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Hook Knives...don't bet your life on them!

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kitezilla
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Postby kitezilla » Sun Nov 25, 2007 2:36 pm

Greg7 wrote:
kitezilla wrote:
Greg7 wrote:They are so cheap I would just get a few per season.
Where do you buy them?

What brand?

It seems that the double bladed hook knives cost about $15 to $54 (plus shipping) each.

I wish I had enough money to consider those prices... "cheap".

How often do you change out your knives?

What do you use as your indicator for "time to replace"?



As already stated, you can get replacement blades pretty cheap.

Many kiters spend more than a grand a year on "the latest" equipment, and a decent percentage spend quite a bit more than that. Relative to how much else you spend on gear, for something that can save your life the cost is ludricously neglible.

As far as knowing when to change. If you ride on the saltwater and leave the knife in it's pouch after a ride so it can rust out, yeah, you might get in trouble fairly quickly.

But if you take a few seconds to take the knife out, rinse, shake, and toss on the counter to completely dry, a stainless steel blade will easily last 2-3 three months and look brand new. So three per windy season is enough.

For anyone afraid they might forget their knife after rinsing it, just leave a brand new spare in your bag in a ziploc, it will remain brand new until you need it.

You bring up a very good point, I didn't think they would crap out that fast, but there are ways to prevent it, and considering it might save your life, and considering a complete one kite outfit can cost over 2 grand, and most of us have multiple kites, do yourself a favor and drop a few bucks on multiple hook knives.

......................................


Gregg,

Thanks for the advice! But, as they say, "you are preaching to the choir".

In the past 5 years, I have bought kite knives from Murrays Marine...by the dozen. Unfortunately, they were the single bladed ones....and the results of my present method of testing the sharpness, and effectiveness of this type of knife make me very glad that I never had to use one of these knives in a desperate situation.

After doing some random testing at the beach, where I carried around a piece of QPower kite line, and challenged a number of kiters to try and cut the line with their hook knife, I began to see the value of the double bladed hook knife. I may be mistaken, but I think that it was Spork, who whipped out a double bladed knife and sliced through the line like butter....while many others tugged away at the line with the standard Dakine single bladed hook knife.

I don't want to give Spork a big head, but while I am paying out compliments, I would like to note that he and the many other kiters, world-wide, who take pride in preserving the effectiveness of their rescue equipment, do so, at their personal expense and effort, and exemplify the personal trait and principle, that in doing so, they will be able to help, not just themselves, but in times of need......others, as well. You guys rock!

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Postby spork » Sun Nov 25, 2007 3:10 pm

kitezilla wrote:I don't want to give Spork a big head, but...
No worries. That ship sailed long ago! :D

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Postby kitezilla » Sun Nov 25, 2007 3:11 pm

[quote="mx5alan"]

Yes, I always carry one (2 blade version)... as it was supplied with my Mystic Warrior Harness.


mx5alan,

You nailed it!

I am reluctant to take sides and "endorse" any product or manufacturer, but, here, I have to restrain myself from giving my whole-hearted thanks and appreciation to Mystic, for going to the extra expense and effort to "do it right". If I ever get to the point of presenting the data and preliminary results of my blade sharpness testing study, you will see why I hold this opinion.

The main purpose of doing this study was not to compare knives for the sake of discrediting any manufacturer or product, but the purpose of the study was to give myself and others, an objective, reliable, reproducible method (using the scientific method) of testing the state of sharpness of the blades, over a period of time, under severe environmental kiteboarding conditions. I have studied a normal sample of single and double bladed knives, using this method, and could not help but notice significant differences. Still, the goal of my testing is to achieve an objective way of knowing when to replace or hopefully, SHARPEN the blades, to maintain the effectiveness of the knife.

This possibility of sharpening these blades is what I am now pursuing, and I am asking for help from anyone who may be familiar with a good method for achieving this goal.

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Postby Greg7 » Sun Nov 25, 2007 3:13 pm

It sounds like you think I am suggesting a single blade knife. I never advocated a single blade, if your life depends on it, get the best, which is obviously double.

It has no bearing on the rest of my post, it is still way too cheap not to get them.

I don't care if the only knife you could get was $50 each, if your $1000+ kite is dragging you to your death away from your $600+ board, you sure as chit are gonna wish you had a lousy $50 knife to bail out...

Since I will be kiting alone a lot, I will carry a spare :wink:

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Postby kitezilla » Sun Nov 25, 2007 4:53 pm

high123 wrote:What really helps in salt water is to cover the blades with a thick layer of high viscosity grease. Then wrap one layer of very thin plastic wrap/food wrap around it so you don't create a mess when you put the knife into the pouch. Obviously you don't need to pull off the plastic wrap before using the knife, just use it as usual... :-)

I tested it after a season and the blades were basically new after many, many sessions in salt water, were cutting Q Power like butter.

PS: I'm also using a double bladed hook knife from http://www.hookknife.com/hookknives.htm with spare blades.


....................................

High123,

Wow! It sounds like you have done your homework, and have it "all together".

They say: "The proof is in the pudding", and hopefully your finished product is the proof... and I would be 98% sure, at this point, that your procedure is a very good way handle the problem of hook knife corrosion....BUT the remaining 2% of me wants to have the following doubt removed:

First, I should say, that in the last year or so, I have learned a lot about stainless steel, and most likely know just enough to be dangerous. So, here, I would like to play "devils advocate", and present the following "strawman", hopefully, to be knocked down...preferably by a Metalurgist.

The argument against coating stainless steel, goes like this:

"Chrome is the element used in ferous alloys to bestow corrosion resistance and shine. Chromium has the remarkable ability to form a film on the surface of stainless steel and to thereby, continually repair itself, even in an oxidative environment. In fact, chromium is so reactive, that, like aluminum, within a split second, it will react with oxygen to form an oxide coat, and counter-intuitive, as it may seem, this oxidation forms the coating protecting the bulk of the alloy from further oxidative corrosion (rust). In practicality, this explains why one can take a hacksaw into a block of stainless steel, and cut deep into it, and still, the alloy remains corrosion resistant…because, the metal heals itself, with every draw of the blade. If this oxidative reaction is inhibited, two types of severe corrosive processes may occur: (1) Chloride Pitting and (2) Crevice Corrosion. Years, ago I remember reading (in a friend's Civil Engineering Journal) of the case of a catastrophic collapse of a swimming pool roof, due to the use of stainless steel in the supporting hardware. The architects mistakenly thought that the more expensive stainless steel hardware would be better….but, in reality Galvanized steel holds up better in a high chlorine gas environment. Two weeks ago, a Mechanical Engineer told me of a Fubar, that a major costal city experienced with their new replacement salt water fire fighting system….using stainless steel everywhere. It turned out that black steel would have been a better choice, in that the residual water, contained in the system, protected the stainless steel interior parts from air exposure, and the result was that the ensuing pitting and stress corrosion cracking insidiously destroyed the components of the system…to the tune of millions of dollars."

Sooooo, I will restrain myself from going on about the Martensitic and Austenitic and “Superaustenitc alloy differences and the relative percentages of carbon, moly, titanium and nickel….consult your local metallurgist for this.

What I want to know, in the face of the fact that apparently, weird types of deterioration of stainless steel can occur when it is not allowed the self-healing exposure to oxygen,….By coating our high carbon content stainless steel blades, do we create an oxygen starved environment, where pitting or crevice corrosion is more likely to occur? Related to that possible risk, also, is there a particular grease or coating which will not only protect the metal from salt water, but also slowly release the needed oxygen to the metal to supply the chromium with its healing reaction?

????????????????????????????

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Postby spork » Sun Nov 25, 2007 5:09 pm

is there a particular grease or coating which will not only protect the metal from salt water, but also slowly release the needed oxygen to the metal to supply the chromium with its healing reaction?
I'm guessing there is no need to self-heal if the steel is truly protected from the elements that would attack it. But I'm certainly no expert on this.

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Postby Greg7 » Sun Nov 25, 2007 5:42 pm

Thanks for the thread KZ, I just ordered 5 from paragear.com :thumb:

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Postby Bagels9000 » Sun Nov 25, 2007 11:44 pm

kitezilla wrote:
Bagels9000 wrote:You really OD'd
jesus
I am interested in everyone's opinion, even when I don't quite understand what they are saying.

Do you carry a kite knife?

A lot of people do not, and from the results of my testing, I can see the merit in presenting a case for not carrying one... The argument would go like this: "Why waste the time, in an emergency, to grapple around for a kite knife, which, even if you find it and fish it out, probably won't cut the line, that you are tangled in!" or "Your time will be better spent on dealing with the tangle, in some other way, and not wasting valuable moments, running a "fool's errand", in fumbling with a dull kite knife, that won't work anyways" or "Knowing that you don't carry a kite knife will keep you more focused, knowing that you can't get yourself out of trouble, and therefore, will make you extra careful not to get into trouble, in the first place".

I would like to think that you were, in a subtle way, presenting that point of view, rather than just being rude.

Either way, I appreciate your participation in the thread.

Okay, my point of view...
I DO have a knife. yes, it is a bit rusty and its double bladed...
But i feel as if i have enough experience that if i had come into this situation, it would not be my fault.
It would be the fault of the equipment, so therefore, why not just worry more about your gear, and double check rather than cutting your lines every time you think something bad happens...
Ive been in some shitty situations but never cut my lines.

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Postby spork » Mon Nov 26, 2007 1:04 am

Bagels9000 wrote:Ive been in some shitty situations but never cut my lines.
I've never cut my own either, but I want to be able to if need be. What happens when you get tumbled in a wave for so long you don't know which way is up? With all your gear in tip top shape you could still find yourself mummified in kite lines.

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Postby schmoe » Mon Nov 26, 2007 3:53 am

Thanks for all that info. The dakine knife was on my todo list, not anymore.

A few questions:
The double hook knives that you link too are 16CM long. Where do you put it?

Are those knives safe enough not to cut your fingers?

I am assuming that in an emergency you will have to pull it out without looking at the pocket, because it may be under water, on the back of the harness, or you have to look at other things. You may not grab it properly.


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