Chainplate sealant revisited

[floatsome]

I have finished potting the sidestay chainplate deck holes to protect the exposed core using this method, which worked great: Chainplate Fix. Now I'm deciding on two issues. I have been scouring the archives here and the Internet, and found lots of discussion on this issue, but nothing recently, so I'm curious about followup experience of those who have tried various solutions.

1. Which sealant to use to fill the gap. He used butyl, but I did not find an update to see how that worked for him. I think butyl would be less than ideal, since it does not adhere to the epoxy on one side, and the chainplate on the other. This is the one place I might use 5200, after prepping the walls with acetone to promote adhesion. I read about etching the chainplate, and I do have an etching product used to prep metal for painting. The downside of 5200, of course, is getting that 3/4" plug out again if the bond fails, I get water drips, and need to revise the seal.

2. How to seat the deckplate screws. I now have hardened epoxy at the screw hole sites instead of GRP skin and balsa core that held those screws before. My fear is that the epoxy will chip and crack if I simply drill pilot holes and dry-screw the screws into the holes. I'm thinking of drilling pilot holes for the screws, dipping them in hardened epoxy, and then screwing them in.

Thoughts?

[US27inKS]

I would use butyl. Where did you hear that butyl doesn't adhere to epoxy or the chainplate? On my boat, I cut a small bevel in the top of the slot to give me a place to pack butyl in. When the upper plate is installed, it packs the butyl into the gap. Worked like a charm.

The beauty of butyl is that it doesn't really dry. Chainplates that pass through the deck like mine tend to leak because of flex between the deck and the bulkhead. Even on the stiffest boat, there's flex. Any caulk that gets rigid or semi-rigid like 5200 or 4200 will shear off the chainplate as it moves. If the butyl gets sheared off, it will reseal itself.

[sailingdog]

I'd have to second what US27inKS said... butyl tape sticks to just about everything, except for some of the "slicker" plastics....

[Maine Sail]

Butyl will adhere well enought to allow any movement youd expect in a chain plate so long as you:

A) have enough gap around the chain plate for a adequate gaskets

B) Beveled the screw holes, potted the deck and beveled a slight reveal all around the chain plate.

You wanted proof? My chain plates were bedded in 1979 and were re-bedded lasts summer. The factory did it with gray flat butyl and I also re-did it with butyl tape. Not one of these chin plates had or was leaking after 29 years!

IMHO products like sillycone, 5200 and 4200 are why we have so many leaking chain plates to begin with. You DO NOT need nor want to "glue" your chain plates to the hull as they flex and move some. You DO want the absolute most flexible non hardening sealant one can buy and that, by a long shot is butyl.

If you need more movement than this you've got MUCH bigger problems...

[floatsome]

Very good - I've been a butyl fan for years, but did not think it would work in that application. Next question: what kind of butyl tape? I have easy supply from a window shop. The fellow who posted that potting procedure tried a tape that did not pack down into the space easily, so he used a hardware store type. He wrote, " It turns out that the butyl rubber was really tough to work with. It sticks to the chainplate and doesn't want to be pushed down into the gap. We re-did the staysail chainplate and used a caulking compound that we got at a Home Depot. It was much easier to apply, as it sort of flowed down into the void. It's called: Henry Elasto Caulk #289 White elastomeric Acrylic Patching Compound/Roof Coating".
Update: http://www.sailnet.com/forums/gear-m...utyl-tape.html

Also: still wondering about seating those screws in the hardened epoxy, which seems chippy to me under screw pressure.

[Maine Sail]

That Henry #289 stuff is NOT butyl, not even close, it's a water based acrylic caulk !

In order to get the butyl in there you need to stuff and cram it in. Warming it with a hair dryer will soften it some to make it more pliable..

[sailingdog]

Leaving the roll sitting in the sun for a few hours works to soften it... just don't leave it there too long.

[brak]

FWIW I had excellent results with Sika products, in particular the UV resistant SIKA 521-UV. It is a lower strength adhesive (fairly weak adhesive actually) with good flexibility and stretch properties, easy to work with and looks good.

[gtod25]

Maine Sail, once again thanks again for your great advice.

What is the general opinion on Boatlife "Life Seal Sealant" for bedding chain plates.

According to the info;

Recommended Usage: Fiberglass, vinyl, ABS, Lexan, metal, glass, wood; above or below water. Adhesion Rating: Tensile: 290 psi; elongation: 350%

Regards

Gerry

[St Anna]

hey guys - new to this thread.
I bumped a post with the backstay. The cap rail is cracked (all newish glass). Should I use epoxy or seal once/ sikaflex or combo to fill/fix??