Zinc changing season is coming

[fstbttms]

Not on the mounting screws -- on the surface of the prop nut itself or on the shaft itself - before one installs the zinc.

1.- Never heard of that one before

2.- Pretty sure the zinc manufacturer would recommend against it

3.- If your zincs aren't making good electrical contact with the part they are intended to protect, they haven't been installed properly

4.- My guess is the anti-seize would wash out in short order, especially on the prop nut

 

[Ralph Johnstone]

When the boat is in the water how does our diver make sure there is excellent contact between the new zinc and the to-be-protected protected shaft/propeller?

Charles

The best way I've found to ensure good contact plus ensure the zinc stays put, is to squeeze the bjabbers out of them face to face with a large C clamp (14") while tightening the set screws.

As far as cost goes, three of us got together some years ago and bought 60 zincs from Boatzincs.com. My 1" heavy anodes came to about $4.50 ea. with shipping. A little more expensive today.

I'm not about to get a chemical analysis of these anodes to determine the purity of the zinc but I can say that they (two of them) are changed every year, lose about 1/3 of their mass, and every piece of metal from the prop to the engine coupling is corrosion free after thirteen years. If I was worried, I'd install three of them to be extra sure.

No, these are not the best money can buy, however IMHO they are the most cost effective money can buy.

 

[Maine Sail]

Would the answers be different for "end of shaft zincs" like this one?

Same answers. Both shaft threads, nut adapter and the inside and ,mating surfaces of the zinc should be very clean. I agree with Faster about using a hex nut and a couple of washers to shim it out. Not so much for getting it on but for getting it off. You'll want blue Loctite on the set screw threads.. For those I use a little emery cloth on the inside of the zinc with my pinky finger.

 

[marian]

Would the answers be different for "end of shaft zincs" like this one?

That is all i have on my 351, the on on the left, for some years now.

 

[Chenega]

Would the answers be different for "end of shaft zincs" like this one?

Maine Sail - what's your opinion on these shaft end zincs..?

 

[fstbttms]

That is all i have on my 351, the on on the left, for some years now.

Nope. This is what you have:

 

[marian]

Nope. This is what you have:

Yes, you are right, thank you.

 

[jibes138]

A certain prominent store eliminating zinc zincs?

Just got a new catalog in the mail and was very surprised to see a prominent marine retailer is no longer selling zincs made out of zinc. They have switched to aluminum claiming they are "better" and better for the environment? If they were better why weren't they recommended all along since aluminum is so readily available, casts easily at low temperature, and low cost? Any thoughts on this transition and why?

 

[fstbttms]

 

[Charles Erwin]

An aluminum anode (mil spec) has greater current capacity thus useful life is longer than zinc by about 25%. If it is not mil spec and from reputable source it probably will not work at all so beware.

The galvanic potential of the aluminum anode is greater than zinc so do not use both zinc and aluminum anodes on the boat.

Also since the potential in aluminum is greater, galvanic isolation is probably mandatory. Otherwise, the aluminum anodes on your boat will protect the zinc on the neighbor's boat. His zinc anode life will improve and your aluminum anode life will degrade.

Obviously, aluminum anodes on wood hulls is a bad idea unless you know exactly what you are doing. The same goes for metal hulls.

Charles

 

[jibes138]

Sounds like another conspiracy to me. I'll bet they have higher margins on the aluminum so suddenly it is the new recommendation. If the zinc is such an environmental concern why not eliminate it entirely since aluminum is a proven "better" material? Zincs cost more don't work as well and are environmentally hazardous so why have they been used for so long when aluminum was always readily available? I'd put this in the same bracket as space aliens and bigfoot.

 

[FourPoints]

what would you suggest for an aluminum outboard or outdrive? I have always installed regular zinc's on them in salt water.