Mercathode Reference Electrode Tester

[Loneranger]

http://www.psepmarineparts.biz/store/mercruiser_mercathode.htm

Does anyone have a better source for the reference electrode tester which I think is part number 76675A1 (or 76675T1) ? Is a reference electrode really >$100? Anyone know the specifications of the electrode? I could make my own.

Thanks
John

 

[Stray Cat]

The going rate is around $100....boatzincs.com has one as well.

http://www.boatzincs.com/corrosion-reference-electrode.html

Is it worth a $120? It is the only way to know you have the correct hull potential.

 

[Loneranger]

http://www.consultrsr.com/resources/ref/agcl.htm

http://corrosion-doctors.org/Corrosion-Thermodynamics/Reference-Half-Cells-Silver.htm

Since this is a silver chloride electrode it can be made for a lot cheaper. The above are great references for anyone interested in making their own. In our use though the filling solution could actually be the water the boat is sitting in. Or you can find it cheaper already assembled. One example below for $89:

http://www.reliabilitydirectstore.com/RDI-CRE-Corrosion-Reference-Electrode-p/rdi-cre.htm

Thanks
John

 

[Stray Cat]

John - very good links...didn't realize there was so much info on the topic on the internet...The one for $89 is a very good alternative.

 

[jcoll]

When using this tester - I'll assume with your DMM - what's the normal (good) reading and what's the threshold for cause for concern or excessive corrosion potential?

 

[dc380]

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Fiberglass w/Outdrive(s) or Outboard(s) -900 to -1050 mV

Greater the -900 (more positive) is cause for concern.
Current or water flow however does have a +-.50 effect

This is with all DC off, and AC disconnected.

I bought mine from Boatzincs.com and they were extremely helpful. Walking me through all the testing.