Rub rail caulking, which one?

04cobra23

04cobra23

Member
Aug 21, 2014
344
Boca Raton Florida
Boat Info
340DA and 215LR
Engines
Twin 8.1's and 4.3 Merc
I removed all the old (whats left of it) caulking on the rub rail and I am going to finish this tomorrow. I bought 4200 to do this project but just read something that says not to use it because it isn't UV protected and will turn to crap quickly. Any suggestions on what to use?
 
You're correct - good catch. I assume you're referring to simply the seam between the vinyl base and the hull? As long as it's sealed properly underneath, you really don't NEED to do that seam. There's pros and cons to both aspects.

There's no one 'best' caulk here. A lot of it comes down to personal preference and what someone has experience with. Try this for some more information and recommendations (there's nothing new to be said about this subject, anyways)... Underneath the Search bar is 'advanced search'. Go to that and enter something like "rubrail caulk" and select "titles only". You should get quite a few threads discussing this very question.
 
Lazy Daze said:
You're correct - good catch. I assume you're referring to simply the seam between the vinyl base and the hull? As long as it's sealed properly underneath, you really don't NEED to do that seam. There's pros and cons to both aspects.

There's no one 'best' caulk here. A lot of it comes down to personal preference and what someone has experience with. Try this for some more information and recommendations (there's nothing new to be said about this subject, anyways)... Underneath the Search bar is 'advanced search'. Go to that and enter something like "rubrail caulk" and select "titles only". You should get quite a few threads discussing this very question.
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Thank you Dennis! I am now debating whether I should re-caulk or not...I most likely will just for the extra "seal".
 
There is a UV rated 4000 series 3M product however from my experience it cannot be "tooled"; it just seems to make a gobbled up mess when used as a seam caulking due to the product immediately skinning. Set up a test to try it on before using it on your rub rail. As an alternative you might look at Life Caulk which I now use for seam caulking. The 3M 4000 and 5000 products I only now use for bedding and adhesive.
 
I've used the UV 4000 on several areas of the boat and have had pretty good results. It has stayed bright white and I haven't noticed any mildew on it either. As ttmott says, you do need to work with it quickly as it can form a skin in short time. But if you do smaller sections at a time it makes it easier to work with.
 
Are you talking about sealing the screw holes or the deck hull joint? You should really not use 4200 for either but if you are talking about the deck/hull joint, you want to definitely use a sealant like 3M Marine Silicone Sealant, NOT any kind of adhesive sealant. As far as the screw holes, I would think 4000UV or a Boat Life product would be fine.
 
jason78 said:
Are you talking about sealing the screw holes or the deck hull joint? You should really not use 4200 for either but if you are talking about the deck/hull joint, you want to definitely use a sealant like 3M Marine Silicone Sealant, NOT any kind of adhesive sealant. As far as the screw holes, I would think 4000UV or a Boat Life product would be fine.
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Rub rail to hull, so from what I've read its just cosmetic. I saw someone used GE UV protectant caulking for it.
 
04cobra23 said:
Rub rail to hull, so from what I've read its just cosmetic. I saw someone used GE UV protectant caulking for it.
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Why are you caulking the Rub Rail to the hull, (if I am understanding you correctly)? Or maybe you have a different type of rub rail than I am thinking. The white plastic rub rail is screwed to the hull and the Stainless Steel trim is screwed in to the hull over that. Of course all the holes should be caulked well but I am not sure I understand a reason to seal the RR to the Hull.
 
jason78 said:
Why are you caulking the Rub Rail to the hull, (if I am understanding you correctly)? Or maybe you have a different type of rub rail than I am thinking. The white plastic rub rail is screwed to the hull and the Stainless Steel trim is screwed in to the hull over that. Of course all the holes should be caulked well but I am not sure I understand a reason to seal the RR to the Hull.
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I do not know if the PO had it caulked or it came from factory like that. The boat is an early 03 340. Either way I removed all the old caulking and I wanted to redo it, mainly for cosmetic reasons as I've read on the forums. Plus I also read that it eliminates black lines running down the hull and in Florida it rains quite a bit.
 
ttmott said:
There is a UV rated 4000 series 3M product however from my experience it cannot be "tooled"; it just seems to make a gobbled up mess when used as a seam caulking due to the product immediately skinning. Set up a test to try it on before using it on your rub rail. As an alternative you might look at Life Caulk which I now use for seam caulking. The 3M 4000 and 5000 products I only now use for bedding and adhesive.
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Had this issue today with the silicone caulk from GE. What a damn mess, going back tomorrow to remove it all. Any caulk that is easy to work with?
 
If you are using caulk and not 4000UV, they snipping a corner of a sandwich bag and use like a pastry bag. It might help. Also you can take the area off and use water to help you work the caulk.


Sent from my iPhone using Tapatalk
 
mquiet said:
If you are using caulk and not 4000UV, they snipping a corner of a sandwich bag and use like a pastry bag. It might help. Also you can take the area off and use water to help you work the caulk.


Sent from my iPhone using Tapatalk
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Because the GE UV is silicone, water makes it worse. I taped the entire area, cleaned it and applied. When I removed the tape is was lifting the caulking also. I think I just let it sit for a too long (5 min).
 
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Personally, I like the BoatLife products. LifeCalk is slightly longer lasting product than LifeSeal, but LifeCalk is awful darn messy. Me... I would use LifeSeal. Still an excellent product made by a small company - and you can even call them and talk to a live person that you can fully understand. The sandwich baggie is great tip - I use that all the time.
 
Lazy Daze said:
Personally, I like the BoatLife products. LifeCalk is slightly longer lasting product than LifeSeal, but LifeCalk is awful darn messy. Me... I would use LifeSeal. Still an excellent product made by a small company - and you can even call them and talk to a live person that you can fully understand. The sandwich baggie is great tip - I use that all the time.
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How is the work time? Acrylic caulk is easy but me and silicone have never gotten along. When I tried to clean the silicone it just created a huge mess, now today is wasted and tomorrow I will remove it..:smt013
 
04cobra23 said:
How is the work time? Acrylic caulk is easy but me and silicone have never gotten along. When I tried to clean the silicone it just created a huge mess, now today is wasted and tomorrow I will remove it..:smt013
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I'm in a drier area than you (less humid) so I probably get a bit more time, but I can say that I've never had an issue on any of my projects and I've certainly worked with it in 90* over the summer. In fact, sometimes I'll mist the sealant with water as this will cause it to "skin up" faster. Remember, less is more when it comes to doing such a small area like the rubrail to hull.
 
alnav said:
The fiberglass guy at the local dealer told me that Sikaflex was the OEM supplier of caulk used by Sea Ray. Not sure if that's true but he used Sikaflex 295 UV on a couple of places on my boat and it has held up well. I tagged along on the install so I can do it myself henceforward and it seemed to be easy to work with. See http://usa.sika.com/en/automotive/automotive-transportation-home/01a006/01a006sa02.html.
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I wonder if any local marine stores carry. I will check tomorrow as the boat will be launched Tuesday (weather permitting) so I need to get this done. Thank you
 
I recently removed a lot of my rub rail. I discovered that the design of the overlap was such that caulking the top of the rub rail provides no functional value. So when I put it back together I only caulked where the top of the rail didn't quite pull tight to the hull. For these gaps I just squeezed Life Seal on my finger and pushed it into the gap using my finger to squeegee the excess off and then a damp rag for any film left. This left me with a cosmetic filling of the gap. Also, I personally would never caulk the underside of the rubrail. That just traps moisture in the wrong places.
 
To achieve a nice clean / neat caulk line - Something that worked well for me was using blue painters (masking) tape. I taped off the hull on one side and the rub rail itself on the other creating a 3/16" or so gap. Apply the sealer into the corner - smooth it out with a wet finger or wet cloth - let the sealer get tacky, go slow and pull the tape.

Taping off the boat is a fairly big job , but it goes quickly and applying and removing tape is a lot easier then cleaning up the sealer if you do not tape it.

Paul
 
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