The life-cycle of a diving knife

[Shotmaster]

Lol, to each his own. I've had my two knifes for over 40 years. I lost theScubapro knife once in the Chipola River hunting Megaladon Shark teeth when I first started diving. I bought the one in the picture as a replacement. I found the Scubapro a year later on a return trip. I had taken it out to stab some kind of sucker fish that had attached itself to my leg. I must not have secured it properly and it was missing when I got out of the water. But I found it and still have it today. It is also good insurance if you encounter an alligator in fresh water. It must un-nerve some people, because they act like it is going to jump out of the sheath and attack! I consider myself properly ataired. ;-)

 

[tarponchik]

This is the one I was talking about in one of my above posts. I couldn't remember the name. The ones I get have a red handle and are even cheaper than the one you linked, but the blade looks similar and is probably made from the same material.
They don't come with a sheath either.
Those things cut through anything like butter.

I have a Swedish Mora Morakniv knife like that but I consider it too sharp for diving. It comes with a sheath w. a plastic release button.

 

[Storker]

Traditionally, the red handle Mora knives were carbon steel, i.e. not stainless. Great edge, but rusts very easily. The stainless Mora knives actually have decent edge properties, but the steel is less rust-resistant than that of my dive knives. I wouldn't use any of them underwater, partly because of the rust, partly because they can be sherpened too sharp for diving, partly because I the finger guard on the handle is too modest. In drygloves or 7mm three-fingers, it's too easy to slip on the handle and cut my hand.

 

[DMDavid]

I've gone from a Sea Hunt style knife strapped to my leg back in the 1970's to just a short little serrated knife for cutting out entanglements and fishing line. What I find most important now is that the knife can be taken apart completely so that you can clean every metal part throughly, that will keep it from corroding.

 

[tarponchik]

Traditionally, the red handle Mora knives were carbon steel, i.e. not stainless. Great edge, but rusts very easily. The stainless Mora knives actually have decent edge properties, but the steel is less rust-resistant than that of my dive knives. I wouldn't use any of them underwater, partly because of the rust, partly because they can be sherpened too sharp for diving, partly because I the finger guard on the handle is too modest. In drygloves or 7mm three-fingers, it's too easy to slip on the handle and cut my hand.

They claim it is stainless, but I've never tested it. The Spyderco folder I've mentioned (the non-serrated one pictured here, only it was $75 back then) resists rust very nicely except for the rivet that holds the clip. The rivet became totally rusty and gave ugly rust stain across the yellow plastic handle.

 

[drrich2]

Years ago I bought a stainless steel dive knife. It rusted.

A friend bought me another one as a gift. It rusted.

I bought a dirt cheap 'titanium-coated' dive knife as a Black Friday special. It rusted.

Sometimes trying to save money costs money. I will not diligently clean & dry knives after diving. Ain't gonna happen. Right up there with eating 'right' and going to the gym regularly, and all the arguments about why I should or how easy it is will not change that.

Which left either a pure titanium knife, or one of the H1 steel knives made by Spyderco (which also makes non-H1 knives, so watch what you buy). I bought a Spyderco Salt 1 H1 steel knife on Amazon for a bit over $60.

It sits in a little accessory pocket on the outside of my BCD pocket on a Sherwood Avid BCD. I don't rinse it unless I dunk the BCD or it's the end of the dive trip. Bonaire. 2 Live-aboards. Plenty of time in salt water. It's done fine. From experience and some digging, a couple of interesting points:

1.) Someone pointed out that they use a drill bit with a different kind of steel to carve their symbol into the blade, and you may see trace rust there because of residue from that drill bit. Well, if you look close at my knife, you can see a faint orangish color right there.

2.) While rust-proof, I'm told you can corrode one if you want. They're too expensive for me to play like that, but I've read someone put one in a bucket on a solid chlorine tablet (sold for chlorinating swimming pools), and while not technically rusting, it did significantly corrode the blade. Assuming that's true, you could damage H1 steel if you wanted to. I've never heard anybody complain about pool or tap water chlorine causing problems.

In Scuba Labs 2015 Dive Knife review, they included the Spyderco Salt Assist and had this to say:

"The newest of Spyderco’s Salt line made of H-1 steel — which in our experience lives up to claims that it’s impervious to rust — is less than 5 inches long. It opens to 8.5 inches with a flick of the thumb (even with 5 mm gloves). The waffle grip is extremely effective, and the handle offers excellent control (although it might be a bit much for small hands). With a cutting edge 3.2 inches long, the blade sliced through all of our test lines like a light saber, and its rounded tip lets you slip the blade in between what you’re cutting and what you very much don’t want to cut. The handle has a carbide tip to break glass or ice, and a safety whistle. Sharp, safe, handy and rustproof, the Spyderco Salt Assist is our Testers Choice in the large-knife category."

One point of criticism of my Salt 1 - it came as a folding knife with no sheath, and if I didn't have that little pocket on my BCD, I'd have had to dream up some way to attach it.

Richard.

P.S.: Also bought a Trilobyte and like it; it rusts, but not real fast, and it's so low profile you can forget it's there. Interestingly, Dive Gear Express now has the DGX Sharp Cut, with a ceramic blade that if I understand correctly isn't supposed to rust. Looks to me like a Trilobtye, and it's inexpensive.

 

[Storker]

They claim it is stainless, but I've never tested it.

Like I said, traditionally. And red, not orange. I may have expressed myself a bit clumsily, I don't doubt that the orange handle is on a stainless blade.

Anyway, the steel Mora uses in their stainless blades is, by definition, stainless. It's a lot more resistant than carbon steel, but it's not very resistant. They don't take the kind of abuse my diving knife sees very well. There are steels that withstand salt water a lot better than the type that Mora uses, but that's at the expense of the edge quality. The Mora stainless knives give a surprisingly good edge for a stainless blade, particularly given the price of the knife. I have a couple myself which I use when I'm boating and/or fishing in the sea. Cheap, good edge, quite easy to sharpen, very decent corrosion resistance, very practical blade shape. Pretty much a near-perfect compromise for that kind of use. But not a knife I'd use for diving.

 

[Killerflyingbugs]

One point of criticism of my Salt 1 - it came as a folding knife with no sheath, and if I didn't have that little pocket on my BCD, I'd have had to dream up some way to attach it.

I dived this knife for years when I was a hardhat diver, what you do is take out the sex bolt that holds the pocket clip on and put a shackle and clip on it.

 

[lucca brassi]

The life-cycle of a diving knife

purchase -diving- loss - rusting on seabed - discovery from other diver

 

[Bubblesong]

On the subject of extending dive knife life, I learned that besides thoroughly drying the dive knife, I have to thoughly dry the inside of the dive knife sheath, or hidden drops of water are invisibly waiting to get started on my blades. Hotel Hair Dryers are handy for this little chore.