Metal coloring can be done in a number of different ways, depending on the type of metal and the result you want to achieve. You can make metal items look like new by applying a new coat or paint, creating an antique patina look, or changing the color by anodizing the metal. The appearance of the finished metallic finish will affect the price significantly. So, choose the method that best suits the project you are working on.
Step
Method 1 of 4: Coloring Metal with Spray Paint
Step 1. Clean the attached fungus
Start by soaking the metal in bleach to kill mold and remove discoloration. Make a solution of a mixture of water and bleach in a 3:1 ratio. Soak the metal in the solution for about 20 minutes. Rinse the metal with water when finished. If the item is new or mildew-free, you can continue the process without soaking it in a bleach solution.
Step 2. Remove rust
Roughen the surface of the object with a wire brush. You can also use an electric sander with coarse sandpaper, an electric drill, or a rotary tool to remove dust. Choose sandpaper with a grit level between 36 and 100 to remove rust and produce a smooth surface.
- Wear eye protection and a dust mask to prevent metal debris from getting into the eyes or being inhaled. Wear protective gloves to prevent injury.
- For large items, you can remove dust, dirt, and old paint with a commercial rust remover product.
Step 3. Clean metal objects with mineral spirit
Mineral spirit is a kind of turpentine-free paint thinner. Wipe the metal clean with a cloth dampened with mineral spirit. Remove any remaining dust and dirt from the sanding process. Make sure the surface is completely clean and dry so that the primer adheres firmly to the object.
- Keep in mind that mineral spirit will peel off any new paint that has stuck to it.
- Also remember that mineral spirit only peels off fresh paint. If you want to clean the paint marks that can't fade with mineral spirit, use turpentine.
Step 4. Apply a coat of primer
Spray the primer on the metal surface until it is smooth and even. You should coat the metal with a primer after sanding as soon as possible to prevent dirt and rust from forming on the surface again. Choose a primer that is made specifically for the type of metal you want to paint.
- Choose a spray primer that matches the paint you want to use, if you can.
- Buy a primer from the same brand as the paint you're using because it will likely be more similar and chemically compatible.
- Buy a primer that is resistant to rust.
- Applying primer with a paint brush without leaving streaks is very difficult. Use a spray primer for best results
- Read the product instructions for use to find out when the primer dries.
Step 5. Make an even coat of paint
Make sure you shake the can first. Hold the nozzle and coat the desired area. Use duct tape or painting tape to cover areas you don't want to paint. Hold the paint can about 30 cm from the object. Start spraying paint from the side of the object and continue moving the paint can around the metal object without stopping. Let the paint dry.
- Master your work environment. If you're painting a small object, place it in a cardboard box while painting.
- If you stop spraying paint, some of the paint will clump together. Use a rag to wipe off the wet paint before it dries. Allow any remaining paint to dry before starting over.
- Galvanized metal has a thin layer of zinc chromate. The main reason paint peels off and doesn't stick to the galvanized metal is that it sticks to the zinc coating or residue on the surface, instead of sticking directly to the metal surface. If you're painting galvanized metal, look for a paint that doesn't contain alkyds, as these oil-based binders can react with the zinc coating.
Step 6. Create a second coat of paint
After the first coat of paint has dried, you will need to apply a second coat of paint on the surface of the object. The addition of a second coat of paint will extend the life of the paint. Let the paint dry.
For best results, wait 24 hours before applying a new coat of paint
Method 2 of 4: Anodizing the Metal
Step 1. Understand the anodizing process
The anodizing process changes the surface of metal objects to the oxide form. Aluminum oxide that has gone through the anodizing process is very strong and resistant to corrosion. It is also more porous than ordinary aluminum so it can absorb a wide variety of metal dyes.
- The conversion process uses an electric current and a strong acid solution. Metal that goes through the anodizing process will be connected to an electrical circuit and soaked with acid to act as the anode (positive electrode). The negative hydroxide ions in the acid are attracted to the positive anode and react with the aluminum to form aluminum oxide.
- A piece of aluminum is also placed in the acid and connected to another wire. This object serves as a cathode (negative electrode) to complete the attached circuit.
- Aluminum is the most common metal of choice for this method, but nonferrous metals such as magnesium and titanium can also be used.
Step 2. Gather materials
Start by finding a space where you can work without potentially causing damage. You can collect the required items individually or purchase a commercial anodizing kit that includes all the tools needed.
- Select the metal to be used. Any type of aluminum or aluminum alloy can be anodized. Other types of metal, such as steel, cannot be used.
- You will need three plastic tubes. Each tube must be large enough to hold a metal object. One will be used for the cleaning process, one for the acid container, and one for the dye container. Large plastic buckets can be used for this purpose.
- Prepare a plastic jug to hold the neutralizing liquid.
- As a reagent, you will need sulfuric acid, baking soda, lye, metallic fiber dye, and distilled water.
- Find an adequate power source. You should look for a power source that is capable of consistently producing a current of at least 20 volts. Car batteries are ideal for this purpose.
- Prepare two power cables to connect to the car battery and the acid solution. This cable must be strong enough to clamp and lift metal objects in and out of the acid liquid.
- You will also need another piece of aluminum to serve as the cathode in the acid solution.
- Prepare a large pot and stove to boil metal objects.
- Wear large rubber gloves. As this is associated with harsh chemicals, you must work safely and avoid direct skin contact at all times.
Step 3. Prepare a neutralizing solution
The neutralizing solution uses baking soda as an alkaline base to neutralize the pH level of the sulfuric acid. You should prepare a neutralizing solution just in case and for cleaning equipment. If you have acid on your skin, use this solution to neutralize it, as water can actually make the wound worse.
Add 392 ml of baking soda to 3.8 liters of distilled water
Step 4. Prepare the metal
You can use any type of aluminum alloy to anodize with this process. Put on rubber gloves before cleaning metal. Any smudges, even fingerprint marks, left on the surface of the object can affect the work result.
- Clean the object with water and dishwashing detergent.
- Mix water and lye. Mix 3 tablespoons of lye with 3.7 liters of water. Wear rubber gloves to immerse the object in the solution for 3 minutes.
- Rinse the object with distilled water. If the water doesn't drip, the aluminum is clean.
Step 5. Prepare a sulfuric acid solution
Mix sulfuric acid with distilled water in a plastic container in a 1:5 ratio.
- Do not use fragile containers such as glass.
- Add the acid before the water to prevent the solution from overflowing. Adding water after the acid can cause the liquid to overflow out of the container.
Step 6. Set the electric power according to the positive and negative energy poles
While the power position is still off, connect one wire to the positive pole and one wire to the negative pole.
- Connect the other end of the negative wire to a metal object and immerse it in a container of acid solution.
- Connect the other end of the positive wire to the aluminum strip and soak it in the acid solution without touching the metal object.
- Turn on the power. The voltage used depends on the surface area of the metal used. Check the power. Start at a low power, about 2 amperes, then increase the voltage to 10-12 amperes after a few minutes.
- Anodizing aluminum for 60 minutes. Negatively charged aluminum will attract positively charged sulfuric acid. There will be a fair amount of bubbles around the aluminum scrap, but there are only a few bubbles in the metal that goes through the anodizing process.
Step 7. Remove the metal pieces and rinse with water
Be careful not to let the acidic liquid drip onto the surface. You may need to hold the container that holds the neutralizing solution under the metal when transferring it to the sink. Soak the metal in water for a few minutes while turning it occasionally to clean each side.
Step 8. Prepare the dye
Prepare a solution of fiber dye and distilled water in several containers to get the desired color in separate containers. Follow the instructions on the packaging of the dye you purchased.
Step 9. Soak the metal object in the dye for 20 minutes
Depending on the color you want, you may only need to soak it for a minute or two. You can also heat the dye to speed up the process. At first, you'll have a hard time getting accurate colors. So, be prepared to experiment several times with other objects whose material is the same as the object you want to color.
The dye can be used multiple times. If you want, you can store it in a plastic container after finishing the painting process
Step 10. Boil the object with water for 30 minutes to seal the color
Heat water in a saucepan. After that, submerge the object into boiling water. This process will seal in the dye, but it will also allow the color to fade a bit. This is why you should first test it with another object, at least once.
Step 11. Let the object cool down
Remove the object from the hot water. Place on a towel for a few minutes to cool. Once the object has cooled completely, the metal will have a new permanent color.
Step 12. Clean all utensils and containers with baking soda and neutralizing solution
Rinse everything off and make sure that no acid remains on anything that comes into direct contact during this process.
Method 3 of 4: Making a Patina
Step 1. Make the patina mixture
There are a variety of "recipes" for making different patina. Patina changes color by creating a chemical reaction with the metal to create a colored coating on the surface of the object. You can apply a patina to any copper or bronze for an antique color and look similar to the green on the Statue of Liberty in the United States. Depending on the material, you can either look up a patina recipe to make the color you want or buy a ready-made product.
- To make a green patina verdigris, mix apple cider vinegar and salt in a 3:1 ratio.
- For a black patina, mix liver sulfur (potassium sulfate) with warm water.
- Some patina recipes require you to heat the metal before applying the patina so you will need to purchase a gas torch to heat the metal.
Step 2. Fill the container with the patina mixture
You can use a regular paint bucket to cool the mixture, but you should use a large metal pan if the patina mixture needs to be heated. The bucket must be large enough to immerse the object in the solution. The patina mixture needs to be heated or cooled. So, use a suitable container and can withstand the temperature of your recipe.
- Some chemicals give off toxic fumes. Work in a well-ventilated area.
- If you are coloring an object that is too large to fit in a container, you can put the patina solution in a spray bottle and spray it onto the metal surface. You can also wet a washcloth with this solution and rub it into the metal or use a paint brush to apply it. Make sure you wear rubber gloves when working with harsh chemicals to avoid contact.
Step 3. Soak the object in the mixture
Put on rubber gloves and place a metal object in the patina-filled container. Depending on the recipe, you may need to let it sit for a few minutes to a few hours. Set an alarm and wait.
Step 4. Remove the metal
Check the object after the time is up. If you want a more intense color, soak the metal longer. Put on rubber gloves and remove the metal once you get the look you want.
Step 5. Let the metal dry completely
The patina will continue to change during the drying process. So be patient. If you want to color the same object again, put it back in the patina mixture and repeat the process.
Step 6. Coat the metal with varnish
Use a sprayed clear acrylic varnish to protect the surface of the object and prevent discoloration.
Method 4 of 4: Heat Coloring Metal
Step 1. Clean the metal
Remove all dust, dirt and fingerprints from metal before starting work. Wash metal with soap and water. Let the metal submerge in the degreasing liquid. Place on a clean surface to dry.
- Do not handle metal with your hands after cleaning. The oil from your fingers can affect the formation of the color.
- Heat can impart additional color to metal unexpectedly based on temperature, humidity, time, and metal composition.
Step 2. Turn on the heat source
You can use this method on any metal that contains copper or iron, such as steel. A small, more focused flame, such as a Bunsen torch, will provide a more dramatic color variation. Open fire will produce a lighter color variant. Depending on the temperature the metal reaches when heated, you can create colors ranging from pale yellow to blue.
- Use tongs, wrenches, or similar tools to clamp metal and prevent direct contact with metal heated by fire.
- If you have an oven, you can also heat the metal with it for a more even color.
Step 3. Heat the metal with fire
There is no way to control pattern or color formation. You can more or less adjust the coloring based on the heating time only. A heated object will have a different color when it cools down. For example, red when heated will produce a bluish-purple color after cooling.
- Make sure you only heat the metal in a well-ventilated area.
- Be careful not to hurt yourself. Wear protective gloves.
- If the flame used is very fine and the size of the metal object being heated is large enough, you can engrave certain patterns on the metal surface.
Step 4. Let the metal cool
Turn off gas torch or heat source. Place the object in a safe area, such as on a concrete floor to cool it down. You may need to prepare a bucket of cold water to dip the object to cool faster.
Step 5. Coat the metal with varnish or wax
When you heat jewelry or art, you may need to apply a protective layer to secure it and give it a shiny look. Once the metal has cooled, apply a coat of beeswax or clear acrylic to protect the color and surface of the object. Let the surface dry.
Tips
- Apply a second coat of primer if the first coat is uneven or uneven.
- Paint the metal in a dry and warm (not hot) well-ventilated area.
Warning
- Working with sulfuric acid carries a high risk; follow safety instructions and have good safety protocols in place.
- Make sure you wear safety equipment when handling all chemicals, as well as when sanding and coloring metal.
