Parkerizing vs hot blue finish

[PaulDiStefano]

Hello everyone, I have been reading here a lot about parkerizing and hot bluing. From what I can gather it seems that parkerizing is much simpler and easier then hotbluing.

I had a question about the difference between the two finishes. I am looking to get my damascus jet black without sanding off the high 15n20 layers. I wanted to keep the whole blade black. I have seen hot blued knives in person before and I like that you can polish it to where after it is blued it has a super shiny and reflective black mirror look. I was curious if this can be achieved with parkerizing. I have never seen a parkerized knife in person but any video I’ve seen or picture of a knife , the blade is more of a matte black. Is it possible to get that shiny buffed black mirror finish with parkerizing alone?
I wanted a really chatoyant high layer count Damascus black blade. Curious if that’s possible through parkerizing or if it will just dull down the shimmer.
Thanks guys!
Paul

 

[seanj]

I've never parkerized a knife but I have parkerized on several guns. Depending on the particular parkerizing solution used I either got a dull gray or dull black finish. I don't believe you could make it shine at all. Many guns are parkerized first and then coated with a second finish which could be shiny if desired. You could try a clear gun coat from such manufacturers as Ceracote, Duracoat, or Gunkote. But the coating will eventually wear off with use.

I have no experience with hot bluing so I can't address that

 

[P.Brewster]

Parkerized finishes are textured on a microscopic scale, which is probably what makes them matte in appearance. See pic here https://onlinelibrary.wiley.com/cms/asset/4339ed43-1bea-4980-8f6f-cf98125d134e/nfg001.jpg

Also Parkerizing won't work on stainless steel; I'm not sure sure how a 2% nickel steel such as 15N20 will respond.

Also the normal prep for Parkerizing is sandblasting. If you omit the sandblasting, the resulting color will be much more subdued.

In conclusion I don't think Parkerizing can do what you want. If it could, everyone would already be doing it.

 

[Bill DeShivs]

And, you can't really polish bluing AFTER it's done- the metal should be brought to the desired finish before the bluing is done.
Bluing is a very thin layer of controlled rust, and it's not durable at all.
On damascus, it might hold up well on the etched surface, but will wear off on the polished parts.

 

[Natlek]

Hello everyone, I have been reading here a lot about parkerizing and hot bluing. From what I can gather it seems that parkerizing is much simpler and easier then hotbluing.

I had a question about the difference between the two finishes. I am looking to get my damascus jet black without sanding off the high 15n20 layers. I wanted to keep the whole blade black. I have seen hot blued knives in person before and I like that you can polish it to where after it is blued it has a super shiny and reflective black mirror look. I was curious if this can be achieved with parkerizing. I have never seen a parkerized knife in person but any video I’ve seen or picture of a knife , the blade is more of a matte black. Is it possible to get that shiny buffed black mirror finish with parkerizing alone?
I wanted a really chatoyant high layer count Damascus black blade. Curious if that’s possible through parkerizing or if it will just dull down the shimmer.
Thanks guys!
Paul

I done this some day ago......when pull out of acid it was black as night.IF I leave it to dry it will stay black but will have lot of ugly stains....I clean it fast so i don t know if black would be durable..I can try tomorrow.
Now it is dark grey and can be polished ......but not high gloss . I found that it is quite durable .

Here is link how i do that , if that is parkerizing ...................https://bladeforums.com/threads/phosphoric-acid.1654333/

 

[coldsteelburns]

I've seen Karl Andersen do some completely hot blued blades in his twist damascus. He usually sands off the 15n20, but on a couple he left it all dark, which looked very nice IMO.

Parkerizing damascus will help provide contrast in the deeper etched layers, but as mentioned it produces a microscopic "porous" surface that's supposed to hold onto oil really well, so I don't believe it will leave the 15n20 polished looking while it's still black. This isn't from personal experience, it's just from what I've picked up from other makers over the years, namely from listening to Karl lol.


You also might try coffee etching and leaving it on the 15n20. Maybe boiling after coffee darkening would help to stabilize the finish a bit?


~Paul
My Youtube Channel
... (Some older vids of some of the older knives I made)

 

[PaulDiStefano]

Thanks for the info guys. I am in love with that black finish Karl has left on a few of his knives. I’ve seen his videos before and that is definitely one with the look I’m aiming for. It seems hot bluing might be the only way for it to come out like how he gets it.

 

[kuraki]

I've played around with polishing parkerizing after the fact. It's a neat effect and it's held up well on a few blades, but even with manganese phosphate and a typical steel that gets very black (Cru Forge V) I haven't been able to get the contrast you're talking about because the 15N20 takes a gray color on.

Basically I etch for actual dimensional contrast and then polish with a rubberized sanding block.

Then I parkerize and it comes out looking like this:

Then I lightly buff it with pink scratchless compound and it goes from matte to a beautiful gloss. You can absolutely over do the polishing and end up having to repark.

This is the most durable finish I've worked with. It does not come off with use the way that coffee etch or ferric etch does.

 

[gudspelr]

I've played around with polishing parkerizing after the fact. It's a neat effect and it's held up well on a few blades, but even with manganese phosphate and a typical steel that gets very black (Cru Forge V) I haven't been able to get the contrast you're talking about because the 15N20 takes a gray color on.

Basically I etch for actual dimensional contrast and then polish with a rubberized sanding block.

Then I parkerize and it comes out looking like this:

Then I lightly buff it with pink scratchless compound and it goes from matte to a beautiful gloss. You can absolutely over do the polishing and end up having to repark.

This is the most durable finish I've worked with. It does not come off with use the way that coffee etch or ferric etch does.

Kuraki-
So I’m taking it from your post that you go from your etch and rubber sanding block to park without any sort of sandblasting, correct? That makes sense to me, but I know at least for mono steels, folks seem to agree upon sand blasting prior to park.

Jeremy

 

[kuraki]

Kuraki-
So I’m taking it from your post that you go from your etch and rubber sanding block to park without any sort of sandblasting, correct? That makes sense to me, but I know at least for mono steels, folks seem to agree upon sand blasting prior to park.

Jeremy

Yeah, that's traditional wisdom. And it's true to a point. That is if you want a nice uniform finish out of the park tank. But it assumes no post finishing on the parkerized surface.

You can kind of see on my park-not-yet-polished photo, it's splotchy and ugly.

If you're going to polish the park, a sandblasted surface isn't really conducive to polishing. If you want a nice uniform matte finish, blast and park. If you want a shiny smooth glossy finish, sand to 400/600, park, then buff.

 

[gudspelr]

Yeah, that's traditional wisdom. And it's true to a point. That is if you want a nice uniform finish out of the park tank. But it assumes no post finishing on the parkerized surface.

You can kind of see on my park-not-yet-polished photo, it's splotchy and ugly.

If you're going to polish the park, a sandblasted surface isn't really conducive to polishing. If you want a nice uniform matte finish, blast and park. If you want a shiny smooth glossy finish, sand to 400/600, park, then buff.

Thank you very much, sir.

Jeremy