I don't like the way this forum discusses corrosion resistance

[curlyhairedboy]

When I had my Advocate in pocket this summer, I think I had a "Vivi experience". The maintenance on the uncoated M4 was SIGNIFICANT. My DLC M4 PM2 is a lot better, but the inspection/protection cycle on the Advocate did make me long for something stainless, even though the M4's cutting performance is fantastic.

[senorsquare]

I suppose I have a body chemistry that makes metals corrode. My "rust proof" SpydieChef was quite a mess after 3 months of riding in my jersey pocket on some long, sweaty bike rides in central Arkansas. When you see the pics below perhaps you will understand why I'm a bit reluctant to carry high carbon blades. I had an M4 Mantra that straight up rusted just riding in some slacks in a air conditioned office.

The photos below are not pretty, but the good news is that 5 minutes with a toothbrush and some BarKeepers Friend had it looking brand new again. I almost sent it in to W&R but it was easy enough to clean so I did it myself. Still carry the SpydieChef almost every day but I now take the Pacific Salt with me on my bike rides.

[ABX2011]

I've often seen it written on the knife boards that a person says his sweat is more corrosive than average. Despite these anecdotal accounts, I'd love to hear from a science person. Is the difference simply the frequency and amount of sweat or can a person really have more corrosive sweat?

[bearfacedkiller]

I had no idea that people's sweat could vary so much until I started reading reports like these. I have run hundreds of miles with all sorts of non stainless blades IWB and not had any issues.

This may be TMI but I also have almost no body odor. I haven't worn deodorant in over 20 years. I wonder if there is some kind of connection there? I don't sweat as much as most people though, even when working out.

[ChrisinHove]

Wow. That’s some staining on the Spydiechef.

I would guess your perspiration composition would depend to some extent on your general hydration levels and also your diet.

[Tucson Tom]

I'm looking hard at those Spydie Chef photos. It is the liners and hardware that is corroding, not the LC200N blade - or am I seeing what I expect to see?

[zhyla]

I've often seen it written on the knife boards that a person says his sweat is more corrosive than average. Despite these anecdotal accounts, I'd love to hear from a science person. Is the difference simply the frequency and amount of sweat or can a person really have more corrosive sweat?

I've heard the same from guitar people about guitar strings. I don't know if it's a real thing. I've heard it referred to as a different in pH but I think that's unlikely as your blood pH is very tightly controlled. But you get rid of salt in sweat and urine and I could see if you have a higher salt intake your sweat might be saltier.

I think it's more likely that some people just have sweaty palms.

I think it's even more likely some people just get their stuff wet and don't wipe it down.

[Doc Dan]

It is true that some people naturally have more salty sweat. https://oem.bmj.com/content/oemed/14/3/191.full.pdf
https://www.ncbi.nlm.nih.gov/pubmed/84491

I find it interesting that the presence of copper inhibits corrosion to some degree.

[Shooter4321]

I’ve never had much problem with corrosion , only really showing up on a SnG that was made of PD1 and a bead blasted s30v (SMF), and I was sweating pretty bad (110 degree days) and both knives were saturated in sweat and eventually showed some light rust spots. I’ve done the same with s30v with DLC and never had anything show up like it did with PD1 that was also coated. My military has never once showed corrosion, no matter how bad I’ve sweated or any acidic foods I’ve cut (enough to feed a herd of elephants)...I live in California and we basically don’t have winter here so that’s never a problem. I’ve owned that same military for about 15 years give or take , and it’s my main edc.
You brought up DLC in the other thread and I couldn’t agree more, that stuff works, it doesn’t create a rough surface so cutting resistance isn’t effected like some other coatings and moisture doesn’t get caught up in pores like it does from a bead blast finish.

It’s interesting how steels react to different body chemistry’s, some people are as salty as the pacific and some can carry carbon steel in their pocket with no rust at all..

[koenigsegg]

Some people have some crazy acid sweat lol

[jalcon]

We all have different needs. Telling someone their needs are invalid is the opposite of what this forum should be about IMO.

It will be tough enough. I carried one for years and used it harder than you will.

Lol at least pick a stance and go with it..

[senorsquare]

It is true that some people naturally have more salty sweat. https://oem.bmj.com/content/oemed/14/3/191.full.pdf
https://www.ncbi.nlm.nih.gov/pubmed/84491

I find it interesting that the presence of copper inhibits corrosion to some degree.

This is me in solid black jersey after several hours on the bike. Yeah, my sweat is a wee bit salty...

[ChrisinHove]

It is true that some people naturally have more salty sweat. https://oem.bmj.com/content/oemed/14/3/191.full.pdf
https://www.ncbi.nlm.nih.gov/pubmed/84491

I find it interesting that the presence of copper inhibits corrosion to some degree.

And the extent of sweating depends upon your temperament!

I would think those with guilty consciences must be particularly corrosive.

[embry386]

I like stainless knives because it bothers me when I spend lots of cash on a pretty new knife and then it gets rust all over. Also I do not want to have to clean and oil them every day. My ideal knife can be used on food and then rinsed off and dried on a towel, and will not rust when treated that way. So far I haven't had any problems, so I don't know which steel types would have issues with this treatment and which wouldn't. So far, S90V, S35VN, ATS-55, and VG-10 have all performed fine. To be safe though, I generally only buy knives that say they're made of stainless steel.

Some people prefer the super-edge-holding knives that rust more easily, and I say, more power to 'em. The only time it even vaguely affects my life is when Spyderco decides to cater to them by making a model of knife I like in the kind of steel that those people prefer, and then doesn't make the knife in any steel that I prefer. Doesn't mean that anyone's doing anything wrong; Spyderco's gotta try to make as many people happy as possible while maximizing profits, and it's great for the people that like those knives! I tend to get a bit louder about preferring stainless steel when that happens though, in the hopes that Spyderco will see that there's also a demand for stainless and decide to make a line of that knife model in it.

One forum member says that you can't tell a difference between S30V and S35VN; others contest this statement.

Perhaps the difference can't be felt when the knives are in use, but according to some tests they've done, S35VN is about 20% tougher than S30V (and easier for knifemakers to machine), while being comparable in all other regards. I don't care much about the ease of machining -- if Spyderco's satisfied with S30V in that regard and they've got the hardware and skill to handle it, then, great -- but between the steel that pretty darn awesome and the one that's nearly exactly alike except with 20% more toughness? I'll take the one with the 20% more toughness, every time. Sure, I'll probably never be in a situation where I need it, but it still feels like a downgrade when they switch to making the S35VN Native in S30V instead, and they didn't even lower the prices to match. It doesn't bother me much, I just buy a few backups in S35VN and move on with life, but it's definitely something I pay attention to. If anyone's interested in the test results that showed that, I can find them for you, but I don't feel like hunting through my hundreds of bookmarked websites right now :)

[vivi]

I've often seen it written on the knife boards that a person says his sweat is more corrosive than average. Despite these anecdotal accounts, I'd love to hear from a science person. Is the difference simply the frequency and amount of sweat or can a person really have more corrosive sweat?

Think about how much diets vary between person to person.

[vivi]

I've often seen it written on the knife boards that a person says his sweat is more corrosive than average. Despite these anecdotal accounts, I'd love to hear from a science person. Is the difference simply the frequency and amount of sweat or can a person really have more corrosive sweat?

I've heard the same from guitar people about guitar strings. I don't know if it's a real thing. I've heard it referred to as a different in pH but I think that's unlikely as your blood pH is very tightly controlled. But you get rid of salt in sweat and urine and I could see if you have a higher salt intake your sweat might be saltier.

I think it's more likely that some people just have sweaty palms.

I think it's even more likely some people just get their stuff wet and don't wipe it down.

If your pocket stays soaked with sweat during the full 12 hour work day, and often times during your down time too, what exactly will wiping the externals down solve? They'll be wet again as soon as the knife is back in your pocket, and the internal parts (See the spydiechef pics) are still soaked in sweat.

Now guitar strings are different, I do wipe mine down to slow down how fast they corrode. But they still need replaced sooner than most people who plays are infrequently as I do.

[vivi]

This is exactly what I'm talking about. This is a model most folks wouldn't rust if they tried, yet you rusted it by carrying it while doing something active.

I think lifestyles definitely come into play in this discussion. Someone like you or me that likes to ride bikes and get sweaty, or Lance spending all that time out on his kayak, we're a lot more prone to have this happen than someone who works in an air conditioned office in a cool northern environment, with no athletic hobbies.

It wouldn't be fair for either of us to try to apply our standards to one another. Best thing we can do is try to learn from people with a different experience than our own.

[vivi]

I'm looking hard at those Spydie Chef photos. It is the liners and hardware that is corroding, not the LC200N blade - or am I seeing what I expect to see?

I'd rather have a blade corrode than internals. Blades tend to be easier to clean than all the crevices around locking mechanisms, pivots and stop pins. If my blade rusts I can usually fix it without taking the knife apart.

[vivi]

I’ve never had much problem with corrosion , only really showing up on a SnG that was made of PD1 and a bead blasted s30v (SMF), and I was sweating pretty bad (110 degree days) and both knives were saturated in sweat and eventually showed some light rust spots. I’ve done the same with s30v with DLC and never had anything show up like it did with PD1 that was also coated. My military has never once showed corrosion, no matter how bad I’ve sweated or any acidic foods I’ve cut (enough to feed a herd of elephants)...I live in California and we basically don’t have winter here so that’s never a problem. I’ve owned that same military for about 15 years give or take , and it’s my main edc.
You brought up DLC in the other thread and I couldn’t agree more, that stuff works, it doesn’t create a rough surface so cutting resistance isn’t effected like some other coatings and moisture doesn’t get caught up in pores like it does from a bead blast finish.

It’s interesting how steels react to different body chemistry’s, some people are as salty as the pacific and some can carry carbon steel in their pocket with no rust at all..

Yeah DLC is the truth. It's amazing to me than in 2018 there is still a "debate" about whether it helps corrosion resistance. That is like there being a debate as to whether driving a car will get you somewhere 200 miles away faster than walking :rolleyes:

Bead blast finishes are no good. Recently I've carried a Cold Steel Voyager, and one the first day the bead blasted lock release corroded a bit. Had to take the knife apart and polish off the finish. Also had a lot of bead blasted Kershaws rust really bad before I realized what the cause was.

I had a DLC Para 2 I brought on my first bike tour, clipped IWB to my basketball shorts. For the uninitied, a bike tour is a week+ long trip where you bike all day then camp out at night.

Never ever rusted the blade on that Para 2....but I did rust everything else. The compression lock, stop pin and liners had a thick (2mm in some spots) layer of rust. You could smell the rust holding the knife a foot from your nose.

This is one of the reasons I bought a Manix XL DLC. They coated the liners and back spacer in addition to the blade. I have yet to see or smell rust anywhere on that folder, and it's been clipped to sweaty pockets all day many times.

[vivi]

We all have different needs. Telling someone their needs are invalid is the opposite of what this forum should be about IMO.

It will be tough enough. I carried one for years and used it harder than you will.

Lol at least pick a stance and go with it..

I'd love to hear you explain how telling someone a knife will be tough enough for their uses invalidates their needs.