Best stainless steel for use in salt water?

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pathfinder74

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Dec 15, 2005
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Thinking of trying my hand at making a knife. If I move forward on this I'm going to make it a dive knife.

I keep reading titanium is very anti-corrosion, but doesn't hold an edge as well as steel.

So I'm wondering, what is the best stainless to use for salt water? I live/dive in a VERY corrosive environment.

Also, any direction for stainless hardware (screws) would be awesome too.

I don't have a design yet. Thinking a design like the Wilson Cop Tool would be good for my purposes.

One of the guys that lives here is working on his own knife so I'm hoping to hook up with him for the build.

Thanks in advance
 
Are all of those reasonably priced?

That'll be my next question: Where's the best place to buy the materials for a good price?
 
A previous post about dive knives prompted me to spend a week researching just such a question. From this limited research I have determined that if I ever construct a dive knife the first one will made from Bohler N680 which is an affordable nitrogen steel. Alpha Knife Supply is the only place I have found it so far. Not expensive. Bohler-Uddeholm claims a working hardness (after tempering) of 56-58 HRC. Vanax would be the steel, also a nitrogen steel, that I would use if I were wanting to upgrade from the N680. It gets harder and is reported (Bohler-Uddeholm) to be equivalent to 300 series as far as salt water corrosion is concerned. I have not found it for sale yet and therefore only have seen it reported to be expensive. I have never worked with these steels nor have I used them, I only offer this to continue the conversation and give you some words to search. Many custom dive knives are constructed from 440C, which I believe would be more than sufficient. I'm sure there are a bunch more suitable steels out there as well.


I have seen it said that a dive knife only has to be sharp for a couple cuts but as I see it the main reason one carries a dive knife is to be able to self extract from underwater cordage, nets, or vegetation. Under such a circumstance I don't think my knife could stay sharp long enough, this combined with the added difficulty of machining titanium, is my justification for steel.


The next question will be handle material (if any) and what adhesives work for such an environment? G10? Rubber aka horse stall mat?
 
Make it from titanium. That will get the most corrosion resistance for the buck. About $30-40 in Ti would make a good dive knife.
 
Does titanium need to be tempered?

Thanks for the info so far.
As for handle material I was figuring on orange G10.
Are adhesives always necessary? I kind of figured if the hard fits right and tight there's no need for it. No?
 
I assume when you said "tempering" you actually meant "hardening". They are two very different things.

The standard 6Al4V titanium alloy is normally used as it comes. You grind and sand it and use it in that state. There are methods of making it a little bit harder, but most folks don't do them.
For a dive knife, edge retention is not a big issue. Corrosion resistance, strength, and toughness is what a dive knife needs.

Unless building a take-down style, it is always a good idea to seal the handle with something when assembling a knife. A resin like G-flex would be a good choice for a dive knife. Strong attachments, like Corby bolts, would also be good.

A lot of how you decide to make a dive knife, and what materials you choose, will depend on your situation and knifemaking skills.
 
Zero skills at this point.
Looking for something to cut line with and pry/scrape. Not looking to battle any sea creatures or anything.

Good to know on the Titanium. Just watched a How-to video on Youtube by a guy that goes by Trollsky. Pretty good for the fact that it was all common items used.
 
When I opened my first knife shop in Morgan City Louisiana in 1979 I made most of my knives out of 440C stainless and many of them are still in good shape and in use today. I don't think you'll find a much more corrosion proof blade steel.
 
Does the heating and tempering process change the corrosion properties at all?

Been watching some youtube videos on knife making and homemade forges. Looks doable even where I am.
 
N360 is so far the best in my experience for combination of cororesistance, edge holding and toughness. it is a new ball bearing steel made by pressed ESR. the downside is that its quiet expansive and usualy only avaliable in rod and thick bars.
 
Stainless steel for knife blades is not stainless or rust resistant until it is heat treated.
 
hammerfall said:
N360 is so far the best in my experience for combination of corrosion resistance, edge holding and toughness.
Click to expand...
I agree N360 is an excellent steel. I wish we could get more thicknesses. We've only been able to find .230" sheet.

N360 is another nitrogen stainless steel. The corrosion resistance of nitrogen steels far surpasses stainless steels.

Chuck
 
hammerfall said:
N360 is so far the best in my experience for combination of cororesistance, edge holding and toughness. it is a new ball bearing steel made by pressed ESR. the downside is that its quiet expansive and usualy only avaliable in rod and thick bars.
Click to expand...

How expensive is expensive?
How thick and how to you remove stock from thicker bars to get it down to a "normal" knife width?

bladsmth said:
Stainless steel for knife blades is not stainless or rust resistant until it is heat treated.
Click to expand...

MIND BLOWN!!! I didn't know that. So, depending on how you treat it can effect how stainless/rust resistant the knife is?
 
Not really, The alloy ingredients are normally spheroidized in some sort of pearlitic matrix when you get the annealed steel. Once it is heat treated, they are locked in grain boundaries of martensite and tied up in strong bonds. This makes it more resistant to corrosion and oxidation. The degree is set by the type of alloys used and their amounts.
 
Perrin said:
Vanax would be the steel, also a nitrogen steel, that I would use if I were wanting to upgrade from the N680. It gets harder and is reported (Bohler-Uddeholm) to be equivalent to 300 series as far as salt water corrosion is concerned. I have not found it for sale yet and therefore only have seen it reported to be expensive.
Click to expand...
I forgot to mention Vanax is no longer available. It is a amazing steel. However, it is very expensive to produce. It was pulled from the market last year.

Chuck
 
I had asked Boker aboud the hardware on the Cop Tool + as I was thinking that would make a perfect dive knife/tool.

Their response was that the bead blasting finish would actually make it somewhat prone to corrosion with continual use in salt water.

BUMMER. So I learned something else about stainless.

Thanks for all the input from everyone so far.
I'm going to have to take a trip to the Woodshop where I am and see what tools are available and what I would have to change out to use them with metal.
I have a bench grinder, angle grinder, files and drill press where I work. The woodshop has all kinds of different belt sanders. I'm just not sure if you need a different kind of belt when using them with metal.
 
I'm not saying you can't make a dive knife with your tools and experience, but I will say that purchasing one might be a better choice.
 
Vanax not being available explains why it is impossible to find. :)

Alright pathfinder74, you are starting to get into an area better explained by others than myself, because I'm learning it too. So follow this link to the Count's Standard Reply to New Knifemakers. It's in the thread, probably a better way to link to it but there it is. That followed by the stickies at the top of this subforum will answer all your questions and then form a bunch of new ones for you.

To briefly answer some of you questions, many people make their first knives with hand tools. I am about to have my first one heat treated and I have used nothing but a hacksaw (high-tension hacksaw is better which I now have), files, and sandpaper. On later ones I have used a 4x36 belt sander with Norzon Zirc belts. Lots of info on belts in the stickies. Good luck, happy reading.
 
I am a Padi Diver and know what you want in a diver knife for clearing fishing line, taking a abalone off a rock and the thing dive knives get used for more that anything!

Tapping the spine on your air tank to get other divers attention.

My experience with working Titanium was only once! I didn't know better and just started grinding it with only clear eye protection. the shower of sparks are in a super bright spectrum that set off a migraine headache that had me on my hands and knees on the shop floor. You need to wear Very dark welders glasses and even the fumes can be headachy for some.

I suggest you just get a bar of 440C stainless in 3/16 x 1 1/2" x 36" You can make three to four knives out of it and have a really small one with a 3-4" blade, another with a 6-9 blade etc.

Any place that HTes steel for us knife makers can do 440C. Have it treated to a rockwell/RC of 58-60 and you will have a reasonably Sea water stain resistant blade that you won't cry over if you drop it while decompressing on the way up in 80 ft of water and can't go get it.

You are welcome to PM me or email me if I can help you in any way with your dive knife.
 
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