Galvanizing metal is putting a protective metal coating on it, generally to prevent rust, but also to prevent wear and tear. The most common usage is applying zinc to a steel or iron object. Industrially, the method mostly commonly used is hot dip galvanization, which involves dipping the object in molten zinc. However, do-it-yourself galvanization uses electroplating, which is much simpler and requires very little special equipment.
How to Galvanize Metal
- Zinc mixture
- Power source
- Zinc anode
- Object to galvanize
Always use safety precautions. Make sure you handle all chemical and electrical components with care. To be extra safe, use face/nose protection in case of toxic chemicals being released due to impurities on the object you are plating, or bad chemical reactions. Do not let the anode and cathode touch.
To ensure a proper galvanizing process, you need to thoroughly clean the surface first. It's easier to tell when the galvanization hasn't worked properly than with most coating, as the zinc simply won't properly bond with the steel. In industrial applications, this is done in a three-step process of caustic cleaning, pickling, and flux removal. However, for do-it-yourself applications, thoroughly washing or sanding down the surface should be sufficient. Make sure that you're aware of and accept any impurities on the surface of the metal after this process is finished.
An easy zinc bath can be made with household ingredients. Put the zinc anode into a vinegar bath, which will slightly dissolve it and allow zinc to diffuse into the bath. After leaving this for a while, use salt (100 g/l) to make the bath conductive.
Connect the negative terminal of the power supply (the cathode) to the object you wish to plate; place the anode into the bath and turn on the power supply. This will begin the electroplating process. After this, all you need to do is leave it to plate.
Things You'll Need
- "Modern Electroplating, 4th Edition"; Mordechay Schlesinger PhD and Milan Paunovic PhD (2000)