Leaking Hatch Reseal

[CnN89]

I have a forward hatch that I have attempted to reseal twice. I removed the plexiglass, cleaned the glass with denatured alcohol & the aluminum frame with acetone. I also replaced the gasket between the frame and hatch base. The first time I used Boat Life "Life Seal" as an adhesive, & 3M 5200 (on the second attempt). Both times I used about 50 lbs of weight to maintain conntact between the plexiglass, gasket & aluminum frame. After 3 days I removed the weight and allowed the adhesive another 3 days to cure. Unfortunately it still leaks between the glass and the frame. Any suggestions?

 

[PhilPB]

I had a small leak on my forward hatch and it turned out that the hinge screws needed to be snugged up a bit.
Of course before looking for an easy fix I rebedded the hatch using butyl tape which was no big job but not necessarily needed.

 

[Comodave]

Those caulks you used won’t stick to plexi for long. Use Sika 295UV. It is made to stick to plexi, etc. I used it on the plexiglass windscreen on our last boat and it was still sticking fine after 4 years when we sold the boat.

 

[STB]

What Comodave said about those sealants...no-good for vinyl.

I use Dynaflex 230. I know it isnt a marine sealant, but I used a ton of it on vinyl windows at home and tried it some years ago to rebed a leaky port ln the bpat that had vexed me in prior attempts. It was problem solved. Years later it has never let me down..problems stayed solved and new installed worked well.

When helping a friend, he got dynaflex ultra, instead. It is seemingly thicker and more expensive. I liked working with it less, but it also permanently fixed the leak that ad been vexing him.

I used to be very timid and hesitant about recommending it for boats since it isn't for that application. But, it keeps working and seems tocstay working, so I am getting less timid. I still don't like using or recommending non-marine products for boatsin general, though. That seems to go badly more often than not, eventually.

 

[TBill36]

Make sure you are not squeezing all the caulk out when bedding the glass. I use pull ties as spacers at the edge at four places. There should also be no contact with the glass around the edges either. Think of it as the glass floating in a bed of caulk. Set the glass in and push down until you hit the spacer. You may want to use spacers around the edges also. If you get to where the glass hits the frame it will leak.

The sun and heat cause the frame and glass to expand and contract at different rates, so the caulk needs to accommodate that. Glass to frame contact prevents that and will create a path for a leak.

From most of my reading on the subject you want to use cast acrylic for hatch windows.

 

[CaptTom]

The glass place I bought the replacement plexiglass from for my hatch recommended a product called "RTV" for bedding it. It wasn't cheap ($48US for a tube) But given the cost of the plexi, and the amount of effort on my part, getting the "right stuff" was well worth it. No leaks one year later.

As to the hatch lens itself, the glass shop said the old one I brought in was plexiglass. I decided to replace it with the same material, figuring the OEM knew what they were doing. I can't speak to whether or not there's a "better" product.

 

[TF_BG]

+1 on Sika 295UV, used it to resealed my forward hatch 2 months ago. So far so good.