MacTech's Corrosion Resistance test II, SAK Edition....

M

MacTech

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I'm setting up my second corrosion test this upcoming weekend, this test will determine the corrosion resistance of the common Swiss Army Knife....

on Saturday i'll stop off at the local pawnshop that has great prices on used SAK's (assuming the shop is actually *open* this time :mad:) and pick up a couple $5 used SAK's (ideally a Victorinox and a Wenger)

the test chamber is a standard 2.5 gallon glass aquarium with a bubblewall spraybar creating salt spray/foam

the SAK's will be placed in the testing chamber and exposed to highly corrosive salt spray 24 hours a day, a knife will be considered "failed" when visible rust spots appear, some tools wil be deployed, others stowed to see if that makes a difference

i feel kinda' bad deliberatly trying to destroy usable SAK's, so i'll get the roughest ones possible, it's all in the name of science!

heck, i'd almost be tempted to put a Swisschamp in the chamber if i can find one for less than $20 at the pawnshop, that'd give me a good overview of the corrosion resistance of most of the tools.....
 
Sounds like an interesting test, Mac Tech. I just found a Rada paring knife that had been lost in the garden for months. The 420 blade held up great. The aluminum handle was pitted, but that just makes it more grippy :) .
 
Hey where do you live?
My local pawn shop (Miami) the only one and closer to my home rarely carries Sak's last time they had a camper for $15 so I did, not bought it and two weeks ago they had a Sog pocket plier and they wanted $16 it was in fair condition so I didn't buy it too. They have a lot of jewerly but i'm not interested on that.
I wish we have more pawn shops around here!
 
My local pawn shop usually has a few SAKs but I've never seen any good deals. They'll ask $12 for a well used Tinker when you can buy a new one at Wally World for $15.
 
I live in York, Maine, the pawnshop is in Portsmouth, NH, a 10 minute drive away

they have 3 price categories;
$5; mainly keyring SAK's
$10; one to three layer SAK's
$20; the "toolboxes"

i stopped of at KTP tonight, and picked up a couple of Vic Bantams, i may use one for the corrosion test, the other one i picked up just to add to the collection, and because i didn't have a SAK with a combo tool yet...

part of me can't bear to potentially wreck a perfectly good brand-new SAK, even if it was only $10, used ones, i can wreck those no problem...
 
MacTech... You definately have lots of "research type of cells" in your brain...;) Try to go get your PhD...

Well... If you can have large amount of SAKs to test and record the time, I maybe able to do some statistical analyses for you:D ...

Great idea, man!! Way to go!!
 
Sounds like a nice test! I think they will all eventually rust, but it sounds like rates will be different, might be primarily a function of chrome content? It might be interesting to have a control sample (I might be misusing the terms) such as a carbon steel knife, or a nail, anything to highlight the differences and maybe provide a reference point to observe the differences. Oh yeah, gotta have pics please! :D
 
Yes, pics will be posted....

to recap the other test i posted on Spyderco's forums....

testing environment;
All-Glass 2.5 gallon aquarium with glass cover
Penn-Plax "bubblewall" airstone bar
Whisper 100 air pump
52 ounces of fresh, cold Atlantic Ocean seawater from York Harbor Beach, Maine

water was poured into test chamber and air pump created salt spray and foam, knives stood vertically in the tank, handles partially submerged, blades directly in the path of the salt spray/foam

knives tested;
Spyderco Pacific Salt (H-1)
Sheffield hawkbill (cheapo purchased at Home Despot, probably cheap 400-series "stainless"
CCC Balisong ("Rostfrei" steel)
Buck Metro (420J2)

the test was performed for 36 hours, but ended prematurely due to rust contamination of the test water

time elapsed before rust appeared;
Sheffield hawkbill; ONE HOUR!, this cheap crap excuse for a knife showed visible spotting in just an hour
CCC bali; 24 hours
Pacific Salt; unaffected, *NO* rust
Buck Metro; no rust on blade, whitish buildup on the edges of the aluminum scales
 
I bet the SAK's last longer than all the other knives, only to be beaten by the H1 Spyderco's. :)
 
SAK is pretty good. A guy did a 7month 3week test salt water immersion. It did rust, but not much - It certainly still functioned fully as a SAK. However, the scissors spring dissolves, its of a different material.

Theres a 4 year story:
Four years in a purification tank
Gilbert V. Levin from the USA tells an almost incredible story in a letter dated 23 September 1991.This time it’s not about the Swiss knife saving a life or being used to rescue some hopeless situation, but about the little red knife itself having survived four years almost undamaged in a purification tank. Mr. Levin wrote to Victorinox in Ibach:"In 1973 I installed my new invention for sewage treatment at Seneca Falls, New York. One morning as I was crossing the bridge over the aeration tank of the treatment plant, I saw that the setting on one of the instruments was incorrect. I took out my dependable Swiss Army Knife to make the necessary adjustment. The knife slipped out of my hand and fell into the aeration tank. The function of the aeration tank in a treatment plant is to oxidize organic waste. This oxidizing environment is very corrosive to metals.

Four years later, in 1977, I received a small parcel by mail with a note from Al Hawk, the supervisor of the Seneca Falls plant. They had emptied the aeration tank and found my Swiss Army Knife at the bottom. The parcel contained the knife. It was in astonishingly good condition. The only thing wrong of any note was that the spring for the scissors was missing: it had dissolved. There was also some oxide on the aluminum parts that keep the blades separate. The plastic casing and cover had only suffered very minor damage near to the toothpick and tweezers. I intended long ago to send the knife back withy complements to the company which manufactures such durable knives. I have looked after the knife and since then have never used it. I enclose it for your attention as evidence to this almost incredible occurrence. I can assure you that very few products could have survived treatment like this; the components would have dissolved or simply disappeared."


Survived salt water
Your Swiss Army Officers’ Knives coped superbly with extensive use. They soon became an indispensable tool for a range of tasks as well as in emergencies. Frank Goodman was very sad when he lost his on Cape Horn Island. I carried my knife in a life-jacket pocket and as a result it frequently came into contact with salt water. Despite this it continued to function perfectly. Many knives advertised as being‹stainless steel rust precisely when they are needed most. But not the Victorinox knives. These are obviously the genuine article. I would like to take this opportunity to thank you for your generosity. Without your help and those of others this adventure would have been impossible. Our success is your success.

Muahahaha. Good luck >:)
 
Hello Cabron50,

As a metallurgist, I must point out that when you couple (electrically connect) steel and aluminum in the presence of an electrolyte (wet soil), the aluminum is anodic to the steel (cathodic). In plain speak, that means the aluminum will corrode (the pits you mention) and the steel will not. This is the principle in cathodic protection of steel (protected) boats using zincs in salt water.

Great example that you mention - Thanks - Joe
 
You might also apply some Tuf-Glide or other protectants to one of the knives and see how effective they are in the tank as well.
 
the experiment is indefinitely postponed, as my source for cheap local SAK's is closed for the forseeable future....

if, and when they re-open, i'll start the test
 
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