Acid patina finish on stainless

Lerch

Lerch

Well-Known Member
Recently i have done a couple of blades with a dark acid etch on stainless steel. I have taken these blades and ran them through my stonewash tumbler to give a nice slate look to the steel. I have had luck with a forced acid patina really improving the rust resistance of 1095 carbon steel and i was wondering if anyone thought this would also aid 440C or CPM154 with a little added rust resistance. I have a guy i am making a bird and trout knife for and i thought if i did a dark etch on the 440C it made give him a little added buffer against rust

Thanks
steve
 
Steve,
My first reaction is,
I don't think so! By pitting the finish you are inviting rust to get started in the small pockets. The Chromium with a satin of better finish I think is best with 440C
I use a lot of it for my Culinary knives.

When customers bring in the knives for sharpening/Recon work, If there are pitts in the stainless you really are screwed in the long run.

Some do put a black or dark powder coat material on 440C etc.. To stop reflection for a combat knife and that will improve it's corrosion resistance.

Good Luck.
Laurence

www.rhinoknives.com/
 
If it were me and I wanted to try it, I would do a satin finish and then the acid etch. I've had pretty good results doing this on a D2 folder I have.
 
Thanks guys,

I have been taking the knives to about a 600-800 grit finish and then etching for my stainless knives. I am not sure how much pitting there is on them but i see where the concern would be Laurence. One of the ones i have recently done is my personal work knife so i will see how it holds up over time. The customer that brought me to this question decided that he wants a 600grit satin finish anyway so no concern here

thanks
steve
 
I don't understand . Do you want to improve thr rusting existance of properly heat treated 440-C ? I never had a problem with it rusting in the many straight knives I made from it. Frank
 
No i know the 440C blade shouldnt have any problem rusting as it sits, i had just been making a few stainless knives with a dark acid etch and i was wondering if anyone thought it might give the stainless blade a added bit of rust prevention. I have had great luck with a forced patina from ferric chloride on 1095 steel really aiding in rust prevention so i was just curious if it might add anything to a stainless blade. before i got curious about it i had just been etching the stainless blades to put a nice dark finish on them.


thanks
steve
 
I just use Ferric Chloride diluted one bottle of acid to one gal of water and soak until you get desired effect.
 
Same here. I the neutralize and buff with a scotchbrite pad and wd-40. If I decide I want it darker, I clean the blade with degreaser and etch it again (repeat til I get the desired appearance).
 
Hi Guys
Forgive my ignorance but I didn't think you could do anything much to 440 stainless.
How do you acid etgh 440? Will you show us pics please?
Thanks MoblMec
 
Lerch
Are those 440c stainless? Did you do the acid etch and buff with scotchbrite you listed for D2?
I LIKE I LIKE!!!
MoblMec
 
Nice looking finish there. Have you played around with muriatic acid too? I etched some cheap 440 (probably A) blade as a test with muriatic and it came out a nice soft grey. Really like the finish. Took a LONG time to get the color though.

How long did you etch those in ferric?
 
Those were both etched for 25min, then washed with dial dish soap and hot water until black stopped washing off, then they were tumbled in a industrial vibratory bowl with water and triangle ceramic media for about 20 min.

I havent tried muratic acid but a nice grey finish might be nice so i will give it a try sometime.
 
No Mobi i never did D2, yes those are 440C but like i etch, wash, and tumble them in abrasive media.

glad ya like em!!

thanks
 
Well this sure has been a timely thread. I've just had a request for a stainless Damascus blade with the grey or non silver finish. Thanks again too all. Frank
 
Sorry, I've never learned to post pictures.I've only done the black but want to know how to do the grey. I think I may be going thjrough some trials very soon. Frank
 
I have been messing with trying to darken up steel after etching today. So far i have had luck etching the blade a couple of times, lightly cleaning it off with Never Dull and then washing it off with dial soap and hot water. After this i coated the blade real heavy in oil (rem oil spray) and let it set for about 8 hrs. after this i wiped it off and the dark portion of the steel seems to have a deeper dark color to it. I thought had read where someone was doing this with WD40 and getting a really dark etch but im not sure .

steve
 
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