[Maine Sail]

You absolutely MUST use the correct size. Otherwise bad things will happen.

From my experience and research I believe in old fashioned flax packing.

1: Graphite packing (black in color) is to galvanically active and will destroy your shaft while sitting at the doc unless you allow it to constantly drip at the dock.

2: PTFE packing (white in color) has the advantage of keeping things cooler BUT IF IT EVER GETS HOT the PTFE expands significantly in size and will wear rings in your shaft. Heat expansion is a big problem with this stuff.

3: Flax packing doesn't have the expansion or galvanic problems and works well. As a bonus it's the cheapest and easiest to find.

MedSailor

In order to expand a PTFE product enough to cause damage you'd have to be so far out of adjustment that it is not even realistic.... Most "PTFE" marine packing products are not made actually from PTFE extrusion yarns, they are acrylic/PTFE impregnated or flax/PTFE impregnated. Remember despite whta the glossy ads suggests all traditional packing boxes are water lubricated even if they don't drip noticeably.

The Gore stuff is 100% a PTFE base that is extruded with graphite in the PTFE mix into PTFE/graphite yarns. IMHO there is no real need for the graphite and it only serves to create galvanic issues and shorter zinc life. They really could have achieved the same means with a true PTFE packing not a PTFE impregnated acrylic or PTFE impregnated flax...

 

[Maine Sail]

Does the PTFE impregnated stuff offer any advantage over flax in your opinion?

MedSailor

P.S. I also experimented with PTFE impregnated kevlar packing for my specialized application, but that's a story for another day.

Absolutely.. Does not swell, less scoring, better lubrication, does not rot and lasts a lot longer. More of a set and forget when compared to flax based or acrylic, which eventually wets out.

The biggest problems with marine packings are the companies who sell them as drip-less and the folks who expect that to be true.

For a while now I have been field & lab testing a new marine packing I am developing. Testing has been underway now for almost three years. It has comparable performance & thermal conductivity properties of graphite based packing yet is 100% galvanically inert. It is a true high performance packing without any galvanic issues..

Unfortunately there is only one manufacturer in the world that can extrude this PTFE based yarn, with the proprietary lube, so getting cost where I need/want it has been the biggest hurdle. I want to be able to compete price wise with graphite based packings but at this point it is just not doable because everyone in their uncle is extruding graphite/PTFE these days and it is dirt cheap to make..