Leaky Portal Sealant ?

[kimballsingh]

So I am in the process of reseating my fixed portals in my Sabre 38. I am pretty confident of the process, but I am getting lots of suggestions for the sealant to use. Most say not to use 5200, but instead a good silicone. I got some 3M marine silicone at West Marine for $20/tube. I am a home builder and use a high grade 3M silcone that I get for about $7. Anybody know if there is really a difference? Or is it just marketing? Am I being a total cheapskate here? Any suggestions would be appreciated.
Thanks, Kimball

[Butler]

I'd pass on the silicone as it causes problems with adherence of anything else once it gets on any surface and is very difficult if not impossible to clean away properly. I agree that 5200, though a useful adhesive is not the best sealant/caulking material. Everybody has their favorite but I like Lifecaulk. There is another less expensive product available at the big box hardware stires called P&L... they have a window/door caulk that a lot of folks in this marina like. Never used it myself. Search the maintenance threads below and you will find plenty on this subject.
Good luck with the project.

[Surveyor]

Butyl Tape

[Seahunter]

Originally Posted by kimballsingh

So I am in the process of reseating my fixed portals in my Sabre 38. I am pretty confident of the process, but I am getting lots of suggestions for the sealant to use. Most say not to use 5200, but instead a good silicone. I got some 3M marine silicone at West Marine for $20/tube. I am a home builder and use a high grade 3M silcone that I get for about $7. Anybody know if there is really a difference? Or is it just marketing? Am I being a total cheapskate here? Any suggestions would be appreciated.
Thanks, Kimball

Silicone is for tubs, toilets and implants; not on a boat (will not seal to fiberglass). 5200 is more than an adhesive than a sealant (and is full of tiny bubbles when dried); try 4200 (more sealant than adhesive) or BETTER, the slow dry Sikaflex (which sands and paints really well; all available at your local West Marine. Do NOT shop the discount isle for this job.

[HopCar]

I would use 3M 5200 but everyone else in the world thinks it is impossible to remove later. If you are in that camp then 4200 is a good choice.
10 oz. White Adhesive Sealant - Fast Cure 4200
If you want a clear sealant Boatlife LifeSeal is good.
BoatLife LifeSeal Clear Cartridge - 1169

[callmecrazy]

I would use lifecaulk, which is a polysulfide sealant, or butyl tape.

[roverhi]

Sillycone belongs in boobs not boats. If the portlights are not a plastic that is affected by polysulfide or polyurethane sealant, use LifeCaulk, 5200, 4200 or Sikkens polyurethane sealant.

Nothing sticks to sillycone and it doesn't stick to anything all that well. It bleeds out into the surroundig area making future painting questionable, at best. The stuff doesn't handle shear loads for beans and usually ends up leaking. It has leaked everywhere the PO used it for a sealant on my current boat. Finally just R&R'd every deck fitting the stupid idiot put down with sillycone to stop the leaks. The worst part about the stuff is trying to clean it up. Nothing cuts it and leaves a messy film that attracts dirt if you don't thoroughly remove the excess. The other sealants clean up easily with mineral spirits in comparison.

[cabo_sailor]

My vote is for the butyl nitrate tape. It's cheap, about $5 for a 40 ft roll from some online supplier of RV stuff. It stays flexible forever and so far, on my boat, has done a great job. This is basically the same stuff that's used to seal the windshield on the car. In fact, I have used the butyl nitrate from the auto supply but its messier, black, and much more expensive. The RV supply version is about one inch wide, one-eighth in thick and light to medium gray.

Personally, I have no use for 5200 or silicone on the boat. If I need the adhesive power of 5200, then I haven't put whatever together correctly. As to silicone, I echo all the comments above about its disadvantages.

Rich

[kimballsingh]

Thanks all for the quick and useful replies. Back to the store.
Cheers, Kimball

[rebel heart]

My vote is for life caulk (polysulfide). It sticks, is flexible, and lasts a while. Impossible to get off so make sure you tape everything well and watch for little stringers that get carried off in the wind. Absolutely wear disposable gloves. I keep paper bag open taped to a stanchion to make it easier to through gooey tape away.

[callmecrazy]

The grey butyl tape is not messy at all, very easy to work with. I've never used the black..

Lifecaulk also comes in black, which is much messier than the white. I put the white around my chainplates last year and now it's an ugly yellow where it's exposed, I'll probably use the black this time (since that's what I have) and see if it lasts a little longer. Both are easy to cleanup with a little stove alcohol

[GordMay]

Polyurethane-based sealants (3M 5200/4200 and Sikaflex -295 UV) are generally safe for use with polycarbonate and acrylic plastics.

The solvents in polysulfide sealants attack some plastics, causing them to harden and split.
Do NOT use Polysulfide to bed plastics, such as:
Acrylic (Plexiglas), Polycarbonate (Lexan), ABS or PVC.
Polysulfides are generally safe for use with Epoxy, Nylon, or Delrin.

Search the Forum for numerous excellent discussions.

[skipmac]

Originally Posted by Surveyor

Butyl Tape

Butyl tape is the only way I would go to bed ports.

[barnakiel]

Why not just go to 3M or Sikaflex catalog and check out the appropriate material?

b.

[sailvayu]

Use silicone or a hybrid such as life seal or 3M 4000. 5200 WILL fail. If the ports are plastic use only silicone as the plastic contains oils that leach out and silicone is the only sealant proven to stick well. Use the marine grade silicone not the hardware store type as there is a difference. One notable difference among the types of silicone sealants is the curing agent used. The three main types are; Acidic systems release acetic acid upon curing (you can tell these because they smell like vinegar); Neutral systems release alcohol during cure; and Aqueous systems release water during cure. The marine is a non acidic cure type. Tape off to avoid the sealant film on other surfaces and clean up using only as little alcohol as needed. Many sealants fail because the wrong solvent was used so use only what is recommended. Make sure all your surfaces are clean and free of old sealant, like painting good prep is everything here. No sealant that I know of will last forever so this is a chore that must be done every 10-20 years. Makes sure you get the bottom of the port carefully sealed I see many leaks here because it is hard to reach and see and often not properly filled.