Using magnesium in the pivot to prevent corrosion on tool steels

[Jesla]

How do you turn an “infact” statement in to a question?

Then proceed with pure fiction about something that is beyond current human ability?

Try approaching it with reality…. Please.

[Jesla]

double post.

[Jeb]

What a truly great thread here. My dealing with magnesium has been a pita but one we have had to have for protection.
You can't put anything on it, clean it off or it effects its abilities, purpose. Always looks nasty, least my opinion lol.
This has been a very good read, and there is obviously some of you here are sure enough rocket scientist that actually like great pocket knifes too lol.
I for one, like rubbing shoulders with you, in hope of learning something I can use in my day to day marching orders lol...

[Bolster]

NACE Corrosion Engineer here...

Great explanation, Fasty. Thanks for the (free) education!

[ChrisinHove]

My first thought was a magnesium liner in the Spydie hole, but of course it would just drop out as it corroded.

I saw a clock from the 1840’s a few weeks ago, using ground electrodes for power, and a coil ended pendulum around an arc shaped armature. It still looked and worked beautifully …. except the ground electrodes need to be replaced every six weeks!

[bobnikon]

NACE Corrosion Engineer here. I'll try to make this a simple read cause it can get out of hand. Just like fire has a triangle of requirements to occur (fuel, oxygen, and heat) corrosion does as well (a material with a polarity imbalance across it's surface, water, and oxygen). When we witness pitting corrosion on steel we're physically able to see which parts of the steel surface are carrying either a positive or negative charge. Corrosion is basically the result of the metals surface acting as a battery. Passive Cathodic protection works by introducing a new metal which will carry a stronger positive charge(the anode) there by turning the metal you wish to save into a negatively charged surface in comparison (the cathode).

While Im unaware of OPs source I would venture to guess the expirement involved a steel being submerged or constantly sprayed with water as a proof of concept and not a knife being edc'd and subjected to humidity. Air is a poor conductor and a great insulator. For cathodic protection to be effective you need the 2 metals to be able to freely exchange ions. Water is great for this especially with an electrolyte like salt, air is terrible for this. That's why you see Passive Cathodic protection used in wet environments like ships and buried pipelines. For this concept to work in a humid environment the entire surface of the steel would need to be coated(galvanized) so that as individual parts of the steel come into contact with moisture particles in the air the anode is there at the point the moisture contacted.

TL/DR: OP's idea would be a great way to have a nonfunctional folding knife that doesn't rust as much in water for a short period of time. OP's idea wouldn't save you from corrosion caused by atmospheric humidity.

No engineer here, but I am a sailor. I tried to explain this concept to the salesman at the car dealership who was offering both a passive cathodic rust protection and an active one. The active one plugged into the OBD slot in the car. I couldn't get out of there fast enough.

[StuntZombie]

Much like bearings, it seems like an unnecessary complication of what should be a simple tool.

[ImaCutSumSchitt84]

So you want to keep your blade shiny by putting in a soft metal pivot bushing which will corrode away instead? That's what a sacrificial anode is, a part that is supposed to corrode away. Are you hoping the oxidation products will act as a lubricant rather than an abrasive? The two possibilities I see are:

1) The corrosion products will fill the tiny space between the blade tang and the pivot pin, causing the two to seize, or

2) The corrosion products will wear away, leaving excessive clearance leading to unacceptable blade play.

This isn't on an outboard motor,it's a pocket knife, from what I've seen it's not affecting the anode enough to cause damage with regular use and care. As long as you aren't mistreating it you'll likely never know the anode is there. I know any company would want to avoid warranty claims but if you're treating it the same as you would any other knife it may never cause an issue. Like I said about Magnesium, it's not as soft as you're claiming, and may not wear like steel but in a folder I doubt it won't last as long as the rest of the knife. Spyderco may be a bad example because they don't have thumbstuds, which would be a better use case, but Spyderco does have a largest variety of tool steels and would be cool to know how it would hold up.

According to Wikipedia, magnesium has a Mohs hardness of 1 to 2.5, which is about the same as a human fingernail. That's how soft I'm claiming it is.

You can quote wiki all you want, I've used magnesium tools and floats on abrasive concrete and sand mix and I've never had one wear out or really wear at all beyond burnishing the surface, no way something with correct tolerances will cause crazy premature wear, also I'm not trying to overcomplicate things too much just asking a question

[ImaCutSumSchitt84]

Hey ImaCut,

Interesting topic, thanx for the spark. I also appreciate the thoughts shared by professionals like, fastidiotus (I resemble that name) and throw in the many great minds that hang here, gives us all a new file.

At this time, I think that some of our Salts are already a good solution where there is concern. Using exotic hyperformance blade steels that do not have good corrosion resistance do at this time, have to be cared for. I do believe in human-kinds ability to perservere to improve will constantly improve "the cut". Concepts like "MagnaCut" is an example.

But I would like to ask the question, keeping an open mind (drafty brain), is there a place for Magnesium to be easily used in our industry for the purpose of reducing corrosion, like an inlay of magnesium somewhere on the knife?

sal

Thanks for jumping in Sal, this is all I wanted by starting this was a good discussion. You're completely right about there being steels available that perform great and are plenty corrosion resistant, it just wouldn't be as much fun if everything were Magnacut and LC200N, even though they rock.

[zhyla]

You can quote wiki all you want, I've used magnesium tools and floats on abrasive concrete and sand mix and I've never had one wear out or really wear at all beyond burnishing the surface, no way something with correct tolerances will cause crazy premature wear, also I'm not trying to overcomplicate things too much just asking a question

Concrete tools are a magnesium alloy I think. But anyways it’s not like magnesium is that much softer than bronze. Bronze is used because of its low coefficient friction though. Magnesium’s coefficient of friction is really high.

I think we can forget about magnesium washers. They would be pretty miserable as washers and pure snake oil as a rust preventative.