How to Antifoul

[Simon391088]

Hi,

I've had my SC35 a few years and always pay others to do the hard work.

However - to save on costs I'm planning on having a go at antifouling and changing the anodes this year.

With antifoul - do you really need to completely remove the old antifoul?
Is the best (most realistic) thing to use an electric sander?
Clearly I don't want to damage the gel-coat so I want to get this right.
How many layers do I need to put on and how long does each layer take to dry?

With anodes (on Sterndrives) is it simply a case of unscrewing what's left of the old ones and putting on the new ones - or is there some other preparation of the surface required?

Many Thanks
Simon

 

[gjgm]

You could have a look here

http://www.ybw.com/expert-advice/antifouling-your-boat-1227

You need a sound base, so scrape off any flaking stuff, but I do not think a few mm of a/f is going to slow your boat down. Well, not compared to taking the empty beer bottles off the boat !
Yes, just unscrew the old anodes and screw on new ones- make sure they are salt water not fresh water ones, and don't use copper a/f on on aluminium o/drives. Trilux is fine to use.

 

[rafiki_]

Yep, as above. Do not sand the old a/f, it is quite hazardous stuff, and you do not want small particulate matter being breathed in if at all possible. Just a light scraping to remove any flaking of the old stuff. A really strong jet wash will clean most of it up! Depending on the ambient temperature, it normally is OK to paint another coat immediately you finish the first coat.

Mask up the water line really well, it looks horrible if the line is not cohesive. Mask up around your outdrives too, you do not want copper based af on your drives. Min 1/2 inch gap.

Yep, anodes is a case of unbolting old and replacing with new on the outdrives. I do not know your engines, but you should find that there are some anodes within the engine, especially around any heat exchangers. I have 10 in each of my engines, but usually it is 6-8.

Make sure you use the right anode material, zinc for sea water, aluminium for brackish, and magnesium for fresh water.

Enjoy!!!!!!!!!!!!

 

[Simon391088]

That's great - thanks for the replies. It's definitely something I am going to do!

I was planning on leaving the engine anodes i.e. the ones inside the boat to the engineers, it's just the outside bits.

Thanks,
Simon

 

[prv]

Certainly do not dry-sand antifoul, but I used to get good results with "drywall sanding mesh" used sopping-wet on the end of a pole (you get pivoting heads that screw onto the end of a standard decorating pole). Use a hose to keep the hull wet, and a large bucket to dunk the sander in, and it thins and smooths out the old antifoul quite nicely. I used to do this one afternoon and then paint (2 coats) the following day.

Pete

 

[Nick_H]

Firstly you need to know which antifoul was used previously. If you know this, and its not flaking off, then you can just jet wash and overpaint with the same a/f, or lookup on the internet to check what else is compatible. If you don't know what was used previously, then it's more difficult. If you wipe it with a wet rag and the colour comes off, it's eroding antifoul, and AFAIK it's OK to overcoat with any other eroding a/f, though I'm not 100% certain so maybe others can confirm. If the colour doesn't come off then it's some form of hard antifoul and not all types are compatible. You either need to find out, paint first with a primer, or risk it.

Depending on which outdrives you have, you may need to remove the props to get one of the anodes on, and you sometimes need a special tool to do this, so best to check before you start the job.

 

[Richard10002]

I remember using International Primocon Primer to touch up a variety of patches, before the topcoat of antifoul.

 

[darryl_g]

I use Hempel Hard Racing on my Sc35 and aluxtra on the drive and props. Single coat on the hull. 2 on the sterndrive which I'd previously put an epoxy primer on. 2 coats of hard racing on the ql trim tabs and bow thruster.. Scrubbing hull with wet nylon scourer on pole with flexible head really quick way to scrub beforehand. 2 days for 2 to do the lot.

Anodes need torx head socket to change I think. Put 2 anodes on the tie bar for better protection.

Darryl

 

[oncewaswafu]

If it's VP outdrive with duoprops, it's props off for the collar type anode. Easy with the VP spanner.

 

[IDAMAY]

You should be able to get a couple of "how to leaflets" from your local chandler. These are produced by both Hempel and International and contain lots of helpful DIY advice. The International one has a compatibility chart that shows which ant foul paints from various manufacturers are compatible. You will find the majority are.

 

[CLB]

You should be able to get a couple of "how to leaflets" from your local chandler.

Or you could have a look at the June 2014 issue of a certain free digital MoBo mag, back issues available online.

 

[Robin]

Certainly do not dry-sand antifoul, but I used to get good results with "drywall sanding mesh" used sopping-wet on the end of a pole (you get pivoting heads that screw onto the end of a standard decorating pole). Use a hose to keep the hull wet, and a large bucket to dunk the sander in, and it thins and smooths out the old antifoul quite nicely. I used to do this one afternoon and then paint (2 coats) the following day.

Pete

+ 10 on the dry wall sander mesh on a universal jointed head fitting and pole. Used to take me 2 hours with one of those to wet sand a 41 footer with SWMBO helping by working the hose. I used to do it if possible same day as lift out and first coat of new antifoul next day, then another on day 2. if the cast iron keel needed places touching up with Primocon I would try and get that done soon after sanding, but only once it was totally dry. Best to use UV resistant masking tape and even then remove it just as soon as the 2nd coat has been applied or it will remain in places forever as a reminder to remove it earlier next time!

 

[salar]

If the boat is out for antifouling, that is the time to service the outdrives. My engineer changes the anodes at that point as well. I have always done my own antifouling but left leg services to the experts.
Apparently this page:
http://www.boat-angling.co.uk/Hints_and_Tips/Howtopaintantifouling.htm
...ranks higher on certain search engines than the equivalent from the site of a major marine paint manufacturer, hence the desire from Teamac to be featured!