Pontiac renovations, part 4.

I decided that although the silvered paint had significantly improved the reflector, the prep I had done was not great (it was more a “let’s try this out and see” action) so it wouldn’t last, and plus, the reflector when viewed through the lens appeared very gray. Aesthetically I found this displeasing and figured I could improve matters.

I decided I would attempt to plate the reflector with a shiny metal surface. I did a bit of research and determined that nickel plating should work quite well. In order to plate nickel onto steel, it is advised first to plate with copper. This is because nickel is chemically different enough from iron not to want to adhere to, so a go-between, copper, which will stick to iron and nickel is used as a substrate.

Note that the chemicals used in this process are poisonous (copper) and toxic (nickel). If you follow this, work outside in a well ventilated area and wear gloves and safety glasses. Also wash your hands thoroughly with plenty of soap and water if you get any of it on your skin. Store the electrolyte in well-marked containers, and keep away from children (ooh, pretty colors!) and pets. 

I bought some acetic acid (vinegar), hydrogen peroxide, a source of pure copper (scrubbing pads), a source of pure nickel (welding rods), a glass dish and made a power supply from an old ATX computer PSU.

Making copper electrolyte.

To begin,I added a 50/50 mix of vinegar and peroxide to the dish and placed a copper scrubbing pad into the mixture. It began to dissolve, creating the electrolyte, copper (II) acetate.

Copper electrolyte.

Then to make the nickel electrolyte, made in a similar fashion- 100% vinegar with a pinch of sodium chloride (table salt) to boost the conductivity. Nickel does not dissolve by itself in acetic acid, the molar strength is not high enough. It is instead made by “helping” it by passing an electric current between two nickel electrodes.

Fizz.

After a couple of hours a modest amount of nickel had dissolved into the acid. 

Nickel acetate.

I plated a piece of bar steel with copper, then plated it with nickel. Positive to the source of metal, negative to the piece to be plated.

Nickel plating.

Although probably a little “fast”, I used 12 Volts across the nickel, which yielded good results. The copper required much lower voltage and current to plate well. The slower the process,the better quality the finish.

High gloss result.

I was pleased with the results on the test piece, so set about taking the turn signal assembly apart.

Turn signal removed.

Thankfully in good shape underneath, this area has been subject to some repairs in the past. 

Reflector and housing.

The lamp broke down into further pieces. You can see the silver painted surface of the reflector. It previously looked the same as the housing. Someone had painted it black, and then it had rusted.

Ascorbic acid bath.

I set the steel pieces into an ascorbic acid (vitamin C) bath and left them overnight for the acid to work on the oxides. As advertised, vitamin C is a powerful anti-oxidant.

12 hours’ soak.

After half a day soaking, I pulled the pieces out and scrubbed the loose oxides off with a wire brush and left them to soak again.

Dirty solution.

I probably should have left the steel in the ascorbic acid longer but I decides that the metal was very pitted from the rust and I could clean it by running current “backwards” in a bath of vinegar, which draws the surface of the steel away to the cathode, leaving it clean.

Acid bath 2 complete
Galvanic cleaning.

Using a random piece of steel rod I had laying around, I ran the reflector at 12 Volts in vinegar with a little salt.

Pitted but clean.

I then used a couple of grit wheels in my Dremel to attempt to smooth the surface of the reflector a little.

Not perfect, but better.

This improved the reflector significantly- after all the plated surface will follow every contour the metal has. The more smooth the surface, the better the appearance of the plating. I put the reflector in the copper plating bath and set it on at 3.3 Volts.

Badly plated copper.

Due to the surface area of the reflector, the current passed on the first run was too high- seen here with burgundy deposits. The copper plates too fast, forms large flaky layers that do not adhere to the base metal. Also, the impurities in the steel precipitate into the electrolyte and stick to the surface, giving poor, patchy plating. Constantly moving the object to be plated alleviates this.

Copper plating again.

Tried again but with some resistance in line to reduce the current.

Nickel plating.

With a good adhesion from the copper on the second try, I then set about plating the reflector with nickel. Nickel electrolyte produces quite a lot of gas and self-cleans its surface whilst plating.

Shiny.

Although not an ideal candidate, the reflector was significantly improved.

Illuminate!

With only the parking light (5 Watts), the light thrown forwards is quite significant. A good result, in any case.

Painted the back black.

I painted the rear sides of the reflector and housing gloss black, as they would have been when new.

Reassembled and refitted to the car.

I also plated the housing, as it is visible through the lens. Previously it looked a bit out of place, black against the gray of the reflector.

Evenly lit now, compared to the other side, which really only glows where the bulb is (as this one was before I began). More visible, which is good as the lights are low down and the turn signals are the wrong color by today’s expectations (white, not orange).

Light off.

Finally, with the light off and the sunshine hitting the lens, it looks a lot more even and matches the headlight a lot better. Just the other side to do now!

Leave a Reply