MagnaCut Corrosion?

[JayHenMac]

I know MC isn't rust-proof. I don't expect it to be. I am surprised that my MC native shows surface corrosion as easy as VG-10. Easy enough to clean off so no big deal
I spent the weekend backpacking. No rain. The only thing the knife was used for was to open a couple freeze dried meals and two instant coffee packets. Otherwise it was in my pants pocket.
Anyone else notice similar behavior?

[LazyOutdoorsman]

Thats weird
On multiple occasions,i've soaked my magnacut pm3 when saltwater fishing and did not wash it down until 12 hours later. Only once did I find a spec of rust in the crevice between the primary grind and the stock, which came off with my finger nail.

So, I feel pretty confident that magnacut is almost rust proof.

Is it possible that you've got a fake or that corrosion is stubborn residue?

[Fastidiotus]

Not trying to be a Spyderco apologist, just out of curiosity. Where the corrosion is present on the blade, is that the part of the edge that was used to open the food and the instant coffee? As you've said OP no steel is technically corrosion proof, though H1/H2 comes so close it truly is a super steel. I could see being in a pocket surrounded by salty humid air for a day and then having something like the miniscule dust from inside a packet of instant coffee powder or freeze dried food causing a steel to corrode.

The surface of steel has areas that carry positive charges and areas the carry negative charges. Corrosion is the result of those areas interacting and completing the circuit. One spot of the steel is losing ions and we can physically see this as corrosion. Water facilitates this interaction, electrolytes like salt speed it up, and having something reduce the pH level like instant coffee throws gasoline on the fire.

[Evil D]

There have been many reports of other brands in MagnaCut rusting, particularly in stonewashed finish. I wonder if the brushed/sanded finish is similarly prone? Nooks and crannies are your enemy regardless of the steel type.

[BeggarSo]

I have read hear treatment is crucial to Magnacuts resistance to corrosion.

That being said I have seen it also but it wipes off. This is true of other steels like M390 also.

I forget the technical details but has something to do with chromium in suspension.

[vivi]

I haven't rusted magnacut yet and I'm usually quick to rust steels others don't.

Let my magnacut military soak for hours in salt water with no issues:

viewtopic.php?t=98677

[JayHenMac]

Not trying to be a Spyderco apologist, just out of curiosity. Where the corrosion is present on the blade, is that the part of the edge that was used to open the food and the instant coffee?

Yeah it is. They're those small packets of instant coffee. I fold the pack over the blade to cut them. Right at that spot. Its the only thing I cut that contacted the blade in that area. The corrosion came easily enough with a little BKF and looks good as new. Maybe I need to find a less acidic coffee brand.

[Wartstein]

Not trying to be a Spyderco apologist, just out of curiosity. Where the corrosion is present on the blade, is that the part of the edge that was used to open the food and the instant coffee?

Yeah it is. They're those small packets of instant coffee. I fold the pack over the blade to cut them. Right at that spot. Its the only thing I cut that contacted the blade in that area. The corrosion came easily enough with a little BKF and looks good as new. Maybe I need to find a less acidic coffee brand.

I´ve read several times that Magnacut can be "contaminated" just on the surface with residue from other steels (probably coming from the grinding device). So if this is the case as soon as this residue is gone the MC itself should be pretty rustproof.

Also still would make sense that the blade (the possible "less rustproof steel residue") is showing corrosion right where it came in contact with the matter that got cut.

[Evil D]

I´ve read several times that Magnacut can be "contaminated" just on the surface with residue from other steels (probably coming from the grinding device). So if this is the case as soon as this residue is gone the MC itself should be pretty rustproof.

Also still would make sense that the blade (the possible "less rustproof steel residue") is showing corrosion right where it came in contact with the matter that got cut.

This can happen with any steel, I've read that it may be transferred from the belt that grinds the blade grind. I've seen speculation of this even happening to H1.

I typically look for other contributing factors, it seems more likely to me that something is ON the blade corroding than the steel itself. This seems way more likely to me than a few knives out of a batch that somehow are more prone to rust than the others. Seems like we'd see more widespread issues if it were the steel itself. I just spent a week playing in the Pacific ocean with MagnaCut on my hip the entire time and that knife looked brand new when I came home.

[JayHenMac]

I wonder if the scrubbing with BKF is enough to prevent it from happening again.