PB Blaster and Stuffing Box Adjustment

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Jun 21, 2007
2,105
Hunter Cherubini 36_80-82 Sausalito / San Francisco Bay
This question is probably more for the attention of Maine Sail, but posted in the open forum if of general interest.

Needing to tighten up a bit on my traditional flax type stuffing box (recently dripping a bit too much after five good years since the last new flax was packed), I first read Maine Sail's very informative tutorial at http://www.pbase.com/mainecruising/stuffing_box.

I took note that PB Blaster can be used if the packing box nuts need some added inducement to break loose. Also Maine Sail"s warning that PB Blaster must not come in contact with the transmission seal.

But what about the stuffing flax itself? Seems that packing flaxes are often impregnated with waxes/lubricants. Any danger that PB blaster can damage the flax?

Thanks.
 

Tim R.

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May 27, 2004
3,626
Caliber 40 Long Range Cruiser Portland, Maine
You should not be applying the PB anywhere near the flax in order to break the nuts. Spray it onto a Q-tip or something and paint it onto the threads and the crack between the two nuts.
 
Oct 17, 2011
2,808
Ericson 29 Southport..
P.B. Blaster is wonderful stuff, and I have used it countless, maybe hundreds of times. But it can bite you. I'm not sure exactly what it'll do to the packing, but I can't help thinking it will not help it. If you are going to change it out, by all means, lay to it. There's nothing else there that it will hurt, for the exception of the transmission seal, as I'm sure you now know about. Just don't go crazy with it, as said, a Q-tip may be an option. In fact, advisable.

Idiot me, even KNOWING what the stuff will do, just recently sprayed it down a sticky whisker pole, thinking the guts were cam lock plastic. Negative. The cam lock was rubber, so guess what. Go ahead, guess. I had to CUT the damn thing apart to get it out. It swelled that rubber lock up so tight, I couldn't BEAT it out. God, I do some moron things some time...
 
Feb 26, 2004
22,760
Catalina 34 224 Maple Bay, BC, Canada
UHM? How could the PB get into the flax until you've opened it all up? Not sure I follow the logic? Once it's open, you don't need the PB.
 
Jun 21, 2007
2,105
Hunter Cherubini 36_80-82 Sausalito / San Francisco Bay
UHM? How could the PB get into the flax until you've opened it all up? Not sure I follow the logic? Once it's open, you don't need the PB.
Hi Stu:

My "project" isn't changing out the flax. Instead just want to break loose the five year undisturbed nut a bit, then tighten a half turn or so to compress my existing flax tight again between the box housing and the shaft ... so to get back to a drop of water getting through every so often instead of a drop every 5-10 seconds that I am currently experiencing when at berth. A "miss" with the PB Blaster on the nut threads (say) on the transmission side of the shaft and the PB could very well get in contact with my flax. Maybe even the PB might penetrate through the threads and contact the flax?
 
Oct 17, 2011
2,808
Ericson 29 Southport..
I was under the impression that is was a matter of getting the gland nut loose, to replace the packing.
Maybe I'm confused, I commonly am..
 
Feb 26, 2004
22,760
Catalina 34 224 Maple Bay, BC, Canada
rardi, I don't get it. The flax is INSIDE the nut. You could spray all day and not get anything inside the nut unless it was opened.

If you want to keep things working, then get the locking nut backed off, and use MS's methods of cleaning the threads, and then put Lanocote or lanolin on them and never have to worry about loosening up the locking nut ever again. Put Lanocote on the faces between the locking nut and the stuffing nut, too.
 
Jun 21, 2007
2,105
Hunter Cherubini 36_80-82 Sausalito / San Francisco Bay
Stu:

Maybe I'm not getting it ... but isn't PB Blaster supposed to penetrate into tight places, like all the way through threads? The packing flax is on the other side of the packing nut threads. I've copied a couple of pictures from Main Sail's article. Water gets through gaps around the packing flax. Seems reasonable that PB Blaster also can. The hole in the nut end is slightly larger than the shaft. Penetrating oil applied too liberally and spills on the shaft would reach the flax from that direction. I'm asking this because my first inclination is to PB the nut a few days before I attempt to loosen it with the wrenches. But won't do if I risk damaging the flax packing. I know that the boat yard did not lanocote the threads when new flax was installed five years ago. With the boat now in the water, I'm not inclined to mostly loosen the packing nut to apply anti-seize compound. Great suggestion, but that step should wait until the next haul out I think. For now it's just loosen the locking nut, gently snug up the stuffing box nut a fraction of a turn and re-lock. Hopefully that will get me back to pretty much drip free at the dock when not running the engine and several drops per minute when running.
 

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RichH

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Feb 14, 2005
4,773
Tayana 37 cutter; I20/M20 SCOWS Worton Creek, MD
Flax is a 'botanic'. PB is a penetrating oil.
When was the last time your cotton undershirt fully released motor oil? and what mechanical damage did the oil do other than cosmetic staining?

Flax packing is loaded with Tallow, a compound similar to 'sheep grease' or lanolin/Lanocote. The tallow is 'impregnated' into the flax braid to lessen 'permeability' of the water through the flax. What happens when the flax packing gets old and eventually loses its tallow .... or you get 0,01 ml of PB Blaster onto the end packing ring?
Answer: you tighten the packing gland.

BTW
5-10 drops per minute calculates to a weekly total of only 0.75 to 1.5 gallons total leakage.
If your bilge pump cant handle 3/4 to 1.5 gallons per week, ..... .

;-)
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
Rardi,

No need to worry just use the PB sparingly, if you need to at all. With the proper wrenches I find I've yet to need any penetrating oil. I'd recommend measuring your nut OD and ordering a good set of packing gland wrenches it makes all the difference in the world. The wrenches I show on my site are a "least cost" option because I know sailors are cheap, "frugal" might get me in less trouble..

Beyond that the PB will get washed away/diluted pretty quickly once it comes into contact with seawater in the nut. Use Tim R.s method it works quite well...
 
Jun 21, 2007
2,105
Hunter Cherubini 36_80-82 Sausalito / San Francisco Bay
Thanks all. Will first try to loosen the lock nut from the box nut without PB Blaster. And use it sparingly only if needed (but by Maine Sail's observation I likely won't).


... If your bilge pump cant handle 3/4 to 1.5 gallons per week, ..... .
;-)
Rich: Haven't been losing sleep over this! :dance:. Three pumps down in the bilge. Each has its own exit hose. Each has it's own fused sub-circuit. The pump mounted right at the aft end of the bilge is a small "working pump" that I frequently manually activate. It will remove all but about 3/4" of water back there which means that the remaining 90% of bilge bottom more forward always remains dry. So the other two pumps, larger and mounted more forward, never get enough water to activate. Except I know they are working at my last test check!
 
Dec 1, 1999
2,391
Hunter 28.5 Chesapeake Bay
When I got my first boat with an inboard diesel (and packing gland), I took a "Diesel Dork" class to learn something about the engine and its environs. We were told that a sure fire way to loosen a frozen packing nut on the gland was to whack one of the flats on the nut with hammer. We were assured this would work and not do any damage. Over the years, I've used this method twice (once on my boat and once on a friends) and am happy to report that it really does work....
 
Jun 21, 2007
2,105
Hunter Cherubini 36_80-82 Sausalito / San Francisco Bay
When I got my first boat with an inboard diesel (and packing gland), I took a "Diesel Dork" class to learn something about the engine and its environs. We were told that a sure fire way to loosen a frozen packing nut on the gland was to whack one of the flats on the nut with hammer. We were assured this would work and not do any damage. Over the years, I've used this method twice (once on my boat and once on a friends) and am happy to report that it really does work....
Hadn't considered the strategic whack technique. Does make sense. Will try before PB Blaster.

In my much younger year's, I spent a summer between college years working as a Wiper in the engine room of a 14,500 dwt T2 tanker. The 3rd assistant engineer (that would be licensed officer) frankly had more than one nut loose. Anything out of the ordinary would stump him. Except he always wore a tool belt. The only tool in it was a ball-peen hammer. Amazing how frequently a good strike on a piece of rusty stubborn machinery would magically restore it to operating condition.
 
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