Rib knife (non rusting)

ChrisB123 · 25 January 2007, 15:32

I have a s/steel knive that is kept on the rib in its holder, but it rusts!!

Although it is s/steel there are different grades, many of which apparently tarnish and rust in a salt water environment.

I want to replace it with one that i can keep on the rib at all times for easy access and it won't rust. I understand that it needs to be of a surgical s/steel grade to ensure total rust proofing.

Is anyone aware of such a knife, how much and where i can get it from?

Cheers

Nos4r2 · 25 January 2007, 15:36

Try titanium-it's not as expensive as you'd think and it won't rust.

AndrewH · 25 January 2007, 15:43

Quote:

Originally Posted by ChrisB123

Although it is s/steel there are different grades, many of which apparently tarnish and rust in a salt water environment.

Generally speak A2 grade (automotive - type 304) doesn't have good salt water properties. However A4 grade (marine - type 316) is designed for purposes such as deck fittings onboard boat and is more more resistant.

Hope this helps

Andrew

codprawn · 25 January 2007, 15:45

Problem you have is that the higher the carbon content the better edge on the knife. Of course this means that the stainless will rust easier - so you can either have a knife that will never rust but has a crap edge or one that you can sharpen like a razor but will be covered in spots!!!

Simon B · 25 January 2007, 15:48

Try a good quality "Kitchen Devil" type knife. The blade is ideally suited to cutting wet rope, its guranteed (they wont know it lives on a boat) it's cheap to replace and most can be modified to make a blunt point. If you do wish to make it further resistant to rust or staining coat it thinly in divers silicone grease.

Titanium is an excellent material, however as a diver there's a never ending number of knives that get put away in Davy Jones's locker, it is unusual to get back a knife of the some quality as the one you lost...weird man!

whiteminiman · 25 January 2007, 16:06

Wikipedia is your friend:

http://en.wikipedia.org/wiki/AISI_steel_grades

or

http://en.wikipedia.org/wiki/Stainle...tainless_steel

or

http://www.bssa.org.uk/nsindex.htm

Cheers, WMM

jyasaki · 25 January 2007, 16:23

Quote:

Originally Posted by ChrisB123

I have a s/steel knive that is kept on the rib in its holder, but it rusts!!

I want to replace it with one that i can keep on the rib at all times for easy access and it won't rust. I understand that it needs to be of a surgical s/steel grade to ensure total rust proofing.

Is anyone aware of such a knife, how much and where i can get it from?

Cheers

Surgical grade does not mean it won't rust.

I don't think that any grade of SS is completely rust-proof; some are more rust resistant than others, though.

The best procedure I've come up with is to keep a coating of silicone grease on all exposed metal surfaces on the knife. A handle that can be disassembled helps here, as you can coat the entire piece of metal. The grease lasts longer than oil does. Use a grease certified for incidental food contact, and you're safe consuming the evidence of being attacked by that rampaging salami.

I've got a Underwater Kinetics dive knife that has been on my gear for years with no discernible rust problems. I think it's made from 420 SS. Their new ones are some proprietary SS blend called Hydralloy.

I dislike the titanium knives because they're too light. I like the heft of steel, as it makes it feel like I've actually got something in my hand.

jky

TubrOnCrakberry · 25 January 2007, 16:33

Titanium alloys can only be brought to Rockwell hardness In the mid 40s and do not hold their edge very well. Any steel alloy that provides a good edge will be subject to corrosion if kept continuously in a saltwater environment. Rather than keeping the knife on your boat, keep it on your person (lifejacket, belt OR both). That way you can rinse it off in fresh water dry it at the end of day. The blade can also be given a light coat of chapstick OR vaseline to help protect it from the elements.

Tomas · 25 January 2007, 16:49

The only option not mentioned are the new ceramic blades. They are VERY sharp and are reported to be durable. I only mention this because it was the only option not discussed.

My own choice is for a high carbon stainless that is easy to sharpen on my ceramic sharpener, is rust resistant and gets a bath in WD 40 from time to time. Other than very slight discoloring on the blade, it remains good as new in extreme salt conditions.

Ian M · 25 January 2007, 16:56

Quote:

Originally Posted by Nos4r2

Try titanium-it's not as expensive as you'd think and it won't rust.

I'm with Matt, and my titanium diving knife holds a very sharp cutting edge wonderfully.

Andy Moore · 25 January 2007, 16:58

What about a Leatherman Wave?

Aidan · 25 January 2007, 17:53

I am with the titanium and serrated edge.
It should work well.

Besides by the time it gets blunt, its normally lost.

Donnie144 · 25 January 2007, 18:43

The titanium knifes work great but are expensive to replace. Before I moved to Titanium I would spry my dive knifes down with a clear lacquer(spelling?) paint bought at any hardware store and it works great. Provides a good protective coating but doesn’t hinder the cutting edge and doesn’t leave an oily residue all over everything.

Andy · 25 January 2007, 21:18

I use one of these, its great.

http://www.andark.co.uk/site/store/c...1/default.aspx

Notice the blunt end, if you drop it on a tube it does not burst it!! RIB bonus!

Matt · 25 January 2007, 21:24

Just polish your A2 knife till it's like a mirror.

codprawn · 25 January 2007, 21:36

Quote:

Originally Posted by Andy

I use one of these, its great.

http://www.andark.co.uk/site/store/c...1/default.aspx

Notice the blunt end, if you drop it on a tube it does not burst it!! RIB bonus!

I also have one but there are a few rust spots showing.

Jono · 25 January 2007, 22:02

Quote:

Originally Posted by MadMat

Just polish your A2 knife till it's like a mirror.

Don't you feckin join in Streako'... I'm struggling as it is....

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Andy · 25 January 2007, 23:01

Quote:

Originally Posted by codprawn

I also have one but there are a few rust spots showing.

The knife probably isnt rusting, could be impurites on the surface and cleans off. Diving knifes do this also. I usually cover mine in a thin layer of silicon grease or vasaline, it does the job.

Its still a good knife and the blunt end to useful.

prairie tuber · 26 January 2007, 00:40

I posted some pics last week in the other knife thread, but this knife has been designed specifically for use with inflatable boats. The combination of a blunt rounded tip and inset concave blade the chances of accidentally slashing a pontoon are considerably less than with any other blunt tipped river knife.

prairie tuber · 26 January 2007, 02:02

Here is a link showing a good variety of river style knives that are available through Mountain Equipment Co-op.

http://www.mec.ca/Products/product_l...=1169780012192