Traditional stuffing box material

[Rustic Charm]

Hi,

I’ve recently purchased a new to me glass sloop which has a traditional stuffing box. It was in dire need of ‘re packing’ as it leaked terrible.

Today I replaced the packing with GFO packing 8000T which is a new packing type made out of Goretex with Teflon and graphite through it. It’s expensive stuff, a meter of 3/8 (9.5mm) was $65. But, it claims to run cold, does not need to drip, will outlast traditional packings and will,not score the shaft.

Swift supplies in Queensland sells it.

https://www.swiftsupplies.com.au/gfo...ibre-per-metre

Now, I was initially after Duramax Ultra, which has the same specs and supposedly can last five times longer than traditional flax or Teflon. But alas, I’ve discovered no one sells it anywhere in Australia. And at $187 ex USA it was too expensive to get it from there. Duramax is specifically designed for the marine environment.

Now I installed this product this morning and went for a short motor. It didn’t drip and remained cold. . But now someone on Sailing Australia FB claims that any graphite products in a marine environment will cause electrolysis damage on the shaft…

Does anyone know if there is any truth to this? I’ve read through a number of threads, but I couldn’t find one specifically on this subject.

[Fore and Aft]

Rustic Charm there maybe some truth in that. Back when I used to repair steel gas pipelines with fibreglass we would always do the first layer with fibreglass then carbon fibre over the top. I forget why, but electrolysis would make sense. These pipes were buried in the ground in lots of different soil types.
Cheers

[JoeRobertJr]

https://www.cruisersforum.com/forums...ml#post3681791

ABYC Shafting Systems P-6
"6.7.4 Graphite impregnated packing material shall not be used because of the possibility of galvanic incompatibility with the shaft material."

Just repeating this post from Boatpoker. I have not verified independently.

[Shanachie]

I've been reading references for years about this ABYC warning regarding Goretex stuffing box material, but I have yet to read about a single case of a prop shaft failing due to it.


I've used Goretex for 14 years on two boats, both with SS shafts, and neither showed any sign of corrosion in saltwater.


It's great stuff compared to flax or that clay-like dripless stuff that West Marine sells.

[rslifkin]

I haven't tried the graphite impregnated packings, but I've been using a teflon impregnated acrylic packing (Palmetto 1347AF). It's cheap and easily available from Amazon (not sold specifically as a marine stuffing box packing). It does need to drip a tiny bit to stay cool, but it's not much. It seems to last well too.

[gonesail]

i used the GFO packing with my last boat. it was almost dripless for a year or so .. maybe it hardened up or something. now have PSS dripless .. so nice.

[Pontoonrob]

Nigel Calder and yhe you tube channel acorn to Arabella just did a video on this very thing.

[maine-cruiser]

Originally Posted by rslifkin

I haven't tried the graphite impregnated packings, but I've been using a teflon impregnated acrylic packing (Palmetto 1347AF). It's cheap and easily available from Amazon (not sold specifically as a marine stuffing box packing). It does need to drip a tiny bit to stay cool, but it's not much. It seems to last well too.

I'll second that particular product. Used it for 2 seasons and only removed it just to see how it was holding up and it really looked almost new. Great stuff. It's practically dripless but still doesn't get more than warm to the touch. And some of that heat is no doubt from the engine.

Bill

[SkipD]

Good write-up from very knowledgeable source on the topic of repacking traditional stuffing boxes, touches on graphite issue.


https://marinehowto.com/re-packing-a...-stuffing-box/

[Bowdrie]

Originally Posted by Pontoonrob

Nigel Calder and yhe you tube channel acorn to Arabella just did a video on this very thing.

Ah, you beat me to it.
Quite interesting.
Yeah, taking two things at opposite ends of the galvanic scale, (Graphite and Zinc,) and then immersing them in an electrolyte, (the salt water.) and connecting them up with the prop shaft didn't seem to be the best idea.
I vote for a Zerk fitting on the stuffing box and pump the thing full of grease, (grease without graphite).
No leaks, no heat, no scored shaft.

[Rustic Charm]

Originally Posted by Pontoonrob

Nigel Calder and yhe you tube channel acorn to Arabella just did a video on this very thing.

They didn’t have much in it about GFO products. It was more a video of how to repackage that type of stuffing box.

[Rustic Charm]

Originally Posted by SkipD

Good write-up from very knowledgeable source on the topic of repacking traditional stuffing boxes, touches on graphite issue.


https://marinehowto.com/re-packing-a...-stuffing-box/

This was really informative. Thanks.

[Rustic Charm]

I think what I’m going to do is run with my new GFO product for a year, making sure it is dripping a little bit, then I’ll pull it out after about a year and inspect the shaft. If there is any sign of anything negative I’ll pull it and put in a Lasdrop. My shaft is close to an inch and 3/8, and long, so it would be an e pensive shaft to have to replace.

I’ve also emailed the manufacturers of this GFO product to ask them for response about concerning graphite encapsulation in the Teflon threads.

[wholybee]

I have the graphite product for a few years. I adjust it so it drips as a normal packing would. I can't imagine it causing any corrosion issues. There is a tiny amount of it, and you have an anode attached to the shaft to protect it. The anode will protect anything electrically connected to it. That is the shaft, propeller, and the carbon in the packing. It might cause the anode to wear more quickly, but given the tiny amount of carbon relative to the size of the anode, I doubt it.

[Bowdrie]

Originally Posted by wholybee

It might cause the anode to wear more quickly, but given the tiny amount of carbon relative to the size of the anode, I doubt it.

Watch the Caldwell vid, (Acorn to Arabella,)
The zinc anode on the prop disappeared in a short time.
With graphite, being "tiny" has little bearing on its cathodic position.
It's similar to a real copper penny laying in a wet bilge against an aluminum hull.
The hull will eat completely thru long before the penny shows much deterioration.
Graphite will cause bronze to "go away", zinc doesn't even have a prayer.
Two things I'll never have on a boat.
1, Anything with graphite or graphite in it, (well, some pencils are ok).
2, Silicone, the bad relative you can never get rid of.