How to Anodize Aluminium
Anodizing aluminum, often spelled "aluminium" outside the U.S., is a quality way of metal finishing and coloring. Aluminum parts are used for various purposes and are found in cars, motorcycles, bicycles, cooking utensils and construction elements like windows and doors. If you want to color an aluminum part or give it a strong, durable and attractive finish, consider anodizing it. Unlike regular metal paint, a finish made by aluminum anodization can't be peeled off and is very hard to scratch.
Things You'll Need
- Sulfuric acid
- Rubber bucket
- 12-volt battery charger
- Brush and cloth
- Liquid soap
- Nitric acid
- Distilled water
- Fabric dye
Instructions
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1
Prepare the solution for the anodizing process. Mix 7 parts of acid with 3 parts of water in a rubber bucket. Choose the amount according to the size of the aluminum part: the solution should be deep enough to cover it whole. Charge the solution with a 12-volt charger by putting both of its ends into the liquid.
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2
Clean the aluminum part you want to anodize thoroughly. Use a soft yet thick brush, liquid soap and warm distilled water to remove any dirt or grease. Dry the aluminum part with a clean cloth to complete the first stage of cleaning.
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3
Clean the aluminum part again, this time using nitric acid. Mix 2 oz. of nitric acid with 1 gallon of distilled water. Pour the solution into a deep plastic bowl and soak the part for at least half an hour.
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4
Rinse the part with distilled water and remove all traces of the cleaning solution.
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5
Put the aluminum part into the anodizing acid solution you made. Ensure that the whole surface of the metal is covered with liquid and that the negative ground of the battery charger doesn't touch the aluminum.
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6
Heat the acid solution to 70 degrees F with the aluminum part soaking in it. Leave the solution for at least an hour.
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7
Rinse the anodized aluminum part with boiling or distilled water. This will stop the oxidation process. If you want to dye the part, proceed with the next step.
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8
Prepare a dye solution by mixing 2 parts water with 1 part fabric dye of your choice. Heat the solution to a temperature of 90 degrees F and then place the aluminum part inside. Use your power supply or battery charger to heat the solution.
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9
Leave the anodized aluminum part in the dye solution for 30 minutes, while you increase the temperature slowly until it reaches 140 degrees.
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10
Rinse the dyed anodized aluminum part with boiling or distilled water and place it in an oven to dry. Set the oven to its lowest heat setting, around 110 degrees F for most ovens. Note that the temperature in the oven has to be only warm enough so that the dye sets gradually.
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Tips & Warnings
It is recommendable to work outside rather than in a closed space.
For the acid solution you can use sulfuric acid.
Do not work near flammable materials or a source of ignition.
Make the area you work in ventilated and try not to breathe in the solution and its components.
Working with chemicals is always a dangerous job, so wear disposable rubber gloves, a protective mask and safety plastic goggles at all times.
References
- Photo Credit aluminium image by pncphotos from Fotolia.com
