Mfgr Says Use Only Silicone! WTH...Everyone Here Says Don't Use Silicone.

[sartorst]

I will be helping a friend remove new ports installed a few years ago with silicone to reseal, what kind of silicone I dont know, but given my past experience with silicone I would not recommend it . I do think there is merit to the ( GASKET) idea which would work on something that will not have to be bolted/screwed down hard

[sailvayu]

I forgot to mention I did a video on resealing portlights. May be helpful to the OP replacing his.

Resealing or Rebedding Portlights, Boat Repair, Sealing portlights - YouTube

[Sandero]

Originally Posted by sailorchic34

I should note that I use silicone sealant on my boat for bedding and sealing. I found it superior to lifecaulk and easier to use then 4200/5200. Plus its cheap and I am all about cheap . But I'm blonde and female and use other things on board the the typical CF sailor would not. But I'm not typical either.

And you're charming and funny!

I use them all for different purposes. But yea silicone is a bummer to get off when it comes time to get it off.

[sdowney717]

Dap makes good sealants. The Dynaflex 230 is very very good but can grow mold.

Dap makes a clear kitchen and bath sealant adhesive caulk which I have used with great success sealing a glass window. That clear also comes in an exterior version.
It sets up like a soft stretchy clear rubber.

I used dap white caulk on the outside and on the inside used the kitchen and bath clear. This is a piece of tempered 1/4 inch glass which sits in a wooden rabbeted frame.

On the inside surface, I used my finger to smooth the bead all the way round sealing glass to wood. The wood is stained and polyurethaned so the clear was perfect choice to use.

[brankin]

My guess is the manufacturer wants a product that is non reactive with the plastic it is constructed with...pick a product that covers their ass and the results are up to you. With that said, I would trust what is said on this forum. Nothing tops first hand experience and if there is a problem with product compatibility, someone will quickly point it out.

[goboatingnow]

Some of the modified silicones might be worth considering , ie the silane types


Dave

[Hudson Force]

Originally Posted by MarkJ

.................. one shouldn't use 5200 on portholes because if you ever need to change it you have to dynamite the boat.

I like MarkJ's thought of using dynamite to remove 3M5200! You have to admit that it has some adhesion qualities. I'm probably in the minority with my use of 5200,- my chainplates, stanchion bases, portlights, ...all over the deck! I will admit to seeing people destroy some fittings or pluck off pieces of deck when prying off a piece adhered with 5200. I've been very successful with a filet knlfe or a thin garrote of stainless steel wire to separate a piece applied with 5200. I'll admit that it's tough to remove, but that's the same quality that makes it work so well for me. Bottom line, like most choices, there are compromises to be made.

[kthoennes]

This might be thread drift (sort of) but after all this talk of 5200, oddly I just used a whole tube of it to fill various digs and gaps here and there all over the boat. Two big digs in the swim platform, filled some screw holes that the previous owner left on deck, filled a big chip in the upper helm cowling. After letting all the spots cure for a week, I poked the little blob on the swim platform - came right off in a chunk, like a piece of stiff jello. I then went around to every repair spot and the 5200 lifted out of all of them, even came out of the screw holes like little plugs of dried caulk. No adhesion anywhere. When I was done I had a handful of firm 5200 globs and bits like dried cottage cheese. Had to go back and fill every spot with white marine epoxy instead, and that worked. I wonder if I got a bad batch of 5200.

[Hudson Force]

Originally Posted by kthoennes

................ I wonder if I got a bad batch of 5200.

I think all paints and adhesives, etc. require some preparation. I usually light sand a clean surface and then wipe with acetone before applying 5200. Also, I have not heard of people using 5200 as a body putty type of filler or to sculpt missing pieces of a structure.

[CarinaPDX]

Agreed, prep or at least conditions (moisture, low temperature?) are the primary suspects. The actual adhesive in polyurethane sealants is cyanoacrylic (i.e. Super Glue), which is highly effective given a good dry surface and warm temps. OTOH a bad batch is always possible, just not as likely.

Greg

[Cheechako]

Originally Posted by CaptForce

I like MarkJ's thought of using dynamite to remove 3M5200! You have to admit that it has some adhesion qualities. I'm probably in the minority with my use of 5200,- my chainplates, stanchion bases, portlights, ...all over the deck! I will admit to seeing people destroy some fittings or pluck off pieces of deck when prying off a piece adhered with 5200. I've been very successful with a filet knlfe or a thin garrote of stainless steel wire to separate a piece applied with 5200. I'll admit that it's tough to remove, but that's the same quality that makes it work so well for me. Bottom line, like most choices, there are compromises to be made.

Yep, I use the stuff everywhere; "do it once, never do it again!" is my motto. Why worry about getting it off in the future if it will never need to be taken off! haha... never say never i guess... and as I commented earlier, I put beckson portlites on with 5200 in the 80's ... no ill effects in teh 4 years after that...

"...after all this talk of 5200, oddly I just used a whole tube of it to fill various digs and gaps here and there all over the boat. Two big digs in the swim platform,...... After letting all the spots cure for a week, I poked the little blob on the swim platform - came right off in a chunk..."
Yep, the hole/surface etc must be absolutely clean, old dirt, salt etc and it doesnt stick....

[Rakuflames]

Originally Posted by Guy

Why would you ignore Beckson and trust this forum?

There are those who know a great deal about boats who do not recommend EVER installing portholes with silicone. Some people, for instance, think the portholes should stay in place if you're caught in extremely rough seas.

Beckson may have their own corporate reasons for recommending silicone. I never beleve that a manufacturer is impartial and has only my best interests at heart.

Just sayin', there's more than one view here. I am influenced by someone whom I respect greatly who flatly states to never use silicone on a boat. However, his last name is neither "Beckson" nor "Defender."

[CarinaPDX]

Did you clean the surfaces with alcohol or acetone first?

[kthoennes]

I prepped some of them, but not all. If I had to guess the dig on the swim platform looked like the PO let the boat come up under a bolt or big nail sticking out of a piling. It was a nasty 1" long x 1/4" deep gouge. The empty #8 screw holes were too small to clean out the insides of the holes so I just smushed it in with my finger and left a small blob on top like a thumb tack - and they popped out like little rubber thumb tacks. The surface chips were easy to clean, so I wiped them with naptha (acetone is just too toxic or nasty to me, I try not to use it if I can avoid it).

[kthoennes]

I wondered too if it gets too old to adhere properly at some point. We don't really have a marine store at our marina so I have to depend on a regular hardware store. That tube of 5200 might have been hanging there for years before I bought it - although it was sticky and messy as usual when it came out of the tube and my wife has a pair of ruined pants to prove it.