Packing material?

[Egregious]

I need some spare packing material for a traditional packing gland.* I've been playing with the tightness of one of my shafts and I believe it is too tight, and I may even remove some of the existing material since it isn't dripping while underway.** Therefore I would like to have some spare material on hand.* I think the boat yard repacked the glands with flax material in the form of disks.* Westmarine sells it by the foot and it comes in several different sizes.* My best guess it that 1/4 inch might be the best size for my gland, but I'm not sure.* My shaft is 1.75 inches.

Anybody care to share any information?* I don't have photos, but I can provide them this weekend, although I'd like to have some material on hand before next week as I'll be working on the boat all week.

Thanks!

 

[Delfin]

Woody, Jamestown Distributors is usually a good source for traditional marine materials, and their prices are good.* Here's a link to the product you need:

http://www.jamestowndistributors.com/userportal/show_product.do?pid=3864&familyName=PTFE+Flax+Packing

I believe the diameter you want is the largest that will fit in the groove and still allow the male half of the gland to be screwed on with two full threads engaged.* A very slow drip is needed to avoid overheating the shaft.* When I've adjusted these (others may have a different approach), I'll over-tighten the new packing to smoosh it into place, then back off before running the boat to get a drip about every 5 minutes, then very slightly tighten it in increments until it appears to stop dripping, then back off a really small amount.* After that, it's just tightening slightly to reduce the drip as the packing wears.

 

[Pineapple Girl]

Our boat came with some extra flax packing material left by the PO, so we set about replacing the packing on the starboard shaft, which was dripping like mad.* Once we had the three rings of the old stuff out, we could not for the life of us stuff the new stuff in.* Turned out it was 1/8 inch too big.* We took a sample of the old stuff to the local chandlery and bought the correct size.* There was not a large amount of water coming in, even with all the packing out, so it was no problem to leave the boat for a bit to buy the correct size.* I don't think you are going to find out the correct size without taking a ring of the exisiting stuff out.

I am calling them rings but they are individual lengths of packing.* It comes in a roll and you cut to length to wrap around the shaft.

 

[Egregious]

Thanks Delfin,

the problem I'm having is that once I had the gland repacked, it did not drip at all.* So*I loosened the male section and completely removed it and still no water came in!* When I ran the boat I put my hand on the shaft and gland and it never got hot.* I'm thinking that the water temp is still so cold that it hasn't had a chance to loosen up.* Since then I've run it for a few hours and now I get a drip every so often, but nothing like the one drop every 10 seconds that I'm told it should be.* So I'm thinking of using an extractor tool to pull out some packing to loosen it up, and therefore I want to have some extra on hand in case I tear a ring up in the process.* OTOH, I'm told that if it ain't hot don't worry about it.* The guy who did the job said it would start to smoke if it got too hot, but I'm nowhere near that point yet.* Could it be it just need to be run to loosen it up some?

Woody

 

[Per]

i re-packed mine while she was on the hard, initially i think the trick is to not over tighten the pack initially as you will then "squeeze" all the wax out of the gland. the idea is to keep the wax inside the packing.
i also did my rudder packs, if you think the shaft packs are hard to do, try the rudder packs.. really difficult to reach, let alone put the packing up in the shaft pack and get the bolt to catch the thread..

how often should shaft packs be done?

 

[Delfin]

Egregrious, if the shaft isn't heating up, and you get a drip now and again, you should be ok.* It sounds like there is some packing wax shoved up the shaft.* If it isn't getting hot enough to melt the wax, it's a "What Me Worry?" situation.* To groove the shaft - which is the concern, you are going to need a fair amount of pressure resulting in heat.* Without the heat, you don't have the necessary pressure - or at least that has always been my understanding of the physics.* The ideal is a fluid film between the packing and the shaft, ergo the drip.

The packing only needs to be changed when you have no more turns on the male fitting.

 

[C lectric]

If you didn't pack the box yourself it may be worthwhile asking the yard that did it what they used.

Your description of no drips and not hot makes me wonder if they used Goretex packing. I use that stuff and that is what I expect, no drips and cool running. I never got that with waxed flax packing or so called tfe impregnated packing.

The Gore packing is more expensive than the waxed flax however the amount used and the cost is small enough compared to the labour cost involved that they just go to the Gore.

You should be able to undo the packing nut and measure the nut id. and figure out the size required. There will be some water come in but you will not flood the boat.

 

[Tidahapah]

Woody,
If you back of the stern gland so that it is just clear of the tube you will be able to measure the width of the gland recess, this is the size of the packing you will require.(sometimes it pays to purchase packing about 1/16" oversize and hammer it to the right thickness so that it is firm in the gland.)
When cutting your packing rings don't forget to scarf the joint (cut on approx 45 deg angle so that there is a bit of overlay)
also stagger the joints so that they don't line up.

If you are just going to top up the gland use greasy hemp packing or a good teflon impregnated packing.
If you have the boat on the hard and you can remove all the packing change over to a goretex packing.
This packing can be niped up so that it almost dripless.

Benn

-- Edited by Tidahapah on Wednesday 9th of March 2011 08:28:15 PM

 

[Egregious]

Benn and Clark,

thanks for the info.* I'll call tomorrow and ask what type of packing they used, but the guy made a major point to explain to me the whole tightening / loosening process and how it should be dripping when underway.

The male and female parts of my gland are held together by two threaded studs and not a single nut.* That is another thing altogether, but at this time I have that system working the way it should and I feel comfortable tightening and loosening them and as I said I even removed the male part altogether and slid it up the shaft.* I didn't measure the gap, but I can guess it is about 1/4 to 3/8.

BTW, before they replaced the packing they said the old packing was all eaten up.* Well on the Port side, that packing had been completely replaced along with the shaft in June '10 before I bought the boat, so I was surprised to find out the packing was already gone in Jan '11.* Obviously it was overtight and that is why I'm concerned to get it right this time around now that I own the boat.

Thanks again

Woody

 

[FF]

Replace all the packing , the modern material is a 90 year improvement over waxed flax or Tefflon , and a 40 year up grade for the dangerous Last Drop setups.

Duramax can do what NO flax or Tefflon can.

Operate with out the need for cooling drips underway and not need a shot of grease when stopped to stop the drip drip drip.

Yes it is expensive , but buy it by the pound roll and it only hurst once.

 

[Per]

thanks FF, i will use that next time..

also, i was considering the packless shaft couplings, very pricey but worth the cost?

 

[JohnP]

Per wrote:

thanks FF, i will use that next time..

also, i was considering the packless shaft couplings, very pricey but worth the cost?
Per,* The packless shaft glands, don't drip..** But there is a 7 to 10 year replacement of at least the rubber bellows, so the extra costs would never stop.

*********Mine is due for a new bellows and if I had the original stuffing box I would put it back on. The newer packing runs near drippless anyway.* The rubber hose on most stuffing boxes seems more robust than the rubber they use in the dripless bellows.

********* The dripless*are worth the cost if you can't get to them to adjust them*without hurting yourself.

JohnP

*