Protecting bare steel from rust

Ok, I know I could just put oil on it and be done with it but that's not what I am looking for.

I have machined a part from 12L14 (4.2" dia. x 5.5" high) which is probably the most rust prone metal out there. Cosmetically it would look better to keep it bare steel as opposed to clear, yellow or black zinc. So, is there anything out there that can be applied to steel to keep its bare looks that would last?

Thanks

Primer????

You do not say why you want it not to rust and for how long. Is it just untill it gets to customer? Do you want it to stay shiny forever? Is it on a boat? What is aplication of the part? Without more info your idea to put some oil on it is probably best. In this weather reaply every few days.

Plating or tough industrial clear coat. Other than that nitriding such as used on shotgun receivers. Not cheap but adds scratch resistance along with rust resistance.

If it's just for the short term how about micro-crystalline wax such as Renaissance Wax? Cab be applied by hand and buffed with a cloth.

Electroless nickel plating is one way. It is relatively a simple process and coats evenly any shape. Another simple method is bluing the steel. This can be done chemically in a process similar to firearms bluing. On smaller parts I often use heat. Heating with a torch the parts sitting on a piece of copper and removing when blue colour is reached ( a standard practice in watchmaking).
Bigger parts can be blued in a oven. About an hour or two (depending on the part size) at about 270 degrees centigrade (520F) will produce a nice deep blue finish. I wrap the part in a thick aluminum foil for even heating. Oil and wipe after.

billzweig said:

Electroless nickel plating is one way. It is relatively a simple process and coats evenly any shape. Another simple method is bluing the steel. This can be done chemically in a process similar to firearms bluing. On smaller parts I often use heat. Heating with a torch the parts sitting on a piece of copper and removing when blue colour is reached ( a standard practice in watchmaking).
Bigger parts can be blued in a oven. About an hour or two (depending on the part size) at about 270 degrees centigrade (520F) will produce a nice deep blue finish. I wrap the part in a thick aluminum foil for even heating. Oil and wipe after.

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Oxide bluing (ie: heating steel until it changes color) offers very little rust protection and is a very different process from 'gun blueing' or 'hot blueing'. Hot blueing is usually done in a bath of hot 'blueing salts' and produces a magnetite layer fused with the surface of the steel that offers a little corrosion resistance, and also helps hold an oil film on top of the part to further increase corrosion resistance.

There is also "cold blueing" which is a solution that produces a layer of selenium oxide on the surface of the part. Easy to apply but does not offer much in the way of wear or corrosion resistance.

"Steam bluing" is another method of hot blueing in which the parts are exposed to 'dry steam' at elevated temperatures to produce the magnetite layer.

You can also 'rust blue' parts easily yourself which produces a nice magnetite layer. This is done by forcing the parts to produce a fine even rust, then boiling them in water to 'hydrate' the rust and produce the black magnetite layer. Rust blueing can be really beautiful if done right, but it's hard to get right and is fairly time consuming.

However all these methods will significantly change the look of the parts. (ie: make them black)

I agree with billzweig, electroless nickel looks pretty close to uncoated steel and is a much more corrosion resistant option. Electroless nickel is also quite durable as it's a lot harder than the bare steel would be.

Rob F. said:

You do not say why you want it not to rust and for how long. Is it just untill it gets to customer? Do you want it to stay shiny forever? Is it on a boat? What is aplication of the part? Without more info your idea to put some oil on it is probably best. In this weather reaply every few days.

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I was just wondering if there is a process that would keep the look of bare steel as well as protect it from rust. This is a finished product and would have to stay that way for years. If there isn't a process I will look into black zinc. It is an industrial product that would be used in a manufacturing plant. I am also thinking about making it out of 303ss.

Paint it with Flood Penetrol. Inside, it will hold up for many years.

Wild West said:

I am also thinking about making it out of 303ss.

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This sounds best, other alloys of stainless could be used if you need stronger/harder parts

Wild West said:

...thinking about making it out of 303ss.

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Make it from 316 if corrosion resistance is a great concern.

Hmmm....? Found this. Won't have a bare steel look but it is a thin coat which for me is much better.


Cerakote Coatings: Finishes

No-Rust rust preventive and inhibitor from Slide Products

This stuff is where it's at...spray it on and it's good to go

There is also "cold blueing" which is a solution that produces a layer of selenium oxide on the surface of the part. Easy to apply but does not offer much in the way of wear or corrosion resistance.

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I do this on many of the oddball colletts and mandrels that I acquire, and that sit around without much much use once I get the inevitable bits of surface rust off. A little Oxo seems to go a long way toward preventing future problems, and requires a minimum of time and effort.

plastikdreams said:

No-Rust rust preventive and inhibitor from Slide Products

This stuff is where it's at...spray it on and it's good to go

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Thanks! I just ordered a couple cans from ebay.

Wild West said:

Thanks! I just ordered a couple cans from ebay.

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Nice, I actually left a piece of fresh turned steel outside half covered with some crc crap and half with the slide. It was outside in the summer so rain and humidity for a few months. The slide side had no rust the crc side was like it was never coated lol. Slide makes good stuff, their bare metal cleaner and their penetrant plus are excellent too.