Monday, June 19, 2017

DIY Tin Plating / Electroplating of Copper Bus Bars or Terminals

I was able to tin plate some of the bus bars and connectors for use in my electrical projects. Copper is an excellent conductor, however, copper connections are prone to oxidation and can become high resistance areas in the circuit over time, especially when exposed to the elements. This results in poor performance and possibly failure. Commercial products often use tin plated contacts and connectors to provide corrosion resistance. Tin is a cheap metal that maintains conductivity over time even when exposed to the elements. It covers and protects the copper. Gold plating or silver plating are other options which are more expensive.

Electroplating works by dipping the material to be plated in a solution and running electricity through the solution to move metal to coat the material. To tin plate copper, the positive terminal of the battery is connected to the tin and the negative is connected to the copper. The solution has tin dissolved in it. Sugar is added as a brightener.

Note: Caution must be taken when handling acid and when working with electricity. Wear protective equipment (such as gloves, goggles, respirator, etc. and use care in handling materials. Vapors may be harmful as well so avoid inhaling vapors and only work in an environment with good ventilation.

This is how I did it. Follow at your own risk.

Steps:

Materials: pure tin (ingot or solder), an acid, alligator leads, sugar, a battery, a non-conductive container, and the material to be plated - copper bus bar or connectors.


1. I dissolved some shavings of the tin in muriatic acid (hydrochloric acid). I only used 2 ounces of acid. I let it sit for an hour. It started bubbling immediately. The fumes smelled bad possibly toxic.
2. I added distilled water approx 5 parts to 1 part of the solution from previous step.
3. I Added some sugar to the solution as a brightener. I used about a tablespoon for a 2 cup glass.
4. I Attached the positive terminal of the battery to the tin and placed on one side of a glass container containing the solution. 2 D cell batteries connected is series makes 3 volts.
Positive terminal connected to tin ingot in solution
5. I Placed the copper bus bar into the container (not in contact with the tin). The part that is submerged was to be plated. The copper to be plated has to be perfectly clean - i scrubbed it with a scouring pad and washed with soap and water and avoided handling with my fingers to prevent skin oils.
6. Attached the negative terminal to the copper bus bar using alligator clip leads. Once this was connected, the circuit was complete and electroplating started and noticed bubbles.

7. After a couple of minutes, I removed the copper and rinsed it off. Then removed some scale from the plated area. Then plated the area a second time.


Here is the end result, tin plated bus bars
Links to sources of information:

http://transistor-man.com/electroplating_busbar.html
http://hackaday.com/2012/10/14/diy-tin-plating-for-bus-bars/
http://www.sharrettsplating.com/blog/the-tin-plating-process-a-step-by-step-guide/


No comments:

Post a Comment