Encapsulating an iron keel do's and dont's.

[vyv_cox]

Yes, two-pack epoxies throughout for priming.

You are right about the investment in Coppercoat. Not having to antifoul every year is a great pleasure.

You mention 'rub down'. Are you talking of the forum advice to abrade the Coppercoat? My experience and the advice of the manufacturers is that it is rarely, or perhaps never, needed. I didn't touch mine for 10 years and since recoating three years ago the same applies.

 

[VO5]

Yes, two-pack epoxies throughout for priming.

You are right about the investment in Coppercoat. Not having to antifoul every year is a great pleasure.

You mention 'rub down'. Are you talking of the forum advice to abrade the Coppercoat? My experience and the advice of the manufacturers is that it is rarely, or perhaps never, needed. I didn't touch mine for 10 years and since recoating three years ago the same applies.

Vyv, I agree.
Rubbing down...seems to be (by general consensus) a ritual applied to the coppercoated surface...and there is division of opinion on this. However,
you are not the only person to tell me abstention from this ritual is equally satisfactory.
I take it your boat is in the Med.
I was told that coppercoat is unsuitable for the Med....but there again the opinion given, shall we say, may contain an element of hidden vested interest , so I am disregarding it.

 

[vyv_cox]

Vyv, I agree.
I was told that coppercoat is unsuitable for the Med....but there again the opinion given, shall we say, may contain an element of hidden vested interest , so I am disregarding it.

You are right to do so. Coppercoated boats are not infrequent in Greece and I hear no complaints. I know one very well, its hull hasn't been touched for many years, never has any fouling. My son's boss kept a Coppercoated boat in Majorca, it wasn't lifted for something like five years but came out almost weed free.

The only problem I have encountered is the subject of your query. The antifouling was working fine on the keel but the rust got beneath after 10 years.

 

[Robin]

Thanks for the detailed explanation Robin, I appreciate the effort.
You reckon then Primocon is the route to follow ?

My Sealord has a glassfibre hull and an iron keel.

I think perhaps the project to coppercoat should be done in two stages, viz, first coppercoating the hull and rudder and antifouling the keel as usual.
Then on the next lift, dealing with the keel as you suggest and then coppercoating the keel.

Is that a better idea ?

It would be one way of doing it but I will admit to personal prejudice against coppercoat. We had a few in the YC with coppercoated hulls and one by one they went back to normal antifoul. One stck with his, but did rub it down every year before re-launching and said that helped. This was in Poole where there is a very significant problem with slime rather than grass fouling.

We had a Westerly 33 for 14 years and I did it with Primocon in year two having stripped it all off to bare metal first. I'm a fussy buqqer and don't like a rough finish or flaky antifoul. So that boat lasted with the Primocon treatment touched up when needed for at least the twelve more years we had it, without needing a strip and repaint. Our last boat was a Jeanneau Sun Legende 41 with a cast iron keel and we never had to do anything with that over ten years of ownership other than to Primocon along the keel to hull join and touch in the odd bits elsewhere.

 

[VO5]

You are right to do so. Coppercoated boats are not infrequent in Greece and I hear no complaints. I know one very well, its hull hasn't been touched for many years, never has any fouling. My son's boss kept a Coppercoated boat in Majorca, it wasn't lifted for something like five years but came out almost weed free.

The only problem I have encountered is the subject of your query. The antifouling was working fine on the keel but the rust got beneath after 10 years.

Aha..yes..this is probably because Westerly had a period of iron keels supplied by the foundry which seemed to have a supceptibility to pitting rusting more than others. The same foundry supplied keels to many other British builders in the period late eighties early nineties apparently.

 

[VO5]

I have had a brainwave !
What about the idea of heating (warming up) the keel with a heat gun during preparation of the keel for primacoating. Would this help in removing residual moisture from the keel surface?
Has anybody tried this...er..."stunt "...?...

 

[Conachair]

I have had a brainwave !
What about the idea of heating (warming up) the keel with a heat gun during preparation of the keel for primacoating. Would this help in removing residual moisture from the keel surface?
Has anybody tried this...er..."stunt "...?...

I think the bigger problem comes from the impurities within the iron itself. Though when i had my steel boat repainted the yard did blow infront with a flame torch, this helps not just with moisture but apparently can help blow off the surface rust which starts forming as soon as the metal is in contact with air.

Owning a steel boat i wouldn't touch single part paint again, 2 part epoxy only now. Ameron is favorite, now sigma i think. this is the best sealer I've found so far - http://www.promain.co.uk/product/PPG_SigmaCover_640_Sealer_Amerlock_Sealer_id3900

 

[rudolph_hart]

I stripped the iron wing keel on my boat 3 years ago. Iron is porous (relatively) and it's practically impossible to eliminate all the rust, because some may remain below the surface.

I used Jotun 2-pack epoxy aluminium-based metal primer, which is designed to be used where immaculate surface preparation is not feasible.

It's very 'high build' and so thick that it's impossible to apply with a normal paint brush without the finish looking like Artex! Because I wanted good mechanical as well as chemical adhesion, I thinned the first coat to allow some 'soak' into the porous surface.

Subsequent coats were less thinned (enough to allow brush application and give a smooth finish), and were applied after a wash and rub down with sponge-backed scouring pad.

I've used 'soft' eroding antifoul on top. It's still good.

Hope this helps.

 

[William_H]

F/g encapsulation

to concur with others. If the fibreglass encapsulation is so thick and strong that it is in effect a new keel molded onto the original iron then rust and the resultant expansion will not burst through the skin. I am talking fibreglass like 10mm thick. (similar to the hull itself)
A thinner coating even with fibreglass as a strengthening medium will blister under the internal pressure of the rust. You won't stop the metal from rusting in practice.
So encapsulation is not going to be a good idea. good luck olewill

 

[VO5]

I stripped the iron wing keel on my boat 3 years ago. Iron is porous (relatively) and it's practically impossible to eliminate all the rust, because some may remain below the surface.

I used Jotun 2-pack epoxy aluminium-based metal primer, which is designed to be used where immaculate surface preparation is not feasible.

It's very 'high build' and so thick that it's impossible to apply with a normal paint brush without the finish looking like Artex! Because I wanted good mechanical as well as chemical adhesion, I thinned the first coat to allow some 'soak' into the porous surface.

Subsequent coats were less thinned (enough to allow brush application and give a smooth finish), and were applied after a wash and rub down with sponge-backed scouring pad.

I've used 'soft' eroding antifoul on top. It's still good.

Hope this helps.

How long have you had it ?

 

[rudolph_hart]

How long have you had it ?

Had the boat 6.5 years, and I actually did the underside of the keel the same year I bought the boat. To be honest, doing the underside of the wing keel was a challenge, owing to its area (about the size of a big coffee/small dining table), its shape (it wasn't flat) and the fact that the boat was standing on parts of it.

I did the rest of the keel 3 years ago, and it was a much easier task.