Keep in mind that mineral spirits will strip any existing fresh paint. Also remember that mineral spirits will only strip away paint that is still fresh. If you want to remove existing paint that won’t come off with mineral spirits, try cleaning your metal with turpentine instead. [2] X Research source
Choose a spray primer in the same color as the finish when possible. Try to purchase a primer in the same brand as the paint you will buy, as colors are more likely to be better matched and chemically compatible. Purchase primer that is rust resistant. For instance, oxidizing primer helps inhibit the growth of rust in the future. Priming with a paint brush is very difficult to do without leaving streaks. Use a spray primer for best results. Read the directions on the product to determine the necessary time for the primer to dry.
Control your environment. If you are painting a smaller object, you can place it in a cardboard box and apply your paint. If you pause while spraying, you may notice a splotch appear. Use a cloth to wipe away the wet paint immediately before it can dry. Allow the remaining paint to dry before starting again. Galvanized metals have a thin layer of zinc chromate. The biggest reason for paint chipping or not adhering to galvanized metal is that the paint bonds to the zinc coating, or the residue collected on the surface, rather than the metal itself. If you have a piece of galvanized metal, look for a paint that doesn’t contain any alkyds,[3] X Research source as these oil-based binders can react with the zinc coating.
To get the best results, always wait 24 hours between applying coats of paint. [4] X Research source
The conversion process uses an electric current and a strong acid bath. The metal being anodized is connected to a circuit and placed in the acid bath where it acts as an anode (positive electrode). Negative hydroxide ions within the bath are attracted to the positive anode where they react with aluminum to form aluminum oxide. A scrap of aluminum is also placed in the bath, connected to the other wire. This serves as the cathode (negative electrode), completing the circuit. Aluminum is the typical metal of choice for this method, but other non-ferrous (non-iron) metals like magnesium and titanium can also be anodized. [5] X Research source
Select your metal. Any aluminum or aluminum alloy can be anodized. Other types of metal, like steel, won’t work. You will need three plastic tubs. Each tub should be large enough to hold your metal object. One will be used for the cleaning process, one for the acid, and one for the dye bath. Large, plastic paint buckets will work well for most jobs. Get a plastic jug to hold your neutralizing solution. For reagents, you will need sulfuric acid, baking soda, lye, metal fiber dye, and distilled water. Find an adequate power source. You will want a power supply that is capable of producing a consistent flow of electricity up to a minimum of 20 volts. A car battery is ideal. Get two power cables to connect the car battery to the acid solution. They should be strong enough to use to grip and lift the metal object in and out of the solutions. You will also want a spare piece of aluminum to act as the cathode in the solution. Have a large pot and stove to boil the metal object. Always wear a pair of large rubber gloves. Since you are handling strong chemicals you will need to handle your materials safely to avoid contact with your skin at all times.
Add 2 cups (0. 83 pt. ) of baking soda to 1 gallon (3. 79L) of distilled water.
Clean the parts with water and dishwashing detergent. Immerse the parts in a bath of water and lye. Add 3 tablespoons of lye for each gallon of water. Using your rubber gloves, lower the metal object into the solution for about 3 minutes. Rinse the object in distilled water. If the water does not bead, the aluminum is clean.
Do not use a container that is breakable like glass. Always add acid to water so the solution doesn’t fizz. Adding water to acid can cause it to splash up out of the container.
Connect the other end of the negative cable to the metal object and submerge it in a container of sulfuric acid solution. Connect the other end of the positive cable to a scrap piece of aluminum and submerge it into solution without touching the metal object. Turn on the power. The voltage you use will depend on the surface area of the metal you are using. Check the power supply. Start with a low voltage of about 2 amps, then increase the voltage up to 10-12 amps after a few minutes. Anodize aluminum for 60 minutes. Negatively charged aluminum will attract positively charged sulfuric acid. You will notice a lot of bubbles around the piece of scrap metal, but very little bubbling around the metal you are anodizing.
The dye can be reused several times, so if you want you can store the dye in a plastic container after you’ve finished this dyeing session.
For a green verdigris patina, add three parts apple cider vinegar to one part salt. For a black patina, add sulfur of liver (sulfurated potash) to warm water. Some patina recipes will require the metal to be heated before applying the patina, so you may need to purchase a torch to heat the metal.
Some chemicals can give off hazardous fumes. Always use a workspace that is well-ventilated. If you are coloring an object that is too large to put in a container, you can put a patina solution into a spray bottle and spray it all over the metal. You can also wet a rag with the solution and rub it on the metal, or use a paint brush to apply it to the surface. Just be sure to wear rubber gloves when using harsh chemicals to avoid contact.
Do not handle the metal with your hands after cleaning. Even the grease from your fingers can impact the formation of the colors. Heat adds color to metals in a fairly unpredictable way that varies based on temperature, humidity, time, and the composition of the metal. [6] X Research source
Use some tongs or a wrench or similar tool to grip the metal to avoid contacting the heated metal after exposing it to the flame. If you have an oven you can also heat the metal that way to provide a more even coloration.
Be sure to heat metal only in a well-ventilated area. Use caution not to burn yourself. Wear some work gloves. If your flame is fine and your metal piece large enough, you can trace patterns onto your metal.
