Maybe you've just finished etching the circuit board in your project and everything looks like a success. But you will also know that the copper traces on the board will slowly turn black and green over time. This article will describe a simple method for tinning copper traces on a circuit board. If you have all the ingredients ready, all the better!

Now that you have your solder, flux, wicks, and flux cleaner ready, you can move on to the next step. If your materials are not complete, I will attach a parts list at the end of this article so you can prepare the relevant materials.

Start by applying solder flux to the bare board - be sure to apply a sufficient amount. Then put some solder on a strip of desoldering tape. Make sure there is enough solder on the desoldering tape as shown in the picture below.

Then put the solder strip on the circuit board. Use a soldering iron to heat the tin strip, and when you see that the solder has melted on the strip, gently "drag" the strip on the trace. Repeat this for all traces. Don't worry if you hit some small copper trace areas while dragging the strip, we'll clean it up in a later step.

The finished effect is shown in the figure below. You can see that the surface of the board is somewhat rough with residual flux on it and some areas that were missed by the desorber tape. The next step is to start cleaning. Again, apply enough flux to the entire board.

Cut off the end of the tinning tape to continue using the remaining clean section. Place the strip on the circuit board traces and heat the strip with a soldering iron. When the solder starts to melt, gently "drag" the strip again. This removes excess solder, if any areas are missed, just drag solder into those areas. This is intended to leave only a thin layer of solder on the board traces. Do this for the entire board and apply some more flux (if needed).

Next clean the board with some flux cleaner and a small cloth. Spray the flux cleaner on the cloth as shown below. While pressing firmly on the board, clean the board in circular motions with a damp cloth dampened with flux cleaner.

Then "polish" the board with a clean dry cloth. Use a little force during this process so that the solder coating will be glossier.