Sacrificial anode

Seraphim · 08-20-2008, 07:24 PM

OK, I turn to you metallurgist wizards for this one.

I have been pondering corrosion issues with high carbon razors, and came across info on sacrificial anodes being used for corrosion prevention on such things as ship hulls and water heater tanks.

Sounds good to me.

So I take a vintage Tuckmar that didn't shave too well

, screwed a piece of aluminum to it (didn'thave any zinc or magnesium handy..), and put it in a high humidity environment (i.e.-bucket o' water) to see what would happen...

pic one is the Tuckmar initial state.

Pic two, is the blade in the drink

Pic three is the day after...

Pic four is a close up of rusty side of the razor...not too surprising, eh?

But surprise, surprise...check out the other side! Pic 5

Is the one side rusty, as it was the side with the aluminum screwed to it? That also happened to be the side that was "up" in the bucket--coincedence?

Any other thoughts on possible implementation of sacrificial anodes in straight razor use?

backpackerx · 08-20-2008, 07:29 PM

Did you put it back in with the other side up now?

Seraphim · 08-20-2008, 07:31 PM

Quote:

Originally Posted by backpackerx

Did you put it back in with the other side up now?

I suppose that would make sense, however, it is air drying on my desk at the moment...

A couple more hours and this baby will be ready for Ebay! "Gently used vintage razor, slight chip on edge...."

EDIT: it is now back in there with the other side up...

I will also say that after I first put the razor in yesterday, I did see corrosion begining on the tang closest to the aluminum within a fairly short period of time (a couple of hours). About 1/4" from the aluminum it discoloered rapidly.

holli4pirating · 08-20-2008, 07:58 PM

I can't believe you've gone and ruined that sweet blade!

I'm also interested in seeing if flipping it over does anything. I'm no chemist, but I would have thought the Al should prevent any rust from forming. I'm curious as to why it would only affect one side, and that makes me think it might have something to do with the orietation in the water.

jimmyray · 08-20-2008, 09:45 PM

I'm not a chemist either, so don't take this as gospel, but I think they use zinc because it is more reactive than steel. I don't think the same is true of aluminum. Otherwise aluminum cans would disintegrate, especially with all the citric acid in sodas. Maybe?

But again, IANAC.

Seraphim · 08-20-2008, 10:50 PM

Quote:

Originally Posted by jimmyray

I'm not a chemist either, so don't take this as gospel, but I think they use zinc because it is more reactive than steel. I don't think the same is true of aluminum. Otherwise aluminum cans would disintegrate, especially with all the citric acid in sodas. Maybe?

But again, IANAC.

Aluminum is more active than steel as well. That is what they use for anodes in water heaters, etc.

Aluminum cans don't corrode as thay are all aluminum. If they were part steel and part aluminum, it would set up the differential that would make the aluminum corrode if I understand the process correctly.

Seraphim · 08-20-2008, 10:52 PM

Now the side that used to be down is up, and it is rusting up quite nicely as well.

Thus it appears as if either:
a)I don't know what the heck I'm doing

b)This process doesn't work for straight razors.

c)all of the above.

P.S.-anybody want to buy a vintage Tuckmar?

Russel Baldridge · 08-20-2008, 11:15 PM

So, it rusts on whichever side is up?

That seems strange.

Detach · 08-21-2008, 02:42 AM

maybe it has something to do with light? (just randomly throwing that out there)

Navaja · 08-21-2008, 03:05 AM

Perhaps this will answer your question: (From Wikipedia)

It is important to understand that for this mode of corrosion protection to function there must be simultaneously present an electron pathway between the anode and the metal to be protected (e.g.,a wire or direct contact) and an ion pathway between the anode and the metal to be protected (e.g., water or moist soil) to form a closed circuit; thus simply bolting a piece of active metal such as zinc to a less- active metal, such as mild steel, in air will not furnish any protection.

baglamas · 08-21-2008, 05:10 AM

Aluminum forms spontaneously a non-reactive aluminum-oxide film on its surface that inhibits further corrosion. This is called passivation.

This protective film makes aluminum unsuitable as a sacrificial anode, but special aluminum alloys have been developed that do not passivate.

In other words your experiment did not work because you can't use regular aluminum as a sacrificial anode.

The reason that rust formed only on the side that was "up" is that more oxygen is available closer to the surface of the water.

Sacrifical anodes can only be used with an electrolyte (like the water in the experiment). So it's not possible to use this method of protection with objects like razors.

A more practical way to protect a blade made of carbon steel is to keep it clean, and coat it with oil before you store it (even cooking oil will do).

Even better solution: switch to stainless steel.

Seraphim · 08-21-2008, 05:19 AM

Quote:

Originally Posted by baglamas

Aluminum forms spontaneously a non-reactive aluminum-oxide film on its surface that inhibits further corrosion. This is called passivation.

This protective film makes aluminum unsuitable as a sacrificial anode, but special aluminum alloys have been developed that do not passivate.

In other words your experiment did not work because you can't use regular aluminum as a sacrificial anode.

The reason that rust formed only on the side that was "up" is that more oxygen is available closer to the surface of the water.

Sacrifical anodes can only be used with an electrolyte (like the water in the experiment). So it's not possible to use this method of protection with objects like razors.

A more practical way to protect a blade made of carbon steel is to keep it clean, and coat it with oil before you store it (even cooking oil will do).

Even better solution: switch to stainless steel.

I was going to revolutionize the razor industry!

But my innovation now sits rusting in a bucket on my desk....

I coulda been a contender

backpackerx · 08-21-2008, 05:20 PM

It won't work out in the air without an electrolyte but you could always store it in water!

(Imagine recommending that to someone)

PonderingTurtle · 08-21-2008, 05:34 PM

Quote:

Originally Posted by baglamas

Aluminum forms spontaneously a non-reactive aluminum-oxide film on its surface that inhibits further corrosion. This is called passivation.

This protective film makes aluminum unsuitable as a sacrificial anode, but special aluminum alloys have been developed that do not passivate.

In other words your experiment did not work because you can't use regular aluminum as a sacrificial anode.

The reason that rust formed only on the side that was "up" is that more oxygen is available closer to the surface of the water.

Sacrifical anodes can only be used with an electrolyte (like the water in the experiment). So it's not possible to use this method of protection with objects like razors.

A more practical way to protect a blade made of carbon steel is to keep it clean, and coat it with oil before you store it (even cooking oil will do).

Even better solution: switch to stainless steel.

I was wondering if that was the problem. Would magnesium work then?

I thought this method was also used with pipelines, to reduce corrosion.

JoshEarl · 08-21-2008, 08:26 PM

I have noticed a similar effect when I was etching razors--the one-sized thing, that is. I think it has to do with bubbles getting trapped on one side of the blade or something. Anyway, if one side of the blade is down and the other is up, the down side doesn't etch very well.

Josh

thebigspendur · 08-22-2008, 12:33 AM

This came up out of a thread over at B&B and I'll repeat what I said there. Those living in the S.W where we use evaporative coolers to cool our homes in summer will put an anode in the water in the tank and attach it to the metal chassis and the anode is about 4 inches or so long and an inch or so thick and at the end of a season the anode is totally gone and the chassis is clean. I really don't know what the anode is made of. I used to think zinc.

So the anode idea is a no go because the razor would have to be submerged in water.

Russel Baldridge · 08-22-2008, 08:25 PM

Quote:

Originally Posted by baglamas

Even better solution: switch to stainless steel.

Them's fightin' words, sir.

(

)

Kevin8888 · 10-21-2008, 04:48 PM

Sacrafichal anode is a good idea, but if u want to be simple about it just store naked blades in oil. lol, oh and one last thing, water isnt an electrolyte, tap water is, because of impruities, but distilled water, aka pure H2O is not,

Lancer · 10-23-2008, 02:37 AM

My guess?

Aluminium forms a tough oxide layer that makes it impervious to further corrosion.

Try a metal like Zinc (most popular industrial sacrificial annode) and you might find a difference.

The general rule of thumb is that the more reactive the anode the better the protection.

cybrok · 10-23-2008, 03:08 AM

Okay, I'm going to bed soon, I have an exam tomorrow, I'll tell more later.

But I can tell you a sacrificial anode is a PREVENTIVE method. It will create a galvanic cell helping in protection of the metal you want to keep.

I think what happened in your case was a mix of galvanic cell and differential aeration cell, so your sacrificial side became the up and the down became protected.

I could try to scan a few diagrams for you. But for the records I think a sacrificial anode for a razor is a bad idea. Cleaning and oiling will be easier and more efficient.

As for the sacrificial anode, magnesium would be the best. That's what is in the water tanks.