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.
PPS.
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).]
