Replacing acrylic portlights and hatch lens

[rajhnsn]

I bought the piece of smoked acrylic from shore plastics. 3/8" 19 X19 will be $88.00. Is Dow 795 the bedding compound to use? How did you use the butyl tape for the hatches? I thought the lens just set up in the bedding compound. I was thinking of adding a bar across the middle of the hatch. I'm guessing that the reason that it started to separate is because we were opening the hatch by pushing on the window instead of the handles. If not a bar then a sign.

 

[Panta Rei]

I bought the piece of smoked acrylic from shore plastics. 3/8" 19 X19 will be $88.00. Is Dow 795 the bedding compound to use? How did you use the butyl tape for the hatches? I thought the lens just set up in the bedding compound. I was thinking of adding a bar across the middle of the hatch. I'm guessing that the reason that it started to separate is because we were opening the hatch by pushing on the window instead of the handles. If not a bar then a sign.

I looked around the web to take a look at the Bowmar hatches. There was not a lot of information.
Once I removed the lense and cleaned them up, my hatches had a 1/2" lip that the lense would sit on. I see some instructions say to place a bead of dow 795 or equivalent on the lip and then place the lense on it. (lightly) allow it to cure then fill the rest with 795. There are problems with this:
1. I've read that new 795 does not stick to cured 795
2. The first bead can ooz out so extra masking is necessary.

I used butyl tape on the lip and then fill the gap around the edge with 795. Nice EASY neat appearance. This is what was done by the previous owner and it worked like a charm. There is no way this lense is coming out !!

 

[rajhnsn]

Thanks. I plan to mask the lens very carefully before the install. I think I'm going to just set it in the dow 795. I think the cause of it coming out of the bedding previously may have been because people were opening the hatch by pushing on the glass instead of the handles. Instead of a bar across the hatch, I may just have a decal made to instruct openers to use the handles instead of pushing on the lens. Thanks for the tips.

 

[TimFromLI]

I'm in the process of replacing the lenses and gaskets in my 1987 superhatches Be careful not to warp your frames removing the old lenses.

I found cleanup was messy but easy if you place the frame at an angle and pour some mineral spirits on the old sealant and let it soak in. Then take a razor and scrape it off. Then go to fine steel wool and mineral spirits and final cleanup with acetone to get any residue.

I had a local marine plastics fabricator cut the lenses for about $80 apiece.I bought the new gaskets and special glue from Select Plastics.

Gasket replacement is tricky but not impossible - I started it last night. First seat the inner lip of the gasket. I used a screen roller tool to help. the corners are tricky but it will work, be patient. Do one side at a time seating first the inner and then the outer lip. A little duct tape to secure your work as you go will prevent all your hard work from becoming undone. Tonight I will glue the ends and next glue the lenses with dow 795.

 

[rajhnsn]

I ended up going to a windshield guy to have the acrylic bedded in the windshield bedding. It did not work. It was easily pushed out when people tried to open the hatch from below by pushing on the acrylic. Live and learn. Back to the drawing board.

 

[TimFromLI]

After I replied I noticed the year of the last post was 2014 not 2015. Oops- old thread. Anyway, from what I have read Dow 795 is the stuff to use and it takes 3 weeks at room temperature to cure. Gluing it tonight, hopefully I don't make too big of a mess.

 

[SailingCal21]

Thanks for re-booting this post. Very timely for me, Karma's starboard fixed portlight split during the big freeze we had a few weeks back. Looks like I'll be studying up on replacing one or both of them this spring.

I know that the screws should not be torqued and are just to hold the material in place while the bedding cures. Just concerned about drilling the holes, i.e.; bit type, speed of drill, etc.

 

[shozbot]

Anybody know how to replace crazed lens in this original 1981 O'Day 28 hatch?

 

[Brian S]

Sail magazine had an article how to replace non-opening port lights. They recommend using 3M VHB acrylic tape, and then filling around with Dow Corning 795. Ah, here's the article: http://www.sailmagazine.com/boatworks/replacing-fixed-portlights

I used this method on my little 192, and I love the look without screws. It looks very futuristic with the smooth plexi. I'm hoping it will continue to hold up well over time...

Thanks for re-booting this post. Very timely for me, Karma's starboard fixed portlight split during the big freeze we had a few weeks back. Looks like I'll be studying up on replacing one or both of them this spring.

I know that the screws should not be torqued and are just to hold the material in place while the bedding cures. Just concerned about drilling the holes, i.e.; bit type, speed of drill, etc.

 

[Brian S]

I suspect the link in my posting #29 will work for this.

Anybody know how to replace crazed lens in this original 1981 O'Day 28 hatch?

View attachment 85644

 

[Panta Rei]

Sail magazine had an article how to replace non-opening port lights. They recommend using 3M VHB acrylic tape, and then filling around with Dow Corning 795. Ah, here's the article: http://www.sailmagazine.com/boatworks/replacing-fixed-portlights

I used this method on my little 192, and I love the look without screws. It looks very futuristic with the smooth plexi. I'm hoping it will continue to hold up well over time...

Brian , your advice pointing to the article is very good but I think Shozbot has a very unique challenge.
Most fixed lights are attached to the outside of the boat. Same as the boat in the article. As I see it, Shozbot's hatch has the Plexiglas attached to the underside of the hatch. I would not be 100% confident in using the butyl tape or acrylic tape and fill method. Not unless a few of you guys with 28's have done the same. Maybe there is some type of frame around it but I don't see one.
Shozbot: Unless someone speaks up, I would follow the last installation, it seams to have held up. What you should be looking for is the Dow silicone 795 (it is used to hold glass panels in on hi rises) and then there may be some tape. If it is a flexible sticky/stretchy rubber and about 1/8 to 1/4 inch thick it is likely Butyl rubber tape. If it has a foam structure to it ,it is the 3M VHB product. Use what you find . It worked.
The 3m VHB is stronger but you must follow the application specifications. (both surfaces must be very clean, very smooth, not porous, and glossy) 3M VHB costs $100/roll butyl about $20. I went with the $20 and drank the savings.

 

[SailingCal21]

Thanks fore the link to the article Brian. I remember reading this several years ago. It has way more relevance now then before.

Looks like the best way method for drilling the holes in the new lens is to not even go there. That's good news for me, definitely gonna subscribe to that method.

 

[Pat]

I ordered my port lights from Rudy. Probably too late to check that.....Good luck....my first one cracked into a million pieces because I used the wrong caulk/adhesive.....Rudy's instruction said to use
Dow 795 .....I did not at first and it did not allow for freeze/thaw excpansion and contraction.....Pat

 

[shozbot]

Yes. The hatch on the '81 28' oday has the lens fixed from below without a frame. It's original and very crazed but I'm thinking that it was never possible to stand on it because of the design. O'day bought hatches in later years but mine is molded by oday. Will try to remove hatch lens and install new lens with 795 but not sure how to get old one out cleanly? Also, should I use acrylic or polycarbonate? I found some polycarbonate that has special UV treatment.

 

[Panta Rei]

Yes. The hatch on the '81 28' oday has the lens fixed from below without a frame. It's original and very crazed but I'm thinking that it was never possible to stand on it because of the design. O'day bought hatches in later years but mine is molded by oday. Will try to remove hatch lens and install new lens with 795 but not sure how to get old one out cleanly? Also, should I use acrylic or polycarbonate? I found some polycarbonate that has special UV treatment.

First off
I would find someone dumb enough to stand on it as see if it holds up. I think you will find if holds up fine .
Then I would remove the hinges so you can take it home and work on it. Maybe buy new hinges.
Then cut the seal with a knife push pull until it starts coming up.
I think you need butyl tape or the foam tape plus the Dow 795.
I think you may find that the area of the lens that is caulked has been painted black. It gives it a nice finished look (again just copy what was done before)
Clamping. Now that it is off the boat, this will be easy. Just a few pounds should be enough to hold it in place.