Acid Wash Cryo fail. help?

R

ronron2112

Joined
Jan 1, 2012
Messages
5
Hello all, long time lurker, first time poster.


I have a Cryo II that I am trying to acid wash in hopes of getting a nice black finish. I have all my contact areas and blade design all marked up with nail polish.

I have dipped the frame and blade in a jar of PCB acid for 20 min. no change of color. So I sanded/tumbled the finish off the items and re-dipped for 60 min checking for color changes every 15. I gave up, and pulled the pieces out and was left for a dull light grey finish.

What did I do wrong?!

Thanks for the help!!

Ron
 
Not 100% positive but I think that the parts you are trying to acid wash are stainless parts. I think the pcb treatment only works on non-stainless steels.

Edit: If you don't wash off the acid well you may end up with some rust spots on the blade but I don't think you will ever get a change of color or patina on that knife.
 
I guess i should have mentioned, I did wash the parts off after I removed them from the PCB. The knife is indeed stainless... but I've read on the interwebz of success using the PCB on this particular knife... but they may have forgotten to post their secrets.
 
No, PCB is able to etch stainless steel.

The problem in your case, if I recall correctly, is that the Cryo has a blade coating. I'm not too familiar with Kershaws, but by the gunmetal appearance of the blade, I think it has some sort of titanium coating. Etchant solution gets into the pores of a steel to break down the surface, but I'd assume DLC coatings have a denser surface that the solution has trouble permeating.

If the Cryo really is a plain blade; please correct me, but I am sure PCB can etch any kind of steel.
 
I am not sure about the coating thing. But you said you sanded the parts so that should have removed the coating . I have had good luck getting a darker finish by wiping the PCB on and letting it dry then repeat until you get the dark color you want. It will look uneven but it will even out after stone washing . Here is a pic of a O1 blade I did with this process. Different steels react differently to the pcb so you might not get that exact finish but you should be able to get a darker finish this way than submerging the parts. Best of luck getting the out come you are after.
12007389923_4d360eb84d_b.jpg
 
Ferric chloride works well on some stainless steels. I did both my Tuff Lite and Voyager (both AUS-8) and they came out a nice gray/black (tried it on a 4116 and 440A, too, and no dice, so you never know). I'd think it would work similarly on the Cryo's 8Cr as is does on AUS-8. The sanding would remove the DLC from the higher surfaces of the steel, but you may not have sanded deep enough to remove it all, inhibiting the etchant from getting down into the steel. Just a guess. :confused:
 
Well thanks guys! I am going to bring the parts to work and give them a light sand blasting and try again!
 
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