What's the problem with silicone on a boat?

[CaptainRivet]

Originally Posted by s/v Jedi

Dow 795 is very good but there are alternatives that are just as good. Silpruf SCS2000 is an example that I am aware of.

Most of the anti-silicone rhetoric on CF is just parroting without actual first hand experience. Because it never ruins paint jobs as it already shows with the primer when it’s a problem and is easily fixed when it does. When the primer coat is fine, then the top coat will be fine as well.

You cannot be all around the world and repaired everywhere the acrylic windows/hatches so you also depend on others give you tips or talk to boatyards, dow 795 is without doubt most used in Caribbean where you have extreme UV conditions.
As dow 795 is very hard to buy in europe, do you know other as good alternatives you can get in europe?
Sikaflex 295UV is definitely non of them as well as others from sikaflex.
3M 4200UV maybe didn't hear a lot about then it's better as sikaflex 295UV but is it equal to dow795...3M what they use here in canaries but well here quality is rare and you have to specifically ask for it or import it and do it yourself.
The 3M5200 is top and glues like hell but is not UV stable and no silicone.

[s/v Jedi]

Originally Posted by CaptainRivet

You cannot be all around the world and repaired everywhere the acrylic windows/hatches.
As dow 795 is very hard to buy in europe, do you know other as good alternatives you can get in europe.
Sikaflex 295UV is definitely non of them as well as others from sikaflex.
3M 4200UV maybe didn't hear a lot about it good or bad...what they use here in canaries but well here quality is rare and you have to specifically ask for it or import it and do it yourself.
The 3M5200 is top and glues like hell but is not UV stable.

You posted your recommendation of Dow 795 and I posted an alternative. Now you tell me you can’t get Dow 795 and there’s nothing for you.

How can you recommend Dow 795 when you can’t even get it?

How can you not read that I wrote Silpruf SCS2000 is a good alternative?

Why would I go around the world repairing windows? I am a retired engineer, I don’t do any of that.

[CaptainRivet]

Originally Posted by s/v Jedi

You posted your recommendation of Dow 795 and I posted an alternative. Now you tell me you can’t get Dow 795 and there’s nothing for you.

How can you recommend Dow 795 when you can’t even get it?

How can you not read that I wrote Silpruf SCS2000 is a good alternative?

Why would I go around the world repairing windows? I am a retired engineer, I don’t do any of that.

Hard to get but not impossible, I imported several times via Amazon from an US store but one cartridge ended up costing nearly 40Euro with shipping/import fees and taxes. And well sometimes there was just Grey available when I would need black.
Used dow795 also in Caribbean helping to rebed the acrylic windows on my buddy boat that was done here in canaries with Sika 295UV by the boatyard before crossing 2 years ago...and several others.
I read silpruf SCS2000 and don't know it. Will check if you get it here.
You are very skilled and sail long and don't do cheap **** so I just ask for your experience, yourself or what you heard is good.

[s/v Jedi]

Originally Posted by CaptainRivet

Hard to get but not impossible, I imported several times via Amazon from an US store but one cartridge ended up costing nearly 40Euro with shipping/import fees and taxes. And well sometimes there was just Grey available when I would need black.
Used dow795 also in Caribbean helping to rebed the acrylic windows on my buddy boat that was done here in canaries with Sika 295UV by the boatyard before crossing 2 years ago...and several others.
I read silpruf SCS2000 and don't know it. Will check if you get it here.
You are very skilled and sail long and don't do cheap **** so I just ask for your experience, yourself or what you heard is good.

Okay, it’s just some miscommunication due to language I think

I believe the SCS2000 is available in Europe. Any structural glazing silicone should be good for this if it’s actually rated for that application and not just some text put on by marketing.

[Tupaia]

Originally Posted by CaptainRivet

Hard to get but not impossible, I imported several times via Amazon from an US store but one cartridge ended up costing nearly 40Euro with shipping/import fees and taxes. And well sometimes there was just Grey available when I would need black.
Used dow795 also in Caribbean helping to rebed the acrylic windows on my buddy boat that was done here in canaries with Sika 295UV by the boatyard before crossing 2 years ago...and several others.
I read silpruf SCS2000 and don't know it. Will check if you get it here.
You are very skilled and sail long and don't do cheap **** so I just ask for your experience, yourself or what you heard is good.

GE UltraGlaze SSG4000 is readily available in Europe/Asia/US, it often comes with an E suffix that I am guessing has something to do with EU import or product restrictions.

Arbo UltraGlaze 4000E

GE UltraGlaze SSG4000E

My wrap around Acrylic windows were done with this in 2013 still sound under tropical and temperate conditions.

[GordMay]

FWIW ➥ https://cdn.prod.website-files.com/5...ta%20Sheet.pdf

Originally Posted by GE

“...
Note: SSG4000 UltraGlaze silicone should not be considered for:
• Structural adhesion on bare metals or surfaces subject to corrosion (i.e., mill aluminum, bare steel, etc.) ...
• Underwater or in applications where the product will be in continuous contact with water...

Structural glazing applications require that GE® Silicones give written approval of the use of UltraGlaze® SSG4000 sealant for each building project. No blanket approval is given by GE® Silicones for structural glazing applications. Check cartridge label and Specification Data Sheet for additional limitations.

[Tupaia]

Originally Posted by GordMay

FWIW ➥ https://cdn.prod.website-files.com/5...ta%20Sheet.pdf


Structural glazing applications require that GE® Silicones give written approval of the use of UltraGlaze® SSG4000 sealant for each building project. No blanket approval is given by GE® Silicones for structural glazing applications. Check cartridge label and Specification Data Sheet for additional limitations.

Definitely check the labelling for your specific application. Doubt that any "sealant" manufacturer will give any approval for use on boats except maybe to a "boat" manufacturer for a specific application.


Here is an example of an "exclusion" from the DOW Warranty
"e. Use on single-family residential structures."


Lawyers just doing their job.

[CaptainMarkS]

Some references:

https://www.practical-sailor.com/boa...adhesion-tests
- Sikaflex 291 voted as best adhesive sealant.

https://www.cruisersforum.com/forums...es-260043.html

https://youtu.be/G-aQzoHqM80
- Another vote for Dow 795 for resealing windows. I've used this on our windows with great results (replacing Sikaflex).

By way of cost benchmarking, delivered cost to Miami, FL as of today:

- Dow 795 (my favorite) McMaster-Carr: $20
- Dow 795 Amazon: $28
- Sikaflex 291 Amazon: $21
- GE Silpruf SCS2000 Amazon: $25

[Goodxcharly]

Silicone works great for a lot of things. That’s what they put aquariums together with. I used it on my fixed port lights that are glued to the glass hull on a Catalina. If you do it right it leaves nicer finish and holds up to the sun better than the other marine products.
Removing is a pain though with a razor blade , acetone and a green pad you can clean it easily so other products will work.. Not that big of a deal. You can go one step farther and finish up the cleaning with a rubbing compound.
Having said all this a friend has talked me into using butyl tape. Like for stanchions, chain plates etc. Way easier.

[sinnerman]

Originally Posted by Goodxcharly

Silicone works great for a lot of things. That’s what they put aquariums together with. I used it on my fixed port lights that are glued to the glass hull on a Catalina. If you do it right it leaves nicer finish and holds up to the sun better than the other marine products.
Removing is a pain though with a razor blade , acetone and a green pad you can clean it easily so other products will work.. Not that big of a deal. You can go one step farther and finish up the cleaning with a rubbing compound.
Having said all this a friend has talked me into using butyl tape. Like for stanchions, chain plates etc. Way easier.

I buy my butyl from this source. Higher grade material...
https://marinehowto.com/bed-it-tape/

My two cents

cheers

[CaptainRivet]

Originally Posted by Tupaia

Definitely check the labelling for your specific application. Doubt that any "sealant" manufacturer will give any approval for use on boats except maybe to a "boat" manufacturer for a specific application.


Here is an example of an "exclusion" from the DOW Warranty
"e. Use on single-family residential structures."


Lawyers just doing their job.

Sadly the laywer pest wouldn't be necessary if the company specs properly what it is for and on the other side it's accepted was common sense is but instead of that we get "don't put cats into microwave", in a coffee cup of freshly brewed coffee stands "caution content is hot" or our chartplotters from the big 5 are "not suited for navigation"
And no normal even highly intelligent and studied person understands what I can use this product really for and whats a product not passing the specs. You need a laywer to tell you that and as a lawyer never gives you a 100% specific answer as everything law is interpretable you know nothing 100% anymore...

So the best that as many people in practise tell you that's what they used it for and it works and hold up well...in case of silicone what properly glues acrylic windows in and withstand best UV...dow 795 was till know the best I know and referred by nearly everyone in high UV areas.
But hard to get in europe...sis who has experience with SCS 2000 or the 4300E?

[CaptainRivet]

Originally Posted by CaptainMarkS

Some references:

https://www.practical-sailor.com/boa...adhesion-tests
- Sikaflex 291 voted as best adhesive sealant.

https://www.cruisersforum.com/forums...es-260043.html

https://youtu.be/G-aQzoHqM80
- Another vote for Dow 795 for resealing windows. I've used this on our windows with great results (replacing Sikaflex).

By way of cost benchmarking, delivered cost to Miami, FL as of today:

- Dow 795 (my favorite) McMaster-Carr: $20
- Dow 795 Amazon: $28
- Sikaflex 291 Amazon: $21
- GE Silpruf SCS2000 Amazon: $25

I think you mean sikaflex 295UV which sucks as its UV protection is not that great...know many cases incl my buddyboat where we redone it after 2.5years with dow795...
291 is no silicone and not UV resistant and 3M 4200 is much better and UV resistant too while 291 not and if wanna glue something really strong 3M5200 is the goto reference.