After decades of hard play, the shiny tin plating on old electric train parts can wear off, leaving a dull surface that doesn’t look great, and is prone to rust. You can get plating kits so you can replate the parts, but the kits are expensive and can involve chemicals you don’t necessarily want to keep laying around. Here is an inexpensive alternative to replating that you can do at home to restore old tin parts.
Restore worn tin plating with Oatey No. 95 paste flux
The secret is a product called Oatey number 95 paste flux. This is a product intended for plumbing that helps make soldering copper pipe faster and easier. But it just happens that the coating is 95% tin. The remaining five percent is a mixture of zinc and bismuth.
When you heat the paste flux to around 400°, it deposits itself onto the metal surface below it. And the paste flux costs about $4.
Here’s how to use it.
Choosing a part
I chose a wheel for my first project and I don’t recommend that. Learn the technique on parts with a flatter surface, like couplers, first. Then try your hand at parts with more complex, curved surfaces like domes and wheels.
Preparation
The catch with the stuff is that prep work is everything. Of course, true electroplating also requires a lot of prep work. The first thing you need to do is ensure that the part is clean and free of rust or contaminants. I swab it down with mineral spirits, and then sand it with fine sandpaper. 200 or even 400 grit seems to work reasonably well. Some people soak the part in acid for a few minutes.
Then you need to heat the surface. Some people use a butane torch. I prefer to use a 200 watt Weller soldering gun. I find a soldering gun easier to control than an open flame.
Heat up the part, and then apply some of the paste flux to the hot surface with a popsicle stick or a flux brush. Keep the heat moving until you cover the entire part. You can tell when it’s working when the surface takes on a shiny appearance.
Let the part cool thoroughly, then clean off the remaining residue. You can use mineral spirits or rubbing alcohol for this. Spray it down with the solvent, then mop up the slurry with a paper towel. This ensures any remaining acid in the flux ends up on the towel rather than staying on the part where it can corrode.
After you clean up the slurry of solvent and flux, you will want to polish the surface. You’ll never bring it to a mirror finish, but you can polish out impurities on the surface and get it to look a little bit nicer.
Don’t expect the part to look new, but it is a step better than painting, and it does refurbish a vintage part, which is nice. It’s always nice to be able to keep a vintage part in service rather than replace it with a modern reproduction part.
David Farquhar is a computer security professional, entrepreneur, and author. He started his career as a part-time computer technician in 1994, worked his way up to system administrator by 1997, and has specialized in vulnerability management since 2013. He invests in real estate on the side and his hobbies include O gauge trains, baseball cards, and retro computers and video games. A University of Missouri graduate, he holds CISSP and Security+ certifications. He lives in St. Louis with his family.