Bomar Hatch Lens Replacement
Posted: April 24th, 2024, 9:51 pm
We bought a 1996 325 this offseason and I have been working on a number of projects while it has been in storage. One of the projects was replacing a cracked lens in the Bomar deck hatch. The marina quoted me about $1,800 to replace the hatch, and my project was about $150 in materials including a new gasket, which was the most expensive part.
I know there are already a few threads on this topic, but none that are very detailed, so I wanted to share my process and what I learned along the way so hopefully others can learn from some of my mistakes!
Before:
After:
(please ignore the dirty deck - can’t wait to get it out of storage and wash the deck!)
First I removed the old lens using a razor blade to cut the silicone sealant, then thoroughly cleaned all the silicone off both the hatch frame and lens. I glued the broken lens back together to use as a template.
I went to a local glass shop to have them cut a new lens for me. All they had was clear Lexan, and I wanted something tinted but I had them do it anyway. I was disappointed with the result. The holes for the hatch dogs weren't the correct size (the holes aren’t a standard size - they’re close to 3/4” but not quite). It also looked like they freehand cut the rounded corners with a jigsaw. I’m a bit of a perfectionist and it bothered me, especially because the material wasn’t what I wanted in the first place. So I decided to redo it myself.
Here’s a helpful read on choosing acrylic (plexiglass) vs polycarbonate (lexan): https://hatchmasters.com/acrylic-vs-polycarbonate/
I bought a piece of 1/4” smoke gray acrylic on Amazon and used the old lens as a template to cut the new one using a router with a flush cut pattern bit. First I rough cut the new lens with a jigsaw about 1/4” wider than actual, then used the router to cut it exactly to the same size as the pattern.
I did some online reading about drilling clean holes in acrylic, and someone said using a spade bit works well. Don’t believe everything you read on the internet… I stupidly tried to use a spade bit, which of course cracked the acrylic because of the pressure from the conical point on the bit
If you do drill the holes, I would go with a forstner bit and a drill press, but I think my alternative method worked well.
I started over, this time doing the holes for the hatch dogs first. I highly recommend doing the holes first in case you run into any issues, then you can start over with minimal waste. This time around, I drilled a small pilot hole in the center of the hole location and then gradually worked up the size of the pilot hole. I then used a 5/8” carbide hole saw to cut a hole slightly smaller than the one I needed, and I finished it with the router and the pattern bit, using the original lens as a pattern (similar to a plunge cut with the router, using the hole I drilled for the plunge). This method worked great.
I called Bomar/Pompanette to get the part number for my hatch by giving them the serial number. They were very helpful and were able to tell me what the replacement part numbers were for the gasket and hatch dogs.
I set the new lens in place and then used DOWSIL 795 structural glazing sealant to bed the lens and tooled it immediately with popsicle sticks. I had the lens perfectly centered with a nice clean bead of caulk and I was feeling pretty pleased with myself. Which of course means I was about to make another mistake. The instructions for the 795 say to remove masking immediately. I had masked the hatch frame with standard blue painters tape, which I removed no problem. However, when I tried to remove the protective factory masking from the acrylic, it was extremely sticky and the lens shifted in place when I tried to pull it off, pushing a bunch of the caulk out of the frame and causing a huge mess. I quickly remasked it and redid the caulk as best I could, but it didn’t turn out perfect. I’m probably the only person who will notice though, so oh well. If I did it again, I would either 1) disregard the instructions and wait until it cured to take the masking off (this worked just fine when I removed the rest of the protective masking from the acrylic the following day), or 2) not tool it at all, and just cut it flush with a razor once it cured. I think both of those options would’ve resulted in a better finished product.
Lastly, I had purchased new black mushroom caps for the hatch dogs, to replace the original white ones. The new caps said they were compatible with my hatch dogs, but when I installed them, the diameter of the inner round piece was just a tiny bit larger so they didn’t fit cleanly in the holes like the originals did. So, I went back to the originals which fit perfectly. I may enlarge the holes slightly at some point so I can use the new caps, but for now I’m going to call this project complete.
Hope this helps someone!
I know there are already a few threads on this topic, but none that are very detailed, so I wanted to share my process and what I learned along the way so hopefully others can learn from some of my mistakes!
Before:
After:
(please ignore the dirty deck - can’t wait to get it out of storage and wash the deck!)
First I removed the old lens using a razor blade to cut the silicone sealant, then thoroughly cleaned all the silicone off both the hatch frame and lens. I glued the broken lens back together to use as a template.
I went to a local glass shop to have them cut a new lens for me. All they had was clear Lexan, and I wanted something tinted but I had them do it anyway. I was disappointed with the result. The holes for the hatch dogs weren't the correct size (the holes aren’t a standard size - they’re close to 3/4” but not quite). It also looked like they freehand cut the rounded corners with a jigsaw. I’m a bit of a perfectionist and it bothered me, especially because the material wasn’t what I wanted in the first place. So I decided to redo it myself.
Here’s a helpful read on choosing acrylic (plexiglass) vs polycarbonate (lexan): https://hatchmasters.com/acrylic-vs-polycarbonate/
I bought a piece of 1/4” smoke gray acrylic on Amazon and used the old lens as a template to cut the new one using a router with a flush cut pattern bit. First I rough cut the new lens with a jigsaw about 1/4” wider than actual, then used the router to cut it exactly to the same size as the pattern.
I did some online reading about drilling clean holes in acrylic, and someone said using a spade bit works well. Don’t believe everything you read on the internet… I stupidly tried to use a spade bit, which of course cracked the acrylic because of the pressure from the conical point on the bit
If you do drill the holes, I would go with a forstner bit and a drill press, but I think my alternative method worked well.
I started over, this time doing the holes for the hatch dogs first. I highly recommend doing the holes first in case you run into any issues, then you can start over with minimal waste. This time around, I drilled a small pilot hole in the center of the hole location and then gradually worked up the size of the pilot hole. I then used a 5/8” carbide hole saw to cut a hole slightly smaller than the one I needed, and I finished it with the router and the pattern bit, using the original lens as a pattern (similar to a plunge cut with the router, using the hole I drilled for the plunge). This method worked great.
I called Bomar/Pompanette to get the part number for my hatch by giving them the serial number. They were very helpful and were able to tell me what the replacement part numbers were for the gasket and hatch dogs.
I set the new lens in place and then used DOWSIL 795 structural glazing sealant to bed the lens and tooled it immediately with popsicle sticks. I had the lens perfectly centered with a nice clean bead of caulk and I was feeling pretty pleased with myself. Which of course means I was about to make another mistake. The instructions for the 795 say to remove masking immediately. I had masked the hatch frame with standard blue painters tape, which I removed no problem. However, when I tried to remove the protective factory masking from the acrylic, it was extremely sticky and the lens shifted in place when I tried to pull it off, pushing a bunch of the caulk out of the frame and causing a huge mess. I quickly remasked it and redid the caulk as best I could, but it didn’t turn out perfect. I’m probably the only person who will notice though, so oh well. If I did it again, I would either 1) disregard the instructions and wait until it cured to take the masking off (this worked just fine when I removed the rest of the protective masking from the acrylic the following day), or 2) not tool it at all, and just cut it flush with a razor once it cured. I think both of those options would’ve resulted in a better finished product.
Lastly, I had purchased new black mushroom caps for the hatch dogs, to replace the original white ones. The new caps said they were compatible with my hatch dogs, but when I installed them, the diameter of the inner round piece was just a tiny bit larger so they didn’t fit cleanly in the holes like the originals did. So, I went back to the originals which fit perfectly. I may enlarge the holes slightly at some point so I can use the new caps, but for now I’m going to call this project complete.
Hope this helps someone!
