Best method for a dark finish

[JW Knives]

I'm looking for the best way to force a deep blue / black finish on some blades that I'm working on. Anyone care to offer some advice on what methods, products can be used to achieve something like this?

Ideally it would be with items found around that house / hardware store...

Thanks in advance!

 

[The_cutting_edge]

For carbon steels I have had good luck with hot vinegar. I heat the vinegar in the microwave then submerge the blade. Check it every 15 min or so and scrub with an old tooth brush. Once you reach the desired color neutralize with windex ands then a quick boil in a baking soda water solution to set the etch

 

[JW Knives]

Nice, sounds simple enough. I'll be sure to give that a try

 

[GrizzlyBear]

Carbon steels can be colored with a patina any number of ways: vinegar, mustard, ferric chloride, etc.

Stainless steels need a bit more work, from what I have read. http://www.caswellplating.com/kits/black.htm#stainless the 307 Stainless Blackening kit works well from pictures I have seen.

 

[melsdad]

Try birchwood casey "super blue", it's for hardened material. I have used it on a few blades and was happy with the results. From what you describe this may work well for you also.

 

[GrizzlyBear]

I've used the Super Blue liquid (not paste) to reblue a vintage octagonal muzzleloader barrel. It does a fantastic job at giving a nice, dark black. There is also the BC Plum Brown that puts a rich brown finish to the metal. I don't think either work with stainless though, it's for carbon only.