Best Antifoul + doing it right?

[Mark-1]

I suspect the answer's going to be "none of them work", but is there an Antifoul of choice at the moment? Any to avoid?

I've never bothered sanding before but google suggests best practice is to give it a bit of a gentle going over with a powered wall sander and wipe it down with white spirit? True? Is that to remove excess of the previous AF or is it just to remove loose AF? Or just to key in the new coats?

TIA.

 

[pvb]

The real answer, which most people ignore, is that they all work - provided you apply the full coating which the manufacturers dictate. If you try to skimp on it, it won't work as well. I use International Micron, paint lots of the stuff on as recommended, and it lasts a full 2 years in the water.

As for preparation, most boatyards will require the hull to be pressure washed on liftout, and this will remove most of the crud. I always then wash my hull with a running hose and a Scotchbrite pad. No need to wipe down with white spirit at all.

 

[cat ketch]

I think that for the best brand you should try to find out what works where you are moored - I am fortunate to be in " low fouling " area and find that cheap A/F is fine. I use a manual plaster sander with a hose taped to the handle. I would not want to use any kind of electric sander because of the dust. This removes the deleted A/F and prevents a build up. If you want to wipe down use thinners not turps, but not needed.

 

[Mark-1]

Thanks both!

 

[Momac]

I am wet sanding my antifoul by hand at the moment , just enough to remove any residue and make the surface smooth, yet creating a key for the new paint. Some white GRP is showing through in some places .
I may be wasting my time and effort but at the moment it is helping work off some belly fat.

 

[macd]

I think that for the best brand you should try to find out what works where you are moored - I am fortunate to be in " low fouling " area and find that cheap A/F is fine. I use a manual plaster sander with a hose taped to the handle. I would not want to use any kind of electric sander because of the dust. This removes the deleted A/F and prevents a build up.

+1, especially about dry sanding, which is hazardous (and antisocial).
The cheapest maintenance job in sailing is applying the best antifoul to the best boat, since neither exists.
I daresay others have worked out the typo for "depleted"

 

[vyv_cox]

In 15 years in the Mediterranean I have used almost 15 different makes of antifouling. There has been no significant difference between any of them. Ranging from very expensive Plastimo due to a delivery driver strike down to the cheapest Greek-made from a fisherman chandler, nearly nothing between them. Three different International grades amongst that lot.

 

[Spirit (of Glenans)]

+1 regarding not using a power sander. Scrape first to remove any unsound material, hand sand with wetordry sandpaper or coarse Scotchbrite pad. Cat Ketch's idea of using plaster sander attached is a good one, better if the hose can be adjusted to a fine spray. No great need to wipe down, the quality of the finish is not an issue
I've just been thinking about some of the suggestions that were appearing in PBO about 20 years ago, when I first started reading it , such as the idea of adding hot chili powder to the A/F to increase its effectiveness

 

[Mark-1]

+1 regarding not using a power sander. Scrape first to remove any unsound material, hand sand with wetordry sandpaper or coarse Scotchbrite pad. No great need to wipe down, the quality of the finish is not an issue

I am wet sanding my antifoul by hand at the moment , just enough to remove any residue and make the surface smooth, yet creating a key for the new paint.
I may be wasting my time and effort but at the moment it is helping work off some belly fat.

Thanks both. Hand sanding suits me fine and it sounds like the 80/20 rule well and truly applies.

 

[William_H]

On this same subject if I sand down to expose gel coat in places do I need a primer to aid antifoul paint adherence. I have not done so in the past but then a/f does seem to detach ain places. ol'will

 

[superheat6k]

I am going to try Hempel Silic One this year. I'll let you know the first year results next Winter.

Not looking forward to the application though - four coatings required - primer, tie coat, two top coats generously applied.

As part of the current maintenance I've already been around about 50% of the hull removing stray barnacles, tube worms and odd areas of loose old paint. I did think about a shot blast off but see little to be gained as the surface is mostly very sound.

I'm also going to try the Silic propellor kit as well.

 

[Neeves]

I ran a big AF trial, in Oz - using Oz approved paints (which may be different to the ostensibly similar paints available in Europe and the US. We all are subject to different rules and regulations. I painted the hulls of our cat with 14 different AFs - and the AF companies were most generous with their advise. The best AF were Jotun's Sea Quantum Ultra and Hempel's Globic - both of which are restricted sale to professionals only - and both of which are noticeably better than the paints that leisure chandlers hold.

William H - some anti fouls are, totally, incompatible with other anti fouls (they have a different resin basis) and if you lightly sand - it will make not a jot of difference if you apply one over the other (the 2 will react and then fall off). You need to know the original AF and then ask the manufacturer of your choice of new AF if the 2 are compatible. If you don't know the old AF you take risk that in applying the new one, without a primer, that you waste your money and time. Fortuitously most AF use the same or similar resin systems.

Personally I'm not keen on removing the old AF, if it is sound - it still has active ingredients - why abrade them away?


Most people when they apply AF try to eke it out - big mistake - you need to accept that applying a generous 2, or even 3 coats, will last longer than 2 thin coats (as mentioned in an earlier post). If you give your AF supplier some idea of the size of your yacht they will give an estimate of how much AF you will need. If you ignore their recommendations do not be surprised if it does not last too well.


The big fear I have of the new rash of silicone based coatings is if they do not work then you need to strip all of the silicone paint off and abrade - any traces of silicone left on the hull will stop any conventional paint adhering in the future. Most of the big commercial fleets have tried or are trying these silicone coatings - and some have reverted back to conventional castings for some areas of the hull. Repairs of the coating are difficult (which is a problem with silicone, Prop Speed, on props - any damage to the coating and that damage provides the location where fouling commences - and attempts at 'cleaning' simply further damage the coating). International coated a racing yacht with their silicone coating some 4 or 5 years ago, Holland or Denmark I recall, the success might be marked by the total absence of any reports.

Jonathan

 

[Momac]

Not knowing which previous products have been used and having sanded through to the gelcoat is lots of places I intend to use a primer /sealer. Seajet 011 or 015 in my case which is on the shelf in the chandlery.

 

[Graham376]

On this same subject if I sand down to expose gel coat in places do I need a primer to aid antifoul paint adherence. I have not done so in the past but then a/f does seem to detach ain places. ol'will

If antifoul is detaching when you apply new, then it's time to scrape off and apply primer coat before new antifoul.

 

[[70521]]

I copper coated last summer, The hull looked like the surface of the moon - I am sure it had never been taken back to base in the 35 years she was afloat. So far, six months after the work was completed nothing is visible on the hull and the boat is faster. Apart from a power wash and changing anodes annually I will never need to antifoul again.

 

[[176172]]

In 15 years in the Mediterranean I have used almost 15 different makes of antifouling. There has been no significant difference between any of them. Ranging from very expensive Plastimo due to a delivery driver strike down to the cheapest Greek-made from a fisherman chandler, nearly nothing between them. Three different International grades amongst that lot.

Having been in the Med for many years, considered a high fowling area, I to had used various makes, until I met, in Barcelona, the owner of a '45, who claimed he had the cleanest bottom in the Med.
His antifoul was the cheapest available sold in bulk to local fishermen, into which he mixed chili powder, the hottest he could lay his hands on. This he mixed into the paint to the point where it was still possible to paint it on without too much difficulty.
My next antifoul I did half the hull just paint and half with a high concentration of chili powder as recommended.
The results were as he forecast, and susequent years have proved to be excellent, where some years only a wash required.
I purchesed the powder from an Asian wholesaler who was agast at my purpose for his countries culinary ingredient, I was foolish enough to put a very small amount on the tip of my tounge which felt like a blowlamp for at least an hour afterwards.

 

[pvb]

Having been in the Med for many years, considered a high fowling area, I to had used various makes, until I met, in Barcelona, the owner of a '45, who claimed he had the cleanest bottom in the Med.
His antifoul was the cheapest available sold in bulk to local fishermen, into which he mixed chili powder, the hottest he could lay his hands on. This he mixed into the paint to the point where it was still possible to paint it on without too much difficulty.
My next antifoul I did half the hull just paint and half with a high concentration of chili powder as recommended.
The results were as he forecast, and susequent years have proved to be excellent, where some years only a wash required.
I purchesed the powder from an Asian wholesaler who was agast at my purpose for his countries culinary ingredient, I was foolish enough to put a very small amount on the tip of my tounge which felt like a blowlamp for at least an hour afterwards.

We just have to wonder why the antifoul manufacturers are so ignorant of this startling breakthrough....

 

[Neeves]

The AF companies do want their AF to work - and will have tried everything legal - and some have tried things that are not legal - and went to prison (Hawk)

At least no-one has suggested adding antibiotics to the mix.

I'm with you PVB

Jonathan

 

[Mark-1]

I'm sure there's nothing legal and effective the yottie can add to improve antifouling, but I do wonder if there are any commonly available substances hat could be mixed with modern antifouling to create something illegal but effective.

Must be something that wouldn't prevent the antifoul sticking and lasting but would stop weed and critters growing.

Obviously I wouldn't do it myself because I like sailing really slowly dragging the cast of "Finding Nemo" along with me.

 

[ashtead]

How much chilli powder for say 2.5 litres of AF of whatever make? It might be of use for those wanting paint their propellers as an experiment in south coast waters.