Wearlon...........

[Puka]

The new products are coming thick & fast.
New to me anyway.
Water based epoxy with silicon???????
Why did the chemist go? Was he giving too much commercially sensitive info away and had his knuckes rapped?
Woe is us!
West reps here don't rate waterbased epoxies as much cop.......maybe
as antifoul tho'........?

http://www.wearlon.com/Emarine.htm

ps I really liked his impartiality.

[Garth Jones]

Well, I'm not "The Chemist", but I'm a chemist (turned furniture maker...). I will certainly try to be impartial (don't work for West, Wearlon, or anybody else but myself).

As I understand it, two of the major problems with a hull in the water are a) the friction of the water on the hull when the hull is moving and b) the obvious problem with marine growth. For us casual sailors, a little extra friction is not a big problem, but folks like Dennis Conner want the smoothest hull possible. Also, people that run large ships can save a bundle in fuel over the long term if their hulls are slick. For example, the US Navy is VERY interested in coatings that make their ships more efficient and repel marine growth.

So, the ideal situation would be a pefectly smooth hull (least friction) that is totally unappealing to marine life (and non-toxic is nice too). Imagine, then if you could coat a hull with a smooth layer of grease - it would repeal water, thus lowering friction and it would be none too tasty for mussels, etc. That's what the Wearlon expoxy/silicone coating is intended to be. Silicone is hydrophobic (repeals water) and the epoxy is the binder that keeps it on the boat. These sorts of coatings are also sold as 'anti graffiti' coatings because paint doesn't stick very well to the cured coating.

Now, how good is it? That's not clear - all the info I was able to find (in an admittedly short search) on Wearlon was on the manufacturer's website and they obviously think it's great. It probably does work quite well to lower friction and make a boat slightly faster, but I'd want to see a published independent study of how well it stands up to a marine environment before I believed it was really good.

As to the question of water based versus solvent based epoxy - all two part epoxies consist two small molecules that react chemically to produce long chains (polymers). Generally, the longer the chains and the more they cross link the harder (and perhaps more brittle) the coating. The final polymer matrix determines the physical properties of the coating, not the solvent. The structures of the two components determine how they will react with each other and how hard, soft, hydrophobic, brittle, etc. the finished product will be. I'm not a polymer chemist (I developed new reactions and synthesized small molecules), so I don't know if there are solvent based trends with epoxies.

Bottom line (IMHO) the Wearlon coatings are new, they might be the best thing since sliced bread, but I'd like to see some independent testing.

I hope this helps,
Garth

[Puka]

Thanks Garth for your time and effort!
I guess the prudent thing is "to wait and sea"!
If it doesn't do the biz it may be hellish to get off.
Water based epoxies seem to have a way lower m. of e. and quite
different characteristics to regular epoxy.Their water vapour permeability would
be interesting.I suspect it is greater than regular epoxy. If I can get some of that wearlon I might consider a test.
(As the silicon is hydrophobic....... )
Roly

[Ken Hutchins]

There is a product called Slick Sea or something like that (CRS) a discontinued item at WM. A customer came into the store looking for some and bought all the leftover stock. He is a pilot of a float plane, he said without using that coating he can't get enough speed for takeoff on the lake he flies his plane from.
When I first saw the stuff on the shelf I thought it was another "there is a sucker born every day" type item, but if a float plane pilot needs on it there must be something good about it.

[Garth Jones]

Roly - no problem. The water vapor permeability of water based epoxies might or might not be more - again, it's hard to say without knowing the structures of the monomers or what sort of polymer matrix they form. Given the presence of the silicone, I would think that the polymer would do a pretty good job of repeling water (vapor or liquid). Your idea of testing it out is a good one.

It certainly makes sense to me that these products improve performance (for racing boats or float planes). A smooth, hydrophobic surface should do that. However, salt water is a tough environment as we all know and marine organizisms that like to grow on boats are remarkably determined. So I really wonder how well this coating would do as a bottom paint for a boat that was in the water all the time. Again, testing is the answer.

Cheers,
Garth