Exterior Silicone Sealant

[dbsea]

It looks like some of the exterior white silicone sealant on my boat needs to get redone. My question is, which product to use, and secondly, if you look in the attached photo, i'm not sure if that opening is supposed to be there? Is it some sort draining area? should this be entirely filled in with silicone?

https://share.icloud.com/photos/0f0B-Ch ... TmJ-Iw7K8w

Thanks!

 

[dbsea]

Bumping this up....

 

[Submariner]

Bumping this up....

Sikaflex 291

 

[dbsea]

Bumping this up....

Sikaflex 291

Would that be too aggressive? I think the current product is some sort of silicone based adhesive. It’s somewhat pliable / flexible?

 

[Submariner]

Bumping this up....

Sikaflex 291

Would that be too aggressive? I think the current product is some sort of silicone based adhesive. It’s somewhat pliable / flexible?

That's what I used when I installed the Mobility 42G antenna. I talked to RT and asked what they used and was told Sikaflex 291.

 

[FlyMeAway]

You'll find endless debates among boaters/sailors about whether Sikaflex 291 or 3M 4200 is the superior adhesive-sealant.

Think is, that location looks like it might just need sealant not adhesive-sealant... Sikaflex might be overkill. Or maybe not. Hard to see.

silicone based adhesive

Generally, there is no such thing in boating as a silicone based adhesive. Marine sealants (like Sikaflex 291 and 3M 4200) are polyurethane based adhesive-sealants. I don't remember the exactly rationale (Google is your friend), but generally silicone-based adhesives are not appropriate (or common) for marine use. Sealants, sometimes (but adhesive-sealants and adhesives are very different products).

 

[dbsea]

You'll find endless debates among boaters/sailors about whether Sikaflex 291 or 3M 4200 is the superior adhesive-sealant.

Think is, that location looks like it might just need sealant not adhesive-sealant... Sikaflex might be overkill. Or maybe not. Hard to see.

silicone based adhesive

Generally, there is no such thing in boating as a silicone based adhesive. Marine sealants (like Sikaflex 291 and 3M 4200) are polyurethane based adhesive-sealants. I don't remember the exactly rationale (Google is your friend), but generally silicone-based adhesives are not appropriate (or common) for marine use. Sealants, sometimes (but adhesive-sealants and adhesives are very different products).

Thanks FlymeAway, in this case i don't think it's ahesive'ing (if that's a word) anything. It's just a seal around parts of the flybridge.

 

[Submariner]

Thanks FlymeAway, in this case i don't think it's ahesive'ing (if that's a word) anything. It's just a seal around parts of the flybridge.

This is sikaflex 291 from the factory... all around the mast, and isn't performing any real adhesive'ing either. 6 screws hold the mast onto the boat.

Taken apart. All that is sikaflex 291 from the factory.
https://www.letsgochannelsurfing.co...kxcpitky-026339b0-a77e-455c-b73f-4a29fd3c25b2

Final install, with sikaflex 291.
https://www.letsgochannelsurfing.co...kxcpitky-31b81806-542a-4b95-bf6a-772f000ce192

 

[CaptT]

This article by Steve will help explain the differences.
https://nam12.safelinks.protection.outl ... reserved=0
Hope this helps!
Terry

 

[FlyMeAway]

This article by Steve will help explain the differences.
https://nam12.safelinks.protection.outl ... reserved=0
Hope this helps!
Terry

This was one of the articles I was looking for and couldn't find when I said Google is your friend! Thanks.

I would underscore (and I can't find the other long article discussing this, maybe someone else can) silicone sealants are impossible to get rid of once you get it on something. That includes the deck. Depending on the formulation it can also be quite slippery. I had a buddy who had a permanently slick spot on the deck of his sailboat... So many people slipped there that he ended up sanding down and refinishing the whole area; it was the only way he could fix it.