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Hello a question regarding the magnificent Police 4 k390. I have used it for a little while and it has gotten a nice rainbow patina. I want to retire it to the safe and use my delica instead. My question is I usually add tuff cloth to blades in the safe just for the added corrosion protection but would wiping it with the cloth ruin the patina somehow? Thanks.

No.
Unless you hit the blade with something abrasive (sand paper, scotch brite pad, some powder cleaner), patina is not going anywhere with just wiping with a cloth. But it is a good idea to store the Police 4 with a blade lighty coated in some kind of oil (if your place is changing humidity some water could condensated on the blade).

General instructions for any metal coating is to clean rust (which patina is) off metal before putting a costing or rust preventative on.

In other words, the concern is more patina or red rust will form, even with tuff cloth coating on top.

From my experience, once oiled, rainbow patina will turn gray/brown.

anycal wrote: ↑

Mon Oct 14, 2019 11:26 am

From my experience, once oiled, rainbow patina will turn gray/brown.

That means chemical reaction is ongoing under the oil/coating.
We saw that in the metals industry,,, a brand new very expensive part was shipped to customer in Asia,,,, under the thick protective coating a hand print had etched into the steel and required grinding of the surface to clean off.

Regards,
FK

FK wrote: ↑

Mon Oct 14, 2019 11:33 am

anycal wrote: ↑

Mon Oct 14, 2019 11:26 am

From my experience, once oiled, rainbow patina will turn gray/brown.

That means chemical reaction is ongoing under the oil/coating.
We saw that in the metals industry,,, a brand new very expensive part was shipped to customer in Asia,,,, under the thick protective coating a hand print had etched into the steel and required grinding of the surface to clean off.

Regards,
FK

I don't disagree. My point was that if one is trying to keep a certain blade discoloration, the pretty stuff does not last. As far as how much ongoing damage is going on blade 'skin' deep? No idea. Had this knife for over two years with no signs of deep corrosion.

The fist time I was able to get color. Not to be seen since.

Two years ago,




Today,

Some good advice in above group of posts. If it was me I would use a soft paste wax like Rennisance wax to clean, slightly polish and seal the knife for storage. As it is you have a rusting knife and calling it a patina will not change anything. It takes me 3 to 4 minutes per knife. Make sure you use a clean and soft cloth for application.

Joe

under the thick protective coating a hand print had etched into the steel and required grinding of the surface to clean off.

I had that happen to me with an expensive custom knife in Rex 20 ( M62). It was a thumbprint and was permanent by the time it got to me.

My opinion would be to polish the whole blade with some Flitz. Clean it off with acetone, then seal it with Renaissance Wax. Lately I've been using Break Free Collector Gun Wipes to protect my Mantra II blade. The wipes are intended for storage, so you can try them instead of the Renaissance Wax.

The rainbow will probably fade into a dull gray eventually. At least that's what happened with this patina on 52100.

phaust wrote: ↑

Mon Oct 14, 2019 11:08 am

General instructions for any metal coating is to clean rust (which patina is) off metal before putting a costing or rust preventative on.

In other words, the concern is more patina or red rust will form, even with tuff cloth coating on top.

The Mastiff wrote: ↑

Mon Oct 14, 2019 1:07 pm

Some good advice in above group of posts. If it was me I would use a soft paste wax like Rennisance wax to clean, slightly polish and seal the knife for storage. As it is you have a rusting knife and calling it a patina will not change anything. It takes me 3 to 4 minutes per knife. Make sure you use a clean and soft cloth for application.

Joe

Rust and patina are not one and the same thing. Rust pitts and flakes off exposing fresh steel which is what makes it so destructive. Patina is more like staining. It doesn't pit the steel, and it doesn't flake off.
Gun bluing is essentially applying a patina is it not? I don't think anyone would call a well-blued gun barrel rusty.

Not trying to be argumentative. Just a little surprised to see this comparison made given the obvious differences.

The base metal in steel is Fe (iron) which reacts to form three types of "rust"

Iron(III) oxide or ferric oxide is the inorganic compound with the formula Fe2O3. It is one of the three main oxides of iron, the other two being iron(II) oxide (FeO), which is rare; and iron(II,III) oxide (Fe3O4), which also occurs naturally as the mineral magnetite, this is gun bluing and is formed by electrochemical conversion,,, also called black oxide. Several types of gun bluing are available, considered the best is "rust bluing". It was originally formed by coating the gun parts in acid then immerse the parts in boiling water which converts the red oxide Fe2O3 to black oxide Fe3O4. The scale of rust is removed with wire brush having very thin dia wires and oiled to preserve the color.

Many years ago I worked for Winchester in the engineering design dept. this was a summer job between semesters. It was interesting to wander the plant during lunch hour and quiz the old timers.

Regards,
FK

Well the rainbow is from light hitting in a certain way. Even if the blade wasn't changing under the oil after applying. Just by putting oil on it, you're going to change the refraction. At least from the blades I've had

anycal wrote: ↑

Mon Oct 14, 2019 11:39 am

Two years ago,




Today,

Hey Peter, that’s incredible! :cool:

Love how the blade lengthen and the CF scales went to Jade in just two years. :)

Bloke wrote: ↑

Mon Oct 14, 2019 9:36 pm

Hey Peter...

To an untrained eye, these could be different blades. Ah, but look at the size of the ricasso and the straight lettering, young grass smoker, and surely you can sense the essence of PM2 in both pictures :p

To capture those nebula colors, pic had to be taken at a drastic angle. As for the scales, that 52100 has been CF, Maxamet gray, M390 red, before it went natural G10, all in the last two years

anycal wrote: ↑

Mon Oct 14, 2019 11:34 pm

To an untrained eye, these could be different blades. ...

Peter, you’re a trickster. :cool:

I would have bet good money one was a PM3 and the other a PM2. :o

FK wrote: ↑

Mon Oct 14, 2019 8:41 pm

The base metal in steel is Fe (iron) which reacts to form three types of "rust"

Iron(III) oxide or ferric oxide is the inorganic compound with the formula Fe2O3. It is one of the three main oxides of iron, the other two being iron(II) oxide (FeO), which is rare; and iron(II,III) oxide (Fe3O4), which also occurs naturally as the mineral magnetite, this is gun bluing and is formed by electrochemical conversion,,, also called black oxide. Several types of gun bluing are available, considered the best is "rust bluing". It was originally formed by coating the gun parts in acid then immerse the parts in boiling water which converts the red oxide Fe2O3 to black oxide Fe3O4. The scale of rust is removed with wire brush having very thin dia wires and oiled to preserve the color.

Many years ago I worked for Winchester in the engineering design dept. this was a summer job between semesters. It was interesting to wander the plant during lunch hour and quiz the old timers.

Regards,
FK

Interesting. Thanks for the info FK.

The paste wax is a good suggestion. I use Vaseline as it is paraffin wax with mineral oil. My K390 gold patina is still golden. I won’t say your colors won’t fade. I’ve had that experience with 1095 and 1095cv. But so far my K390 has not faded.

Rust and patina are not one and the same thing. Rust pitts and flakes off exposing fresh steel which is what makes it so destructive. Patina is more like staining. It doesn't pit the steel, and it doesn't flake off.
Gun bluing is essentially applying a patina is it not? I don't think anyone would call a well-blued gun barrel rusty.

Not trying to be argumentative. Just a little surprised to see this comparison made given the obvious differences.

I don't take this as being argumentative. I often wish I was a skilled enough writer to disagree with someone without having it come across badly and it sometimes works for me:) Sometimes not though.

Anyways, I am aware of the difference and have hot and cold blued firearms and knives myself for decades now. My favorite rifle finish is a nice deep glossy blued quality finish on a Mauser or Winchester action. Even the high quality blue finishes won't really prevent rusting and I've had hand/finger prints etch into rifles within a half hour here in the summertime. They need to be kept as covered in oil as any unblued knife I've ever had. When sweating and out in the heat adding layers or grease and or gun oil is pretty unpleasant to me which is why I began using wax. It's less slimy.

We pretty much all have developed our own preferences and techniques suited to our own needs. Mine quite honestly might be completely unsuited to you for any number of reasons but it's what I do .

Joe

The Meat man wrote: ↑

Mon Oct 14, 2019 2:25 pm

phaust wrote: ↑

Mon Oct 14, 2019 11:08 am

General instructions for any metal coating is to clean rust (which patina is) off metal before putting a costing or rust preventative on.

In other words, the concern is more patina or red rust will form, even with tuff cloth coating on top.

The Mastiff wrote: ↑

Mon Oct 14, 2019 1:07 pm

Some good advice in above group of posts. If it was me I would use a soft paste wax like Rennisance wax to clean, slightly polish and seal the knife for storage. As it is you have a rusting knife and calling it a patina will not change anything. It takes me 3 to 4 minutes per knife. Make sure you use a clean and soft cloth for application.

Joe

Rust and patina are not one and the same thing. Rust pitts and flakes off exposing fresh steel which is what makes it so destructive. Patina is more like staining. It doesn't pit the steel, and it doesn't flake off.
Gun bluing is essentially applying a patina is it not? I don't think anyone would call a well-blued gun barrel rusty.

Not trying to be argumentative. Just a little surprised to see this comparison made given the obvious differences.

The are actually, by definition; patina is a type of rust. I acknowledge though, as you point out, that red rust and black/blue rust (patina) are different. Thst isn't lost in what I said there.

You bring up gun bluing. If you know about gun bluing, you know there are different ways to do it, and different types have different effectiveness. In general, cold bluing is the least effective at preventing red rust. A patina like this coming from use is spotty and uneven (no offense--looks very pretty--just talking red rust prevention here) is not going to be even as effective as cold bluing. That's not to say it will have no effectiveness, but the topic here is keeping it as-is in long term storage.

Not trying to be argumentative either. My point is just having a patina from use doesn't mean it won't continue to oxidize and/or form red rust in addition.