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Compass Marine How To | all galleries >> Welcome To >> Re-Packing A Traditional Stuffing Box > Packing Nut Off & Old Packing Out
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Packing Nut Off & Old Packing Out

I don't advise, and can't with a good conscience, suggest the use of "miracle lubes" such as the moldable packing materials like the "West Marine Moldable Packing Kit". While some have claimed good success with these miracle clays or lubes I did not.

On our older C-36 I installed the "West Marine Moldable Dripless Stuffing Kit" and it became a nightmare. The green stuff in the picture is the "moldable clay" shown with the two rings of Teflon flax that came out of my female flax nut. Read below for more info on why I had problems with this stuff.

EDIT: Since writing this I have conducted extensive temperature testing of packing glands with a fixed temp probe mounted directly to a traditional bronze stuffing box. The digital temp display was mounted in my cockpit. What I have learned is that packing gland temperatures can be anything but static.

Air can become entrapped in the shaft log and with no cooling water you can, quite suddenly and without warning, develop a massive temp spike. Some boats are more prone to this than others. Our old C-36 was quite prone to this. Even after converting to a PSS dripless seal, before they introduced the vent, I found it needed to be burped multiple times per season due to entrapped air.

At one point during testing we had motored for over 3 hours using graphite impregnated packing set for less than a drip every three to four minutes. The temp stayed at steady at 85-102F for over three hours. We hit some prop wash from a large yacht and within 3-4 minutes the packing gland was pushing 300F. Ouch!!! This same event happened about 14-16 times over a 6 month period. My goal in testing was to find the happy medium for the least drips to the most consistent temps. I adjusted the gland for 1 drip per minute and the temp spikes were gone.

This is why stuffing boxes are intended to drip some. When they drip they also displace any entrapped air. Not all boats are prone to entrapped air in the shaft log, but many are. The simple act of backing down on an anchor can force air bubbles up into the shaft log and with no drip there's no way for the air to escape.

It is my best guess that this is what happened with our "miracle clay" packing...

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Guest 26-Aug-2012 03:29
Thanks so much for this site! I had the right tools (dental pick and drywall screw) and did a great job. All without a hitch. Tanks!
jan 22-Sep-2007 14:11
Thanks for the absolutely AWESOME pictures and descriptions of this necessary task. We were having trouble finding only one picture of a stuffing box and then finally landed on your site. We hit the jackpot. We would have been content with a drawing. It was so easy to show a fellow boater what he nedded to do. This is extremely helpful information for the novice or the seasoned boater.

Jan "The Harbormaster"