Penetrating Oils

[swall]

Anyone know the science (if there is any) behind how penetrating oils are supposed to work? I can understand the penetrating part, since we have products like dye penetrant and wicking Loctite. But, how does a rusted up joint come loose after the stuff gets in? I am thinking that for anything to happen, there would have to be an acid component, chelate, or something to dissolve the rust.

 

[micalbrch]

No, there is no acid or something in it. The rust (the oxidated metal) is not dissolved or something like that. Penetrating oils displace the water/moisture out of the rusted up connection. That in combination with their penetrating capability is the science behind. It is more physics than chemistry.

 

[unclesyd]

I've seen several explanations on why they work, sometimes. It has been my observation they do in fact work especially where the initial joint didn't have extremely close tolerances.

Here are some tricks I've observed in using the penetrating oils. The better one is to slightly warm the joint prior to application. Another one is the tap the nut or stud while applying the oils.

One of the very best penetrating oils is Oil of Wintergreen applied to a warm joint and allowed to soak for at least an hour. It is not used much anymore as it is now considered too toxic. It was available sufficient quantities in a lot of over the counter ligaments to do the job until they cut down on concentrations. This is why some of the better penetrating oils disappeared.

 

[metengr]

Best explanation I have seen is that it acts as a low viscosity lubricant;

http://en.wikipedia.org/wiki/Penetrating_oil

 

[HDS]

PB B'laster says it is a catalyst. It does work but I don't know what is happening chemically.