hatch sealant

[Ed Shankle]

I'm expecting to get my cabin top hatch back from Select Plastics any day now. Sent it out to replace the lens. Question is, it was originally installed with silicone, but should I use butyl tape this time? Reason I'm questioning is, the hatch is only screwed down with 1/2" screws. Can't really tighten down like with bolts and nuts. Since butyl isn't really an adhesive, although it sticks like crazy, I'm thinking I should stay with silicone.

thanks,
Ed

[Stu Jackson]

Ed, I redid my saloon hatch with butyl, screws only, in a recent Mainsheet Tech Notes.  No leaks, you may need two layers of butyl underneath the flange.

[Noah]

A week or so ago I installed a brand new Bomar replacement hatch for my old damaged saloon hatch and used Butyl tape. It took at least double thickness of tape and even more on corners. Where I still had a bit of a gap, I packed in butyl with a putty knife after the fact. I also used 3/4 screws instead 1/2. Have not yet thoroughly leak tested, but will do so this weekend and report back.

[Ron Hill]

Ed : Re read my Mainsheet Tech note article Replacing the Salon Hatch. 

Bomar recommends 3M5200, but I used 3M4200.

A thought

[Stu Jackson]

That was before butyl became readily available.  5200, and to a lesser extent, 4200 are SATAN'S GLUE and shouldn't be sold to recreational boaters.

Since the old hatch had to come out, the new one should as well.  Therefore, glue shouldn't be used.  The concept is to seal the hatch to prevent water intrusion.  Butyl does that very well.

[Ron Hill]

Guys : I agree with Stu on his analysis of 3M5200.  You only want to use that stuff on something that must NEVER come apart.

However, 3M4200 is a good sealant an does come apart. 

Butyl rubber is good for a lot of tasks, but sealant still must be used for certain jobs - like fixed side ports.

A thought

[Stu Jackson]

Ron's right in that the ONLY place on my boat that silicone is still used is to bed the Beckson ports, because that's what Beckson specifies.

Oh!  One other place: to fill the old holes in the head when I installed my new head.