GFO is a square braided graphite flax
replacement impregnated with teflon. Gore says GFO is mil-spec certified
by the USN as the only replacement for conventional flax packing.
Graphite will (or definitely should) play hell with the shaft.
It is more noble than nearly anything, and will potentially create
galvanic corrosion at the stuffing gland--right where you want the shaft
smooth and shiny. Graphite grease is also to be completely avoided. The
US navy has plenty of our money to spend, and their considerations are
quite different from the average trawler-yacht.
Ordinarily a maximum potential difference of no more than 0.2 volts in
sea water will provide for a compatible pair of metals, and ideally would
be less. With stainless and graphite, the difference in potential is 0.8
volt with SS in its active state, and 0.3 volt with SS in its passive
state.
Based on the difference between graphite and stainless on the galvanic
scale, your test of graphite packing being in year two without troubles
is nearly miraculous...
Michael Kasten
Louis B. Brydon
>GFO is a square braided graphite flax
>replacement impregnated with teflon. Gore says GFO is mil-spec certified
>by the USN as the only replacement for conventional flax packing.
Graphite will (or definitely should) play hell with the shaft.
It is more noble than nearly anything, and will potentially create
galvanic corrosion at the stuffing gland--right where you want the shaft
smooth and shiny. Graphite grease is also to be completely avoided. The
US navy has plenty of our money to spend, and their considerations are
quite different from the average trawler-yacht.
Ordinarily a maximum potential difference of no more than 0.2 volts in
sea water will provide for a compatible pair of metals, and ideally would
be less. With stainless and graphite, the difference in potential is 0.8
volt with SS in its active state, and 0.3 volt with SS in its passive
state.
Based on the difference between graphite and stainless on the galvanic
scale, your test of graphite packing being in year two without troubles
is nearly miraculous...
Michael Kasten
