GFO (goretex) gland packing, anyone want to share cost of minimum quantity?

skyflyer

skyflyer

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I wanted to try this "dripless" packing, available in the USA but not in UK, then after following some old threads on here, discovered something called Fluograf made by James Walker that is the same, made from Goretex and PTFE; basically it does not require water cooling, so doesn't drip but at the same time doesn't overheat or score-damage the shaft.

I need 6.5mm square section (1/4" in old money) for a 1 inch shaft, but the minimum they will sell me is - wait for it - EIGHT METRES! Thats nearly £205 including VAT and delivery!!!

On basis that for 3 rings of stuffing I need something like 0.3 metres, that's about £8 worth!

If there were adequate numbers who also wanted to try this stuff, I'll order some and we can divvy up the costs.

Any takers?
 
Why not go the whole hog and replace the gland with a modern one that does not drip for a fraction of that price!
 
Tranona said:
Why not go the whole hog and replace the gland with a modern one that does not drip for a fraction of that price!
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for a fraction of £8?

So to answer your question more sensibly, to fit a new seal the shaft has to be pulled and that means lifting the boat, dropping the rudder, remove and replace cutless whilst you have the chance, replace bronze shaft with s/s whilst you have the chance, refit coupling flange and realign everything.
Total nearly £1600 of yard* fees; obviously less if i do some myself, but dropping the rudder and lifting the boat is not an option.

Whereas GFO packing is fit and forget. No drips, no shaft wear.

That's why!

* To be fair, owners association tell me that the shaft can be withdrawn without dropping rudder if a bearing puller is used to extract gutless bearing and then the space created plus similar space in stern tube allows just sufficient clearance. Yard say they don't have a puller, they just "tap" it out once shaft is out :-)
 
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No. Fraction of the £200. Should not be necessary to draw the shaft to replace the gland. Just disconnect the half coupling and pull it off the shaft which should move back far enough to get the new gland on.

Even if you fit the new packing it will still be water cooled - you can't change that. So the drips will only stop if you can tighten the packing enough to stop the water coming through. This assumes a perfect shaft and housing - lack of this is the common cause of glands dripping, not the material of the packing.

BTW the blurb does not claim it is dripless nor does it not require water cooling- just likely to drip less. Prepare to be disappointed.
 
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LittleSister said:
Does conventional stern gland packing require water cooling? I would have thought not, and that it's the cutlass bearing that's water cooled or lubricated.
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Yes. That is why water is allowed all the way up the stern tube and why, normally if you do it up to tight so that water can't get in, it overheats. Can also overheat if you squirt too much grease in there as it fills the tube. The grease is only there to create a seal between the packing and the shaft when the shaft is not turning. Hence the advice to give a turn when you stop the engine or leave the boat. The drip will restart as soon as the shaft starts turning.
 
What is so wrong with conventional gland packing? I am just about to repack mine for the 4th time in 32 years. Hardly onerous. 1m of 1/4" cost me £4.50 post free, and as you say is enough for 3 complete changes ..... so likely to outlast me!
 
Nothing wrong with conventional gland packing, worse case scenario they drip a bit.
with a modern rubber drip-less thingy, they can catastrophically fail.

Plank
 
PlankWalker said:
Nothing wrong with conventional gland packing, worse case scenario they drip a bit.
with a modern rubber drip-less thingy, they can catastrophically fail.

Plank
Click to expand...

No they can't - at least the Radice/Volvo type. They have double lip seals so although these may wear they give plenty of warning - just like a gland. Glands on rubber hoses are the worst of both worlds - seal that has to drip to work and a hose that can fail catastrophically.
 
LittleSister said:
Does conventional stern gland packing require water cooling? I would have thought not, and that it's the cutlass bearing that's water cooled or lubricated.
Click to expand...

Tranona said:
Yes. That is why water is allowed all the way up the stern tube and why, normally if you do it up to tight so that water can't get in, it overheats. Can also overheat if you squirt too much grease in there as it fills the tube. The grease is only there to create a seal between the packing and the shaft when the shaft is not turning. Hence the advice to give a turn when you stop the engine or leave the boat. The drip will restart as soon as the shaft starts turning.
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You have not convinced me. Seems to me -
  1. There is very little water flow, and hence cooling, at the stern gland as it's at the end of a relatively long dead end.
  2. There is little need for cooling, as the packing is not firmly pressed against the shaft and it contains a lubricant (and there will probably be grease around too), but fins to aid air cooling could do the job were it required and I've never seen them.
  3. Water is not 'allowed' up the stern tube, that's where it'll go regardless as there's nothing to stop it because that's the job of the stern gland itself.
  4. I doubt it'll overheat through too much grease, as the grease will provide good lubrication, but it might mean that there will be reduced cooling to the cutlass bearing (like wot I said).
 
LittleSister said:
You have not convinced me. Seems to me -
  1. There is very little water flow, and hence cooling, at the stern gland as it's at the end of a relatively long dead end.
  2. There is little need for cooling, as the packing is not firmly pressed against the shaft and it contains a lubricant (and there will probably be grease around too), but fins to aid air cooling could do the job were it required and I've never seen them.
  3. Water is not 'allowed' up the stern tube, that's where it'll go regardless as there's nothing to stop it because that's the job of the stern gland itself.
  4. I doubt it'll overheat through too much grease, as the grease will provide good lubrication, but it might mean that there will be reduced cooling to the cutlass bearing (like wot I said).
Click to expand...

However:
if the compression of the packing, or the greasing, is continually ramped up, there comes a point with a spinning shaft where the gland becomes too hot to touch. I know this from personal experience. From many threads on the subject, plenty of others do, too. Since Maxwell's demon probably isn't responsible for the heating, my money's on friction -- unless you can suggest a more credible candidate?

If the gland's running too hot on a good shaft, it drips less, or does not drip at all. I also know this from personal experience. You may draw your own conclusions as to cause and effect, but I've tended to follow the pragmatic approach. Does it actually matter whether the usual one drop per minute indicates that a seawater-cooling effect is actually occuring, or is merely a convenient indicator of correct compression/greasing? I don't think it does.
 
We had poor experience of PTFE packing. I repacked the gland, which was in a very poor state when we bought the boat, the packing seemed to be made up of small fragments of cotton packing with no obvious likeness to the conventional split rings. I bought PTFE packing, pulled out all the old stuff and inserted three rings of the new, lightly tightened the yoke and all seemed well. We took the boat out on a short trip to check and the gland housing ran very hot indeed, in the end we were pouring seawater over it to keep it cool.
Returned to the marina, loosened the yoke plate again to ensure that there was very light pressure, same result. In the end the yoke was dangling on studs with loose nuts, packing hot.
Next visit, replaced the PTFE with conventional graphitised cotton, ran perfectly straight away. Soon after did 150 miles on delivery, packing performed faultlessly.
 
In the dim and distant days when I kept a 40 foot narrowboat my father got me some high tech gland packing used in industry for heavy plant wheel valves at the time. I believe Kevlar, a very new material, was mentioned.

It had superb sealing capabilities, but like Vyv's experiences it overheated badly. Even with the gland lightly nipped up and the shaft perfectly free to turn by hand, after ten minutes use we could hear a nasty burning smell. On inspection the gland housing and shaft were too hot to touch.

Replacement with conventional packing fixed it.

I gave some to another guy, warning him about what happened to our boat. He used it and he told me later the shaft was glowing in the dark of the engine bay after traveling only two locks on the Oxford Canal.

Stick to what works, or fit one of the excellent and trouble free Volvo or Radice types.
 
A lot of packing materials are only suitable for applications like valves where the shaft doesn't turn at high speed so friction and the associated heat is not a problem. A drive shaft is somewhat different and heat is a consideration. I read Vyv's experience with PTFE and decided to go with the old graphite impregnated stuff and had no problems. Some users of PTFE packing also report having no overheating problems which puzzles me.
 
I love this forum - you ask one question and as a bonus you get answers to dozens you didn't ask - or instead of the one you asked :-(

Anyway, the 'Fluograf' and 'GFO' packing brands, made from goretex fibres (and I have no idea if goretex and PTFE are the same?) are rated for a shaft speed of 22m/s. By my calculations on a 25mm (~1 inch) diameter shaft, it would need to turn at 18,000 RPM to go that fast. Think my Yanmar might give up first!

This stuff is supposed to be the cure to the problem of balancing too much dripping against too much shaft heating - thats why I want it.

The cost of buying a sensible amount is trivial, for the opportunity to see if it does what it claims.

Whether any other sealing system is better or worse is irrelevant; if this stuff does what it says then I have saved myself a lot of effort. If it doesn't then I am barely a tenner out of pocket (if I can buy a reasonable quantity)

My OP was not intended to stimulate a debate on which system is best - anymore than if I said "where can I buy a good priced CQR anchor" I would want pages of discussion about why a CQR isn't right for me! [although i suppose i might reasonably anticipate it!])
 
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