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09-25-2015, 08:49 PM
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#21
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Guru
City: Vermont
Join Date: Jan 2013
Posts: 10,092
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Getting back to zincs, sealant is fine, but don't be tempted to use teflon tape as it will interfere with conductivity.
__________________
MVTanglewood.com
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09-25-2015, 09:02 PM
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#22
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Guru
City: Miami Florida
Vessel Name: Possum
Vessel Model: Ellis 28
Join Date: Aug 2011
Posts: 5,307
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Since you guys are talking anodes, do you use shaft zincs with the copper crush contacts?
Do you even know what I'm talking about?
The reason I ask is that I sell Camp brand anodes that do have the contacts. The local divers don't buy them because they are not the cheapest available. If the copper contact isn't important to you guys, maybe I can switch to a less expensive brand.
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Parks Masterson
Retired from Hopkins-Carter Marine Supply
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09-26-2015, 06:31 AM
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#23
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Guru
City: Sarasota/Ft. Lauderdale
Join Date: Apr 2014
Posts: 5,438
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Quote:
Originally Posted by HopCar
Since you guys are talking anodes, do you use shaft zincs with the copper crush contacts?
Do you even know what I'm talking about?
The reason I ask is that I sell Camp brand anodes that do have the contacts. The local divers don't buy them because they are not the cheapest available. If the copper contact isn't important to you guys, maybe I can switch to a less expensive brand.
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Yes I know what you're talking about. And yes I've used them.
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09-26-2015, 12:18 PM
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#24
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Valued Technical Contributor
City: Litchfield, Ct
Join Date: Aug 2012
Posts: 6,785
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I think that the crush contacts are an important feature and I would pay more to get them.
If you just bolt up a non contact egg anode, it may not make good contact with the shaft. The crush contact concentrates the force at one point so it makes good contact.
David
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10-03-2015, 04:35 PM
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#25
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TF Site Team
City: Saltspring Island
Vessel Name: Retreat
Vessel Model: C&L 44
Join Date: Nov 2007
Posts: 5,663
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For the past two years I have been unable to get the shaft anodes with the copper contact. What I can get is an egg shaped anode with a hinge system that provides a larger surface of the zinc in contact with the shaft.\There is a difference. I haul once a year, not always at the same time. In the summers, I always get to dive and inspect. The copper crush kind have never, NEVER presented for a summer inspection. Last year was the first year with the hinge kind, and some zinc was still there for my next haulout, 14 months later. I won't be going back to the copper contact kind if I can control it.
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10-03-2015, 05:42 PM
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#26
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Enigma
City: Slicker?
Join Date: Oct 2007
Posts: 16,565
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Greetings,
Mr. K. Sounds like the crush type may have been doing it's job better than the hinge type.
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RTF
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10-03-2015, 07:04 PM
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#27
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Guru
City: Melbourne, FL
Join Date: Dec 2014
Posts: 1,731
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Quote:
Originally Posted by koliver
For the past two years I have been unable to get the shaft anodes with the copper contact. What I can get is an egg shaped anode with a hinge system that provides a larger surface of the zinc in contact with the shaft.\There is a difference. I haul once a year, not always at the same time. In the summers, I always get to dive and inspect. The copper crush kind have never, NEVER presented for a summer inspection. Last year was the first year with the hinge kind, and some zinc was still there for my next haulout, 14 months later. I won't be going back to the copper contact kind if I can control it.
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if it is being dissolved, it is doing it's job. If it is still there after 14 months, it's not doing you any good. You might want to use a VOM to see what the voltage it reports.
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10-03-2015, 09:17 PM
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#28
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Guru
City: North Vancouver
Vessel Name: Phoenix Hunter
Vessel Model: Kadey Krogen 42 (1985)
Join Date: Apr 2011
Posts: 2,877
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Wouldn't zinc deterioration be related more to engine hours rather than calendar?
Jim
Sent from my iPad using Trawler Forum
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10-03-2015, 10:03 PM
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#29
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Enigma
City: Slicker?
Join Date: Oct 2007
Posts: 16,565
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Greetings,
Mr. JD. I think zinc depletion is a function of current density rather than time or engine use.
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RTF
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10-04-2015, 07:14 AM
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#30
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Guru
City: Melbourne, FL
Join Date: Dec 2014
Posts: 1,731
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Quote:
Originally Posted by JDCAVE
Wouldn't zinc deterioration be related more to engine hours rather than calendar?
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A zinc is a sacrificial anode to balance the electrical potential of your boat. It is installed to let the free electrons eat on the zinc, rather than your boat's running gear and thru-hull fitting, etc.
Once the zinc is depleted (eaten away) the electrons go to work on your boat parts.
There are lots of things that cause zincs to be eaten away, boat hull material, salinity of the water, stray currents from bad electrical wiring (on both dock and boat), and flow of water over the surface of the boat. The faster you go, the higher electrical potential it builds and faster the anode will erode.
Best thing to do is test the electrical potential of your boat regularly using a silver/silver chloride reference electrode and a volt meter. You hook the reference cell to the volt meter positive lead and the ground lead to a known ground and see what the display reads. This is also a good way to test for stray currents in both your boat, other boats, or the dock power system.
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10-04-2015, 08:45 AM
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#31
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Guru
City: gulf coast
Join Date: Jun 2014
Posts: 3,440
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Quote:
Originally Posted by Capt.Bill11
Zinc holes are tapered thread as I recall. So if tightened properly they almost never leak. If you're worry about leakage and inhibiting electrical contact, just don't put sealant on the first few threads of the plug.
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True, they are called NPT, national pipe thread and are tapered to create a seal. Tightening distorts the threads on the brass plug and creates the seal. IMO they are designed for single use.
Reusing the plug again may not create the same distortion and seal. I little rector seal will help.
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10-04-2015, 09:06 AM
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#32
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Technical Guru
City: Wilmington, NC
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 6,194
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When changing engine zincs, it's good to chase the NPT threads with a tap to clean things up. A little sealant is a good idea. I've checked with an ohm meter and NEVER seen one insulated.
My engine zincs last between 6mo-1yr. Fortunately, only two. Some Cats are annoying with zincs everywhere.
I too use the shaft zinc and was dismayed by the lack of the copper balls. But after changing my shaft zinc a few times while diving, the ones without the balls are working just fine. Half or more eaten up at change. I do clean the shaft real well before mounting and also noticed that it has a real good grip on the shaft. I don't worry about the balls any more.
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10-04-2015, 10:36 AM
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#33
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Guru
City: North Vancouver
Vessel Name: Phoenix Hunter
Vessel Model: Kadey Krogen 42 (1985)
Join Date: Apr 2011
Posts: 2,877
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Rt and Stubones. I understand about the effect of the electrical potential on zincs, but all things being equal (I.e.electrical potential) a pencil zinc in a vessel in use should deteriorate faster than a zinc when the vessel isn't in use: 1) the concentration of zinc in within a heat exchanger has to be higher when the water inside is stagnant than when it is flowing, hastening deterioration; 2) the associated erosion from flowing water is higher than with stagnant water. I check my zincs more frequently in the summer when the vessel is in use than when it is sitting at the slip.
Jim
Sent from my iPad using Trawler Forum
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12-25-2020, 11:19 PM
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#34
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Guru
City: Burien
Vessel Name: Intrepid
Vessel Model: North Pacific/ NP-45 Hull 10
Join Date: Apr 2020
Posts: 684
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I bought some pencil zincs for cummins 6.7. Been is service about 6 months so i thought i would check for wear. Not much wear but the new zincs came with new brass caps and the zincs are loosely threaded. Do i need to use lock tight on the pencil? Would hate for them to come loose and drop in the heat exchange.
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12-26-2020, 12:47 AM
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#35
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Guru
City: Gulf coast
Join Date: Aug 2016
Posts: 2,271
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I've never used lock tight or any thread sealant between the zinc and plug. Just give it a good twist by hand.
Remember, at some point in the future when that zinc is half as long and half as thick and somehow seemingly softer -- in order to replace it, you'll want to be able to unscrew it by hand without breaking it.
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12-26-2020, 06:10 AM
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#36
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TF Site Team
City: Seneca Lake NY
Vessel Name: Bacchus
Vessel Model: MS 34 HT Trawler
Join Date: Nov 2014
Posts: 7,826
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Quote:
Originally Posted by Ski in NC
I too use the shaft zinc and was dismayed by the lack of the copper balls. But after changing my shaft zinc a few times while diving, the ones without the balls are working just fine. Half or more eaten up at change. I do clean the shaft real well before mounting and also noticed that it has a real good grip on the shaft. I don't worry about the balls any more.
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Ski
Just wondering if you do a similar cleaning on the inside of the shaft zinc. I have started to us a small wire wheel in a drill to ensure the ID is clean and bright. Im in fresh water and use alum but procedure should be same for zinc.
Also assume you seat them well, but will mention it for others benefit. When tightening the zinc on the shaft I tighten it up and then fully seat the zinc using a hammer while rotating the shaft and retightening.
I do this all while on the hard before spring launch but wonder what those that change zincs in the water do?
__________________
Don
2008 MS 34 HT Trawler
"Bacchus"
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12-27-2020, 11:44 AM
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#37
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Guru
City: Nanaimo
Vessel Name: former owner of "Pilitak"
Vessel Model: Nordic Tug 37
Join Date: Feb 2018
Posts: 1,703
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Don,
That is the method described by Rod at marinehowto.com for installing anodes. He says clean attachment point(s) are necessary with a "solid" contact. He has a good article posted on his site.
__________________
Tom
Nanaimo, BC
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12-27-2020, 02:48 PM
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#38
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TF Site Team
City: Seneca Lake NY
Vessel Name: Bacchus
Vessel Model: MS 34 HT Trawler
Join Date: Nov 2014
Posts: 7,826
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Quote:
Originally Posted by firehoser75
Don,
That is the method described by Rod at marinehowto.com for installing anodes. He says clean attachment point(s) are necessary with a "solid" contact. He has a good article posted on his site.
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Tom
Thanks CM is the best... go there often.
Don
__________________
Don
2008 MS 34 HT Trawler
"Bacchus"
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12-27-2020, 06:59 PM
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#39
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Guru
City: Gibsons, B.C., Canada
Vessel Name: Island Pride
Vessel Model: Palmer 32'
Join Date: Oct 2007
Posts: 4,414
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For years I have cleaned the mounting areas FOR and OF ALL the zincs, shaft zincs, plate zincs, all zincs and so on. I then always check with my ohmmeter for continuity of less than 1 ohm, hopefully in the range of less than 0.5 ohm. Several times I have to dismount a zinc and reclean the zinc AND/OR the area it is mounted to.
I have seen zinc protection failure unless that is done and especially the ohm check.
Just fastening a zinc in place is NO guarantee it will actually work if the mounting surfaces are not adequately clean.
For pencil zincs I use a wrench to hold the cap and a pair of pliers to SNUG the anode into the cap. I no longer lose the zincs.
I then apply some sealant to the cap threads and check that. I realize that the water the anode is immersed may create a pathway to fool one but I have also checked when the raw water system was drained.
Every 6 months or so I then check for anode activity with my silver/silver cell and meter. I have caught a couple problems before they could cause damage.
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12-27-2020, 08:38 PM
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#40
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Guru
City: Here
Join Date: Sep 2012
Posts: 2,940
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Quote:
Originally Posted by Marin
The Chinese have learned just a wee bit about boats in salt water over the last few thousand years so I suspect they have "figured out" zinc metallurgy by now.
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They also figured out how to bulk up powdered milk with melamine.
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