Grate black for prop anti foul

[Richard D]

A year ago I said I was putting the old grate black on my prop to stop fouling, as this is my first boat I have no knowledge as to how contaminated a bronze prop gets in a year, all I can say is that mooring in stranraer is propbablt one of the worst places for getting growths ddue to fact we are 6 miles down a dead end that the never cleans out and the growth is really bad on hulls. The results I thought were good, just a light covering of small barnacles that b rushed off easily and imagine if I had used the boat ( engine ) as much as most it would have had less, so there you go, maybe a good thing for a prop maybe not for the environment.

Richard

 

[25931]

Interesting - thanks. I suppose that you had a good reason to try it ? I don´t even know what grate black contains.

 

[pampas]

Think its Carbon Black. In its pure form the dust will get everywhere,carried drums Sealed tight as deck cargo from the States to UK for the Tyre industry horrid stuff.

 

[Neeves]

How do you apply carbon black (as a dust) to a prop and get it to stick. Graphite used to be used in lubricants (as did Molybdenum disulphide) as they are both slippery -are they options?

Jonathan

 

[oldbilbo]

There is a black additive for SP epoxy - and probably for other systems - which provides 'slip'. This is intended for the insides of daggerboard casings....

 

[tokoloshe]

Think its Carbon Black. In its pure form the dust will get everywhere,carried drums Sealed tight as deck cargo from the States to UK for the Tyre industry horrid stuff.

Also used to make vinyl records black.

 

[pcatterall]

I think we called it Zebart or similar, it was liquid and applied with a rag or brush. That was always my job..... before I had to whiten the steps!!

 

[Spirit of Glenans]

I think we called it Zebart or similar, it was liquid and applied with a rag or brush. That was always my job..... before I had to whiten the steps!!

Zebo, get it in your local hardware shop.

 

[Richard D]

Yes it was Zebo, you just clean the prop and rub it on with a rag and polish it in, after a year the original coating was still on and came off when I was cleaning the dirt off, so it sticks on no problem. How much encrustation would you expect in a year so I can perhaps judge if it really worked.

Richard

 

[fergie_mac66]

ahh there was a small article in PBO in the late nineties seem to recollect it said put on several layers then polish to a high shine !!

 

[Bodach na mara]

But would the graphite not react with the metal of the prop?

 

[BUNGAR]

I think the clue may be that here it is known as "stove black lead" therefore poisonous. I have been using it for years with success. I clean the prop with fine sand paper then with an old toothbrush apply pure lanolin. This I spread evenly over the blades with the help of a gas blow-lamp. I then apply two coats of the black lead with a cloth. No polishing, just a heavy coat. A year later there is a light growth of small barnacles but they fall off with ease. when I sand the prop it is still sticky with lanolin and completely black.

 

[Neeves]

Graphite is just another form of carbon and would not react with anything, in the absence of heat (and then it will oxidise, or burn). Natural graphite is a mineral and will contain contaminants (usually silicates) and they are also inert. It sounds very messy - but if it works, well worth it.

Jonathan

 

[Richard D]

No, Not messy at all, it is in a paste and you just squeeze some out of the tube on to a soft cloth and wipe it on, then polish it hard. I only put on one coat but you could put several on. If you are worried about getting it on your fingers, put on some nitrile rubber work gloves, it comes off easy enough with a good wash.

 

[doug748]

Graphite is just another form of carbon and would not react with anything, in the absence of heat (and then it will oxidise, or burn). Natural graphite is a mineral and will contain contaminants (usually silicates) and they are also inert. It sounds very messy - but if it works, well worth it.

Jonathan

But cast your eyes over this one:

http://www.books-for-sail.com/mecha...ortant-to-be-able-to-tell-the-difference.html

 

[Bodach na mara]

Graphite is just another form of carbon and would not react with anything, in the absence of heat (and then it will oxidise, or burn). Natural graphite is a mineral and will contain contaminants (usually silicates) and they are also inert. It sounds very messy - but if it works, well worth it.

Jonathan

As the link in Doug748's post shows, graphite (and carbon) are both possible electrodes in a corrosion cell. Carbon in fact is the positive terminal in a Leclanche cell (better known as a "dry cell" of the old type) with zinc as the negative terminal. And remember how the zinc used to get eaten away and let the electrolyte leak out. I remember once marking a piece of steel for cutting using a pencil and being told off for it on the grounds that the residue of the pencil graphite would cause corrosion of the steel.

 

[Neeves]

Just proves we are never to old to learn something. Might, do not the anodes protect this electrical corrosion?

There was mention of lead, its another product used in lubricants - there was a Belgian company, whose name escapes me (Baudier?) but I think they were bought out by Eckardt, who made powdered lead that was used in lubricants. Lead might also be poisonous to barnacles and the like (I would think graphite just slippery - non toxic? - someone will show me wrong) One might think a cocktail of powders of lead, graphite and molybdenum disulphide in lanolin? might be an answer.

If anyone comes up with an answer there is a huge market - its the big unsolved problem (I know Prop Spped works - but it is extortionate - primarily because there is nothing else)

Jonathan

 

[Richard D]

All I can say is that after 11 months in one of the most stagnant harbours there is, (Stranrear) for lack of water flow out to sea, hence max growth of algea etc it cleaned up to new looking bronze in 10 mins. My sacrificial plates are being eaten away lovely so dont think there is nay risk of elctrolysis on the prop.

Richard

 

[Poignard]

Worth a try. I think I have a tube of Zebo in the garage.