Too bad that you took it personally... It's an opinion, not a lecture. I am not an oil engineer, but I am a chemical engineer who have been working in this field for almost 30 yrs and deal with polymers, chemicals and CoF (if you know what it is). So, please take it as my personal opinion, no more no less, and I have no intend to offend anyone. We are all here to pass on opinion and info to others who may want to use it. In my company, we are very "data driven" ... So I don't shoot things off my hip.