Sealing Deck Plates

[Skippa]

I hope this one has an easy answer. After reading the warnings about using silicon sealants, I am wondering about what to use to seal deck plates. I plan to install a 6 inch deck plate on each cockpit coaming just aft of the jib tracks and one on the interior bulkhead inside the cuddy. Boat is a DS II.
Looking at one of the popular national suppliers I noticed that products like "Boat Life" are not recommended for FRP to ABS joints.
As always, Thanks in advance.
Kevin

[GreenLake]

Butyl tape.

[Skippa]

Thank you GreenLake,
I happen to have a roll of that. Way too easy !

[jdoorly]

If it has an "O" ring I use Vaseline.

[Moose]

If you're not worried about removing it 3M 5200.

[talbot]

But you SHOULD worry about removing it. Deck plate rings can crack. Put on with something like silicone, it's a few minutes' work to replace one. With 3M 5200, you would have to grind off the plastic, or more likely, cut the entire section of the hull out and install the next larger size plate. The approved sealer will depend on the material used in the plastic, and the deck plates usually come with that information. I believe for ABS, only silicone is recommended, and I've never had a problem using that. My understanding is that best-quality exterior home silicone is cheaper and just as good as products labled "marine."

[GreenLake]

There are two advantages to butyl tape, as far as I understand it.

One is mechanical. The tape is not liquid when you apply it. so it doesn't squeeze down as much - leaving you with a seal that still has enough material so there's less problem with too little sealant being stretched too far. That comes into play more in applications where there are higher stresses.

The second is chemical. Silicone gets into gel coat and is "impossible" to get rid of, which will bite you if you ever have to paint.

I could well imagine that house paint would be more tolerant of contamination than varnishes or high quality deck/hull paint.

Finally, I've read about butyl tape surviving for decades longer than household silicone (at least as tested in my bathroom).

[hectoretc]

Thank you GreenLake,
I happen to have a roll of that. Way too easy !

Hi Skippa

If you can remember, do you recall where you got your butyl tape in town?
And if it's not simply called butyl tape, what should I ask for?

Thanks - Scott

[Skippa]

Scott,
I purchased it at an RV supply store to seal window frames and a roof hatch that needed to be resealed.
It is just a gum like sticky tape.
Hope that helps.
Kevin