How do I blacken a blade?

L

lerner

Joined
Sep 1, 2008
Messages
125
Note: This is not another "How do I paint a blade?" thread.

I've heard of the following methods/coatings for finishing blades:
bluing,
parkerize,
anodize,
teflon,
boron carbide,
dlc,
ferric chloride,
vinegar...

What I dont know is:
How dark does it make the blade?
How permanant/tough is it?
Can I do it myself, with a kit, or send it to someone?

I would like a matte black finish on a AUS8A TiLite.
Thanks in advance.
 
Bluing is a soft surface treatment, and it is not wear resistant.
Parkerizing is also not very wear resistant.
Steel can not effectively be anodized.
Teflon does not wear well.
Boron carbide and DLC are very wear resistant, but they must be commercially applied.
Ferric chloride is primarily used for etching damascus steel. It does not wear well.
Vinegar is a method of bluing, and does not wear well at all.
Other than the nitride-type coatings, nothing will effectively permanently blacken a blade if the knife is to be used.
 
Cold blueing solutions, like Birchwood-Casey(probably available at gun stores, since Walmart no longer carries it...), are good so long as it's a carbon steel.

You can thin the solution quite a bit and it's still effective, so it's easy to make a large container for dunking(as oppose to rubbing on, which gives a mottled effect).

First clean with WD-40. Then DO NOT touch the blade with your bare hands.
Dunk the blade in the solution, then rub with a VERY VERY VERY fine abrasive pad.
Repeat this many times, and you'll eventually get a nice, deep, dark finish. You probably won't get jet black, but it'll look quite good.

To reiterate, it will not stand up to use. On the bright side, it can be touched up fairly easily.
 
Don't use WD 40 to clean the blade!
Scrub ut with detergent and very hot water. Or, you can use alcohol, or acetone.
 
Bill, why not? Will it damage it?

I've used the home made spray and bake polymer coatings from Brownells. It worked very well, but the parts to be coated must be sandblasted first, or bead blasted at the very least. Otherwise the coating will peel off in long strips and wont last any longer than coloring the blade with a Sharpie marker. The coatings also add thickness to the blade, a few thousandths of an inch. This may affect blade play and smoothness in a folder, unless you mask off the pivot area. If its not coated, it shouldnt be sandblasted either. Mine was a Cold Steel fixed blade (the old Green River Scalper in Carbon V), so pivot action was not an issue.
 
No, WD 40 won't hurt the blade at all. WD 40 contains petroleum distillates. All petroleum must be removed before bluing.
 
When I cold blue small gun parts such as extractors, screws, etc...I always heat the part first, often by setting it on a kerosene heater for 20 minutes or even in the oven at about 250 long enough to bring it up to temp. This seems to deepen the bluing you normally achieve with cold blue. Also I would repeat this several times. If you are not taking the knife apart you can still heat the blade with a heat gun or torch...just use a wet rag to heat sink the handle.

I also use a non-residue break cleaner to clean the parts before bluing.
 
Boron Carbide, DiamondLikeCarbon, TiNi, or other nitride-type coatings: How can I get these applied (via mailing away the blade, I suppose)?

Cold blueing (Birchwood-Casey), spray-and-bake polymers (Brownells), K-Phos, Gun-Kote:
How dark/non-reflective can they get Stainless Steel (AUS8A)? Pics or links are nice!
How durable are they? Since they are used on gun mechanisms & screws, shouldn't they be very wear-resistant?
Are the bake-on types considered "hot-blueing"? Will an hour at 300degrees change the blade temper?
 
Cold bluing will not darken a stainless blade at all. The spray and bake stuff is still paint, and won't hold up on a blade that is used. 300 deg. should not hurt the temper if you decide to try it- but I can save you a lot of trouble. It won't work for what you want to do. The applied PVD coatings are the only things that will work, and you will have to send the blade off. Most PVD companies won't do a single blade, or wouldn't last time I enquired. Best bet is to forget the black blade and live with what you have.
 
A couple of guys have used this black oxide kit and have reported good results.
They make one kit for stainless steel.
They make a different kit for alloy and carbon steel.

It's not inexpensive, but it does not require any special equipment.

http://www.caswellplating.com/kits/black.htm
 
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