Finish on Unpainted Brass

All brass will oxidize , short of gold plating it, it will continue to oxidize. They are meant to be painted.

I purchased an unpainted Brass Santa Fe Northern from Scott Mann in the late 1990's. He didn't want me to purchase the unpainted engine, but I wanted one. He "painted" the engine with a clear coating. It looks the same now as the day I received it. So although I don't know how to do it, I know it can be done and a professional can get great results.

Gerry

You will get suggestions by searching with a variety of words containing brass, cleaning, tarnish, etc.  Here are some examples.

https://ogrforum.com/...n-for-cleaning-brass

https://ogrforum.com/...leaning-brass-trains

https://ogrforum.com/...leaning-brass-models

My trick, is to soak for a few hours in plain old lacquer thinner in a metal tray.    Use a very soft brush to agitate the surface, being careful not to snag any parts.   after drying overnight, you should be good to paint.   Some older brass (NJI) need longer soak times to remove the thick varnish like coating.   Good luck!

To avoid confusion, I want to answer R Nelson. I don't intend to paint the steam engines I'm collecting in any kind of road colors. I only display them in their natural brass, I cannot have a layout where I live and the nearest O 2 layout (private) I know of is two hours away from me. I just like the look of the unpainted brass, including perhaps those (I suspect) that may actually be painted with brass-colored paint. So I have no intention of ever painting these engines. I just want them to remain in their brass (colored?) splendor.

That said, for some models, if the appearance deteriorates, removing the old finish, as Mr. Nelson says, and then somehow refinishing them with a clear coat, as Gerry mentions, or maybe even painting them with some sort of brass color, if that indeed is ever what some engine makers do, may be an answer.

I'm hoping there are some out there that can give me more specifics on what is done (if anything) when preserving brass or brass-finished locomotives.

Bare brass is going to tarnish, …period,….it’s the nature of the metal,….in cases of high humidity, or any moisture intrusion, it will corrode. Any nick or scratch on a brass surface that’s been clear coated will certainly tarnish. Clear coating brass to retain that “ fresh “ look is tricky business,…..brass can turn colors even under clear coat due to a number of environmental reasons, the biggest being UV exposure,….the best brass colored locomotives I’ve seen weren’t clear coated raw brass, but pained a brass color, THEN clear coated over the color for ease of maintenance, ie; hand cleaning. …..hope that helps ….

Pat

(Answering harmonyards) It is what I suspected, that there is either 1. a clear coat over shiny brass or 2. some sort of brass paint. This bears out in my engines, which while similar in appearance, look as if they may belong in two classes. Do you know any more about what kind of brass paint is used, and where I might get it? I assume it is sprayed on. This is one way a deteriorating model with just a clear coat, or nothing, could be rejuvenated in appearance. Better yet, maybe there are people out there that have actually done this and know all about it. While I don't need there services at this time, I would like to know about them.

Hi Jack!   I did go back and re read your post.  I was under the impression that you had intentions of painting the model.   My bad!   Like what has been posted,  trying to retain that "new brass" look is going to be hard.    Uncoated brass can be cleaned up with the likes of Tarn X, but will eventually discolor again.   Even overcoating with a clear coat lacquer will not stop the brass from tarnishing again.    If the look is not bothering to you, I'd perhaps just let be.   Sorry I can't be more help.

@Jack Simpson Jr posted:

(Answering harmonyards) It is what I suspected, that there is either 1. a clear coat over shiny brass or 2. some sort of brass paint. This bears out in my engines, which while similar in appearance, look as if they may belong in two classes. Do you know any more about what kind of brass paint is used, and where I might get it? I assume it is sprayed on. This is one way a deteriorating model with just a clear coat, or nothing, could be rejuvenated in appearance. Better yet, maybe there are people out there that have actually done this and know all about it. While I don't need there services at this time, I would like to know about them.

In all my years of painting brass steam locomotives, I’ve never had a request to paint one a brass color, or to clear coat a bare brass engine,……you will either have to pick an off the shelf gold color that might satisfy you, or go to a specialty paint shop ( like an automotive body shop supply store) and ask about having a color custom made. ….some shops can package colors in aerosol cans ……I’ve never personally done this, but I’m certain I can make a close to brass color and spray your locomotive if desired,……but just simply clear coating over brass, as mentioned by a few of us on this thread will result in tarnishing under the clear, …..as there is environmental issues that would affect the brass, ….UV, etc., etc.,

Pat

Good questions Jack, my take on them as follows -

• Places where someone must have touched these models in the past can show corrosion - sometimes even a noticeable fingerprint…… Can this process be arrested?

Yes and no, skin acids over years can dissolve the clear coats most factory brass is treated with prior to shipping, virtually any clear coat degrades over time regardless and skin born acids are often pretty sturdy chemically albeit slow acting. The process can be slowed down if you see it before it exposes the brass surface though if you’re seeing green oxidation, likely too late. Briefly applying,brushing a diluted alkali or soda then wiping off can arrest the effect but will not reverse any discolorations off the corroded metal albeit it will change the color itself from green to brownish or darker or a clearly different pitch of the brass base color. If the metal itself is  corroded to the point of the surface is etched, which can happen, you’re usually in strip and re-coat territory, likewise poorly cleaned soldiered joints can develop corrosion from the flux residue over time as well. Severe examples like that usually require bead blasting too.

• Some with the shinier brass finish (perhaps just clear coated?) appear as if they may be slowly darkening with age. Do people sometimes spray or wipe on something to arrest this process? Perhaps something that would neutralize any acid (maybe traces of salt spray if you live near the ocean) to halt this darkening process.

Periodically wiping down the car body with a clean, soft cloth might slow that process down but, but really as clear coats age they often “yellow or tan up” which on brass can look darker, handling unpainted factory brass car bodies with latex gloves is always a good idea too especially if you’re looking to resell as factory new.

• It would seem that a somewhat corroded engine could be brought back by dipping in some bath and then recoating the brass. Maybe such a process could require a prohibitive amount of labor and prep, as well as reassembling everything later. I’m just curious if that is ever done.

That does get done occasionally, not that hard to do with original factory pieces, a prohibitive amount of labor is a relative thing where potentially stupidly high sale prices are in play but my experience it rarely restores the piece's color to new.

• Anything else anyone knows about long term preservation and/or repair of the appearance of unpainted brass engines.

Though I’ve successfully painted clear coated engines from the factory (mostly Korean) without dipping and priming, I’ve never been able to truly bring back that gold luster from the original factory after dipping off or fiddling with fingerprint discoloration. In my experience, it’s mostly a fool’s errand. I would like to hear other opinions about any of this as I am actively buying and reselling on top of custom painting.

I thank everyone for their answers. It's good to hear about other experiences. I'm not sure I have much actionable information and am not sure that much such exists. I want to leave this out here in case someone who actually has done brass restoration might see it and give some more specific answers, or perhaps even offer services. Either would be good to hear.

I'm displaying locos I get in brass cabinets built by Mastercraft company in the 70s for use in department stores. They are definitely brass with some kind of clear coat. These have been around since the '70s, handled and touched by many (I remember admiring them in department stores back then, running my hand along the finish, etc.) While handled and touched, they did not take the beating a brass doorknob would. They are somewhat of a commodity at internet furniture auction houses now and all have a great finish unless they have met with some sort of a collision making them unsellable. Maybe their grade of brass is different than what is used for engines? (It is a sheet brass over some dense composite substrate - they are not solid brass - that would really expensive and probably too heavy to use as furniture). On the other hand, I've had experience with high-end brass hardware, specifically doorknobs. In the end, they get messed up due to being grabbed by hands wearing rings - that scratch through the finish so that eventually I've seen deterioration where the other metal hit them, but the finish does stay where fingertips, but not rings, touched them. My doorknob experience only stretches over 10 years, however.

Not sure how the engines are finished, or if perhaps the type of brass (mix of metals in the alloy, etc.) used is different for some reason.