Brass Loco Corrosion

[NWsteam]

Hi all,

Wow it has been a long time since I posted. I am having some trouble with a brass locomotive I recently acquired. The locomotive is a KEY Imports N&W K-1 4-8-2 that is factory painted. After close examination I found some areas that are gray in color and look fuzzy. I can only assume that this is some type of brass corrosion...curious since this model is factory painting. I do not believe it to be foam rot as both the locomotive and tender are wrapped in plastic and the foam insert is in excellent condition. I have changed the way the locomotive is stored (It is current in a display case) but still need to know how to clean up the mess. The fuzz is found on the lead pilot truck, several screws, and a few other random places. The pilot truck is the worst off. What I want to know is:

1. How and what do I use to clean it?

2. If I clean it and then paint over it, will that seal it or will I be back to square one in a couple of years?

Thanks in advance!

-Brad

[J3a-614]

Hello, Brad,

I have never owned brass, so you may want to take my comments with a dose of salt, but I think you may have foam rot. . .just not from the main packaging in the box.

Based on this listing for a brass Key K-1 that may be similar to your own, a look at the photographs from the front reveals a small foam piece in grey that's used to secure the pilot truck.  This may be the source of the grey fuzz you have.

While the photos do not show materials due to this being a painted model, it doesn't look like you would have zamac or white metal rot. . .there doesn't seem to be any of that material used in this model at all, so you don't have to worry about that.

Hope this helps.

https://brasstrains.com/Classic/Product/Detail/039859/HO-Key-Imports-N-W-Norfolk-Western-4-8-2-K-1-114

Open up the second image on the link (head on shot in the thumbnails under the main image), and blow it up, and you can see the small foam block added to secure the lead truck.

[jonathan]

Brad, you are lucky the damage is just the pilot truck.

If it were me, I would repaint the truck.

I have found a tried and true method is to remove the old paint with a bath of lacquer thinner.

Then, boil the part in a pot with water and a couple tablespoons of baking soda.  This removes any unseen lacquer applied at the factory.  30 minutes should do the trick. This will discolor the brass... anywhere from pink to brown, but the part is now clean.  Since you're painting it the discoloration is not important.

Finally, a bath of vinegar, a couple hours to a day, will etch the brass a bit, so the paint will stick.  Wash with soap and water and let dry on the paint stand for a day or two.

I prime my brass with a common gray primer from Home Depot.  It's good for metal, wood or plastic.

Others have other methods I'm sure.  This works for me.

Oh, don't do this to the truck wheels.  Just wash 'em and decorate as desired.  You don't want to eat off the shiny finish on the wheels.

Regards,

Jonathan

[ryeguyisme]

yup, that's foam damage

I'm an avid brass collector, from what I've been told is to take a q-tip dipped in lacquer thinner and gently swab away at the foam and if you're careful enough you won't hurt the clear coat too much.

Key Imports/Sunset with the Samhongsa red foam packing was always the killer on decent paint jobs due to deterioration. Most novice sellers on auction sites won't even think to wrap engines in plastic to protect them from inevitable the red stains.

[Len]

Something I learned working at an auction house years ago is acid free packing tissue is a better choice than plastic for long term storage of locos. Plastic, and bubble wrap, has a coating that can attack model paint finishes over time.

Len