Steve, Thanks. Very informative. Ron On 3/9/2017 12:38 PM, Stephen Offiler wrote: > Hi Ron: > > Check out some discussion of platinum-iridium vs. tungsten, see page 8 of > this PDF: > > http://www204.pair.com/bbg46/FM%20Mag%20Manual/Mag%20Early%20Ign%20Systems(23-31).pdf > > And this: > > http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?t=1711 > > > SO >