a router with a sharp bit. If you use a thin panel, sandwiching the lexan between two thin sheets of plywood with double-sided tape will prevent the lexan from flexing and cracking when hit with the spinning router bit. Just trace the shape you need on the top piece of plywood and then follow that line with the router. If you don't think you can control a router that precisely, make a template out of wood and then use a router bit with a bearing on it to follow the template. Lexan comes in a wide range of sizes and thicknesses, many of which are sold at Lowes and Home Depot, so you should be able to find what you need for your application without much trouble.
 
Aug 1, 2011
3,957
Catalina 270 255 Wabamun. Welcome to the marina
Resin isn't very strong, and certainly nowhere near as strong as either of the materials that Matt suggests, and, by the time you're done farting around with the castings, you'll have put forth more effort than buying replacements.
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Lexan (the trade name for polycarbonate) is a poor substitute for the original cast acrylic port material. It also has poor UV resistance and isn't scratch resistant. There really is no suitable alternative to the acrylic port and hatch lenses other than plywood, and you should have some pieces of that available if you want to play around with alternative DIY fixes. More.
 
Mar 23, 2009
139
Rafiki 35 North East, MD
Lexan (the trade name for polycarbonate) is a poor substitute for the original cast acrylic port material. It also has poor UV resistance and isn't scratch resistant. There really is no suitable alternative to the acrylic port and hatch lenses other than plywood, and you should have some pieces of that available if you want to play around with alternative DIY fixes. More.
I absolutely agree that nothing will be better than the original cast acrylic lenses. But if obtaining a factory replacement is not feasible or affordable, I do think polycarbonate is an alternative worth considering. The Lexan panels I have seen for sale at Lowes are labeled as having been treated to be UV and scratch resistant. They will eventually cloud from being scoured over time by wind and water but that will take years. I read the link you provided about acrylic vs. polycarbonate but in my experience, the polycarbonate readily available in the local market has better UV resistance/strength/etc. ratings than the acrylic alternatives locally available. It may be that professional hatch designers have access to a higher grade acrylic panel, in which case an acrylic panel may be a better choice than a polycarbonate panel.
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Actually the SailboatOwners parts store on this website is a great place to find replacement ports and port lenses.
And the folks at Select Plastics / Hatchmasters will custom fabricate pretty much anything you need in addition to off-the-shelf replacement lenses, gaskets, hardware. Pretty good sources for doing it right, with the right part.
 
Jan 4, 2006
3,794
Hunter 310 West Vancouver, B.C.
There really is no suitable alternative to the acrylic port and hatch lenses other than plywood, and you should have some pieces of that available if you want to play around with alternative DIY fixes. More.
Interesting article (More.) with the reference to maximum portlight size:

Portlight.JPG


I guess that's why I seem to develop a small leak(s) every 3 - 4 years in the front portlight.

Front Window Showing Landings.JPG


No measurements on hand but that piece of acrylic is about 6-7 ft. long. Got to wonder what the cabin dimensions are doing during that time but just not a good idea at all. Aw, crap :cuss:.

As far as "no suitable alternative to the acrylic port and hatch lenses other than plywood", would that be transparent plywood or ........... ? :dancing:
 
Nov 9, 2008
1,338
Pearson-O'Day 290 Portland Maine
Interesting article (More.) with the reference to maximum portlight size:

View attachment 126048

I guess that's why I seem to develop a small leak(s) every 3 - 4 years in the front portlight.

View attachment 126049

No measurements on hand but that piece of acrylic is about 6-7 ft. long. Got to wonder what the cabin dimensions are doing during that time but just not a good idea at all. Aw, crap :cuss:.

As far as "no suitable alternative to the acrylic port and hatch lenses other than plywood", would that be transparent plywood or ........... ? :dancing:
Yes, but cast acrylic has a thermal coefficient of expansion of 45 . . . worse than polycarbonate which is 39. Also, this is for clear materials. Put a tint to it and the thermal creep essentially doubles! FRP's COE is 14, about 1/3 of polycarbonate. All the more reason NOT to use fasteners for attachment. VHB tape w/ DOW 795 for fixed lights if possible.
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
...then someone steps on these fixed cabin-top port-lights and pops the adhesive sealant loose. The question isn't whether they will leak, but when. I shake my head every time I encounter this stuff.
 
Jan 4, 2006
3,794
Hunter 310 West Vancouver, B.C.
...then someone steps on these fixed cabin-top port-lights and pops the adhesive sealant loose.
Someone standing on a portlight will not break the seal. The 795 or 3M VHB tape is waaaaaaaaaaaaay too strong for that (due to the large adhesing surface areas involved). Dirty shoes might scratch the surface of the acrylic :angry:.

But differential thermal expansion ................... when an unstoppable force meets an immovable object, all bets are off. WAAAAAAAAY OFF.