How to waterproof holes in the deck?

[Azul]

Originally Posted by defjef

I've removed deck hardware with 5200 or something like boat life... I would suppose it depends on how much surface area is involved. It's strong but if the surface is not perfect for the bond the bond can be broken.

Probably because the surface was contaminated with silicone residue before the 5200 was used, or used on stainless steel which it won't adhere to properly. To remove silicone residue you can't just use acetone as is often done, it has to be physically ground off the fiberglass. With 5200 (which is a glue with something like 700 pounds per square inch holding power) it is simpler, if it is used "properly in the improper place" it will just delaminate the fiberglass when you take it off. Then you get to sand.

[HopCar]

It's pretty easy to remove metal fittings bedded in 5200. No need for a hot wire, just warm the fitting with a heat gun or propane torch. The fitting will pop right off. There are also several solvents on the market designed to break the 5200 bond.
I hear 3M is coming out with 52000, but they will only sell it to real men.

[sarafina]

In addition to amazing instructions, MainSail sells good quality butyl tape, which was the original sealant all those years ago!

Re-Bedding Deck Hardware Photo Gallery by Compass Marine at pbase.com

Need Butyl Tape ?? Photo Gallery by Compass Marine at pbase.com

[delmarrey]

Originally Posted by mark0978

Very interesting way to seal the screw holes. How well does that work in plywood decking? In my case I'll have to tape the bottom since the holes already exist.

The Butyl rubber tape I'm finding is 3/16" thick. Is that the right stuff? It seems terribly thick and would hold the stanchion away from the deck by a enough to make them wobbly.

Really sharp looking boat you have too, you have some amazing skills.

With existing holes, yeah, to tape the underside does the trick.

With a plywood core you just have to get a larger diameter Allen wrench and grind the end sharp, and short enough to get in the hole. It takes more effort but still works.

Once the holes have been recored with epoxy filler and a good base has been established it only takes a little butyl, or other sealer around the bolt to seal off the leaks.

As for a backing plate I use different thicknesses of G10 Material that is epoxied to the underside, which becomes part of the surface. Generally, 1-1/2 to 2 times the base of the object is the size of backing plates. The thickness is determined by bolt size. For 1/4" bolts I would go with a minimum 3/8 to 1/2" G10.

On my vessel I installed a 1" thick cap rail, plus the 3/4" cored deck (at the edges) I just used the stock SS backing plates. My stanchions would brake off before the base would loosen up.

Over!


.

[minaret]

Forget the Allen wrench and just chuck the appropriate router bit into a cordless drill. Does a perfect job to clean fiberglass in seconds per hole.

[roverhi]

5200 is indeed an adhesive but it's not permanent. There is a product called Debond that will soften the stuff and makes removal relatively easy. The few pieces i've bedded with it and had to remove, just applied steady pressure with a halyard cranked up tight and the fitting popped off after a short while.

Personally use LifeCaulk. It's somewhat adhesive but not nearly as much as 5200 and remains pliable over time. If the fasteners pass through the core, rout out the core, fill with thickened epoxy, and redrill the holes. Easy to apply and clean up with mineral spirits.

Butyl is a good sealant but a PITA to apply and to clean up. It sticks to itself instantly. If you run a screw through it, it will pull all the sealant away from other areas and wrap it around the screw. Then it's a bitch to pull the fastener down tight as it's got so much butyl wrapped around it. Best to apply the butyl to the fitting with the fasteners all the way in and then pound the fasteners through the deck, don't rotate them. Takes two people which is a hassle. Clean up is a problem. If you use mineral spirits, the butyl turns to an ugly slurry that will permanently stain older porous gel coat. Ended up painting the deck to get rid of the evidence of butyl clean up. Soapy water and the butyl itself is the safest clean up. Butyl sticks to itself so well, you can pick up the little stuff by rubbing a glob of butyl over it. Having said all that, for hardware that will see a lot of movement like lifeline stanchions, it's probably the best.

Sillycone belongs in boobs not boats.

[MarkSF]

Also wanted to mention Boatlife LifeCaulk which is specifically meant to be paintable.

[lancelot9898]

I used 5200 to mount a radar pole on the stern of the boat. The base of the pole sits on the teak cap rail and that base was held to the cap rail by 5200 and 4 screws. Within a year of that installation I needed to remove the pole and due to time constraints I did not have time to carefully attack the 5200 and expected to split that teak cap rail. However the pole came off without damage to the cap rail after a significant amount of prying.

[mark0978]

Originally Posted by minaret

Forget the Allen wrench and just chuck the appropriate router bit into a cordless drill. Does a perfect job to clean fiberglass in seconds per hole.

How do you get the router bit to clear out the material? If I were to put a router bit into the deck, the hole on the top side would have to be bigger. The Allen wrench will reach outside the hole in the top of the deck.

Are you saying to just make the hole bigger from the top, fill it with epoxy then re drill size hole you want?

[pwhitburn]

Does anyone know where you can buy Butyl Tape sealant in Australia? I have read about how good it appears to be but have not been able to find a supplier in Sydney.
Phil

[Hydra]

Originally Posted by mark0978

How do you get the router bit to clear out the material? If I were to put a router bit into the deck, the hole on the top side would have to be bigger. The Allen wrench will reach outside the hole in the top of the deck.

Are you saying to just make the hole bigger from the top, fill it with epoxy then re drill size hole you want?

To install a windlass on my boat cored deck, I followed the process described here by MaineSail:Sealing Deck Penetrations to Prevent Core Rot Photo Gallery by Compass Marine at pbase.com

The Dremel bit went nicely in the 10mm holes through the fiberglass and removed the balsa core, making room for epoxy.

Alain

[finding41]

Why is it leaking now? Product failure! Don't use it again.
Butyl tape only. Other products are not as good. One role will last a lifetime. Do it once. Right.

[delmarrey]

Originally Posted by Hydra

To install a windlass on my boat cored deck, I followed the process described here by MaineSail:Sealing Deck Penetrations to Prevent Core Rot Photo Gallery by Compass Marine at pbase.com

The Dremel bit went nicely in the 10mm holes through the fiberglass and removed the balsa core, making room for epoxy.

Alain

"Bent nails"?
Not a person with a brain in their head would use a bent nail! Allen wrenches are heat treated and work very well, thank you!. I've "potted" hundreds of holes using allen wrenches of different sizes.

Some the holes were for #6 screws. Try to get a dremel bit in one of those. Besides I cant figure for the life of me how one could get enough out (top & bottom) with a dremel to create an epoxy mass that wouldn't just crack and break under the stress of the bolt. One actually needs to build an epoxy sleeve between the deck laminates.

A thin layer of epoxy just doesn't do it. One literality has to build an epoxy column around the hole to not only seal out the water, but to also support the crushing effect of the bolt. And on a balsa core, that's critical. There wasn't one piece of plywood in any place I reworked on my vessel.

Excuse the rough drawing, a quickie.
But at the top is a hole with a allen wrench in it. It can clean out a whole column from top to bottom.
In the middle it's shown with an epoxy column in it.
The last is a very weak pour that will eventually crack at the edges (top & bottom) and start to crush and/or leak.
.

[Cheechako]

You weill see varying opinions on what to use, I'm in the "do it with 5200 camp and never have to do it again". But I do like Lifecaulk also. The common thread should be: You have to remove all traces of any silicone that was used. Clean the mating surfaces well, apply whatever "goop" you decide on liberally, and tighten the bolts. Use new bolts and a plate or big fender washers inside. Clean the excess goop off afterwards or even the next day... (another matter of choice)

[roverhi]

I use a Dremel tool with a #199 cutter 199 High Speed Cutter / Model: 199 The head is about 3/8" with a 1/4" shaft so it will undercut the fiberglass deck out about 1/4" back from the initial hole. Will easily cut plywood as well as balsa core deck. After routing out the core, use a syringe to squirt in unthickened epoxy then suck it out. That makes sure all the surfaces are epoxy coated to get a solidly bonded epoxy core. Thicken the epoxy with structural epoxy thickener and then squirt the thickened back into the hole with the syringe. Redrill the holes when the epoxy sets. That gives a thoroughly bonded solid layer of epoxy around the fasteners that cannot be compressed.

I've tried the Allen Wrench trick but it did not want to cut into the core material unless I cut it so short it took out less material than the 199 bit.