Patina vs Rust

[jfn]

Like I mentioned in my previous topic, I recently got a Case CV Chestnut Stockman that I've put on apple cutting edc duty.
After my first apple, I washed and rinsed the clip point blade and found that, lo and behold, a patina had already formed in the 10 minutes of apple eating. I was stunned, but not unhappy by any means. It couldn't have formed any better. A dark grey that graded to a lighter grey over the grind toward the spine. It was fantastic. So needless to say, the other blades needed to follow suit...

The very next apple was offered up to the wharncliffe and pen blades. After rinsing and reoiling, lets just say that the results were not as spectacular as the clip point. The markings were more spotty, less consistent, but still had a look that I didn't object to, so all in all I was happy.

So I've spent a few days admiring my handiwork. How the subtle greys came together in certain ways. I opened up the wharncliffe and saw the subtle hint of orange red...

Aw hell no...

I was in a panic this morning. I didnt have any sort of metal polish at home, so I resorted to the one thing I knew I could count on... Crest toothpaste came through for me in re end, purging the wharncliffe and pen blades of the invading rust. I just want to know where I went wrong. I kept the blades covered in a thin layer of mineral oil (and oil from my fingerprints when the mineral oil wore off). Kept them clean and dry, but still rust reared it's ugly head.

Any advise for me as I undertake my next attempt on a patina?

 

[chogue1980]

After the patina use something ammonia based to stop the reaction. I use the original formula of Windex, works great, then just oil as normal

 

[jackknife]

I just want to know where I went wrong. I kept the blades covered in a thin layer of mineral oil (and oil from my fingerprints when the mineral oil wore off). Kept them clean and dry, but still rust reared it's ugly head.

Any advise for me as I undertake my next attempt on a patina?

But you didn't keep them clean and DRY.

Okay, jfn, listen to me. I was born and raised on the Chesapeake Bay here in Maryland. My family on my dad's side are all working watermen on the bay. All carried carbon steel pocket knives when I was a boy there. None rusted. And that was a salt water environment.

First, stop oiling your knife. Yes, I know this is counter intuitive, but trust me. Oil floats on top of water. If you have not totally dried your blade, some moisture can get trapped. Also you state your finger prints were on the blade when the oil wore off. Okay, why do you thing people wipe off a nice old blued gun after it's handled? Because the oils in your finger prints also contain salts! Finger prints on a blade is not clean and ry, your leaving salts behind. Some people have more or less in thier prints than others.

I carry a Case peanut as my edc. Either my yellow handle CV, or my chestnut bone CV, or my Devin Thomas damascus with amber bone. I never oil the blades. I get up in the morning, and take a clean DRY bandanna and wipe the blades down, and drop in pocket. During the day, that little knife may be used for anything. Breaking down boxes from a Sam's Club trip, or slitting open a pan fish belly for cleaning. I'm retired, and spend a lot of time in the spring, summer, and fall, fishing. I just use my pocket knife to gut and scale. It gets swished around in the water and wiped off on my jeans and dropped in pocket. Later that night it gets wahsed down with Dawn dish soap, and dried off. A drop of Hoppes gun oil is dropped in the joints. That's it. Wiped off clean and dry before I go to bed. I do not oil the blades. They are a dark gray now, but no rust. And that's with a great deal of time on the Potomac River, the lake at Black Hill regonal park, the Chesapeake Bay, and the Patuxant River, all in an Old Town canoe.

From now on, after the apple duty, just wash off the blades with soap and water, Windex, or what ever, and dry them off, but do not oil them. Just let them darken. THe more they darken, the more rust resistant they get. It's like a nice deep blue on a gun.

Carl.

 

[jfn]

Thanks guys.
If clean and dry is good enough for jackknife, it's good enough for me.

 

[Obsessed with Edges]

I'm encouraged by the support for the Windex. I'll admit ignorance here. I didn't actually intend to prevent rust by using it, but I have been using it for a long while on my blades, merely as a matter of convenience. After sharpening/stropping, after handling with dirty/sweaty hands, after using it to cut an apple, etc (most recently with my 8OT Old Timer). I have noticed it's great for removing the oily fingerprints (and therefore, the salts, as Carl has pointed out). And the beauty is, I haven't had any rust issues at all.

 

[dannyp]

Also you state your finger prints were on the blade when the oil wore off. Okay, why do you thing people wipe off a nice old blued gun after it's handled? Because the oils in your finger prints also contain salts! Finger prints on a blade is not clean and ry, your leaving salts behind. Some people have more or less in thier prints than others.

Interesting stuff, Carl. I've noticed my prints staining the backsprings of new knives before but never even considered it being from salt. They always disappear after a little use so I didn't think much of it. I also think you hit the nail on the head about trapping moisture under the oil. I never bother to oil my blades as all it seems to do is attract dirt or lint. Just a drop or two in the pivot every once in a while.