A New Corrosion Killer?

[DaFrogman]

A couple of months ago, I found myself inspecting the lower unit of our twin 175 outboard motors prior to a routine change of the gearcase oil.

With me at the time was the intrepid Mr MacGyver i.e. Kahar and I remarked on the use of the Zinc anodes to prevent corrosion on the outboards. I then asked him if he had some old anodes I could cut up and polish to try an experiment on my Kaikon 4000 which spends most if its harried life being mercilessly punished by Kahar's commercial fishing schedule.

The idea certainly got Kahar's attention and he proceeded to dig up a chunk of anode salvaged from an old Mercruiser Alpha III drive, from which he ground off and shaped a small chunk and then drilled and bolted it to a reel clamp hole on the reel foot of the Kaikon.

Now some 6 months down the line, the Kaikon has come in for its periodic resuscitation and medical check and guess what.... zero corrosion anywhere, even in all the usual suspect areas despite quite a bit of salt residue in the sideplate and gear areas.... very interesting.

In contrast, an Ocea Jigger 5000 I serviced a month or so ago, which had been similarly maintained (but without the zinc anode) and had a similar level of salt residue had extensive light to medium pitting in the inner plate and damage to the anodisation on the inside of the sideplate.

Kahar told me that he noticed that the zinc anode on the reel reacted exactly like that on the outboards, seeming to form an oxide layer rapidly after exposure to saltwater and seeming to draw all corrosion to itself. Even the usual area under the handle of the Kaikon and the contact points between the handle and shaft had no new signs of corrosion.

I will now start making a similar setup for the 665 and if possible the Saltiga too... I will post some pics later of the simple setup Kahar made. It does not affect the handling or use of the reel in anyway and you wouldn't notice it unless you took a second look.

Just as an additional thought, I have been using OMC Triple Guard Outboard "sticky as toffee" grease on my reels too and that could have helped too I guess.

Any further ideas guys?.

Saimee

[Sportfisherman]

Saimee ,

Sacrificial Zinc Anode is meant for preventing / minimising the galvanic corrosions due to stray currents from engine's electrical system to the
other components . Somehow I fail to see how it will have any effects
on your reel unless it is an electrical reel but if it does so , perhaps you
should suggest this to Shimano to add some kind of plug shaped sacrificial zinc anode that can be screwed onto the side plates of the reel to prevent
the galvanic corrosion due to dis-similar metals in the reel .

keep us posted on this in the next few months , photos will greatly help .

Sportfisherman .

[DaFrogman]

Jon,

I am actually referring to Galvanic Corrsion which involves some form of reaction between dissimilar metals, especially in fishing reels where you have aluminium and stainless steel components in contact with each other.

The electrical problem you refer to for the engines (e.g. a ground leak) causes electrolysis which is really deadly to engines and in which sacrificial zinc anodes can only partially protect your engines. I have seen the effects of a minor ground leak on a Mercury outboard in just one trip out, where the entire lower unit and gear case were encrusted with salt and it wasn't long before the electrolytic problem made its way to the engine components...it was a costly oversight.

This is a random extract from the net on sacrificial zinc anodes used in saltwater for non-electrical related gear (in this case a crabpot);


"Galvanic corrosion, often misnamed "electrolysis," is one common form of corrosion in marine environments. It occurs when two (or more) dissimilar metals are brought into electrical contact under water. When a galvanic couple forms, one of the metals in the couple becomes the anode and corrodes faster than it would all by itself, while the other becomes the cathode and corrodes slower than it would alone. Either (or both) metals in the couple may or may not corrode by itself (themselves) in seawater. When contact with a dissimilar metal is made, however, the self-corrosion rates will change: corrosion of the anode will accelerate; corrosion of the cathode will decelerate or even stop.

Smart watermen know this fact and employ the use of sacrificial zinc anodes on their zinc-galvanized metal crabpots. With the sacrificial anode attached, the crabpot becomes the cathode. The result is that the anode will corrode (hence "sacrificial") and the crabpot won't. This effectively doubles the life of the crabpot."

I also seem to recall somewhere, where big game crews I think it was in Kona, used small sacrificial zinc anodes on their big game Marlin hooks to prevent the blunting of the hooks in saltwater. I'm sure that if anyone knows about that, Makaira might have an idea or two.

In any case, I will post a picture or 2 tonight of the tiny anode Kahar made. Thanks for your thoughts Jon, I always appreciate them.

Saimee

[Sportfisherman]

These are list of dis-similar alloys which will cause galvanic corrosion in seawater ( from NiDI - Nickel Development Institute ) ;

Gold with Cast Iron .
Monel with Alloy steel .
Stainless steel 316 with Low steel .
Stainless steel 304 with Aluminium 5052 ( Aluminium sheet / plate ) .
Stainless steel 430 with Aluminium 6063 ( Aluminium extrusion ) .
Silver with Aluminium 6061 .
Aluminium Bronze with Aluminium 3003 .
Copper with AlClad 3003 .
Red Brass with Zinc .
Yellow Brass with Magnesium .

Sportfisherman .

[fishpullipull]

just wanna say this is really deep stuff..hats off to you guys!

[sk8]

Sacrificial anodes are also used on boats and boat trailers here in NZ too.

Sounds like a great idea to use the same idea on a reel.

[DaFrogman]

Sorry the pics are late guys,

Been busy with Hari Raya still here and dinner with grandma....

3pics, one is a closeup. I figured that if around 800g of anode could protect a 500lb outboard, then the 15g anode here could do the job for a 670g reel.

The nut is a stainless steel locknut and the anode is bolted directly on to the reel foot at the reel clamp slot which is unused on my Kaikon.

Since the anode was installed, the reel has probably seen about 480 hours on the water being used only with rudimentary washing. I did not get the reel back for service during this period.

As Mikey knows, my reels get a LOT of saltwater spray and Kahar uses the reel every time he goes to sea, sometimes 3 trips a week. I would usually see minor corrosion on the AR bearing metal surfaces, the handle section where the knob shaft meets the handle, the thin sideplate cover where the line keeper is and also the bearing directly under the star.

This time round, no corrosion aside from small spots of rust on the stainless steel nut that bolts the anode in. The nut is 316 Stainless Steel, very corrosion resistant and even washed down regularly, it had rust spots, whereas the rest of the aluminium and stainless steel parts of the reel which are in direct contact metallically had some salt build up internally, but no corrosion or pitting as I would expect.

I leave the conclusions to you guys and I will experiment more with some other reels too.... next step is probably my Accurate 665 which is notorious for right spool bearing issues.

Saimee

[MarkR]

Hi Saimee,

Interesting stuff. Have you removed the line and had a look at the spool?

cheers

[DaFrogman]

Mark R,

Good point, haven't had time to despool the line, may try to find time to do that tomorrow morning or maybe late tonight....

Saimee

[edylie]

Interesting stuffs there Saimee. I would love to know more information if there is any more updates from your side!!!

If it really works, i would love to modify all my reels

Cheers,
Edy