Alrob
Well-Known Member
would adding copper powder to a tin of antifouling do any good or harm ?
copper powder
- Thread starter Alrob
- Start date
oldsaltoz
Well-Known Member
I suspect any benefits would be lost due to the fact that the copper would be contained rather than exposed as in copper-coat.
No doubt someone will be along soon with a more scientific answer.
No doubt someone will be along soon with a more scientific answer.
Elessar
Well-Known Member
copper isn't a biocide but cuprous oxide is. Antifoul is 100% porous so it would probably oxidise. You'd probably be making something illegal, it may oxidise too quickly so not help much, and it would be expensive.
Just put CopperCoat on and be done with it.
VicS
Well-Known Member
As a means of producing a cheap version of coppercoat you might find that you cannot incorporate enough copper powder to be effective while retaining a robust enough paint film.
With coppercoat the coating is an epoxy resin. The surface has to be abraded initially to expose the copper.
With coppercoat the coating is an epoxy resin. The surface has to be abraded initially to expose the copper.
electrosys
Well-Known Member
WHAT ??? So the Admiralty made a huge error of judgement in cladding the wooden hulls of their ships of the line with copper sheet ?
Of course copper is a biocide.
"Copper was found to be one of the most toxic metals to heterotrophic bacteria in aquatic environments. Albright and Wilson [25] found that sensitivity to heavy metals of microflora in water was (in order of decreasing sensitivity): Ag, Cu, Ni, Ba, Cr, Hg, Zn, Na, Cd."
http://www.pedorthicnewswire.com/pdf/Copper as Biocidal Tool.pdf
Trundlebug
Well-Known Member
That's exactly what you do when you buy a tin of International VC Offshore antifouling; it comes with a pouch of copper powder which you stir / mix into the biocide and solvent.
They wouldn't add it if it didn't do anything...
VicS
Well-Known Member
I think you will find that the powder is copper (I) oxide. Not copper!
Most other antifoulings have the CuO ready mixed in but for reasons I know not it is supplied separately with VC Offshore and has to be mixed in by the user.
However the powder supplied with VC17m and VC17m Extra is in fact copper, but AFAIK neither contain CuO in the base.
nimbusgb
Well-Known Member
Cue a rash of silver bottomed boats!
nimbusgb
Well-Known Member
If you want to try it I have 25 kg of copper powder ( ala coppercoat ) to hand!
prv
Well-Known Member
There may be a chemical etc reason, but it could simply be to pander to the feeling that more work or esoteric steps mean a treatment must be better. If it involves lots of sanding, or ferocious solvents, or very restrictive application conditions, it must give a better result than something you can just slop on any old how, right? The extra work has "earned" you the better result
...a core component of the above thinking
(To which I am as vulnerable as anyone else, as can be seen from the spar-fettling shed erected on my patio for the winter)
Pete
KevB
Well-Known Member
I'd try a couple bottles of Tabasco..
Trundlebug
Well-Known Member
Ah, maybe it was VC17m I was thinking of. I get mixed up between the two, (only applying it once every other year.. memory not that good!!). As our boat was treated with VC Tar, International state that the only compatible antifoulings are VC17m or VC Offshore. The powder's certainly copper in colour though, and heavy. What colour is CuO? Green?
Both antifoulings seem fine, but perhaps not a fair comparison with other people's experiences because the boat's in fresh water most of the time and only occasionally gets out to brackish or salt water. The switch from fresh to sea itself cleans the hull, so the antifouling gets quite an easy time of it I guess.
I get the point about making people think it's scientific / more effective if they have to mix it themselves. A rather cynical view - but you could be right of course!
Doesn't make any difference to me, I buy the stuff at boat jumbles anyway and save a fortune.
No stated shelf life as far as I can tell, and it's always been OK so far.rob2
Well-Known Member
Well, as far as I know, all the manufacturers of long term coatings use a nearly pure copper powder which on exposure to the water turns to copper oxide which is the toxic antifouling. As with most metal oxides, the oxide is not as well bonded as the parent metal so as it depletes, the newly exposed copper again oxidises, replenishing the antifouling component.
That was also the mechamism with the Royal Nave copper clad ships, with the secondary effect that the copper plates prevented damage from boring beasties (plenty of those in most sailing clubs!).
Rob.
That was also the mechamism with the Royal Nave copper clad ships, with the secondary effect that the copper plates prevented damage from boring beasties (plenty of those in most sailing clubs!).
Rob.