Corrosion and Edge Retention

[TkoK83Spy]

That's a lot of mentioning.

[JonLeBlanc]

I have noticed that (pretty humid here), and as others have said, one or two passes and you're good as new.

edited to add: especially on the thin K390 of my Police 4

[K1500]

That's a lot of mentioning.

Not my most eloquent post.

[aaronkb]

Does anyone have experience using edci? Does it leave any tangible residue?

If I have to touch up my knife every time I use it, it kinda takes the joy out of having a super high edge retention steel. It would only be useful for one really long cutting task.

[aaronkb]

Just wanna bump this to see if anybody has experience using edci.

[JRinFL]

I use EDCi and have not noticed any residue. Spray it on, wipe it off like it says on the label. I have not tested it for efficacy, yet. I need to get a cheap 1095 blade and coat one side and leave it in my garage for a few weeks.

[JRinFL]

There is a product called Blade Guard paste that is designed for protecting the edge of reactive steels like 1095. I have a tube, but have not tested it yet either.

[Wartstein]

(Thought I´d rathewr revive this thread which already offers some good info instead of starting a new one about that very same question)

I am still and always really interested in peoples real life experiences concerning "edge degredation" through corrosion.

As some might know, I have no need for completely or even moderate corrosion resistant steels, despite I do use my folders in muddy, wet, snowy conditions, carry them iwb on sweaty runs, cut all kinds of stuff including fruits and the like.
Just don´t experience rust issues, and some tiny spots or discolorations on steels like REX 45 don´t bother me at all.

That said:

- The one point where I sometimes think the superhigh rustproofness of steels like MC or LC 200N could really offer a benefit for me is that it could be the case that my not so stainless knives dull faster when NOT used at the very apex due to corrosion there - so in a way the long term edge retention could be better with for example MC as in I´d have to sharpen less frequently, cause the very edge does not "rust away"

Any experiences on that folks here could share?
Or has anyone perhaps even done somewhat "controlled tests"?

[Larrin]

Any experiences on that folks here could share?
Or has anyone perhaps even done somewhat "controlled tests"?

https://knifesteelnerds.com/2019/01/21/ ... retention/

[Ryder]

Dive knives are highly polished to help guard against corrosion. This works with the edge as well. Also using mineral oil lightly embedded in a cloth and then wiping it with a clean, dry paper towel will protect without being sticky.
For any edged tool of mine I do that no matter the steel. For the edge I strop my K390 with Beavercraft green over leather to a gleaming edge. It definitely lasts longer and is more corrosion resistant. I hardly ever have to do anything else. I’ve been using and taking care of carbon steel since I was a kid. At this point they will have to pry my K390 from my cold dead hands.

Just to add I always convex my edges, makes them stronger and more durable.

[Wartstein]

Any experiences on that folks here could share?
Or has anyone perhaps even done somewhat "controlled tests"?

https://knifesteelnerds.com/2019/01/21/ ... retention/

Dr. Larrin, thanks a lot!!
This is exactly what I was looking for!

[Coastal]

I live 400 yds from the beach. I haven't experienced this phenomenon personally, but it makes sense to me that it happens. In fact, I'd be surprised if it didn't happen. Probably the reason it hasn't happened to me, besides the fact I store my knives indoors with A/C, is that when I actually use a knife, it's usually a Salt, which I wouldn't expect it to happen to. I use my culinary knives so much that there's no way to tell if they're dulling due to ambient humidity. Also, I sharpen most of my knives with 220 grit, and never polish. Intuition tells me what Vivi stated above: a rougher, toothier apex/bevel will be less affected by ambient corrosion than a refined edge. It might corrode more, but it will still cut better.

I've seen this topic come up before, and I'm following with great interest. It strikes me as "important," as forum topics go, since it definitely affects cutting performance. I'm surprised no controlled testing has been done. Stainless vs tool vs Salt steel. High grit vs low. Humidity level. Saline vs non-saline humidity. This topic is rife with possibilities for testing!

[Coastal]

LOL! Just noticed this is an old thread.

[Wartstein]

LOL! Just noticed this is an old thread.

It is, but I revived AaronBKs thread instead of starting a new one, since I have pretty much the exact same question like he had and wanted to gather more insight just like the one you offered (thanks!) .
So it actually is a "new - old" thread

[navin johnson]

For those that have knives dull in a drawer, or when climbing a mountain, what objective measurement do you use to determine this?

A thumbnail or feeling it with your fingers has too many variables

[weeping minora]

A thumbnail or feeling it with your fingers has too many variables

I think the who is as much of a variable as the method in experiencing this phenomenon/characteristic.

As a former meat cutter/butcher and home cook
and having an intimate relationship with sharp knives, I absolutely can feel a loss of sharpness in knives that have not seen usage post sharpening, using Murray Cater's 'three-finger method'.

I have experienced edge degradation in my pocket knives, especially during summer weather, and FWIW I live in Southern California, where it remains mostly dry, for much of the year. I do however work in temperatures ranging from sub-0°F (controlled), to over 100°F (natural), and am prone to excessive sweating when working and enduring physical activities (even whilst not at work). My sweat and circumstances certainly can and have had an affect on a knife when clipped in-pocket that can and will cause edge degradation to the apex of a knife. Regularly, I can pull a knife out-of-pocket and there will be condensation and/or rust forming on my knives (steel dependent, though I can and have rusted steel up to S30V levels of CR, for what that's worth). I have also experienced this with knives that have sat untouched for periods of time, exposed to open air and temperature/seasonal changes. Larrin makes a good point in response to a commenter within the shared KSN article, in that a thinner edge could possibly experience this more noticeably, due to less material being present behind the apex. Paraphrasing, anyway.

I think Jason Stone also makes a great comment on Larrin's study of the subject:

"JASON STONE January 21, 2019 at 8:25 pm

Interesting results. I wonder if some of the earlier reports of severe edge sharpness decline was from a small mirco-burr being left on from sharpening and then corroded off."

Things to consider.

[Wartstein]

For those that have knives dull in a drawer, or when climbing a mountain, what objective measurement do you use to determine this?

A thumbnail or feeling it with your fingers has too many variables

I actually don´t know (yet..) if my (tool steel..) knives "dull when climbing a mountain".
The question IF this could be the case is what made me revive this thread.

Till very recently I thought I personally would have no real need for the high rustproofness of steels like LC or MC, cause any corrosion I experience with tool steels is just of cosmetic nature to me and does not bother me, or I even like it (lookwise).

But now it came to my mind, that perhaps tool steel knives I carry in my pack and/or iwb all the time, they get wet, they get used and perhaps not always dried and cleaned, could loose sharpness more and quicker than LC, MC, or H2 folders, just due to corrosion on the very edge.

This, if true, would be the first and not unimportant point for leaning more towards "salt" steels for me personally.

Perhaps I can come up with a way to measure if lets say my REX45 Manix or 4V Goddard dull more just by carrying them iwb and in wet, moist conditions than lets say my H1 Pac Salt or my LC Waterway (with no resp. the exact same amount of use)

[sal]

An "edge" is thin, and exposed on both sides, so it it the first part of a blade to respond to corrosion. This was the main problem in trying to find a Salt Water Steel. Even with blades that are coated or chrome plated, the edge is sharpened so it is not protected by the coating or plating.

sal

[Deadboxhero]

An "edge" is thin, and exposed on both sides, so it it the first part of a blade to respond to corrosion. This was the main problem in trying to find a Salt Water Steel. Even with blades that are coated or chrome plated, the edge is sharpened so it is not protected by the coating or plating.

sal

Speaking of chrome plating, back in 2018 I found the original guy that did the chrome plating for Gerber back in the late 70s early 80s

I had him flash chrome some samples for testing.

I envisioned the ultimate blade would have been CPM 4V which had an excellent balance of strength and toughness but with the chrome plating to make it invincible to rust on the blade. Initial testing was good however the problem was the chrome plating accelerated the rusting of the exposed edge compared to if there was no plating.

Than Dr Larrin comes along and does the impossible and makes a stainless CPM 4V.

So the chrome plating for me was completely abandoned.

[N. Brian Huegel]

When David Murphy started making knives for Gerber in the late 1930s, I believe he recycled used M2 High Speed Tool Steel power hacksaw blades that he ground to shape and had chrome plated. They had cast aluminum handles that in time, long after Gerber took over production in their own factory after WWII, were chrome plated as well (1960s).