Remove Chrome Plating
Chrome plating is process by which a thin layer of chromium is applied to a metal surface through electroplating (usually on top of a layer of nickel). The ultra-shiny results are decorative, corrosion and tarnish resistant, and very durable. However, chrome plating is routinely removed for many reasons. For instance, despite the durability of chrome plating, it can be damaged through wear and tear and become unsightly, requiring removal. A variety of options are available for removing chrome, some of which use common everyday materials and others which use highly toxic chemical solutions - whichever method you choose, use all necessary caution and observe relevant safety protocols.
Contents
Steps
Removing Chrome with Specialized Machinery
- Use an abrasive blaster. Abrasive blasting (e.g., sand blasting, bead blasting, etc.) is a process by which materials are abraded with a spray of fine-grain powder or tiny pellets. Often, auto body shops and construction companies will have access to such devices. Prolonged abrasive blasting can remove an object's chrome finish, though touch-up work may need to be done on the object's hard-to-reach areas afterwords.
- You may want to use a relatively fine-grain medium (for instance, 400-grit sand) when blasting your chrome to prevent damage to the underlying metal.
- Note that the airborne dust and sediment produced by chipping off tiny pieces of chrome while using an abrasive blaster can be toxic, so use appropriate face/mouth protection.
- Use an ultrasonic cleaner. Ultrasonic cleaners are special devices that use sound waves to clean delicate, difficult-to-clean items like jewelry. Ultrasonic cleaners can even remove chrome in some situations (especially when the chrome has already been loosened with another method). Place chrome items in the ultrasonic cleaner's basket and submerge them in a cleaning solution (often ordinary water), then allow the cleaner to run according to its instructions.
- Using a solvent that can dissolve chrome (for instance, bleach, as noted above) rather than water can enhance the chrome-removing power of an ultrasonic cleaner. However, only do so if the solution you use will not corrode the cleaner or otherwise react with it in any way. For instance, as noted below, lye will react with aluminum containers.
- Note that, while ultrasound machines come in a variety of sizes, most will only hold relatively small items, such as jewelry, lug-nuts, tools, ornaments, etc.
Removing Chrome with Chemical Solutions
- Use hydrochloric acid (muriatic acid). Hydrochloric, or muriatic, acid, is a strong, corrosive acid. In high concentrations, it can be used to remove chrome plating from metal objects. For removing chrome, an acid solution of about 30-40% concentration should suffice. Proceed as below:
- Mix 1/3 part hydrochloric acid to 1 part water in a vat used for chemical mixtures (like a heavy-duty plastic bucket, etc.) to produce a 30% acid solution. Alternatively, purchase a pre-mixed acid solution of sufficient concentration.
- Submerge the chrome-plated object in the solution until chrome strips off.
- Wash the object thoroughly in soap and water, and rinse before drying.
- Use sodium hydroxide (lye) to strip chrome from ferrous metals and carbon steel. Sodium hydroxide, commonly called lye, is a caustic, highly basic chemical. It can dissolve several types of metal plating, including chrome, but reacts dangerously with water and aluminum, corroding the aluminum itself and producing flammable hydrogen gas. Thus, it should only be used on items that do not use aluminum as a base material. Proceed as below:
- Mix 8 to 12 fl ounces (about 227 ml to 355 ml) of sodium hydroxide with 1 gallon (3.785 L) of water in a vat made of neutral material (like a heavy-duty plastic bucket).
- Soak the chrome-plated object in solution until chrome comes off. This may take a fairly long time, so frequently check on your item's progress.
- Wash the object thoroughly in soap and water, and rinse before drying.
- Perform a reverse electroplating. Chrome is affixed to metal through the process of electroplating, in which electric current is used to bind chrome to the metal at a molecular level. By reversing this process, chrome plating can be removed extremely effectively. However, doing so can be extremely dangerous. Not only does the process involve a live electric current, but also produces several toxic, carcinogenic chemicals as products of the reaction. Hexavalent chromium, for instance, is one extremely dangerous product. Thus, this process is best left to professionals - the steps below are for informative purposes only.
- Mix chromic acid and sulfuric acid in water in an approximately 100:1 ratio. For example, you may add 33 oz. (936 grams) of chromic acid crystals and .33 oz. (9.36 milliliter) of sulfuric acid fluid to distilled water to make 1 gallon (3.79 liter). Mix solution in a proper immersion tank used for electroplating, materials testing, and/or chemical treatments.
- Heat the solution. Keep the temperature of the solution from 95 to 115 degrees Fahrenheit (35 to 46 degrees Celsius) for decorative chrome. Keep temperature from 120 to 150 degrees Fahrenheit (49 to 66 degrees Celsius) for hard chrome.
- Run a negative charge from a DC power source through the chromic plating solution via wire.
- Attach the positive cathode to object intended for stripping and submerge the object into the solution. The positively charged exterior chrome metal will be pulled from the object.
- Rinse object in agitating running water, then rinse again. Have waste products professionally processed and disposed of.
Removing Fake or Light Chrome with Household Materials
- Use a homemade abrasive to remove especially thin or weak chrome. One of the simplest, most beginner-friendly ways to remove chrome is via simple mechanical action - i.e., scrubbing with an abrasive. Mix baking soda or a solid household cleanser with water to make an abrasive paste that can be rubbed onto the chrome with a soft cloth until the chrome begins to give way. This method may work best with especially thin, weak chrome plating or with "fake" chrome plating (for example, plastic painted with a fake "chrome" material). Even in these cases, considerable elbow grease may be required.
- Check your progress frequently as you scrub. Scrubbing for too long may scratch the underlying material.
- Use oven cleaner. Some types of chrome (especially fake plastic variants like you may find on model cars, etc.) can be removed with commercial-grade oven cleaners. These powerful de-greasing solutions usually come in an aerosol can as a foam or liquid spray. Give your chrome part a generous coating of cleaner, then allow it to sit for 10 minutes. Wipe the chrome off along with the spray-cleaner.
- Note that some oven spray-cleaner may darken any underlying metal if left to sit too long, so you may want to apply the process repeatedly in short increments until you have the result you want.
- Soak the chromed item in household bleach. Another favorite method of model car enthusiasts for removing chrome is the use of a bleach bath. In this method, chromed parts are simply submerged bleach and left to sit. After about a day, depending on its thickness, the chrome should be loosened if not stripped entirely.
- The primary benefit of this method compared to the others is that bleach should leave any primer below the outer chrome layer intact.
- After using bleach to remove chrome, it should be properly disposed of and never re-used (for laundry, etc.)
- Use brake fluid to remove chrome plating. Standard automotive brake fluid works like paint thinner to remove chrome layers from plastic objects. However, this method can take several days to work. Additionally, it requires the proper handling and disposal of the brake fluid, which is toxic. Rub the chrome object with brake fluid and let it set about 10 minutes before rinsing it off. Repeat as needed to completely strip the chrome.
- Note that brake fluid can dissolve plastic, so be very cautious when using this method on chromed plastic parts (or opt for another method).
Tips
- Familiarize yourself with nature of the substrata or metal that has been chromed, so you avoid damage to that metal.
Warnings
- Using household products is not without safety risks to eyes, skin, and respiration; be sure to wear safety equipment and have first aid/emergency plans at hand.
- Hydrochloric acid, sodium hydrochloride, and sulfuric acid are particularly volatile, toxic, and even carcinogenic; reduce risks by wearing safety equipment and having first aid/emergency plans at hand.
Things You'll Need
- Baking soda or household cleanser
- Rags
- Oven spray-cleaner
- Popular brand of cola
- Hydrochloric acid
- Electroplating system with power source
- Sodium hydrochloride
- Chemical mixing vat
- Safety equipment, including: goggles, acid resistant apron and gloves, and respiration mask.
