Favorite sealant for bedding deck hardware

[lharmon]

All I can say is there have been a lot of great posts on sealing/resealing deck hardware on sailnet. I have not seen anything too recent on peoples favorite caulks for leak proofing stantions, chainplates, etc. I do not need to rehash drilling outfilling with epoxy, etc - that's all been done. Three years later I want to pull the strantions and chainplate covers and rebed them I've got a drip at a stantion bolt and want to stop it before putting the boat in.

A lot of people swear by Boatlife. Then again many people think McDonalds serves food. And maybe Boatlife is the answer. I saw a 4000 guickdry not the 4200 that may be just an elastomeric sealant and was also wondering about other products you all know about and might recommend. I thought I would toos this out and know what to order by morning! I thought the old posts would do it but decided to get the latest and the greatest on sealants.

Thanks in advance for your help.

Regards,

LH

[sailingdog]

I like 3M 4200.

One thing that will help with the stanchions is to counter sink the bolt holes in the fiberglass slightly. This will allow the sealant to form a natural o-ring seal under the stanchion. Doing this makes the seal last a lot longer, especially on heavily loaded fittings.

[lharmon]

Sailingdog thanks for the fast reply. I was thinking of going with 4200 since the Boatlife has a drip after three years. I did have one person use the lifelines heavily - they held - and this may be the cause of the drip. I'll definitely try your slight countersinking tip. I also plan a 2 stage tightening process and will wait a few days for the final tightening.

Thanks again.

LH

[Maine Sail]

I prefer 3M 101 (polysulfide) for most deck stuff and Sikaflex (polyurethane) for bellow water or 3M 4200.

[lharmon]

halekai

Why do you prefer the 3M 101 fo on deck use? It was one of the ones I read about earlier but couldn't remember. Thanks for bringing it up. What would make you use it before 4200 on deck? This is good stuff. I really want to know.

Thank you.

LH

[Maine Sail]

Originally Posted by lharmon

I also plan a 2 stage tightening process and will wait a few days for the final tightening.

Thanks again LH

Unless you can guarantee that you will absolutely, positively 100% NOT budge that bolt during the 2nd stage DO NOT use the two step process! I'm convinced this is a process created by boatyards for future revenue of deck repair.

Countersinking is and a full tightening is enough!!! See evidence bellow...

This pad eye was installed on my RIB using the countersink/bevel method with immediate and full tightening. It is now 6 or 7 years old and has NEVER, EVER leaked even one drop of water! The big clincher here is that it's BELLOW the waterline and is used to lift my RIB into the davits so it does see stress and full immersion bellow water something your stanchions don't...

Exterior View:

Interior View:


P.S. I learned the countersink trick from the guys up at Hinckley about 18 years ago and since then have never once had a re-bedded fitting leak..

[sailingdog]

I'd second what Halekai said about not doing a two-stage cure process. It isn't necessary if you countersink the bolt holes as I suggested above.

BTW, be careful as some sealants aren't recommended for all materials. Some of the sealants are not safe for use on some plastics, and will attack ABS, Plexiglass, etc.

[lharmon]

Great shots of the countersink trick at work. Below the waterline on a RIB can't get any worse with the high speeds and pounding. Plus the lifting.

I will use it faithfully. I had already grabbed a countersink bit to take out to the boat. I also found five cleats for my Dyer dink, a cushion tip for one of my air hammers and a rescue whistle while finding the bit. Countersinking is already paying off in spades!

I really love the fact it is a one step process!

LH

[Maine Sail]

Originally Posted by lharmon

halekai

Why do you prefer the 3M 101 fo on deck use? It was one of the ones I read about earlier but couldn't remember. Thanks for bringing it up. What would make you use it before 4200 on deck? This is good stuff. I really want to know.

Thank you.

LH

Since you asked...
Over the last 35 years of my boating life I've learned NOTHING is permanent not even a keel joint and it WILL eventually need to be re-bedded in the future. For me, with mechanical fittings such as stanchions I find that e ven 4200 is MORE adhesive than necessary for mechanical fittings..

I like 3M 101 because it's easy to remove in the future and it does not have the "DEATH grip" of 5200 or the "half death" grip of 4200 that is not needed in 98% of mechanical connections.



In my experience the polyurethane sealants continue to harden until they become almost brittle and polysulfides tend to stay rubbery for the duration depending on UV exposure.. My Take, from years of experience, is that in 5, 10 or 20 years the 3M 101 polysulfide will still be very close to it's 416% elongation at break and the 5200 or 4200 will be less than that of 101 given nature of polyurethanes and how they continue to harden/cure over time....



Here's a summary of the products in the 3M line:


Elongation at break and tensile/grip strength:

3M 5200 = 1350% Tensile Strength = 700psi
3M 4200 = 900% Tensile Strength = 300psi
3M UV4000 = 800% Tensile Strength = 300psi
3M Silicone = 350% Tensile Strength = 220psi
3M 101 = 416% Tensile Strength = 139psi



Some additional things to consider:


The tensile strength of polyester laminated & resinated fiberglass (what your boat is made of) is between 400 and 500 psi!



Why one would want to adhere something to their hull at 700 psi, that will literally tear the gel coat clean off the substrate, if not removed patiently and carefully, is out of my realm of comprehension!!!!

If you must use a polyurethane use 4200 not 5200 but I find 3M 101 to be a great product that has never leaked on me. I also use Sikaflex products but they don't make a polysulfide. I don't find the BoatLife polysulfide as long lasting or flexible as the 3M 101.



4200 is a fine product but it's still a bear to remove compared to 3M 101. I've tried UV4000 but don't like the clean up and it turns yellow so it's really not all that "UV"...


P.S. You can not use polysulfides on many plastics..!

[CS271409]

This is a useful thread. Thanks for the pics halekai. I am in the midst of replacing my seacocks on my CS27 and I'm following your advice on your website including your recommendation to use Sikaflex 291 to seal the deal.
Others thoughts on below the waterline sealant.
Toerail and stanchion bolt sealant?