How to Set Up Chrome Plating
Chrome plating is a popular finishing treatment for the metal trim on cars. Deposits of chromium coat the metal, giving the surface a mirror-like finish that covers and restores any wear or damage to the car's frame. Usually, chrome plating is done by professionals, because setting up chrome plating is an expensive and hazardous process. Chrome plating must be bathed in a solution of highly-concentrated chromic acid. If you do set up your own chrome plating system, handle all hazardous materials with care, and abide by all laws and regulations on the safe disposal of chromic acid.
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Things You'll Need
- Chromic acid crystals
- Sulfuric acid fluid
- Water
- One-gallon steel containers
- Electric heater
- Electric fish tank air pump
- Copper wire
- DC ammeter
- Acid-lead batteries
- Lead anodes
- DC power supply
- Hydrochloric acid
- Sodium hydroxide
- Buffing cloth
- Lubricated greaseless silica compound
- Rubber gloves
Instructions
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1
Prepare the chromic acid bath by making a solution of chromic acid and sulfuric acid in water. Use a ratio of 100 to 1 for the proportion of chromic to sulfuric acid. To make one gallon, use 33 ounces of chromic acid crystals, 0.33 ounces of sulfuric acid fluid and one gallon of water. Always add the acid to the water, not the other way around. Wear rubber gloves throughout the process for safety.
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2
Set up the electric heater and the electric fish tank air pump in the acid bath solution. The heater provides temperature control and should maintain a temperature between 113 and 120 degrees Fahrenheit. The air pump provides the necessary agitation to keep a fresh supply of chromic acid circulating to the parts receiving a chrome plating.
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3
Connect up the DC power supply to the anodes, which will be submerged in the acid bath. Set this up in a well-ventilated area to vent the hydrogen gas produced during this process. Use acid-lead batteries, copper wire and an ammeter to control voltage. This provides the current necessary for the plating process.
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4
Suspend the part to be plated in a solution of sodium hydroxide at room temperature while connected to the negative DC supply terminal. Connect the positive DC terminal to the stainless steel container. Increase the DC current through the bath until gas is produced. Maintain this for one to two minutes. The current should be in the range of 0.1 to 1 amp per square inch. Excessive current will cause burning.
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Rinse the part in clean, cold water, then dip it into a commercially-prepared hydrochloric or sulfuric acid solution for a few minutes. Rinse the part in water again.
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Buff the parts to as high a finish as possible before chroming. Use a buffing cloth and a lubricated greaseless silica compound.
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Dip the part to be plated into the chromic acid solution and turn the power on. How long it should be submerged depends on what kind of metal the part is made from. 400-grade stainless steel takes three minutes, while nitrided steel takes only 15 seconds.
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References
- Photo Credit Chrome bumper image by Dreadman from Fotolia.com
