GFO vs. Natural Flax
I use Gore GFO (actually I use a PSS but have used GFO a number of times
). GFO does not contain any flax. Flax is a natural fiber derived from the Linum/Flax plant (Flax seeds & where linseed oil comes from) and has very low self lubricity and needs to be combined with paraffin, graphite or PTFE plus water in order to lubricate and not score a shaft.
There is a common confusion that all packings are flax fibers. Flax is a type of natural fiber like cotton is. Cotton is not Gore-tex, just as GFO fibers are not flax.
Gore GFO is a proprietary synthetic fiber made by Gore Labs. It uses PTFE base, some graphite and some other proprietary ingredients, which gives it the gray/black color. GFO should not be confused with a graphite impregnated natural flax, or PTFE impregnated natural flax.
I only asked because I have never seen a graphite impregnated natural flax for sale in a marine chandlery. I have seen paraffin & PTFE lubed natural flax in marine stores but not graphite/natural flax. The stuff Defender sells is not a natural flax with graphite it's Gore based synthetic fibers.
I know graphite natural flax is made but this is mostly in commercial/industrial valve seal applications. Most manufacturers, including one I used to work for, now use GFO in their pumps.
I agree would agree 100% that using graphite impregnated natural flax is probably not as good as PTFE impregnated flax but neither are as high performing as GFO..
The natural flax/synthetic fibers thing is confusing that's why I asked.
GFO fibers:
"Some users have tried “trading off” GFO® packing performance
for lower price. However, low-price competitive “look-alike”
black PTFE fiber packings perform differently.
Recently, some look-alike products have targeted one performance
criteria – thermal conductivity – suggesting that this attribute
makes them “equivalent” to GFO® packings. Close inspection of
some competitive products show that these products consist of
pure PTFE with a thermally conductive layer. The design is much
like a wire: a thermally conductive interior surrounded by an
insulator. Pull on these fibers and they will turn white. The material
in contact with the rotating shaft is pure PTFE, known for its thermal
expansion and shaft scoring behavior at higher service temperatures.
This outer PTFE layer of the look-alikes also raises questions
about how efficiently this packing is able to provide lubrication
during break-in and service of the packing."
