Stainless steel fittings and preventing rust

[Zanshin]

Last week I spent hours on deck with Nevr-Dull wadding and elbow grease and got all my fairleads, cleats, lifeline stanchions and other outside stainless steel all nice and shiny.

Now, after a couple of rather wet passages with lots of salt spray and after my daily dose of buckets of salt water on the teak decks, all of that pretty shiny "bling" stuff is showing rust spots again.

I did search around on board and found a bottle of baby oil, and proceeded to put a thin coat on the re-cleaned stanchions but don't know if that will keep or is the right thing to do.

Thus my question on this thread - what means are commonly used on deck hardware that is exposed to the elements to prevent recurrence of rust spots?

[jjablonowski]

I use SpotlessStainless (advertised a lot here) followed by Rust-X [edit: I meant to say Corrosion-X].

Seems to work.

[Vasco]

I've found Spotless Stainless to be excellent without any elbow grease. If I feel energetic I wax it after cleaning. Seems to help a bit.

[Zanshin]

Once I see it I'll try the spotless stainless, but now the boat is pretty clear of rust and stains and my worry is how to keep it that way. What sort of wax do you use, is there a special stainless wax or just normal carnauba car wax?

[Vasco]

Just normal boatwax. Right now I'm using McGuires.

[RichH]

Stainless can be made virtually 'rust free' by enhancement of the surface finish. Rusting will quickly emanate from 'any' surface irregularity or 'roughness'. Stainless that is prepped then polished to a MIRROR quality surface will greatly retard the 'rusting'. Sanding, grinding welds smooth, etc. to remove all surface visible roughness, then followed by mechanical buffing to a mirror-like surface will usually prevent 98% of all 'rusting'. This can then be followed by 'electro-polishing'.

The 'technical' surface finish is 'flatness' to 10 micro-inches (Ra).

[Zanshin]

RichH - what level of grit could one use to get a mirror surface on stainless, and is it available for mere mortals rather than commercial buyers? I've read that one can try to passivate exposed stainless with nitric or prussic acids as well.

[RichH]

For Passivation - simply go with Spotless Stainless, a temporary/mild 'passivation'.

For mirror polishing - start at the appropriate grit (belt sanding is the fastest) that will most quickly give a uniform 'scratch pattern' - 100 ---> 180 ----> 220 ----> 320 ---> 400, then power buff using fabric high speed sewn fabric WHEEL using a 'white metal' rouge such as "Tripoli".

Modern 'tripoli' is a buffing compound especially for 'white metals' made from very fine white clay and diatoms - fossilized marine one celled animals. Available in most industrial hardware stores in 'stick' form and usually stored next to where they have the 'jewelers rouge'.

[NoWet]

Isn't there an issue with stainless that if there's no oxygen available to the surface, it can crack and fail? Wouldn't covering stainless with wax or some other "barrier" lead to the oxygen deprivation?

[MarkSF]

Stainless steel is covered in a layer of chromium oxide - that's what stops it rusting and imparts the shinyness.

Passivation just encourages that layer to grow, and removes iron oxide / rust. You can apply an acid, or just leaving it in air can work. It's amazing stuff really.

Have you tried thoroughly washing it down after the voyage and then just leaving it for a while? Once the salt is gone the finish might recover.

Covering it in oil AFTER it has corroded will just seal OUT the air/oxygen and PREVENT the chromium oxide from forming!