Anode bolt grease

[cleddau1]

Just removed the anode under the cavitation plate on my 9.9. Anode only slightly pitted so it is now in the dishwasher and will be reused.
Had to use all the tricks to get the bolt out so was wondering what I could put on the thread to make it easier next time.
Presumably the bolt has to be in electrical contact with the anode and the leg and ordinary grease would be insulating. Would copper grease be OK?
Any advice much appreciated.

[DennisG01]

NO! Definitely don't use any grease with metal in it, or you set yourself up for MORE corrosion (galvanic corrosion from dissimilar metals in an electrolyte). I normally don't use any grease for the reason you mentioned. I suppose a small amount of something like wheelbearing grease (check the ingredients) would be OK since the threads will still cut through. But if you make it a habit of at least loosening them on a yearly (or semi-yearly) basis, it shouldn't cause too many issues at removal time.

Just out of curiosity, why are you washing the anodes? If anything, just brush off the crustiness with a brass or SS brush -- a steel one is OK, just make sure you remove any broken strands (compressed air works well).

[fairdeal]

I'm looking forward to what others have to say on this.

I recently installed the four M6 bolts holding the "handle anode" to the bracket

and after much consideration, I coated the threads with "dielectric silicone grease".

Now, my Eighth Grade science education told me that "dielectric" is pretty much the same as "insulator".

But I know first hand, "dielectric grease" certainly doesn't stop 12 volts from passing freely, when I've applied it to wire terminals.

The story I've read, is that forcing two metal surfaces together squeezes the grease out, hence no "insulation" occurs.

In any case, I've committed to the experiment.

I will be sure to post here if my bracket disintegrates...

[cleddau1]

Diolch

Thanks for replies.
The dishwasher method gets all the crud off the anodes and they come up nice and shiny and it saves me some time.
The only "grease" I can think of that conducts electricity well and might be OK otherwise is the stuff that is put on the electrodes that go on your chest and limbs when you have an ECG (EKG in USA)......

[DennisG01]

Tef-Gel will prevent corrosion AND conduct electricity. I use it for most electrical connections where corrosion is a possible issue. But it's also VERY expensive and I'm not sure how well it would hold up to being immersed in water all the time. It might be just fine - I just do not know as I've never used it for that purpose.

[TownsendsFJR1300]

I've used simple (not high temp, etc) anti-sieze on it, no issues...

I suspect a little bit of Yamaha's waterproof grease on the threads would work as well...

[rodbolt17]

I use water proof grease.
you can use the nickel(silver colored) anti sieze.

[99yam40]

when you run the bolt in with grease on it all of the threads are not insulated by the grease you put on them, some will be making contact when pulled tight. but the grease should keep the air and water away from the contact areas.
As Rod said nickel is OK,
copper is not. throw some pieces of copper wire or penneys into the bottom of a aluminum boat for a while and see what happens

[boscoe99]

when you run the bolt in with grease on it all of the threads are not insulated by the grease you put on them, some will be making contact when pulled tight. but the grease should keep the air and water away from the contact areas.
As Rod said nickel is OK,
copper is not. throw some pieces of copper wire or penneys into the bottom of a aluminum boat for a while and see what happens

Saw a relatively new Yamaha one time where the boat and the motor below the waterline had been painted with a copper based anti-foul paint. The motor was dissolving into nothing.

[cleddau1]

Thanks for replies. The Tef-Gel sounds useful stuff.
It costs approx £2 per Gram in UK. Current price of ****en ingots is £25 a Gram
It would be interesting to try each suggestion and measure the electrical resistance.
Will avoid copper grease although I do not really understand how a zinc anode will protect an aluminium engine as aluminium is above zinc in the periodic table....

[DennisG01]

With Rod's post, I took a look at Anti-Seize's website and sure enough, the stuff that Rod mentions is not corrosive. Good to know! I also noticed that they specifically make a "marine" formulation.

Take a look at a galvanic scale - you'll see the theory is correct. Also take into account that there are different formulations for anodes (Zn, Al, Mg) - and certain "cheap" anodes may not protect very well, at all. Also, you may find that Al anodes work better for you... again, depending on the manufacturer.

[cleddau1]

Thanks Dennis,
A Zinc & Magnesium anode would be theoretically best then.

http://www.corrosionist.com/Galvanic...n_Seawater.htm

My 9.9 purchased new is fine and the anode is pitting as expected, though not excessively. The engine is on a sledge so is lifted completely out of the water when sailing or moored. Generally run for an hour to get up or down river to where the estuary opens out to the sea.

All comments and advice very much appreciated.

[DennisG01]

Thanks Dennis,
A Zinc & Magnesium anode would be theoretically best then.

http://www.corrosionist.com/Galvanic...n_Seawater.htm

My 9.9 purchased new is fine and the anode is pitting as expected, though not excessively. The engine is on a sledge so is lifted completely out of the water when sailing or moored. Generally run for an hour to get up or down river to where the estuary opens out to the sea.

All comments and advice very much appreciated.

Except because you are running in fresh water and salt, neither is the best option. Al is going to be your best solution as it is the only one that can be safely used in both waters. In fact, there's even times when it's better than Mg (fresh) and Zn (salt) when used STRICTLY in those waters. For what it's worth, I really like the anodes made by Performance Metals, near Philly, PA here in the states. It's a special composition of Al. Although, I'm not sure what type of access you have to them given your location.

[bajakeith]

Noble metal's

I have used OMC triple guard grease for many years with good results..zinc and aluminum anodes are for salt water and magnesium is for fresh water.. With aluminum being the best ALL around noble metal..and a "Zinc" today refers to a Anode more than the type metal that it's made of and for cleaning a light sanding is best....

[bajakeith]

Grrrr !!

I tried to edit this like 6 times and no Stick..............Aluminum is in most cases your all around best bet..And (today) when someone refers to a zinc,, they are NOT talking about the type of metal its made of..