12L14 and rust

[mklotz]

12L14 is a leaded steel that's an absolute dream to machine. I use a lot of it in my models.

However, it does have a well known tendency to rust much more easily than standard CRS or other common steels.

Recently, I've noticed mild surface rust developing on 12L14 parts on several models housed in a closed display cabinet in my office. I live in the semi-desert environment of Southern California so rust of any kind is unusual and rust inside an indoor cabinet is frankly astounding.

I noticed a correlation. The models showing rust were all placed in a part of the cabinet that is exposed to the morning sun. My guess is that the resulting warming of the metal makes it even more susceptible to the low humidity present in the air inside the cabinet.

The rust is only minor surface rust and, caught early, is easily removed with a bit of fine steel wool. A coat of LPS3 or Boeshield (my preference) should prevent more rust from forming on these parts.

Anyway, a heads-up for all you modelers. If you use 12L14, be careful about how you store models, especially if you don't run them often.

 

[shred]

hmm.. I would have expected condensation from cold parts more than hot ones, but who knows. I do know 12L14 loves to rust.

We did a rust-off at my club a while back-- I turned a very fine thread on 8" of 12L14 and left it outside for a month. I then chopped the resulting rusty stick into short bits and gave them out for people to de-rust using their favorite methods; the goal being maximal rust removal with minimal damage to the threads and preferably minimal work. Evapo-Rust is the overall leader, though one member with a chunk moldering away at the bottom of a vat of molasses claims the results will be nothing short of miraculous once it finally deigns to emerge.

I need to redo the test with various rust-preventatives.

12L14 does take blueing well, which resists rust better than bare metal, though I'd be tempted to coat anything where I am. A local live steamer seems to have found a very good clear-coat.

 

[artrans]

hello I meet fellow in my shop and some of my machines have light surface rust and this guy said clean off the rust and take car wax and wax the metal and it will not rust so i tried it and sure enough
it works great and the plus side the chips blow right off or brush off.works very well.

 

[ksouers]

Marv,
You will be surprised how much condensation collects in a closed vessel!! Something well known here in the midwest with our 60%-80% humidity. The humidity here in winter runs around 15%, quite low.

I have a 22 foot cabin sailboat that gets closed up all winter long. It is not tightly sealed up, but tent-covered with plastic and open at the extreme ends. I check on it frequently and you would be amazed at the amount of water that collects in it just from condensation! Come the first warm days of late winter/early spring I can easily pump out 5 gallons of water. The garage is just as bad, that's when my tools get the most rust.

I keep small packets of silica gel in each drawer of the toolboxes just because of that.


Kevin

 

[radfordc]

Check out this test of rust preventatives. Interesting to see how well plain old WD-40 did.

http://www.brownells.com/aspx/NS/GunTech/NewsletterArchive.aspx?p=0&t=1&i=503

"I began by selecting ten products commonly used to protect firearms from rust and corrosion. These were: Birchwood Casey Sheath, Boeshield T-9, Break-Free LP, Break-Free Weapon Wipes, Brownells Cosmoline, Brownells Rust Preventive No. 2, Hoppe's Lubricating Oil, Rig Universal Grease, and Tetra Gun Lubricant. To curb my own curiosity, I also threw in a couple extra lubricants – Valvoline 5W-30 motor oil and the universally recognized WD-40.

The test-bed would consist of 1/8" thick, raw, flat steel plate cut into individual pieces measuring about 5" to 6" long x 1¾" wide. In order to achieve accurate results, each test-bed would need to be as consistent as possible, so I bead blasted the plates to a uniform surface texture. This process removed any pre-existing corrosion and exposed a fresh, unadulterated test surface so every sample would start on the same playing field. Bead blasting also produced millions of microscopic pockets in the metal that would help capture moisture and accelerate rust formation on what would otherwise be a smooth, polished finish.

Each sample, with the exception of Break-Free Weapon Wipes, was applied to its respective test plate with a fresh, cotton bore patch to prevent cross-contamination. Weapon Wipes are pre-saturated cloths ready for use, so transferring the product to a patch was not necessary. Since the fluid consistency of the samples varied, I applied them with the mindset that I was protecting a firearm for six months of indoor storage, be it a cabinet or humidity-controlled gun safe. This meant one, even, easy to apply layer on the front face and edges of the plate – no puddling or extra thick coverage was allowed.

Let The Testing Begin
All test plates were positioned flat, sample side up and spaced approximately 2" apart on an unprotected picnic table in my backyard for three days. If you're at all familiar with weather in the Midwest, you know it's not uncommon to experience two or three seasons of weather in a single weekend -– this particular 72-hour period was no exception. We had high humidity, scorching heat, followed by some horrific thunderstorms that produced pounding rains and cool evening temperatures – perfect conditions to grow some serious rust and corrosion on raw steel!

The test plates were inspected at around 24 hours into the study with negligible results, but by day three, things had shaped up nicely.

The Results
After 72 hours of exposure, all test plates were brought indoors for evaluation and photographing. You will notice there are two photographs per plate. The first photograph shows the plate immediately after testing. The second depicts the same plate after degreasing with TCE to remove all loose corrosion. It provides the more accurate representation of overall protection. Note that raw steel is especially susceptible to corrosion and is not a true indication of how blued, parkerized, plated or painted gunmetal will react to different environmental conditions.

Boeshield T-9
Test plates reveal minimal moisture penetration and negligible rust formation. Collection of some dust/debris on surface is present. Minor blemishes present after degreasing. Overall metal condition is excellent.

COSMOLINE
First test plate shows collection of dust/debris on treated surface but no moisture penetration or rust formation. Slight darkening of the steel was apparent after degreasing. Overall metal condition is excellent.

RIG UNIVERSAL GREASE
Test plate on left shows the typical collection of dust/debris common with grease-based rust preventives. No evidence of rust formation or discoloration. The degreased plate shows the metal is unmarked.

WD-40
Test plates show excellent moisture displacement. Minimal rust formation is present; almost no pitting is visible after degreasing.

 

[Orrin]

For a very long time I was on an electrolytic de-rusting kick. As a consequence, for a number of years, now, I have had piles of bare antique iron and steel in my welding shop, awaiting a paint job, some day. All of it is rust-free and rather attractive just the way it is. On the other hand, some steel bar stock in that same unheated shop has picked up some unsightly rust.

It's this way. After I've used electrolysis I immediately treat the parts with a phosphoric acid with salts preparation. There are a number of such products out there, such as Metal Ready, Metal Prep, etc. They can be found in some paint shops, hardware stores, and sometimes at Home Depot.

The phosphate treatment produces an inert layer on the surface that is resistant to rust. It is similar to Parkerizing.

I would never suggest using this treatment on some prized equipment or models without experimenting with it, first. If it is globbed on too thick it may cause an unsightly white deposit. I generally apply it with a brush, let it work for a while until a uniform appearance is achieved, then blot it off with soft cotton rags or paper towels.

Beware! Although some folks will argue the point, do not use bare naked phosphoric acid! I've tried it and had serious rusting problems a few weeks down the road.

Here is the link to a paper I wrote about the process.

http://www.oldengine.org/members/orrin/rustdemo.htm

The downside to the phosphate treatment is its fragile nature. If water is splashed onto the surface it will cause unsightly white spots. All is not lost, however, because it can usually be fixed with spot re-treatment.

IMHO, the phosphate-treated surface is rather attractive. It almost looks like bare iron or steel, only a bit darker.

Good luck.

Orrin