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-   -   stuffing box repacking and flax size (http://www.sailnet.com/forums/gear-maintenance/67612-stuffing-box-repacking-flax-size.html)

dreuge 08-23-2010 03:24 PM

stuffing box repacking and flax size
 
Hi,

I have a 1979 C&C 29 Mk1, and I need to repack the stuffing box with the boat in the water. I have already tightened it a few times with short term sucess. I plan to use an old sliced-open bike tube to wrap around the stuffing box while I am working on the repacking, but I want to minimize the time which I have the gland nut off. Does anyone know what is a packing size a C&C 29 would use? I believe it has a 1" shaft.

The marina at which I keep the boat is not conveniently close to a marine supplies stores so I am hoping someone familiar with a C&C 29 would know which size flax to purchase or which size is likely. Given a probable size, I may tempt to purchase several sizes (say 1/8, 3/16, 1/4 ) and try to arrange a return after the work.

I see that West Marine sells Teflon Flax and GTU Gore. But in googling GTU, I came across GFO Gore-Tex dripless packing (see www.gfopacking.com ). Does anyone have experience with GFO?

Any input into the size or even which type of packing material would be great. Thanks.

Gene T 08-23-2010 03:39 PM

Don't worry about sinking the boat. If you have an automatic bilge pump it will only run every few minutes. There really isn't much water that comes in around the shaft. I would unscrew the nut and measure the packing, then snug up the nut again and go buy the packing. Probably 1/4 but possible 3/16.
A small hook is handy for pulling the old packing but a small screwdriver works. The also sell a puller that screws into the packing and makes it easy. You could pull one piece out to get the correct size. It should still seal up good enough for a while with what is left.

I always had good luck with Teflon Flax. Read up a bit on how to do it. 3 pieces are generally used offsetting the cuts. I always liked to snug it up good and then back it off until it would drip a little. (not much dripping needed). Check the alignment while you are down there too.

Gene

SEMIJim 08-23-2010 03:39 PM

Quote:

Originally Posted by dreuge (Post 635721)
I see that West Marine sells Teflon Flax and GTU Gore. But in googling GTU, I came across GFO Gore-Tex dripless packing (see www.gfopacking.com). Does anyone have experience with GFO?

Gore GTU and GFO are the same thing, to the best of my knowledge. I used whichever one WM sells. Works great. It's not entirely drip-less, however, just very low drip rate, once it's settled-in.

Sorry: Can't help you with the size.

Jim

JimsCAL 08-23-2010 03:58 PM

Don't know about the C&C 29, but FWIW my previous 30 footer with a 1 inch shaft used 3/16 packing.

sailingdog 08-25-2010 11:14 AM

the GFO is good stuff... I'd point out that under sail, the GFO packing should still drip slightly... it is drip "less" not drip "free"... and if you adjust it to the point where it doesn't drip at all, you're likely going to damage the propshaft.
Quote:

Originally Posted by dreuge (Post 635721)
Hi,

I have a 1979 C&C 29 Mk1, and I need to repack the stuffing box with the boat in the water. I have already tightened it a few times with short term sucess. I plan to use an old sliced-open bike tube to wrap around the stuffing box while I am working on the repacking, but I want to minimize the time which I have the gland nut off. Does anyone know what is a packing size a C&C 29 would use? I believe it has a 1" shaft.

The marina at which I keep the boat is not conveniently close to a marine supplies stores so I am hoping someone familiar with a C&C 29 would know which size flax to purchase or which size is likely. Given a probable size, I may tempt to purchase several sizes (say 1/8, 3/16, 1/4 ) and try to arrange a return after the work.

I see that West Marine sells Teflon Flax and GTU Gore. But in googling GTU, I came across GFO Gore-Tex dripless packing (see www.gfopacking.com). Does anyone have experience with GFO?

Any input into the size or even which type of packing material would be great. Thanks.


dreuge 08-25-2010 01:34 PM

Thanks to ALL for their inputs. I am leaning towards the GFO packing. The link I provided above points to an out dated site where the "buy-now" link fails.

I read in other posts that e-marine sells GFO online. The site is eMarineSystems.com and select the menue item "Packing-Shaft".

The website has some useful info, in particular, a table of packing size for standard Buck Algonquin Bronze Packing Boxes. See this link:
EMarine Systems Packing Shaft

I also talked to them over the phone. They claim that GFO can be used dripless but warned about over tightening. They suggest adjusting from the lose side, tightening the gland nut until the dripping stops (as oppose to over tightening and easing the gland nut).

Even though, I will still let it drip a drop or two per minute (Just to be on the safe side).

CalebD 08-26-2010 12:04 AM

Here is the best tutorial on stuffing box repacking (if you haven't seen it already): Re-Packing A Traditional Stuffing Box Photo Gallery by Compass Marine at pbase.com Check out his other 'how-to' articles as many are just as thorough.
The correct size might be 3/16", 1/4" or even 5/16". I doubt it is bigger then that but it depends mostly on the shaft diameter and stuffing box size.
For my 27' Tartan with a 1" shaft it was 1/4" that fit the most snug.

Omatako 08-26-2010 12:12 AM

Quote:

Originally Posted by sailingdog (Post 636544)
the GFO is good stuff... I'd point out that under sail, the GFO packing should still drip slightly... it is drip "less" not drip "free"... and if you adjust it to the point where it doesn't drip at all, you're likely going to damage the propshaft.

I've always held the philosophy that the stuffing box should not drip unless the shaft is turning. So I would want mine to drip once in a while when I'm motoring but not when I'm sailing.

I haven't heard of the GFO/GFU products, they sound good, I may try and get some. I still use the old waxy flax stuff.

sailingdog 08-26-2010 12:55 AM

Whether the stuffing box should drip with the shaft at rest is really dependent on a few factors: 1) Number of rings of packing; 2) Type of packing material; and 3) How much friction you consider acceptable.

With traditional flax packing material, you may need to allow some dripping when at rest to keep the flax sufficiently waterlogged to prevent the packing material at the inboard side from drying out and scoring the prop shaft. With the GFO packing, this is not as necessary, but the box should still drip a tiny bit when the propshaft is turning.

Checking the temperature of the stuffing box while the propshaft is turning is a good idea. It shouldn't be more than about 15-20˚ warmer than ambient temperature of the water. Anything greater than that, you're probably risking scoring of the propshaft.

With all packing materials, but more so with flax-based packing, you should allow the packing material to absorb water for a while before adjusting. The flax-based packing, IIRC, will swell a bit as it absorbs water and adjusting the box before it has done so will lead to an overtightened box that will score the shaft.

Quote:

Originally Posted by Omatako (Post 636774)
I've always held the philosophy that the stuffing box should not drip unless the shaft is turning. So I would want mine to drip once in a while when I'm motoring but not when I'm sailing.

I haven't heard of the GFO/GFU products, they sound good, I may try and get some. I still use the old waxy flax stuff.


jackytdunaway 03-11-2011 07:00 AM

Where can i get the Gore GFO? I am having a hard time finding it.


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