Most of the popular pastes don't have an electrolytic base.It is to avoid the galvanic reaction between the copper spreader and the aluminim heat sink.
If you are a professional, lapping means mating the sink.
It does no such thing.The slightly dished center of the heat spreader actually helps prevent the thermal interface material from creeping out of the junction and leaving it dry, with heavily degraded thermal performance.
You couldn't get a copper surface that smooth with a simple file or sanding block in any case; it will always have tiny nodes for the paste to cling.
O_oI've only been at this for 30+ years professionally.
*insert witty tautology*
It always makes me laugh when people claim age as being equivalent to experience and wisdom.
Is your profession actually the design an application of thermal pastes?
Do you personally track trends in pastes and experimental with them in your own time?
Want to know how many professional C++ programmers I work with that don't keep their education current?
All of them; thirty years of experience just makes you old if you don't keep up and doesn't mean that any of it is necessarily applicable.
Second edit failed...
I just realized who I responded to.
Well, I'm off to practice violin.