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John Kruse-Kanyuck

Steel options for a saltwater diving knife.

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Hello everyone,

 

Today I am trying to find a good option for a saltwater diver's/fisher's blade. My friend is quite the avid sea-farer and has complained that his blades often rust out rather quickly. His birthday is coming up in a couple months and I'd love to surprise him with a blade that might hold up a bit better... Not to mention something he can show off to his diving group to possibly bring in some market.

 

Any help or tips is much appreciated! Thank you!

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Actually I've heard that people use titanium blades on diving knives for exactly that reason. Just a thought.

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Elmax or Nitrobe77 perhaps?

 

//DQ

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I've never tried a Ti blade but years ago I was asked to make something similar for a customer and ended up using 440C. No steel likes salt water but with 18 1/2% chromium it will work better than most at resisting corrosion. Remember that the handle & sheath need to withstand the water as well which usually means a synthetic material. For the handle you might try using some horse stall mat. I've used it before and it works nicely as well as being very comfortable. I believe that I used kydex for the sheath with rubber straps.

 

Gary

Edited by Gary Mulkey

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I'm fully outfitted for kydex and holstex production, and I'm a big fan of the Tek-Lok systems for them.

 

As for the grip I'm looking at a poly that I can mold straight onto the full tang, and then grind/sand to final dimensions.

 

I suppose I should do a static test with a couple different materials in a bowl of saltwater with similar chemistry to what he dives in. Both for the resin and metals of choice.

 

I'm looking at Ti, Elmax, and 440C. Is Chromium the only denominator I should consider for a "stainless/corrosion resistant property?

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You may try any of the CPM class of stainless/powdered steels. They are very expensive, but worth the money for saltwater exposure.

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Ti, eh? A specific composition of it, or just in general?

 

Not sure, my last post just about summed up the extent of my knowledge on titanium. I'm sure there are some different grades of titanium that are better for blades, I'll do a little looking for you and see what I come up with.

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Whatever steel you use. Buy a box of vaseline to Go with it. I put å thick coat on

my ss scubaknife, and I only have to clean it after Iv used it. And there is next to no

rust on it. And Iv done more than 200 salt water dives with it. I expect the hidden tang

is what will fail someday.

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It looks like any type of grade 5 titanium is good for knives. It won't hold an edge as good as steel, from what I've heard, but I can't see that being an issue for a diving knife.

Like others have said though, it might be better to just get some SS with unholy amounts of chromium and coat it with something.

Edited by Collin Miller

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Unfortunately Vanex is not sold in the States, does anyone have a section of it they'd be willing to sell? I'm looking for around 3 inches wide, by 10-12 long, and between 3/16-1/4 thick.

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One thing to keep in mind, diving knives seem to be the exception to the 'knives are not prybars' rule, as they are usually used as prybars and every once in a while they might be used to cut something.... due to this, considerations for toughness will greatly out-weigh edge-holding. Choose your steel and temper accordingly. Serrations might be in order, as the points of the serrations tend to protect the edges in between.

Edited by GEzell

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I was planning on doing some serration at the base of the blade, and a chisel tip, that will hopefully hold up better than a pointy tip for prying. It is also going to have a shackle key, as he recovers lost anchors.

 

I have not been able to find Elmax or Vanex by Uddeholm in the north American continent. I am looking into CPM-S35-VN as a possible. If that's not a decent hold, I'll do some experiments with Ti, and an old carbide mill bit, with a stick welder to try and carbidize the edge.

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;) The high vanadium CPM steels can be tougher than many stainless steels but can also be more finicky on the H/T. If you haven't H/T'ed them previously I would recommend doing some research first.

 

Gary

Edited by Gary Mulkey

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