On Sep 6, 2016, at 11:56, James Alton lokiyawl2@... [amelyachtowners] <amelyachtowners@...> wrote:

Bill,

   I must say that this was the best explanation I have ever read for why I have had so many problems with stainless on stainless threads over the years..thank you!  I can now imagine the little batteries that are formed between the active and passive locations in such a fastener after Mother Nature adds her natural electrolyte…..  

  Bronze and stainless threads seems almost never gall.  Is the softer bronze acting as sort of a lubricant?

  I was thinking that on Sueno that I would probably start with a clean stainless windlass bolt and a clean hole.  Add the Never Seez with a Q tip or something similar to the embedded plate only, keeping it off of the fibreglass.  Then apply my sealant between the interface of the windlass and the deck but hold the windlass up off of the deck as much as possible while the bolts were inserted to keep from carrying the sealant down into the Never Seezed area.  The objective being to avoid contaminating the faying surfaces for the sealant to insure a good seal.   It’s too bad that a good seal to keep the water out also excludes the O2 needed for the stainless oxide for form but I feel that keeping salt water out of those holes is more important.  I can imagine that once salt water migrates in around the plate that there is no cleaning/drying it out.

   Please tell me how you would do it since I am sure that you have put a lot more thought into this than I have.

Best,

James Alton

Maramu #220 Sueno

Sardinia

On Sep 6, 2016, at 12:04 PM, Bill greatketch@... [amelyachtowners] <amelyachtowners@...> wrote:

If your intent is to take it apart every two or three years to clean salt build up from between the deck and the windlass housing as recommended by Lofrans, pretty much anything will probably work.  

I assume the deck plate is stainless, as well as the bolts, so in this case you are protecting against two issues, galvanic corrosion and "galling" or "cold welding".  

Most kinds of stainless steel can exist in two forms "active" and "passive" depending on the availability of free oxygen.  These two forms are quite far apart on the galvanic scale.  When stainless on stainless threads are wet it sets up a good environment for active and passive forms to exist close to each other and potentially cause issues.  For this reason using a product that excludes water from the joint is a good idea. Lanocote, tef-gel, Never-Seez, or standard waterproof greases would all do this for a least a couple years. 

A simple way to think about stainless galling is that under very high pressures the protective surface oxide layer rubs off, the "pure" metal underneath "melts" into itself and the parts become welded together.  In preventing this, in my experience, Lanocote is good, Tef-Gel and Never-Seez are better.  Some greases are good, some not so much, at this.

So...  All told my recommendation would be either tef-gel or never-seez, and I'd know I could get them apart at any time in the future with no problems. On my boat I'd most likely use tef-gel only because it lives in my rigging tool bag, while the never-seez lives in the engine room!

Bill Kinney

SM#160 Harmonie

Narragansett Bay, RI, USA

On Sep 6, 2016, at 09:37, Alexandre Uster von Baar uster@... [amelyachtowners] <amelyachtowners@...> wrote:

 

Good morning, 

To make story short, I removed the windlass, etc. 

What type of product would you put on the bolts attaching the windlass to the deck?  
Lanocote? Marine grease?  

one was extremely difficult to remove (4 hours) and i would prefer avoid that in the future…

Thanks in advance, 
Sincerely, Alexandre
SM2K #289 NIKIMAT
Club Nautico de San Juan, Puerto Rico