Lets talk about RUST!

J

J.Davey

Joined
Feb 10, 2004
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In the next issue of Blade, they will have an article about rust being an over-rated problem. What are some of your opinions? Try to address issues such as the following:


Does rust on the blade effect over-all performance?

What is the best protection against rust?

What works best for removing rust?

What carbon steels rust the fastest (or slowest)?


Well, you get the gist. Just throw in your thoughts!
 
"Does rust on the blade effect over-all performance?"

No, unless you let the knife sit there forever and the blade corrodes away.

"What is the best protection against rust?"

Use the knife and clean it when you are done. Store it properly. Don't stick it in the damp leather sheath, wrap it in plastic when on a boat on salt water, and clean the blood off of it right away.

"What works best for removing rust?"

No strong opinions here. Never had a serious rust problem.

"What carbon steels rust the fastest (or slowest)?"

I have heard that L6 rust pretty fast.
 
I have used carbon knives most of my life and have never had a problem with rust or corrosion. I just clean the blade after use and oil/wax the blade if not to be used for months.
I personally think that the rust issue and carbon knives is overplayed, unless you live near the ocean, etc;
 
Depends on how serious the rust is.Prevention is easier than removing it .Keep it clean ,dry, oiled. ....And then we metallurgists invented stainless steel !!
 
I have quite a few carbon blades and have had no problem with rust; however, I keep a light coat of gun oil on my knives when they're stored.

Does rust on the blade effect over-all performance? Only on the edge and that's easily treated with a sharpening stone. When my Randall (O-1 tool steel) was parkerized a Force Recon Marine had another Randall in for the same treatment. His had been swimming with him in salt water and it showed. After sand blasting and treatment in the acid and parkerizing solutions it still had pits, but the knife as a tool was just fine.

What is the best protection against rust? Parkerizing or one of the newer teflon blade coatings such as Benchmade uses on their BT blades.

What works best for removing rust? Steel wool and Breakfree.

What carbon steels rust the fastest (or slowest)? All things being equal? I'd like to know. The high carbon, zero chrome steels such as 1095 would seem to be very prone to rust without protection.

Edit: A knife I came very close to buying was all Damascus carbon steel. Unfortunately by all they meant the handle too and that's when I cancelled my order. Other pure collectors jumped right in and AFAIK the entire production run is sold, so it seems to me that carbon steel is still highly desirable. I will probably kick myself for cancelling that purchase, but a carbon steel handle just didn't seem right.
 
Rust?
You mean the orange stuff, right?
Never had a problem with it.
I used my trusty Schrade Sharpfinger saltwater fishing for years. It cut bait, cleaned fish and did all of the other tasks like trimming line and spreading mayo.
Now it looks like an old hammer. Gone is the shiney factory finish.
That knife oxidized (patina), but never turned bad crusty brown/orange.
After cutting bait I'd rinse it in fresh water, dry & sheath it.
If there was no fresh water available, I'd wipe it dry and sheath it.
At the end of the day *hot* soapwater followed by WD40.
I stress hot water because the blade will hold the heat and the heat will help it dry.
If you can live with the patina, you have no problems.
If you want your blade to look *brand new* all of the time, you have to use oil or wax for long term storage and watch what you cut. Acidic foods will patina your blade while you look at it. Eggplant makes a cool purple-brown on my Old Hickory kitchen knife.

The best protection for rust is keeping your blade dry. Followed by a light coating of oil. If you can maintain your firearm, the same goes for your knife.
Patina will not affect your knife. Orange/brown rust will. Pitting is bad, the pits are deep and hard to even sand off.
Mineral oil works wonders on rust. I found an 1940's vintage pocket knife in my garage. Couldn't open it, immersed it in mineral oil for a week and now it not only opens but looks alot better than it did before.
I don't know which steels are more rust prone, but methinks heat treat has something to do with it.
 
I'm not sure how to spell it, but where is the line drawn between rust and patina?

One is destructive and one makes an old-world style protection, AFAIK.

Chris
 
Rust really only affects the appearence of a knife. There may be some reduction in slicing ability if the blade is excessively rusty.

Paul
 
My 1970 issued kabar has both patina and rust. It's been kept in the sheath forever, not used in years at this point.

It's still fully functional and razor sharp. 1095 always takes a great edge.

About the only knife that I store that way that would be considered not wise [ in leather ].

All of the rest of the high carbon blades are soaked in clp in knife rugs. Years upon years go by with no effect on the blades stored this way in my neck of the woods.

Brownie
 
I own a few forged, high carbon bowies, which I do not use, so, they are never exposed to anything corrosive, and, I treated them with Birchwood-Casey Sheath, keep them in a Bill's case, which is said to contain padding which cannot absorb moisture and I have still had some knives develop small isolated rust spots. Had a Fitch bowie treated this way, and in a few months, there was a small, pencil eraser size spot, easily removed, but it still bothered me. Same for another carbon steel hunter.

I think im going to try Eezox next.
 
Rust can be a serious problem if not addressed - normal surface rust which occurs when you forget to clean a blade is not a problem if fixed straight away unless the rust has attacked the edge. Personally I have never had a problem with rust but that is because I like many other Knife Knuts am diligent and clean my blades properly but I have seen some bad cases of rust/corrosion/staining when the owner/user has been lazy. I owned a Schrade Old Timer Stockman for many years and never had a rust problem but recently I sold a Stockman to a person, who should have known better, and within 2 weeks all three blades were a mess. He had used the knife on fruit and never cleaned the blades - once the fruit juices had got into the works the folder needed a good bathing in "LANOX" a lanolin based rust inhibitor. The edge on the clip blade was so bad it had to be reprofiled to clean it up. The problem with rust and folders is that it attacks all parts and esp. those parts that are not obvious like the blades and this can impact upon the efficiency of the folders mechanism.

The problem with rust on a blade is that it does weaken the edge, can create pitting and will carry nasty micro-organisms. I have found "LANOX" the best preventative there is.
 
I live right next to the sea and due to strange weather paterns, the air is practically a salt bath!

Rust can be a real problem for me, esp my high carbon steels if I am not careful...

Long term storeage I use Ren Wax
I also use Marine Sentry Tuf Cloth, though this does need to be used at least once a week in experience if the knife is unused. I use Militech-1 as an oil and rust protector on my swords and it works well. I use Flitz to remove rust spots etc and polish.

I sometimes use Chris Reeve RIG or a teflon white grease by Finish line.
 
I always doubted my dad when he said his knives took a better edge when he let them rust up a little, and then cleaned them up. I remember reading an atricle about the old 426 HEMI that dodge/chrysler would let the raw engine blocks sit outside for a year to "season". Don't know if there is anything to this or not, but thought i'd mention it.
 
I think rust formation would affect performance fairly quickly under the right conditions, especially high humidity with exposure to corrosive substances including salt water, sweat and so on. A blade coating works great for protecting all but the most important part, the edge. The easiest protection against rust is stainless steel, and of course some are more stainless than others.

Gene
 
cmd said:
I'm not sure how to spell it, but where is the line drawn between rust and patina?

One is destructive and one makes an old-world style protection, AFAIK.

Chris
Click to expand...

Most metals are susceptible to oxidation, Aluminium and Titanium, for example are much more reactive than iron (and steel). What happens with them is that as soon as the metal surface is exposed to air (say if you scratch it), it oxidises, leaving a very thin oxide layer on the surface, and undergoing no further reaction. You can leave it in salt water all day long and nothing will happen.

In iron, the oxide, iron (II) oxide IIRC, has different properties. This is called rust and is the only compound to which the name applies. The oxide expands and lifts away from the surface, exposing fresh metal. This all happens locally, which is why you get pitting, rather than the entire surface turning red. What is more, the reaction is autocatalytic, meaning that the presence of iron oxide accelerates the reaction, this is why it is important to remove all signs of rust as early as possible.

Patina is where the surface has been oxidised by other means, and the resultant compound is not iron oxide, but "iron x,y,z", or it could be iron (III) oxide which has different properties to rust. I don't know much detail on this, but the principle is used for blueing steel, and you can DIY with a carbon steel knife. When you get a new blade, clean it and then cut lots of citrus fruits with it, then wash it. You should get a nice dull fairly even patina, that will provide a barrier to the attack of oxygen, thereby inhibiting rust.

Sound theory which I've never tried.

In a using knife, rust shouldn't be a problem as you are cleaning it and touching up the edge regularly, and it should build up a nice patina. For a safe queen, it shouldn't be a problem because you can leave it oiled (or otherwise protected) and unsheathed. If you keep a knife in your car or something, for emergencies, then you may want to condsider a stainless. Same goes if you're one of those people who likes to carry a dedicated SD blade that is never used for anything else (not a good idea IMHO).
 
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