Lexan Hatch Cover Tops

The translucient tops of the two hatch covers on my E-27 (1976, wheel version) are developing some cracks, and probably need to be replaced. I checked with my local glass store, and they said I would need Lexan, not plexiglass, as plexiglass will crack if you drill holes, and Lexan will not. The 3/8 iinch thick by 21 inches by 21 inches, smoked or bronze color, are pretty expensive, but I want to do it right. The panels are fastened by lots of screws, so lots of drilling. Has anyone had any experience with a project like this, or some advice?

Thanks,

Neil (boat name Cantata)

Hi, I just did a quick search on lexan hatches on this site, and there are about a dozen posts that you may find helpful on doing this project.
Good luck!
Frank.

I appreciate the information. I sail on Lake Superior, in the Apostle Islands area, and I will try to find a lexan company in Wisconsin or Minnesota. I live in Albert Lea Minnesota, and the local glass company says that I should have no trouble drilling the holes myself. I am not so sure about that.

Thanks again,

Neil

Polycarbonate vs acrylic

Polycarbonate is less UV resistant, once it develops scratches they are very difficult to remove, crazing has more effect on strength that does crazing on acrylic. Polycarbonate is more difficult to work with and will tend to crack more if being worked on with incorrect tools. In situations where the polycarbonate is 1/2 or less it has a tendency to shatter upon impact.

Acrylic is a much better product for you application. Every major hatch manufacture utilizes acrylic.

Which ever you ultimately choose, bedding and bonding is generally only successful in the long term utilizing the 209, 295 products together from Sika Corporation. Which will also allow you to use significantly less screws.

Guy

drilling plexi or lexan

If you drill the holes yourself, do not countersink them as you would with wood. V shaped countersinks cause cracking. Drill the countersink first with a carbide Forstner bit that will produce a flat bottomed hole, then drill through that. Use pan head screws or bolts with an appropriate washer under the head and use care in tightening. I have had some success using butyl rubber caulk as a sealant, but did not rely on it for any bonding strength. It is sold in Lowe's and Home Depot as gutter sealer. It is a pain to use and skins and dries slowly, but remains flexible forever.

rfriend

I have found a wet or dry diamond saw blade like you use to cut tile works great for cutting plastic sheeting. It doesn’t chip and gives a smooth cut.

Drilling acrylic

I bought a special bit for drilling holes in acrylic from the plastic company. It's supposed to reduce the chances that you'll crack/chip the around the hole. I have not used it and have had problems with cracking and chipping when using a regular metal bits. I think the acrylic bit has a shallower tip angle or something.

I tried rubbing out frosted Lexan once and I gave up when I discovered how much the stuff had yellowed. I think the effort would not have been very successful for an amateur anyway.

If you plan to sit/stand on the hatch, you'll need pretty thick stuff, like the 3/8" stuff that is there now.

I just sent mine to www.hatchmasters.com Sure, its not cheap. Actually the price of a rebuild is just shy of a new hatch at deeply discounted prices. Of course a new hatch would require considerable time/effort to install and likely require fiberglass and/or trim work to install correctly. The rebuilds were much simpler. Just remove and then reinstall the tops. Looks like new. Functions like new. More time to sail. Send them in at the end of the season so you don't miss out on the good weather now. RT

The comments

about using special plastic drill bits and pan head fittings are valid. Anything you can do to prevent stress risers will reduce/prevent cracking. Also, acylic will serve better than poly in the long run.