How to ‘blue’ a knife and what is the advantage?

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Pietje010

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Dec 30, 2005
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I’ve seen some pictures of knifes and project knifes that have been blue-ed. Mostly done on carbon steel blades whit the cold-blueing technique. It looks very cool but is this look the only advantage? And how do I a
actually ‘blue’ a knife?

Thanks for every input!
 
i used to work on a lot of guns and i have done some hot bluing as well as cold bluing. there is a maker here that blues his knives. maybe he will see this and tell you more about doing knives. on a gun or a knife however, the bluing will protect the metal from rust but it will still form rust if not properly taken care of.
 
You can find cold blue compounds for do-it-yourself at a lot of sporting goods departments. I can tell you from experience that its appearance and rust-proofing qualities are quite inferior to hot-blueing, which needs to be professionally done. The chemistries and processes are completely different.

I've never even heard of blueing being done on stainless steels, just the carbons. On stainless steels, I have seen vacuum-deposited coatings.

Hot-blueing any knife will require complete disassembly, removing the scales, etc, which is typically going to be impractical. Give cold blue a try if you think you'd like the look. You'll get instructions with the product.
 
So blueing is used for some extra rust prevention, next to normal care of the carbon steel blade.

But how to hot or cold blue a blade? I never have seen any compounds for DIY-blueing in knife stores overhere...how can I bleu completely DIY (no special kit's or whatever)?
 
hot blue requires heating bluing salts in stainless steel tanks. it takes about a half hour soak for a gun in the salts. its an expensive process to get started up but the best way to blue steel. cold blue is exactly that, cold blue. it comes in paste or liquid. i use a paste blue since its easy to apply to a gun. i have yet to blue a knife. a friend of mine is setting up a set of bluing tanks for guns. i might have to do a knife or two and take some picks of the process. pietje010, if you know someone over here in the states, i'm sure you can get them to ship you a tube of cold bluing. i would check with customs on your end first just to make sure they wont stop it from coming through.
 
Pietje010 said:
But how to hot or cold blue a blade? I never have seen any compounds for DIY-blueing in knife stores overhere...how can I bleu completely DIY (no special kit's or whatever)?
Click to expand...

I blued a Schrade Old Timer with a broken blade tip that dad was going to toss. I reprofiled the tip and decided to see how it would turn out using cold blue.

I used Birchwood-Casey paste (cause I had it on hand) and just followed the directions. I think I applied four "coats" for lack of a better term. It turned out okay. Certainly not bad for a user but far from anything professional.

From memory:
1) Clean and degrease. I used acetone.
2) Apply paste and let sit for a minute or so. Wipe off excess.
3) Buff with "0000" steel wool.
4) Repeat.
5) When blued enough for your tastes apply a protective oil.
 
Funny thing... I was just thinking about this today.

Why isn't it common for knifemakers to blue their carbon steel blades? I know it helps prevent rust, but are there drawbacks?

Nicely blued steel certainly looks nice....

[BTW - an excellent (many consider it the best) cold blue is Brownells OXPHO-Blue.]

Stay sharp,
desmobob
 
Pietje010, check at a gun store or hunting store if you want to try to pick something up locally. Otherwise, try searching on the internet and I'll bet you'll be able to find an on-line store that will ship the cold bluing paste to you.
 
thanks for the help,I checked it out but dont think the cost or even the effort is worth to get into bleuing. Maybe nice for show knifes that stay in the drawer. The extra trouble is not really worth it. Freshwater cleaning and oil works well enough IMO.
 
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