Antifouling preparation...how long?

[Iain C]

I have about 4 weekends in April to finish the never ending jobs list, and re-antifoul. I've never done it before, so I was wondering how much preparation time I need to factor in. Is it just a quick sanding job?

The boat was launched in Oct 2009, after 10 years ashore. She'd been stripped right back and then had several coats of VC Tar applied by the previous owner so was very smooth...I just applied 3 coats of International Micron Extra and a 4th coat over leading edges/rudder over the VC tar...took two of us about a morning!

Since then she's been in the water in Portsmouth Harbour, summer 2010 on a swinging mooring and winter 09/10 and 10/11 on a drying mudberth with very little time per tide floating. She's coming out at the end of March and will be pressure washed by the yard.

I'm guessing as it's self polishing a bit of a blast with some 80 grit and another 3 coats...possibly one of my four weekends (weather permitting!)

Does this sound right or am I about to enter a world of sanding pain?

 

[Playtime]

I'm guessing as it's self polishing a bit of a blast with some 80 grit and another 3 coats...possibly one of my four weekends (weather permitting!)

Does this sound right or am I about to enter a world of sanding pain?

Sand if you must (wet) but a rub down (wet) with a green pan scourer (big thick version) is usually sufficient. You just need to ensure that all weed and slime are removed and that the surface is clean ready for the next coat. It's still a mucky job, though.

BTW - 3 coats is too much IMHO. If you put 3 coats on every year you will find it cracking and peeling after 5 years or so and will need to scrape or blast it all off again. Two coats around the waterline and leading edges and one thick coat over the rest should be sufficient if 3 coats were applied last year.

 

[VicS]

Most people do no more than scrub clean and then paint.

If you do get into sanding areas you think may need it remember due to the toxic nature of the material it should be done wet, not dry!

Best tool for applying is small paint roller. A big one gets arm achingly heavy by the end of the day and wastes too much paint.
Foam ones are attacked by the solvent, the mock lambs wool ones fair a little better IMHO but have a pack of spare rollers to hand so you can replace it when it starts leaving bits behind. Long handled ( radiator) roller useful too.

Unable to say how long it will take .. depends how big the boat is. It takes nearly twice as long if you have a boot-top

Apply 2 coats per season plus a third coat on leading edges
For two seasons protection apply 3 coats + 1 extra on leading edges


See the product data sheet for all the necessary info http://www.yachtpaint.com/MPYACMDatasheets/Micron_Extra+eng+A4+Y+20100722.pdf

See also the relevant sections of the "Boat Paint Guide". http://www.yachtpaint.com/LiteratureCentre/1726 BPG 09_79 Page_Online_UK.pdf

Scotch -brite type pot scorer suggested above is good but get one of the big scouring pads for a floor cleaning machine and cut it up. If you cannot scrounge one from the office cleaners get one from Screwfix

 

[Zagato]

Great question & timing for me also, hope you don't mind me adding to yuor question but how do you paint the waterline band as well? Presume that also has to be an anti foul paint but in a different colour.

 

[Pye_End]

I will really depend on what the condition is when you get her out.

If you have been in the mud, then you may wish to scrape or wet sand back to paint, which can take a while. If the existing antifouling has cracked then you will also need extra time.

If you are able to get at her as soon as she comes out, and you find you need some hard work on her, then the first couple of hours is the easiest time.

 

[benw]

IMHO once the yard have pressure washed attack the green slime residue that may well be on the boot top. If this dries it can be more of a pain and worse if you dont clear it as we found to our cost afew yrs back- a week or so after launch and a beard had started to form.
We use Micron Extra and they say 2coats and extra on the leading edges for a season and 3coats plus extra on leading edges for 2 seasons. Others have already stated this.

Feeling quite smug as I made the most in the break in the weather and managed 2 coats on hull and outside of keels (twin keel Sadler 32) but couldnt get the inside of the keels dry enough. Too much condensation on the steel with the warmer air of Thursday and Friday. An absolute first at a Feb half term hol! Usually its freezing and the the anti foul spreads like putty.

With two on the job providing the air temp is good (cant remember the actual temps and drying times but its on the tin) over a dry weekend you could get the hull done. The boot top is more fiddly with masking on the anti foul area bordering the boot top lower leading edge.

If the weather is kind a couple of weekends and you have it all done - maybe even a topsides polish!

I agree completely with the small roller application we use radiator roller type. Foam rollers last about 1 coat worth before disintegrating.

 

[Iain C]

Thanks guys. To confirm, it's just the prep that I was not sure about...the painting was easy! A mate, a couple of rollers, a nice day and a few cans of Stella and it was all done in a morning (it was thirsty work!). Forth Road bridge job...by the time the rudder was done the bow was dry!

I did 3 coats last time to try and get a couple of seasons so I'm hoping most of it will still be there and the new coat(s) will almost be "cosmetic". In addition the antifoul is black, which apparently gets less growth on (darker, less light, but might be an old wives tale!) and as she's sat in the mud for most of the time there's no "beard".

I won't be able to get to her until about a week after she comes out but I'll ask the yard to give her a good blasting and hopefully all will be well. I was worried people were going to say "a week of sanding" but that seems far from the case.

Cheers

 

[GrahamM376]

Sanding isn't usually necessary except on any areas which are flaking off. Good powerwash and then green pan scrubs around the waterline.

I'm surprised by the amount of antifoul some people use. We've always had swinging moorings with tidal flow past the boat and found that 1 coat all over + another around the waterline and skeg is sufficient, even sometimes for 2 seasons. Using Jotun Seaforce 30.