Originally Posted By: doitmyself
Last time this discussion came up I promised I would call Permatex. Here's what they said today.
All three will work. Plug temps. can get quite high, almost near 1600 F (Is this true??).. The silver is o.k., but close to the 1,600 limit. The copper is better because it has both higher temp. rating AND better conductivity. The Nickle is best because it has highest temp. rating and still has good conductivity.
Why not use the Nickel? Why isn't plug use listed on the TDS? He mentioned that for "non" high performance engines
it might be viewed as over kill and it tends to not be available in smaller package sizes, costs, etc..
So, Nickel - Copper - Silver in that order, with the Copper being the best "practical" choice.
Regarding lug nuts, they used to recommend it in their literature. He said they still "recommend" it in theory, but due to today's climate (bad application practices AND liability) they can no longer endorse it publicly.
The kind I recently used(Permatex 133A) states it is:
A highly refined blend of aluminum, copper and graphite lubricants.
the msds:
linky