Bonding stuffing box.

L124C · #1 02-08-2012

Posted regarding my stuffing boxhttp://www.sailnet.com/forums/gear-maintenance/83015-pink-metal-stuffing-box.html . I came to the conclusion that I need to bond the stuffing box to ground. I'm looking at various brush systems, and wonder if there is anything wrong with simply wiring the stuffing box to ground (motor ground). While this might not effectively bond the shaft (not the issue), it seems to me it would be simpler and would provide a better bond for the box. Lots of controversy regarding whether or not I even need to bond in the other thread. However, if I am going to bond, anything wrong with my idea?

CalebD · #2 02-08-2012

I think I see where you are going with this. The idea is to positively ground the stuffing box to the engine to reduce the corrosion on the bronze stuffing box?
I don't see why this would not work. I also don't see anything 'wrong' with your idea. I'd be interested to hear if this does in fact help reduce your stuffing box corrosion.
I'll add that most of the drive train set ups I've seen on keel boats don't do this - for whatever reason.
I just posted to your other thread as well. I still wonder if your set up has a drive saver included between the couplings - which in effect would isolate the end of your shaft from the engine.

Maine Sail · #3 02-08-2012

Quote:

Originally Posted by L124C

Posted regarding my stuffing boxhttp://www.sailnet.com/forums/gear-maintenance/83015-pink-metal-stuffing-box.html . I came to the conclusion that I need to bond the stuffing box to ground. I'm looking at various brush systems, and wonder if there is anything wrong with simply wiring the stuffing box to ground (motor ground). While this might not effectively bond the shaft (not the issue), it seems to me it would simpler and would provide a better bond for the box. Lots of controversy regarding whether or not I even need to bond in the other thread. However, if I am going to bond, anything wrong with my idea?

1-Unless you have a "Drive Saver" your shaft is already "bonded" to the engine. I have yet to see a single shaft not be electrically connected to the engine UNLESS a Drive Saver or similar was added.

2- Yes you can bond your packing gland to the engine but it may not be necessary if using one of the newer packing's like Gore GFO. If using a graphite impregnated packing continuity between shaft and stuffing box can be measured even when a boat is on the hard thus it is already electrically connected. With bronze shafts graphite packings should ideally be avoided though... So simply connect it to the engine for a sure fire bond.

This ideally should not be necessary. there are hundreds of thousands of boats out there with un-bonded packing glands doing fine..

L124C · #4 02-09-2012

Quote:

Originally Posted by CalebD

I think I see where you are going with this. The idea is to positively ground the stuffing box to the engine to reduce the corrosion on the bronze stuffing box?
I don't see why this would not work. I also don't see anything 'wrong' with your idea. I'd be interested to hear if this does in fact help reduce your stuffing box corrosion.
I'll add that most of the drive train set ups I've seen on keel boats don't do this - for whatever reason.
I just posted to your other thread as well. I still wonder if your set up has a drive saver included between the couplings - which in effect would isolate the end of your shaft from the engine.

As you probably saw in the other thread, the diversity of opinions (several that are credible) on the effectiveness of bonding the Stuffing Box (among other things) made my head spin! So, I'm thinking, if I can simply attach a wire from the stuffing box to ground whats the harm?

CalebD · #5 02-09-2012

If you are asking me I say go for it. Attach a wire from the stuffing box to the engine, no harm, no foul. The only potential I see for harm is if the wiring is done such that it could get caught on the spinning coupler or shaft somehow. I don't see this as a big liability if the wiring is done sensibly.
Even MaineSail wrote: "Yes you can bond your packing gland to the engine" but you may not need to. I happen to think that his opinion carries more weight then mine.
I am really mostly curious if bonding the stuffing box cuts down on the corrosion that occurs there.
I say go for it and report back after a season, a few seasons, 10 years from now. It should be a simple thing to implement.

I am not going to bond my stuffing box because I feel that the corrosion that does take place there is largely due to the fact that the stuffing box is supposed to drip outside water into the boat when the shaft is spinning, which gets water on the packing nuts.

I still think it is an idea worthy of experimentation though.

L124C · #6 02-19-2012

I asked the manager of one of the boat yards about using a shaft bush to protect the stuffing box. He basically said the box was "isolated" and didn't really need it. He went onto say that it is protected by the shaft zinc, that some boats use brushes when they don't have room for a external shaft zink. I told him, I have a external zink, but my stuffing box is turning pink (I'm a Poet and don't even know it!) He said, "well, like anything else, your stuffing box won't last forever". He didn't have any brushes on hand, so I went with my original idea (see next post) I'm probably missing something, but if the box is isolated, how is it protected by the external shaft zink? Wouldn't there be electrolysis generated between the Stainless shaft and the less noble stuffing box which also happens to leak salt water by design?

L124C · #7 02-19-2012

I decided to test the continuity between the Box and Motor. I set my Ohm meter to 2000k. The reading between the Stuffing Box and motor fluctuated between 230 and 250. I ran a ground (bonding) wire between the Stuffing Box and a ground bus near the battery bank. The reading between the Stuffing Box and motor then fluctuated between 0 and 10.
So, the bond certainly makes a difference. My questions are:
1. Is it a substantial difference?
2. Does fastening the bonding wire to the box with a SS hose clamp (see picture) create any problems?

Capt Len · #8 02-19-2012

How many electrons can an atom of zinc lose before it can be considered sacrificial and let the bronze's copper show pink?. If you can measure it ,it's happening; Maybe slowly but bonding everything to your outside zinc costs maybe $2 of wire and dammed if I can understand the problem .Solder the wires so corrosion doesn't defeat the purpose.

L124C · #9 02-19-2012

Quote:

Originally Posted by Capt Len

How many electrons can an atom of zinc lose before it can be considered sacrificial and let the bronze's copper show pink?. If you can measure it ,it's happening; Maybe slowly but bonding everything to your outside zinc costs maybe $2 of wire and dammed if I can understand the problem .Solder the wires so corrosion doesn't defeat the purpose.

Wait a minute..... The more I learn, the less I know!

By bonding to ground (the motor), I'm bonding the Stuffing Box to the motor and it's internal zincs. Correct?
Should I solder the wire to the Stuffing box?