Lead keel - What sticks well ?

[duncan_ellison]

Hi,

I have a Hunter sailboat with a poured lead keel. Out of the factory the lead was faired out with some kind of polyester filler (probably some kind of Bondo) which cracked and fell off badly leaving big chunks of unfaired lead visible.

I spent ages chipping / sanding it all off and getting back to the lead surface, then recoated it with West System with aluminum powder and microballoons.

Damn if that didn't fall off of its own accord too.

Anyone got any thoughts on how to get a key onto solid lead and what materials to use ?

Duncan

[Target9000]

When you put the epoxy on the lead did you sand it in?

Lead will oxidize almost immediately and nothing sticks to oxidation. You actually have to "scrub it in".

[duncan_ellison]

Hi Target9000

Well, I sanded it with 100 grit on an angle grinder pad and it looked fairly shiny in parts, but it was probably a couple of days between sanding and doing the epoxy.

I figured there was some oxidization issue going on here and wonder if there's something like an acid wash I could apply before the epoxy, but thinking through your comment about scrubbing it in I'm now thinking about applying the first layer of epoxy using a scotchbrite pad rather than a brush.

Duncan

[Lagoon4us]

I've had same problem on a mono years ago, I prewarmed the lead keel wich was roughed up with 80# then brushed the epoxy on and sanded it into the lead when half off.

Worked for me and this is probably similar to TARGETS method?

[minaret]

Originally Posted by duncan_ellison

Hi Target9000

Well, I sanded it with 100 grit on an angle grinder pad and it looked fairly shiny in parts, but it was probably a couple of days between sanding and doing the epoxy.

I figured there was some oxidization issue going on here and wonder if there's something like an acid wash I could apply before the epoxy, but thinking through your comment about scrubbing it in I'm now thinking about applying the first layer of epoxy using a scotchbrite pad rather than a brush.

Duncan

Couple of days is WAY too long. Grind it shiny everywhere with 24 grit discs and apply WEST immediately. While the resin is still wet, wet sand the whole keel with 100 grit emery paper. Make sure to use medium or slow hardener so you have enough time to do a thorough job. Do not apply on cold lead. It won't fall off again if you are thorough.

[duncan_ellison]

As always, the very best advice is here on CF.

Thanks guys, I'll combine your ideas and give it a go.

Duncan

[Lagoon4us]

When i say half off i mean as it tacks a bit, you'll find it all goes grey as lead filings blend in.

[micah719]

What about an etch-primer? Is there such a thing for a boat's bottom?

[Lagoon4us]

Are you talking lead still or the bottom of a boat in general?

[micah719]

Well, in particular for Dunc's non-stick lead keel (hmmm, must investigate the feasibility of a lead frypan...but I digress)....but also for general benefit, though I should start a thread for that.

Yes, an etch primer, if there is such a thing for a boat's bottom, could be a solution to Dunc's problem, and the folks with aluminium hulls. For my desired boat in steel, I'm curious as to how to best go about having a good antifoul while preventing anything nasty getting in contact with the steel. I'm a painter at the moment and had experience with steel construction in the past so I want to avoid having a coating that looks fine on the surface but hides a calamity underneath.

Something else just occured.....can one metalspray lead? Sounds as if the factory were less than diligent in making the keel and passed on a ready-made headache to Mr Ellison, and using composite on rapidly oxidising lead again seems to be risking having it happen again. If one could get the lead itself as fair as possible one would have less need to putty up the thing, with all the expansion fatigue and capillary action and other wonderful things.

[Lagoon4us]

The questions you ask are all answerable by the manufacturer that you choose for the system you choose.

His problem was solved in the first posts, it's an every day job.

Polyester is not a great bonder Epoxy is...

Cheers