Corrosion Reports

[Stas]

I pulled apart my K390 Endura today to put some new scales on it and just as Vivi reported with his Police 4, the stainless liners had more corrosion than the blade. Weird.



Dan

Thanks for sharing. Could you provide more details? Did it get wet or experience heavy perspiration? I'm curious about the conditions that lead to rusting the liners.

[R100]

I pulled apart my K390 Endura today to put some new scales on it and just as Vivi reported with his Police 4, the stainless liners had more corrosion than the blade. Weird.



Dan

Thanks for sharing. Could you provide more details? Did it get wet or experience heavy perspiration? I'm curious about the conditions that lead to rusting the liners.

I live in a part of the world that gets hot at times and I think the corrosion is mainly from sweat. I do use a food safe Camelia oil on my tool steel blades but it seems that it hasn't penetrated into the pivot as much as I thought. This knife has accompanied me on some really hot work field trips where I am doing long days and out camping in remote areas for 2-3 weeks at a time and maintenance can get a bit lax. These are the times when I
have really noticed the corrosion.

I also use my folders for food prep. I wipe them down immediately and am careful to avoid getting water in the pivots but this is probably also a source of corrosion.

Dan

[vivi]

Really makes you wonder what the liners are made out of that they seem to rust more readily than K390 blades.

For reference, here's the thread about my Police - viewtopic.php?t=84857

Maintaining tool steel blades is the easy part IMO. It's keeping liners, hardware etc. clean that's the tough part. That's why I applaud Spyderco for coating liners and hardware in most DLC models these days. For me it makes maintaining them a lot easier. No corrosion issues on my 4V Manix XL, for example, and I've hiked with it in the rain more than once.

[Stas]

I pulled apart my K390 Endura today to put some new scales on it and just as Vivi reported with his Police 4, the stainless liners had more corrosion than the blade. Weird.



Dan

Thanks for sharing. Could you provide more details? Did it get wet or experience heavy perspiration? I'm curious about the conditions that lead to rusting the liners.

I live in a part of the world that gets hot at times and I think the corrosion is mainly from sweat. I do use a food safe Camelia oil on my tool steel blades but it seems that it hasn't penetrated into the pivot as much as I thought. This knife has accompanied me on some really hot work field trips where I am doing long days and out camping in remote areas for 2-3 weeks at a time and maintenance can get a bit lax. These are the times when I
have really noticed the corrosion.

I also use my folders for food prep. I wipe them down immediately and am careful to avoid getting water in the pivots but this is probably also a source of corrosion.

Dan

Thanks a lot! I think Bar Keepers Friend or FLITZ will easily remove it.

Just dreaming of an affordable injection molded material more durable than FRN that Spyderco could use to reintroduce all Seki models linerless again

[Vamais]

It's possible that the liners have more rust because of crevice corrosion, and not because they are less stainless than K390.

[JSumm]

I think Vamais is right. I've also had corrosion on my Sekis liners. It seems to start out in the cutouts towards the corners. Just enough to trap moisture and enough exposure for oxygen. As Vivi brought up, I have not seen any on black coated liners. I don't think the liners are DLC coated, rather painted. Painted is probably better since it would make sense it is a less porous coating. Since they are internal liners, it doesn't get scratched like a painted clip.
#paintalllinersandleavethetoolsteal.

[R100]

Thanks a lot! I think Bar Keepers Friend or FLITZ will easily remove it.

Just dreaming of an affordable injection molded material more durable than FRN that Spyderco could use to reintroduce all Seki models linerless again

I actually did use Bar Keepers Friend and it worked perfectly. I also did a little bit of polishing to reduce the surface area before I oiled the liners and reassembled the knife with its new scales. Maybe that will slow things down.

FRN is actually extremely durable and strong. I would love a K390 Stretch 2 XL and think it would be much more corrosion resistant than a linered model like the Endura. The VG10 model I have is a really solid knife and I have a SE Salt version on the way which I intend to give some heavy use.

Dan

[Stas]

Thanks a lot! I think Bar Keepers Friend or FLITZ will easily remove it.

Just dreaming of an affordable injection molded material more durable than FRN that Spyderco could use to reintroduce all Seki models linerless again

I actually did use Bar Keepers Friend and it worked perfectly. I also did a little bit of polishing to reduce the surface area before I oiled the liners and reassembled the knife with its new scales. Maybe that will slow things down.

FRN is actually extremely durable and strong. I would love a K390 Stretch 2 XL and think it would be much more corrosion resistant than a linered model like the Endura. The VG10 model I have is a really solid knife and I have a SE Salt version on the way which I intend to give some heavy use.

Dan

I didn't imply that the FRN isn't durable. I have confidence in my Pac Salts and linerless Matriarch, which I consider as reliable as the Endura 4 or Matriarch 2. The addition of liners in the fourth generation of Delica and Endura aims to enhance the knife's strength IMO. So simply reverting to linerless construction with the same material might not be justified…

[Senfkarte]

It was close this time. I nearly started without taking pictures. So here they are:

After a year of CPM 15V, I thought I could try K390 again. Dug up my Stretch 2 and found this:
(Click on the images, to get a bigger one)

There was a small part of the edge that had visible damage. Not only visible, one also could feel it. Haven't seen something like this ever. This blade just laid there for the past year.

Here is a picture of an unaffected part:

Here you can see the effected part from one side:

And the other side:

Hard to see in the pictures but on the one side, there were dimples ant the other side had some nubbles.
Don't know if this really is corrosion. The asymmetry really is what puzzles me here.
Either way, I was able to sharpen it out. There may be some remaining spots, since there is a very small part, where I can feel some irregularities, but I'm not sure, if they are leftovers or just a poor part on my side. Haven't marked the spot.

[Mat_ski]

I think Vamais is right. I've also had corrosion on my Sekis liners. It seems to start out in the cutouts towards the corners. Just enough to trap moisture and enough exposure for oxygen. As Vivi brought up, I have not seen any on black coated liners. I don't think the liners are DLC coated, rather painted. Painted is probably better since it would make sense it is a less porous coating. Since they are internal liners, it doesn't get scratched like a painted clip.
#paintalllinersandleavethetoolsteal.

Technically speaking when there are two dissimilar metals in contact with each other, the more reactive one will corrode first. Stainless steel is lower on the galvanic series than carbon steel meaning that in a corrosion cell made from the these two metals, carbon steel should corrode first.
However, high alloy tool steels may not be aware of this ‘rule’ and I have no clue where does k390 sit in the galvanic series relative to whatever the liner is made of.

[JSumm]

I think Vamais is right. I've also had corrosion on my Sekis liners. It seems to start out in the cutouts towards the corners. Just enough to trap moisture and enough exposure for oxygen. As Vivi brought up, I have not seen any on black coated liners. I don't think the liners are DLC coated, rather painted. Painted is probably better since it would make sense it is a less porous coating. Since they are internal liners, it doesn't get scratched like a painted clip.
#paintalllinersandleavethetoolsteal.

Technically speaking when there are two dissimilar metals in contact with each other, the more reactive one will corrode first. Stainless steel is lower on the galvanic series than carbon steel meaning that in a corrosion cell made from the these two metals, carbon steel should corrode first.
However, high alloy tool steels may not be aware of this ‘rule’ and I have no clue where does k390 sit in the galvanic series relative to whatever the liner is made of.

Check the post right before mine. This was concerning some of the hidden nooks where water can reside a bit longer in the cutouts of the skelonitized liners. This is not where the liners meet the blade. I have typically seen it at the corners meeting the FRN.

But what you say is another interesting point. Not sure how K390 in particular would react.

[Mat_ski]

I did see it. I didn’t mean to single out your comment when quoting you, only addressing the latest in regards to that specific corrosion picture.

I brought it up exactly for the reason you thought was interesting.

Given the background provided by R100 I think there is good chance that there was moisture in the crevice between the liner and the blade.

[StuntZombie]

It's possible that the liners have more rust because of crevice corrosion, and not because they are less stainless than K390.

This is it right here. This is why I've never considered adding liners to the FRN models an upgrade. I've always had more issues with corrosion on liners than I have on blades.

[TimButterfield]

If you want the strength of a liner, but without the corrosion risk, perhaps the liner could be embedded within the FRN.

[StuntZombie]

If you want the strength of a liner, but without the corrosion risk, perhaps the liner could be embedded within the FRN.

I've thought about that as well, and I have to imagine there's a reason why it hasn't been done. I wish they'd at least just go back to solid FRN on the Salt series if nothing else.

[ladybug93]

If you want the strength of a liner, but without the corrosion risk, perhaps the liner could be embedded within the FRN.

I've thought about that as well, and I have to imagine there's a reason why it hasn't been done. I wish they'd at least just go back to solid FRN on the Salt series if nothing else.

if they did that, there would be no way to reach corrosion and it would still form because of the holes for the screws. it would probably be even worse too because there would be no way to dry everything out.

[TimButterfield]

If you want the strength of a liner, but without the corrosion risk, perhaps the liner could be embedded within the FRN.

I've thought about that as well, and I have to imagine there's a reason why it hasn't been done. I wish they'd at least just go back to solid FRN on the Salt series if nothing else.

if they did that, there would be no way to reach corrosion and it would still form because of the holes for the screws. it would probably be even worse too because there would be no way to dry everything out.

If not an embedded liner, perhaps a coated liner would do better. DLC may be too expensive, but some other less expensive coating might work. Of course, a screw hole may still wear the coating off, but it would at least help limit it to just those spots.

Someone with something like some Boeshield T-9 might be able to test spraying it on a liner to see if it helps. I remember that used to work well on the Delta Unisaw and other woodworking tools I used to have. (Don't have them or the spray any more, though.)

[StuntZombie]

If you want the strength of a liner, but without the corrosion risk, perhaps the liner could be embedded within the FRN.

I've thought about that as well, and I have to imagine there's a reason why it hasn't been done. I wish they'd at least just go back to solid FRN on the Salt series if nothing else.

if they did that, there would be no way to reach corrosion and it would still form because of the holes for the screws. it would probably be even worse too because there would be no way to dry everything out.

It wouldn't be a problem if the liners were entirely encapsulated by the FRN. And the threaded inserts would be completely separate from the liners.

Really, just get rid of the liners altogether. Solid Zytel doesn't need them. Threaded inserts are better than having clip screws threading into liners anyway.