Best Anti Seize for aluminum saildrive zinc

[bluzzin]

I will be soon hauling out and at that time replacing top zinc on Yanmar Saildrive which is aluminum cased. I have gotten by in past years by saving the anti seize that was previously used but its about gone so I want to replace it and dont want to use anything with copper in it. Does anyone have recommendation for best anti seize lube in the this situation?

Thank you for your help
cheers
michael

[colemj]

I am a bit confused on where and why you want to use anti seize. You don't want to electrically isolate the zinc from the aluminum drive.

However, there are versions of anti seize that contain aluminum rather than copper.

Mark

[bluzzin]

On the top of Yanmar SD31 there is a bolt. On water side of that blanking bolt the zinc screws into bolt. Where the bolt meets the saildrive is where I want anti seize. Sorry for confusion.

I found some at Fisheries Supply that has no metal in it.

Ultra Safety Systems TG2 | Fisheries Supply


Thank you
michael

[Allan S]

There is a nickle based anti sieze available.

[David M]

Tef-Gel is what the riggers in the yards are using when screwing stainless fasteners into aluminum. I have used it for years for doing the same thing on an aluminum boat. It does not dissolve in water and works seemingly forever. It contains no metal. Applying it will not prevent an electrical connection. I apply it to electrical connections in moist environments all the time to prevent corrosion.

[GordMay]

Ideal’s “Noalox” Anti-Oxidant Compound contains suspended zinc particles which penetrate and cut aluminum oxide, and the carrier material excludes air to prevent further oxidation.
➥ Ideal Industries - Noalox® Anti-Oxidant Compound

There's also Burndy's “Penetrox”, and GB Electrical's “Ox-gard”, all widely available

[noelex 77]

I am not familiar with the exact bolt you are talking about but like Colemj I would have reservations about putting anything on the bolt, if the bolt is connected to zinc.

Most of the stuck SS bolts in aluminium are caused by dissimilar metal corrosion. This will not occur if the bolt is protected by the zinc.

It's very important to maintain good electrical contact with zinc. The voltages are low and the effect of the zinc is easily blocked.

The products like Tef-gel and Duralac prevent corrosion partially by providing some electrical isolation. The zinc may be directly in contact with the sail drive leg, but the best electrical contact is generally via the bolt.

You risk compromising this connection.

[GordMay]

Originally Posted by noelex 77

... It's very important to maintain good electrical contact with zinc. The voltages are low and the effect of the zinc is easily blocked...

“Noalox”, “Penetrox”, & “Ox-Gard” are all electrical antioxidants, containing zinc.

[noelex 77]

Originally Posted by GordMay

“Noalox”, “Penetrox”, & “Ox-Gard” are all electrical antioxidants, containing zinc.

I have not used the above products, but owning an aluminium boat Duralac, which i suspect is similar, is my friend. It contains a high concentration of zinc to reduce the dissimilar metal corrosion, but this is in an electrically non conducting base for the same reason.

When I have attached a fitting with Duralac I always measure the electrical resistance and if done well it provides a moderately high resistance connection

[GordMay]

Originally Posted by GordMay

“Noalox”, “Penetrox”, & “Ox-Gard” are all electrical antioxidants, containing zinc.

Anti-corrosive pastes, containing conductive Zinc particles in suspension, should not be confused with insulating dielectric grease.
These Antioxidants are only conductive under pressure, not as a loose ‘blob’.