Silicone spray retards fouling

Reading the thread about barnacle fouling I thought I'd share this. This year I tried something on my 17' skiff and was surprised how well it worked. Over freshly dried bottom paint I applied dry silicone spray lube, doused it thoroughly, wiped off excess, let dry, repeated 2 more times. I used about 2/3 of an $8 can. This boat had been my daily commuter, in the same location, and lived in the water for 4 years and I know how fast it gets fouled. It's just seasonal use now. We had a tidal grid and I put it up and cleaned it regularly. In summer it would be bogged down (it has just 50hp) after 6 weeks. I pulled it out after 3 months, July-Sept and there was very little on it and there hadn't been a noticeable loss of speed. What there was could be wiped off with a sponge, it was clean in less than 10 min with a pressure washer, no bottom paint even touch up will be needed. I think if it wasn't being put up a little attention in the water with a soft brush would have kept it good for weeks longer. It made a big enough difference to me - and cheap as borscht, that neither boat will go back in the water without it, save for some issue arising, it is a new trick...

The can I used, from 3-in-1, didn't have anything on it about toxicity. I see you can get this stuff that's approved for food contact, and silicone is basically inert, certainly so compared to copper oxide, and it seems like it will help keep the copper in the paint and the paint on the boat.

I think a key thing is the fresh bottom paint, clean and porous. It probably won't last (as) long over gel coat or metal. The bigger boat gets new paint next year so it's going to be 3 years for a good update on this...

Greetings,
Mr. E. Interesting BUT will paint stick to your bottom the next time you have to re-coat. THAT will be the test. I'm guessing no.

Silicon based antifouling paint exists and are used by cargo ships. Difference from pleasure trawlers and cargo ships is the speed, cargo are going at 25knots while pleasure trawlers are going at 8knots. Would these antifouling work at 8knots, I do not know.

L

There are silicon bottom paints for recreational boats too. Don’t know much about it but heard a rumor that there can be problems with the boats slipping when they are hauled due to the slippery bottom. Anyone know anything about that?

Como,
Boats “slipping” .. from where to where?
Or slipping out of the slings?

EngNate,
I use ArmorAll on my prop. Apply more every time we haul out. Very little (almost undetectable) lost thrust.
Never did put it on a hull as I feared adhesion would be next to non-existent for next hull painting.

Yes, out of the slings. Don’t know if it is true but thought maybe someone here knew.

Nomad Willy said:

Como,
Boats “slipping” .. from where to where?
Or slipping out of the slings?

EngNate,
I use ArmorAll on my prop. Apply more every time we haul out. Very little (almost undetectable) lost thrust.
Never did put it on a hull as I feared adhesion would be next to non-existent for next hull painting.

Click to expand...

I think ArmorAll is silicone.

Getting paint to stick to silicone can be a real problem. So there's a good chance the bottom will need to be chemically cleaned and then have some of the paint stripped before any new paint will adhere.

rslifkin said:

Getting paint to stick to silicone can be a real problem. So there's a good chance the bottom will need to be chemically cleaned and then have some of the paint stripped before any new paint will adhere.

Click to expand...

It may take a sanding to prep for new paint but the heat from sanding may drive it into the hull. I am not sure what you would have to do to prep it...

Prior to retirement I worked in chemical production plants, one of which made additives for plastics and paints. Nothing with a hint of silicone was allowed in the unit including lubricants, gaskets, even fluids used inside sealed instrumentation. Very small amounts of silicone contamination would show up down stream as cratering and fish-eyes in coated surfaces. Quality control was extremely stringent. The auto industry was a major end user so the spectre of a complaint involving a large number of new cars was highly motivating.

Greetings,
Mr. DC. That's one of the reasons I've always ranted and railed against any silicone on boats. It's great for its intended and designed purpose but it's very difficult to remove completely and even a pinhead sized sample will spread faster and farther than the bubonic plague.


In a former life I refused to deal with or even touch any laboratory glassware that had come in contact with silicone greases or oils. Primarily, silicone grease was used to lubricate glass stopcocks (valves). The better grease (non silicone) could be baked out of the glassware in a glass annealing oven thereby rendering it "clean". Even a fingerprint of silicone would bake into the glassware rendering it potentially unusable and most definitely unworkable when glassblowing. Staff used it because it was cheaper (probably 10x) than the better product.

That would be my concern about putting it on the bottom, how do you ever get anything else to stick? What if 3 years down the road you want to use a different bottom paint???

BruceK said:

I think ArmorAll is silicone.

Click to expand...

Probably; this is from their MSDS sheet, which is otherwise very cryptic:

Thermal decomposition will generate oxides of carbon, silicon dioxide, and
formaldehyde

BruceK said:

I think ArmorAll is silicone.

Click to expand...

That’s why I mentioned it Bruce.

DCDC said:

Prior to retirement I worked in chemical production plants, one of which made additives for plastics and paints. Nothing with a hint of silicone was allowed in the unit including lubricants, gaskets, even fluids used inside sealed instrumentation. Very small amounts of silicone contamination would show up down stream as cratering and fish-eyes in coated surfaces. Quality control was extremely stringent. The auto industry was a major end user so the spectre of a complaint involving a large number of new cars was highly motivating.

Click to expand...

I also worked at a manufacturing plant and we had a powder coat line. We had to ban all silicone from the factory because it caused issues like fish eyes in the paint. It could not even be used on the opposite side of the building from the paint line as lubrication for machines. Any drop would contaminate the cleaning solutions and mess up the paint.

OK, if you cant get it off,isnt that what you want from a coating the minimizes growth? Maybe repainting will nbever be needed????

jimisbell said:

OK, if you cant get it off,isnt that what you want from a coating the minimizes growth? Maybe repainting will nbever be needed????

Click to expand...

Shhhh! Interlux and Petit are listening.

Hi,

Here's one silicone antifouling product for the European market, I don't know if Hempels products are US.

Link: https://www.boatpaint.co.uk/acatalog/Hempel-Silic-One-System-Brochure-UK-2018.pdf


NBs

So, I didn't get around to hauling the bigger boat this year for painting and treatment. I re treated the small one over last year's bottom paint, which didn't look very good after sitting in the dry, it had orange peel appearance. It had looked fine when it came out in the fall. It's Fiberglass Bottomkote, I don't think it can be out for that long, but the solvent in the silicone spray may not have been good for it. (Next will be a water based paint) Anyhow, it has been in the water and untouched since June and it is amazingly clean, little of anything around the waterline, feel just a thin layer of slime reaching underneath, and there's just a little reduction in speed. This compared to having to clean because its sluggish after 6 weeks in summer. I've been running the same boat, same motor, in the same water year after year.

Next update in the spring when I repaint and treat both boat's bottoms.

North Baltic sea said:

Hi,

Here's one silicone antifouling product for the European market, I don't know if Hempels products are US.

Link: https://www.boatpaint.co.uk/acatalog/Hempel-Silic-One-System-Brochure-UK-2018.pdf


NBs

Click to expand...

I have not tried Hempel bottom paint, but I do use their 2 part polyurethane top coat. Great paint but very hard to purchase in the US. You basically need to set up a corporate account with them. Even though they have a distribution outlet in town, they usually don't stock what I use.

I'm waiting for some reviews of their silicone bottom paint