Tuf-Cloth vs. Ren Wax (FINAL RESULTS)


May 31, 1999
Hello everyone....

Back on June 7, 1999, I started an experiment. I took a piece of steel, divided it into 6 sections and applied a "protectant" on 5 of the sections. I then placed it outdoors to simulate a knife left carelessly outside ('course none of us would REALLY have that happen!).

Periodically I posted what was happening. Well, it has been over a month. During that time I have moved the metal to different locations, wiped it with a finger, "scratched" each section and let it age naturally.

For reasons I cannot explain, the section that faired the best was the UNTREATED section! That just completely defies logic. At any rate, if you would like to view the metal yourself, I have it all on a web page at: http://www.bright.net/~wrs/steel_test/

Send me a case of that "Untreated" stuff, it worked great!

Congratulations, welcome to real science. You constructed a really nice test setup that virtually precluded you from subconsciously favoring the expected "best" solution and you got surprises. Aren't you glad you had an untreated "control" sample on your metal plate. This is something to show your kids who have to do science projects.

I can't say what went wrong, but I have a guess or two. Maybe your problem was your last cleaning step of wiping the metal down with "mineral spirits". The mineral spirits are petroleum based and often leave a layer of a volatile light oil like kerosene. This might be incompatible with your silicone and wax based protectants and prevent them from adhering to your metal surface. The one protectant that would happily work with the light oil would be WD-40 which is also oil based. In the end your untreated plate faired best because it had a little light oil and it was very clean. An absolutely clean metal surface will corrode less than dirty. If you had your metal plate in a vertical position rain and dew would tend to rinse the metal plate clean (assuming minimal smog). The more gunk you had on the surface the more ionic (salt like) contaminants could hang on the surface. If the protectants were not bonded to the surfaces to offer true protection they would just be dirt catchers.

Another possibility relates to sunlight. If the plate was directly in the sun, some of your protectants might have been degraded by ultra-violet light exposure. Once degraded they might just serve as dirt catchers.

I would repeat the experiment, but not wipe the surfaces with mineral spirits. I would use acetone or hot detergent followed by a distilled water rinse in place of the mineral spirits. Drip dry completely, but apply your protectants within about a half hour. Do all your surface preparation within a brief period so that the surface is fresh when you apply your protectants. I would use 400 grit Wet Or Dry paper instead of steel wool. I think there may be some waxy or oily material on the steel wool to keep it from rusting.


Nice job!

[This message has been edited by Jeff Clark (edited 16 July 1999).]
Very interesting!

Thanks for doing the tests. Nicely documented too.

Now, if I could just understand why you got those results. This is puzzling. Perhaps Jeff is right about the "mineral spirits".

Maybe some of the company experts will provide some insight here. I'd love to see reactions from Sentry and the others.

Thanks for the current results. May be next time try using some thing that will evaporate and not leave a substance behind like denatured alcohol (NOT rubbing alcohol) would have been my #1 choice. We have to clean up steel here at times and we have also used acetone with good results. Just an idea

Tuf-Cloth contains mineral spirits. It is the carrier for the corrosion inhibitor so it can't have caused any problems with the Tuf-Cloth. I would be concerned if it prevented bonding by the other materials as mineral spirits and such are often used in cleaning. If this is the problem it would be worth knowing. You should not have to take such great care when applying an inhibitor. Its not like you can do it in the field. Breakdown of the products due to UV light is interesting and another concern as obviously this is a real use "stress".

What would be a more practial test is to not be as careful. Take a piece of steel and get a uniform surface with sandpaper as suggested in the above but then cover it nicely with goop like lemon juice, salt water or anything else. Use your imagination. Then clean it with just water and a rag and apply the various protectors. If you get too artifical using cleaning products you will make extrapolation of results to field use impossible. Use as large a piece of steel as possible to get a significant sample size. I'll see if I can get some mild steel and do a similar test with Marine Tuf-Cloth, Mineral Oil and WD-40.


[This message has been edited by Cliff Stamp (edited 16 July 1999).]
Looking at the pictures, I curious about the depth of the rust on all sections. Did they begin to pit or was it surface rust. Though you can't tell from a picture, the Tuff-Cloth and WD-40 sections look like surface rust. They appear similiar to steel I have seen with only a light surface rust to it. Not that you want rust, but a light coat of surface rust will act as a barrier to an deep pitting and severe rust.

Great work by the way. Like real science, the first experiment ended up creating more questions than answers. Maybe you could get a Gov't. grant for further testing. Heck if some group can get a million to find out why small pieces of peanuts settle to the bottom of a can, being more practical research should be worth that much.

Thanks for the info.
I would take exception to what Cliff suggests. You will always need your protectant to wet the surface you are guarding unless you are encapsulating it in a grease or plastic. I studied problems of surface protection when I worked in the Caltech physics department building submillimeter wavelength telescopes. These assemblies need to last for decades out in the weather. A surface that you have not cleaned and dried will have a monomolecular water layer on the surface. This layer doesn't bond well to most organics like paints, waxes or oils. It is also a potential medium for galvanic corrosion processes (not to mention the other ionic surface contaminants you have before cleaning).

You just can't slap on a thin layer of some miracle substance and have it block corrosion.

When you initially corrosion protect a material start with a fresh surface if possible. Clean in hot detergent then sand the surface. This gets rid of the water and contaminant saturated "low energy" surface. (You are not trying to roughen the surface, just get down to fresh material).

If you need to protect your origional finish you will have to make due with simple agressive cleaning. Hot detergent (in moderation since it can etch or discolor surfaces) and/or acetone or MEK (Methyl Ethyl Ketone) make good cleaners. If you use detergent, rinse with the cleanest water you can find (preferrably distilled or deionized). Dry with the cleanest towling you can find.

Rub protectant thoroughly into the clean surface. This is now your base coat.

In the field always clean your knife by wiping and clean water rinsing. Then wipe it with more protectant. If you clean the blade using solvent or detergent you want to immediately resaturate the blade with protectant.

The above is the most reliable way to insure that you get protection with a thin and infrequent application of protectant. If you frequently tend the blade, simpler means will suffice, but if you plan to neglect it you will need to really treat the surface. If you really soak the blade in oil, simpler means suffice. The oil acts to both clean and treat the surface at the same time.

Anyway, when you do experiments you don't just mimic random field conditions. You try and isolate and control your variables. If you haven't managed to control your results in this already simplified experiment it is certainly not the time to start injecting more variables like lemon juice and simulated "goop". After you resolve your current experiment you can develop a reasonable field-maintenance test procedure.

I also think that Cliff is making an unwarranted assertion when he says that "You should not have to take such great care when applying an inhibitor." While we don't want it to be inconvenient to apply an inhibitor to get reliable results, the real world is not sympathetic to our attitudes. Your test shows that with a broad range of reputable products you do indeed need to take special care. Never assume that you "shouldn't have to do something" because it goes beyond bounds of convenience. You need to look to experience or scientific evidence to show you the necessity of a procedure.

PS. I had another thought about what might have caused you so much corrosion in your tests. What did you use to chemically clean your steel? Acids and products like Naval Jelly really promote corrosion if not fully removed from a surface that they have been derusting. I would post-clean any surface I used these materials on with detergent and deionized water. This might be your most critical step. If your etchant was not fully removed with water-based solutions it would not come off with mineral spirits. Subsequently rain might remove your deruster from your "untreated" steel while wax coatings might hold it around.

Maybe your test is just too severe for light surface treatments. The army historically used really heavy greases to encapsulate arms that would be subject to long term exposure to moisture in storage. They have actually run many corrosion experiments over the last couple hundred years and have military specifications for surface protection. Thin coatings outdoors may just not be up to the task.

[This message has been edited by Jeff Clark (edited 16 July 1999).]
Hello everyone.....

I am really enjoying reading the comments to my little experiment here. A wide range of thoughts and insight!

I think sometime soon I may try this experiment again. However, this really wasn't meant to be a big, scientific venture. (although I do like the idea about getting a grant!This is better than peanut crumbs!).

My whole point was to just simulate a knife that has been coated with a protective film in a "typical" way recommended by the manufacturer. Then, just leaving "out" as though it were dropped outdoors and forgotten.

I am sensing that my surface preparation perhaps wasn't the "best" for a true, fact finding type experiment. (The web page explains what I did) But, then again, how many knives are prepared any better before a protectant is added?

I too hope someone representing any of the makers of the protectants I used adds to these discussions!

I am sensing that my surface preparation perhaps wasn't the "best" for a true, fact finding type experiment. (The web page explains what I did) But, then again, how many knives are prepared any better before a protectant is added?

I think Jeff is right. The point is not how knives are prepared typically in the field, but first to determine which protectant works best when the steel is prepared as best it can be before the coating is applied. That gives you a benchmark for further work, including the differences between application under "ideal conditions" vs. those of simulated field use.

I do wish to comment though that I personally don't take *any* protective substances into the field with me, I don't want the extra weight and/or hassel. When I'm done with my knife for the day, I clean it off with water and dry it if I can spare water. My dirty pants leg is always available for the drying. I don't bother doing any serious cleaning and coating application till I return home. This has worked fine for me even though all of my camp-using knives are ordinary carbon steels.

My personal favorite coating hasn't been mentioned yet, it is MILITEC, a special weapons lube that "bonds" with metal I suppose very similarly to what the treatments in tuf cloth and the like also do (I'm guessing here though the Militec people insist theirs is not the same compound as the others). You can check them out at: http://www.apdinc.com/Milstart.htm. I have no affiliation with them.
I like RIG GUN GREASE. Sounds yucky but it works. I like the Ren wax for Ivory and pearl gold ect..
Chain lube oil ( yuck) works great to . You can lay a blade up for weeks and the oil does not drip off from one side and rust!

Web Site At www.infinet.com/~browzer/bldesmth.html
Take a look!!!


Could climate (namely prevailing winds, sun or rain) play a part in your experiments? Corrosion is worst on the left side and least on the right side.

Rotate the position of the protectants. See if the rust appears more on the left side again.
What about drying the metal in an oven to remove any moisture?
Steel wool has a coating on is that will burn in contact with an electrical charge (9v battery). It will smolder and heat up, try it, its cool.
Possible contamination. If you can clean the metal with a wire wheel, and avoid any application of solvents or cleaners, you may find that the moisture problem may lessen.
Also, if the piece is laid on its side the rain will run off almost completly, but some will stick at the bottom. Further dust contamination could cause a wicking effect and draw moisture up from the ground, if that was where it was left.
Just some thoughts.
When you put electric current through steel wool it is the iron that burns rather than a coating (it is rusting REAL FAST). BTW if you have a chemistry set or some root killer it is fun to put steel wool in copper sulfate solution. The copper ions steal electrons from the iron which causes the copper to precipitate out of solution and the iron to go into solution (dissolve). This reflects a common corrosion cause--contact of dissimilar metals causing the exchange of electrons (galvanic corrosion).

PS. Copper sulfate is a lot like sulfuric acid. You can get sulfuric acid from sulfer-rich smog and moisture (acid rain). It tends to happen more where people burn coal.
Hmmm... I can't believe the part which was treated by Tuf-Cloth rusted. So I gave my dad a bottle of Tuf-Glide, and have him treat one of his older "barong" machete, which rusts so fast, he gave up oiling it already.

It's been three weeks now, and the blade is still rust-free, much to the surprise of my dad.

Of course, it's not being weathered and all, but it did stop the rust spots that comes out of nowhere before it got treated by Sentry's Tuf-Glide.

Jeff :

Anyway, when you do experiments you don't just mimic random field conditions

If your experiment is under conditions that are not inline with actual use stresses you will get very precise indications of behavior under conditions that are different than those you are actually interested in.

Your test shows that with a broad range of reputable products you do indeed need to take special care.

I would not jump to such conclusions so quickly. In any case, no one actually does take this kind of care nor are they going to. It is simply not practical. If you are out in the field are you carrying around sandpaper, detergents and other solvents? Of course not. So what is the value in knowing how they work in this manner for those who are interested in field protecting their knives, which I assume is the purpose here.

Maybe your test is just too severe for light surface treatments.

It isn't. I have used Marine Tuf Cloth to protect knives that have been left wet and have been abraded (normal work + sheath wear). I have never seen significant rusting, nor have I used excessive care when applying it.


[This message has been edited by Cliff Stamp (edited 19 July 1999).]
Face it Cliff, you just like to make your tests unrealistically severe. The scenario the experiment was based on was that he took a knife into the field and left it there. It is reasonable to assume that he applied protectant to the blade before he went into the field and he only used it moderately. In this case it would probably have been used in Ohio. His test stresses are reasonably representative for an unsheathed knife left on a rock or something (except maybe the sample is exposed to a more urban air pollution).

You indicate that the simulated field conditions needed to be more representative, but your suggested stresses are: "...cover it nicely with goop like lemon juice, salt water or anything else. Use your imagination". Nowhere do you suggest anything particularly like actual field conditions. Where in Ohio is he going to run into sea water? Where in Ohio (or Newfoundland) is he likely to run into a lemon grove? My point here is that WRS did a very nice job of setting up a modest representative experiment and you are suggesting that rather than solve the mysteries of this simple experiment he should go try more complex less relevant tests. Next you'll tell him he needs to chop up cars.

On the other hand your criticism of my statement "Your test shows that with a broad range of reputable products you do indeed need to take special care." is valid. It is still quite possible that surface preparation or protectant application are not at fault in the observed corrosion. The question we are all interested in is "What did cause all of the protectants to fail and be worse than nothing and how can I insure this doesn't happen to me?"

I still stand by my doubt: "Maybe your test is just too severe for light surface treatments." I would say that it has been proven in this experiment that the specific test conditions were indeed too severe for the protectants. The original intent of the experiment was to compare the relative protecting powers of the protectants. The test is obviously too severe since it exceeded the protecting power of all of the candidates making comparisons impossible. The big question is why? There is something WRS did (or didn't do) that is not representative of the experience of many of the contributors to this discussion. What is it? I would love for some minor continuation or reproduction of this test to explore what it could be.

My suspicion is that the test samples were unusually exposed to the weather in this test. Something like sunlight or circulating damp air or acid rain are not typical of the stresses these protectants normally handle. I assume that sheath knives live in sheaths and folding knives live in sheaths or pockets. They don't get out into the light all that much. They also don't get much exposure to circulating air and precipitation cycles. Maybe the test should be run with some dark cloth or leather draped over the material.

Why, Why, Why, did the unprotected sample turn out the best??!!

PS. Cliff--I love your knife tests. I think we learn a lot from examination of various kinds of stresses to knife edges. I suggest you try cutting up car tires if you want a cheap and reasonably repeatable medium for severe edge testing.

[This message has been edited by Jeff Clark (edited 19 July 1999).]
Jeff :

Nowhere do you suggest anything particularly like actual field conditions.

Food prep. would involve similar contact with acids, salts and other non-blade friendly materials. The reason I suggested smearing and a large surface was to get a decently coherent large size sample. Sprinkling or something similar would localize the effects and drastically reduce the sample size.

You do make a good point about centering the testing stresses (what are my blades likely to come in contact with?) but the downside to that is if you do this too much you end up with a result which is valuable to you and you only. A broader stress range would lead to more people being gaining insight from the experiment, and if it is not overly difficult to do, why not just do it?

I would say that it has been proven in this experiment that the specific test conditions were indeed too severe for the protectants.

Something was too severe. I think it is a little to soon to say it was the initial application method and that care as extreme as you have noted is needed for application. As others have noted there is a trend from left-right that seems odd among other things.

I suggest you try cutting up car tires if you want a cheap and reasonably repeatable medium for severe edge testing.

You wouldn't believe how upset people get when I do that. I have tried to be reasonable and polite - "Excuse me sir I am conducting an experiment here.", but it rarely works. I think my attitude needs some work.

Speaking of testing material, I have found recently that one of the more abrasive things is fibreglass as in fishing rods. I have a decent supply of this. The low diameter , high abrasion factor and low compression make it really wear down blades fast.