Cleaning rust from stainless

C

Casey

New member
Over the years our stainless bow rail and bimini hardware have developed some surface discoloration and a bit of rust-like stain.

We'd like to clean it up, but don't really want to try a dozen products before finding the Right one.

What have you found that works the Best?

Best,
C&M
 
I use this stuff: Davis Rust Remover. It's not an abrasive, but uses oxalic acid. I've used it for years and it's worked well. I do flush it off after it's done it's job. Doesn't hurt fiberglass.

There's also a citrus based stainless steel rust remover: CitriSurf.

I would think a polish is an abrasive, and doesn't remove all the rust.

Boris
 
Just plain oxalic acid works. There is also "rust away" . BarKeepers friend has a mild abrasive, but also works very well, and we carry it aboard.
 
I have been using Nevr-Dull on stainless for years - it takes the staining off (um, isn't that supposed to be "stainless"?? :crook ). Then, when waxing the hull, I put a light coat of wax on the stainless. In places where the stainless staining has run onto the fiberglass, Starbrite Hull Cleaner takes it off... then needs another coat of wax in that area.

http://www.nevrdull.com/
 
I like Spotless Stainless (Scan Marine sells it as I recall). It's supposed to somewhat re-passivate the stainless IIRC. I've also used Wichinox.
 
Thanks All !

I bought some liquid Barkeeper's friend this afternoon at Walmart.

I have no idea when I'll get around to the stainless ... but at least I don't have an excuse anymore.

Best,
C&M
 
Barkeepers Helper has always done a good job on my boats, but I also keep a Miracle Polishing Cloth [ http://www.polishingcloth.net/ ] in each boat's tool kit, as it works well, it reusable and last for a very long time without taking up much space or weight. I had read an article in Practical Sailor that steered me to this product about 5 years ago. I purchased the product on-line in a package of 10 for cheap...
 
Casey,

You took the words right out of my mouth. And Jim, Stainless--ya right, right?

If you are speaking of the bow rail and cleats, those are most likely 316 Stainless Steel. (Now, I am not a metallurgist, chemist, machinist or welder so this is all second hand info......) 316 is more brittle, and takes a higher polish. the other common "stainless" is the 304 version. Softer, less brittle, and contains a higher amount of iron.... so it rusts more, more easily. I found this out, practically, when I had my splash well arch bracket built for my inflatable. I specified 316, but the 304 was substituted without my knowledge. Long story short, the 304 takes considerably more effort. This spring I took the whole rack off and took it to a fellow in Portland who "polished" the whole thing. It looked great, but any salt spray shows and the not so good looking brown spots.

I have tried a thin coat of WD-40, recommended by the polisher, and just recently picked up the Barkeeper's Friend, liquid but have not tried it yet. The WD-40 is not doing the trick so moving on.

It is interesting that everyone seems to have different product that works. I'm curious if they have a common component. I believe that "stainless" has to have access to oxygen to block the rust, so I have avoided using a wax on it. Of course, I could be wrong --but it might be the first time :shock: :oops:

I'll be watching this thread with interest.

Some of the things I have heard that I have not seen here is to use crumpled tin foil to clean the rust off with, and another is Mr Clean Erasures. I have used the tin foil on a stainless hitch ball. it worked, but it took some time.

So a question to add to the original (what do you use to clean the rust off?) is: After you get the stainless polished, what do you do to keep it that way?

Harvey
SleepyC :moon

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Harvey,

I think you have the numbers somewhat reversed. At least as I have always understood it, 304 stainless (which is the "common" type) is stronger/harder, but more corrosion prone than 316 stainless. On the other hand, 316 is slightly softer/less strong. However, most hardware on boats is not so closely sized that substituting 316 for 304 causes any sort of strength problem. It's not like 316 is actually "soft."

I try to use 316 fasteners (when using stainless at all), and when replacing hardware on my boat will also go for 316 if possible. The original Sea Dog cleats were 304; I changed them to 316 (Sea Dog offers a 316 alternative). I would imagine the bow rail is 304.

McMaster Carr is a good source for 316 fasteners (except for oval headed), whereas most hardware stores seem to only stock 304 (why I buy at McMaster instead).

As far as what to coat stainless with, I'm not sure. Stainless relies on contact with oxygen to remain "stainless," so I don't know that you would want to block that. That's one reason why you can have a problem if you, say, tape over an area of stainless (blocks air, corrosion/rust can happen). Don't know if wax or etc. would do that, but I like to leave my stainless open to the air. What I understand is that passivating/re-passivating is good for protecting it from corrosion, and products like Spotless Stainless and Wichinox are supposed to do that to some extent, I think (read up on it years ago but now forget the details).

I still prefer bronze to any stainless, but in a way stainless seems to "suit" the 22 (and of course it is already loaded with it) so I stick with it, but go for 316 if at all possible.
 
GENERAL PROPERTIES – TYPE 304
Type 304 stainless steels can meet a wide variety of physical requirements, making them excellent materials for applications including auto molding and trim, wheel covers, kitchen equipment, hose clamps, springs, truck bodies, exhaust manifolds, stainless atware, storage tanks, pressure vessels and piping.


TYPICAL ANALYSIS – TYPE 304
Represented by ASTM-A240 AND ASME SA240.
Elements by Percentage by Weight - Maximum Unless Range is Specified.
C = .08 / Mn = 2.00 / P = .045 / S = .030 / Si = 1.00 / Cr = 18.00 - 20.00 / Ni = 8.00-12.00 / N = .10


RESISTANCE TO CORROSION – TYPE 304
The 18% chromium, 8% nickel, provides good resistance to moderately acidic or caustic solutions. Type 304 may be considered to perform similarly in most non-severe applications. A notable exception is in the case of welding. Low carbon (304L) is the recommended alloy and provides increased resistance to intergranular corrosion.


MECHANICAL PROPERTIES OF TYPE 304 AT ROOM TEMPERATURE
Typical Mechanical Properties required for annealed material covered by ASTM A240.
Yield Strength .2% offset = 30,000 / Ultimate Tensile Strength = 80,000 / Elongation = 50%. Hardness R = 90 max.

TYPE 316 STAINLESS STEEL
Type 316 is an austenitic chromium-nickel stainless and heat-resisting steel with superior corrosion resistance as compared to other chromium-nickel steels when exposed to many types of chemical corrodents such as sea water, brine solutions, and the like.


GENERAL PROPERTIES – TYPE 316
Type 316 alloy is a molybdenum bearing stainless steel. It has a greater resistance to chemical attack than the 304 family. Similarly, Type 316 is durable, easy-to-fabricate, clean, weld and finish.


TYPICAL ANALYSIS – TYPE 316
Represented by ASTM-A240 and ASME SA240.
C = .08 / Mn = 2.00 / P = .04 / S = .03 / Si = 1.00 / Cr = 16.00 - 18.00 / Ni = 10.00 - 14.00 / Mo = 2.00 - 3.00


RESISTANCE TO CORROSION – TYPE 316
The addition of 2% molybdenum makes 316 considerably more resistant to corrosion and oxidation than the 304 family of alloys.


MECHANICAL PROPERTIES OF TYPE 316 AT ROOM TEMPERATURE
Typical Mechanical Properties required for annealed material covered by ASTM-A240. Yield Strength .2% offset = 30,000 / Ultimate Tensile Strength = 80,000 / Elongation = 50%. Hardness R = 90 max.
Click to expand...

The main difference is the addition of 2% molybdenum. I doubt if the average person can tell the difference. But much of the SS which comes to the US, especially in fittings, is made in china, and I suspect that the specs are all over the place. If you want a good quality product, then buy US, from a manufacture who tests the SS for composition before fabrications. It used to be we could sail in salt water races for years, and no corrosion. I note that a lot of the stuff we get now corrodes in short order. I suspect it is not only the composition, but also how it is blended. I'll check with my metallurgist friend….
 
From a local fabricator I have been talking to lately:

"Welding either one is easy. BUT, if they are not flooded with argon during the process, rust will appear in time. The 304 will rust sooner than the 316.

Keeping the rust away is still an issue. Both need oxygen to delay rust incursion and corrosion."

Harvey
SleepyC :moon

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I'll try. The chromium in the alloy in the form of its oxide forms a protective coating on the underlying alloy. If the stainless is held in an oxygen free environment (aka "anoxic"), it is possible for the chromium oxide to be degraded, exposing the underlying alloy, and allowing it to be eroded away. The technical term I know for this is "crevice corrosion".

That said, my local shipwright claims stainless burried within a wooden structure and not exposed to water will last forever.

One source which explains the corrosion in more formal terms: http://www.corrosionist.com/Pitting_Cre ... rosion.htm
 
Quote:
"Stainless steel is not resistant to chemical or physical attack. The corrosion resistance of stainless steel depends on the formation of a 'passive surface film' composed of nickel and chromium oxides (Cr203 & Ni0). Passivation involves removing free Fe or 'tramp Fe' from the stainless steel surface."
End quote

Boris
 
smckean (Tosca)":1vzut9xb said:
Both need oxygen to delay rust incursion and corrosion
Click to expand...
Harvey, I am confused by this. Can you explain it to me? Thanks
Click to expand...

Dave and Boris are much better at it than I am for the technical side. Practically, if you put tape on a stainless tube, it will corrode or rust under the tape faster than on the rest of the surface.

Harvey
SleepyC :moon

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Hi Brats!
Sure, Oxalic acid in all its various forms will remove rust tarnish from SS, but also your Poli-Glow clear coat (outlier alert!) or wax if you like wax, and it will stain your aluminum trailer (wet it down first) and it's not good for your skin or eyes.
For years I've been using Woody Wax...a cheap Lowes type cotton glove over a vinyl glove (optional, but it keeps the harmless stuff off your hands), spray the outer cotton glove with Woody Wax. Use some bronze wool in stained areas and just The Glove on nonstained SS rails and bimini supports. The cotton glove allows you to get the liquid around post bases etc without hitting your Poli-Glow and is very, very fast and easy and benign. Leave it on as little as 1 hour or 24 hours for tough stains, then wipe it down with a terry rag (or microfiber cloth) and you will have a shiny protected SS rail for up to 3 months in the Deep South. Stash the Cheap Cotton Glove and the used bronze wool in a zip-lock bag for future use (if you're as cheap as I am). Don't even try to use SS or steel wool. The bronze wool can be re-used many times. I bought a gallon of Woody Wax (half price) at the last day of the 2011 Miami Boat Show we are still using. It's also great to get the wax off the plastic black nav light housings and shine up any plastic/composite plastic, as well as a non-skid cleaner and non-slick wax/protectant for your non-skid areas. Also, it tastes great sprayed on Rocky Road Ice Cream (JUST KIDDING!). I've also liked Miracle Cloth but you can't let it contact water and overall Woody Wax is cheaper.
Here are the West Marine prices, but you may well find better searching elsewhere.
http://www.westmarine.com/buy/western-p ... 26_004_510
http://www.westmarine.com/buy/woody-wax ... z--3745320
Cheers!
John
 
I spent some time with a metal fab shop today. The owner said I need to look into "passivating"

So I found it is a chemical process and not something I can brush on and mask around. Anyone have any practical experience with that?

Harvey
SleepyC :moon

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