New antifoul on top of old.

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chrisbitz

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18 Sep 2012
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509
Location
Bromley, Kent - Sail in Medway
www.freyacat.co.uk
I've never done antifoul before, so I just wanted to clarify a few things.

It's got international UNO on it at the moment, and it seems a reputable product, so I'm happy to buy some more...

I understand it's an eroding antifoul, and there are a few white patches just beginning to show through, maybe from too enthusiastic use of the jet wash on the keel?

Do I have to remove the old UNO, or can I just top it up, considering it's self eroding??

If I have to remove it, can I use a jet wash and maybe one of those Velcro-like scrubber pads, or do I have to use sand paper or a scraper or something?

Should I do it sooner rather than later, in case the cold weather prevents me from doing it in 2 months when it really needs doing? I'm not planning on taking her out for the winter too....

Thanks!
 
Have to say I have always done my boat in warmer climes...............but that aside jet wash her bum and if you are staying with the same brand just slap it on........or preferably get SWMBO to do it!!!

If you are changing brands then just slap on a "tie coat" of the new brands primer/undercoat.

BTW Compass24 were doing a very reasonable deal with A/F.
 
The recommendation from International is to lightly sand with fine wet-and-dry soaked in cleaning solution. Rinse. Jet washing probably has the same effect. Touch up the bare patches. Then apply a complete coat of anti-fouling.
 
Dry sanding antifouling isn't recommended - the dust is toxic. Even if you wear a mask, you have no control over where the dust goes, unless you have someone standing next to you with a vacuum cleaner or you put a tent around your boat. Just letting the dust blow away into the environment isn't acceptable. Well-wetted wet and dry is the way to go as all the surplus can easily be mopped up with a cloth..
 
greenalien said:
Dry sanding antifouling isn't recommended - the dust is toxic. Even if you wear a mask, you have no control over where the dust goes, unless you have someone standing next to you with a vacuum cleaner or you put a tent around your boat. Just letting the dust blow away into the environment isn't acceptable. Well-wetted wet and dry is the way to go as all the surplus can easily be mopped up with a cloth..
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The amount of rubbing down makes little difference to the enviro ( as we now call it). as a lad i was breathing in aframosia dust & i reckon that was worse for me
 
I would just give it a light sand and repaint .

Because it was and is erodable antifouling used. I would have thought the layer now showing is now a little of the stuff about to be washed off or eroded .
So sanding will give the next layer a good key..
 
chrisbitz said:
Do I have to remove the old UNO, or can I just top it up, considering it's self eroding??

If I have to remove it, can I use a jet wash and maybe one of those Velcro-like scrubber pads, or do I have to use sand paper or a scraper or something?

Should I do it sooner rather than later, in case the cold weather prevents me from doing it in 2 months when it really needs doing? I'm not planning on taking her out for the winter too....
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You don't have to remove the old Uno, but you should wash it down to ensure you remove any loose bits. Most boatyards now insist on jetwashing the hull as soon as they lift the boat out, and this will normally suffice as preparation. If your boatyard doesn't do this, just rub the hull with a plastic scouring pad whilst holding a running hose on it - this will get rid of any growth on the hull and remove the top layer of any remaining Uno. Don't use sandpaper; don't ever dry sand antifoul.

As for timing, I'd do it now, whilst it's still almost warm. Antifouling in the winter is miserable work. I do mine in the summer, when the marina has cheap liftout offers, and then it goes back in the water for 2 years, but I use Micron antifoul. I'd recommend you consider this regime, because the extra cost of the Micron antifouling is way offset by the need to only liftout every second year.
 
Having cleaned off with a jet wash, lightly key (wet) the remaining surface, removing any loose bits or flakes etc. A nylon scouring pad works well - no need to sand really. Then just before you paint, wipe the whole thing over with AF thinners. This makes the surface almost sticky and provides a very good key for the new coat. Do an extra layer (coat) at leading edges and around the waterline. You'll find that each manufacturer will tell you which other competitors paints you go straight over. I have tried many and find Jotun is the best - but others prefer different.
 
pvb said:
I'd recommend you consider this regime, because the extra cost of the Micron antifouling is way offset by the need to only liftout every second year.
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Thanks, fortunately, my club has it's own scrubbing trolley, and you pay £80 a year for as many goes as you like!

So at the moment, she comes out every month or so for a quick (and gentle) jetwash...

But I'm really thinking about doing it before the temperature drops another 10 degrees!
 
chrisbitz said:
Thanks, fortunately, my club has it's own scrubbing trolley, and you pay £80 a year for as many goes as you like!

So at the moment, she comes out every month or so for a quick (and gentle) jetwash...
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Every month??? You're just washing away your expensive antifoul. Paint the boat properly with decent antifoul, and then just use it.
 
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