Keel Joint

[Euphonyx]

Coppercoat going on next week weather permitting. Am prepping the keel at the moment. Removing the old antifoul has been pretty horrendous. In a previous life someone epoxied over old antifoul on a couple of occasions. have had to work through it to the original gelcoat. have gouged out epoxy over antifoul at the lead keel/hull joint and cleaned it back to lead/gel. The join is pretty flush except at the front 6 inches or so. how to fill seeing as coppercoat is going on? is epoxy a bad idea? Thanks

 

[Behome]

Coppercoat is epoxy based and many people epoxy coat before Coppercoating so one wouldn't expect problems. You could always double check with Coppercoat direct for a recommendation.

 

[Euphonyx]

Apparently you just coppercoat away! no need for epoxy coat first. Its the joint I am concerned about. epoxy = rigid.... joint = def not rigid!

 

[Bosun Higgs]

Coppercoat going on next week weather permitting. Am prepping the keel at the moment. Removing the old antifoul has been pretty horrendous. In a previous life someone epoxied over old antifoul on a couple of occasions. have had to work through it to the original gelcoat. have gouged out epoxy over antifoul at the lead keel/hull joint and cleaned it back to lead/gel. The join is pretty flush except at the front 6 inches or so. how to fill seeing as coppercoat is going on? is epoxy a bad idea? Thanks

Had exactly your situation with a lead keel hanging off a grp sump. The yard did the coppercoat and they werent happy to put it on over the existing rubber band seal so they removed that and filled the lead / grp gap with epoxy. I was concerned that this might crack but despite an embarrassing incident with a rock of newton ferrars, the joint hasnt flexed and cracked. The only issue I have is that there is a 1 inch length where clearly the filler wasnt properly mixed and is still sticky.

My experiece wont necessarily apply to you - it depends on the engineering of your hull / keel joint. How rigid it is. But one thing is for sure, the coppercoat is quite hard and it will crack if applied over a felxible filler so you dont have an option as I see it.

 

[Euphonyx]

I think you are correct. I dont see that I do have the option. I think I have to either fill the whole gap with epoxy filler and coat over the lot or coat the hull and the keel leaving a narrow strip to be filled with uncoated uncoated sikaflex or similar.... favouring the first option at the moment

 

[EwanClark]

Indeed the choices are either fill the crack with two-pack epoxy prior to coating the whole underwater area (hull and keel) with Coppercoat, or fill the crack with a flexible mastic such as Sikaflex and leave this narrow band un-Coppercoated. Most people go for the second option, but both are fine.

 

[geem]

if you speak to the guys at coppercoat they will be able to supply you a good 3M epoxy filler. The filler was made by Thistlebond (now taken over by 3M). I used the Thistlebond epoxy filler to do the osmosis treatment on my boat and it was excellent. very easy to apply and sand.