Through hull sealant that can go in water before cured

[donradcliffe]

I would recommend 5200. Difficulty in removal is myth. To remove the old through hull, just take a 4 inch angle grinder from the outside perpendicular to the hole and rotate 180 degrees to grind off the flange on the outside. Then knock the remains of the through hull into the boat. Takes less than 5 minutes.

[Kello]

Originally Posted by s/v Jedi

The story about not being able to remove fittings when 5200 was used is a myth.

Fittings bedded (glued) with 5200 can "easily" be removed, the 5200 cannot. Inadvertently you said that it is easier to cut out fittings bedded with 5200 than to unscrew them ... The 5200 still needs (should be) removed so the fresh sealant is in contact with the hull, not the old 5200. And, even with the chemicals, that part sucks.

Originally Posted by s/v Jedi

I have one leaking fitting and this is where I used polysulfide. It is just above the waterline but it is a plastic fitting.

Instructions for bedding plastic fittings specifically say to NOT use polysulfide. I wonder if yours were leaking because of that? Regardless, 5200 is an adhesive more than a sealant, and since everything on a boat will eventually need renewing, inspection, or removal for some other problem, it is ridiculous to use a cantankerous "permanent" adhesive when a sealant is all that is necessary.


Do like your method of cutting out a recalcitrant thruhull tho! Will memory-bank that method.

[Kello]

Originally Posted by Bowdrie

If I had to replace a bronze thru hull whilst in the water, I would use 5200 without a second thought.

Go close a seacock, detach its hose, then open it for a mere five seconds. Then re-post here about replacing a thru-hull "whilst in the water".

Originally Posted by Bowdrie

As to its permanency with that use?
No, applied against a dirty wet surface, (underwater,) does not result in the same level of adhesion as would be so if used on a dry surface which has been abraded and chemically cleaned with Acetone/Alcohol.

THIS is interesting. What is your experience with applying 5200 to a wet, dirty surfaces that allows you to make such a claim?

[Kello]

Originally Posted by donradcliffe

I would recommend 5200. Difficulty in removal is myth. Takes less than 5 minutes.

My boat's PO's bedded the transducer in 5200 - removing the transducer was relatively easy, but it took most of a day to remove the 5200. How could I have done it in five minutes?


They also bedded the mast step with 5200, and when I (finally) got it off, it was because the 5200 stuck to the gelcoat and the gelcoat gave up. Took a lot longer than five minutes to remove the 5200 from the mast step. What am I missing?

[s/v Jedi]

Originally Posted by Kello

Fittings bedded (glued) with 5200 can "easily" be removed, the 5200 cannot. Inadvertently you said that it is easier to cut out fittings bedded with 5200 than to unscrew them ... The 5200 still needs (should be) removed so the fresh sealant is in contact with the hull, not the old 5200. And, even with the chemicals, that part sucks.

Instructions for bedding plastic fittings specifically say to NOT use polysulfide. I wonder if yours were leaking because of that? Regardless, 5200 is an adhesive more than a sealant, and since everything on a boat will eventually need renewing, inspection, or removal for some other problem, it is ridiculous to use a cantankerous "permanent" adhesive when a sealant is all that is necessary.

Do like your method of cutting out a recalcitrant thruhull tho! Will memory-bank that method.

Yes, the failure may well be to me using polysulfide with the plastic Marelon fitting.

For the old 5200: it’s gone when you run the holesaw through. Even when you screw or knock the fitting out, you can still run the holesaw through.

Edit: the method with angle grinder described above works good too, but it’s messy and more likely to damage the fiberglass.

[foufou]

While Cris Cringle recommended Boat Life caulk I had an experience, granted thirty years ago, where the boat Life caulk had not set up totally after a day, under a fitting and nearly sank my boat! Luckily I managed to sail back to the dock and being a small boat, hoisted it out and remedied the problem. I don't know if Boat Life caulk is formulated the same as back then, but I would be very cautious using it.

[foufou]

5200 can be removed with careful use of a heat gun. But be careful not to overheat adjacent fiberglass

[Bowdrie]

Originally Posted by Kello

THIS is interesting. What is your experience with applying 5200 to a wet, dirty surfaces that allows you to make such a claim?

Spend 2>3 years working in a haul-out/repair facility as low man on the totem pole where you get to do all the "fun" jobs, (like seacocks and toilets,) on wet/dirty boats and you'll start to get an idea of what works and what doesn't.
Then spend a couple of years in a production factory where on occasion you have to change a seacock location on a new/clean hull that has sat in the yard for a week>month and the difference is apparent.

Originally Posted by Kello

They also bedded the mast step with 5200, and when I (finally) got it off, it was because the 5200 stuck to the gelcoat and the gelcoat gave up. Took a lot longer than five minutes to remove the 5200 from the mast step. What am I missing?

That was not a good or proper use of 5200, a Polysulfide would have been a better choice.

[s/v Jedi]

Think of it like this: a polysulfide is a bedding compound, not an adhesive. This means you always need another means of fastening, like mechanical fasteners.

5200 is an adhesive and a sealant. It does it all.

If 5200 says it needs full cure before immersion then I would adhere to that, even when it seems to work okay with a launch straightaway.

[donradcliffe]

5200 is best for a joint that gets heavily stressed, and one which you only need to rebed every 10 years. My best application was for a plate which held a upper rudder bearing on the cockpit sole. It was through bolted, but it moved when sailing, and was wearing the bolt holes larger. Cleaned the joint thoroughly and applied 5200. A hundred thousand miles later the plate still hasn't moved again. I also use it for babystay and shroud fittings which penetrate the deck.

If I do have to remove fittings like that, I start with a spring steel putty knife or a razor blade and a hammer, and cut the seal around the fitting. I have also used thin piano wire wrapped around two pieces of wood to complete the cut. Some people swear by debond, but my primary use for that is to clean the surfaces once the fitting is out.

https://www.boatingmag.com/marine-so...removing-5200/

https://www.youtube.com/watch?v=bBYAR0NNwCQ

[merrydolphin]

Yes, I have changed thru hull with 5200 while in the water. I have also changed drive shafts while in the water. Just have to fast with the bungs.

5200 cures while wet. Just use plenty and then handle the mess ha ha. But it works.

[GordMay]

According to Forespar [‘Marelon’]:
“Bedding compounds such as 3M’s #5200, Sikaflex or Boatlife* are to be recommended as well as others that are equally suitable.”
➥ https://www.forespar.com/MarelonThru...allation.shtml

* ‘5200' & ‘Sikaflex’ are polyurethane based products.
Boatlife makes both polysulfide [‘Life-Caulk’], & silicone/polyurethane [‘Life-Seal’] products. Forespare doesn’t specify which.

According to TrueDesign:
Recommended Hull Adhesive Sealants & Glues.
• First clean all surfaces to be bonded with a general-purpose cleaner.
• 3M™ Marine Adhesive Sealant Fast Cure 5200. A one-part polyurethane adhesive/sealant. Starts to
cure (tack-free) in approximately 2 hours, after which ball valves and or hoses can be attached. Full
cure takes 24 hours – refer to manufacturer’s product literature.
• SIKAFLEX® 291i Marine Sealant. A one-part polyurethane adhesive/sealant. Starts to cure (tack-free)
in approx. 2 hours, after which ball valves and or hoses can be attached. Full cure takes 24 hours –
refer to manufacturer’s product literature.
• SIKAFLEX® 591 A multipurpose sealant designed for marine applications. It is suitable for elastic, vibration-
resistant joint seals - refer to manufacturer’s product literature.
• Bostik® 920 Marine Sealant. A one-part urethane adhesive/sealant. Starts to cure (tack-free) in
approx. 2 hours, after which ball valves and or hoses can be attached. Full cure takes 1.5 – 3 days –
refer to manufacturer’s product literature.
• West System® (or similar) two-pot epoxy that mixes to a paste. Tip – adding filler to the West
System® will increase the viscosity and help minimise “running” of the epoxy.
➥ https://trudesignplastics-com.s3.ama...e99ba29f86.pdf

[donradcliffe]

Originally Posted by GordMay

According to Forespar [‘Marelon’]:
“Bedding compounds such as 3M’s #5200, Sikaflex or Boatlife* are to be recommended as well as others that are equally suitable.”
➥ https://www.forespar.com/MarelonThru...allation.shtml

* ‘5200' & ‘Sikaflex’ are polyurethane based products.
Boatlife makes both polysulfide [‘Life-Caulk’], & silicone/polyurethane [‘Life-Seal’] products. Forespare doesn’t specify which.

According to TrueDesign:
Recommended Hull Adhesive Sealants & Glues.
• First clean all surfaces to be bonded with a general-purpose cleaner.
• 3M™ Marine Adhesive Sealant Fast Cure 5200. A one-part polyurethane adhesive/sealant. Starts to
cure (tack-free) in approximately 2 hours, after which ball valves and or hoses can be attached. Full
cure takes 24 hours – refer to manufacturer’s product literature.
• SIKAFLEX® 291i Marine Sealant. A one-part polyurethane adhesive/sealant. Starts to cure (tack-free)
in approx. 2 hours, after which ball valves and or hoses can be attached. Full cure takes 24 hours –
refer to manufacturer’s product literature.
• SIKAFLEX® 591 A multipurpose sealant designed for marine applications. It is suitable for elastic, vibration-
resistant joint seals - refer to manufacturer’s product literature.
• Bostik® 920 Marine Sealant. A one-part urethane adhesive/sealant. Starts to cure (tack-free) in
approx. 2 hours, after which ball valves and or hoses can be attached. Full cure takes 1.5 – 3 days –
refer to manufacturer’s product literature.
• West System® (or similar) two-pot epoxy that mixes to a paste. Tip – adding filler to the West
System® will increase the viscosity and help minimise “running” of the epoxy.
➥ https://trudesignplastics-com.s3.ama...e99ba29f86.pdf

All good, EXCEPT for the West System epoxy. Loctite also makes some really expensive stuff that goes off quickly.

[Ozzlawrence]

Originally Posted by Celestialsailor

Guess who snapped of the head water intake valve handle?... I will need to hang in the slings and replace the valve and probably the thru-hull as I'm guessing the set up is 44 years old. Is there a sealant I can use that will be able to splash in a few hours and still cure fully under water. Thanx in advance.

Here in Australia, I use Fixtech 190 and Fixtech 15. The 190 has a faster cure time and higher strength and is rated for below water marine use. I used it on 3 below water line through hulls and am very happy with it. It is a high bond strength product now used by the commercial operators I spoke to at Gold Coast City Marina.

[GordMay]

“FIX190HT” is a Modified Silicone Hybrid [MS Polymer, similar ‘to Life Seal’] moisture cure sealant, suitable for below waterline applications.
It’s not clear, to me, if FIX190HT can cure “under water”, or if it must be fully cured, prior to submersion.
➥ https://assets.cdn.thewebconsole.com...pressed-16.pdf