Frequently Asked Questions (FAQ)
Short, practical answers about chemical blackening, electroplating, electrolytes, electroforming, patina and sealers. Tailored to the products of Verzinkshop.
Terms Explained
What is an electrolyte?
An electrolyte is a liquid that is electrically conductive thanks to dissolved metal salts or acids. Under the influence of a direct current, the positive metal ions move to the negatively charged workpiece, where they precipitate as a solid metal layer. Electrolytes are essential for processes such as electroplating, electroforming and electropolishing. For it to function properly, an electrolyte must be pure, have the right pH and concentration, and be properly filtered to prevent precipitation or contamination.
What is electroplating?
Electroplating is the electrochemical application of a thin metal coating to a conductive surface. This is done using an electrolyte, a power source , and a metal anode. Common applications include applying copper, nickel , or zinc to steel or brass, to provide corrosion protection, electrical conductivity, or a decorative finish. It is important that the surface is properly cleaned and activated, otherwise the metal layer will adhere poorly or come loose.
What is cold chemical blackening/black oxidation?
Cold chemical blackening or black oxidation is a chemical process in which a black conversion layer is formed on iron, steel, or cast iron. This layer is not a paint or coating, but a reaction product with the metal surface itself. Products such as Black Oxide or Black Oxide Ultra cause this discoloration at room temperature. Stainless steel requires Black stainless steel oxide , which requires acid cleaning beforehand. Aluminium is not suitable because it does not enter into a similar reaction. The black layer offers limited protection and is almost always sealed.
What is electroforming?
Electroforming is an electrochemical process in which metal is built up layer by layer on a conductive surface. Unlike traditional electroplating, where the layer thickness usually remains thin, electroforming can make the deposit a few millimeters thick. It is often applied to organic or plastic objects that have been made conductive with conductive lacquer such as Verzinkshop Conserve. Copper (such as V-BRITE 100 or V-BRITE 200 electrolyte) is the most commonly used metal because of its fine deposit structure, but nickel and silver are also used.
What are sealers?
Sealers are liquids or coatings that are applied to treated metals to protect them from rust, oxidation, discoloration, or mechanical wear. After black oxide or patina, sealing is essential to maintain the color. Verzinkshop DeepSeal is an oil-based sealer that penetrates deeply and offers long-lasting protection both indoors and outdoors. Verzinkshop Acrylic Sealer is a water-thin acrylic layer that dries transparent and is suitable for indoor use or on decorative objects. Alternative sealers are wax, WD-40 or clear coat.
What is electropolishing?
Electropolishing is a process in which a thin layer of a metal surface is electrochemically removed. The aim is a smoother, shinier and cleaner finish, especially with stainless steel. The process requires a specific electrolyte, a DC power source, and precise control of temperature, current density, and time. It is often used in medical, food or high-tech applications due to its reduced roughness and better surface cleanability.
Metal chemical blackening
Does black oxide work on any metal?
On steel, iron and cast iron with Black Oxide or Black Oxide Ultra. For stainless steel: Black stainless steel oxide. Aluminum not suitable. A separate product is required for zinc.
My coat is blotchy or grayish
Cause: insufficient cleaning, activation or poor rinsing. Clean better, activate correctly and rinse thoroughly. Do not allow parts to dry between steps.
Do I always have to seal after blackening?
Yes. The conversion layer does not provide long-term protection. Use DeepSeal for maximum protection for indoors or outdoors, or Acrylic Sealer for a thin finish suitable for indoors.
Can I let parts dry in between?
No. Keep parts wet between activate, blacken, and seal to prevent flash rust and staining.
How many times can I reuse black oxide?
Until color and effect decrease. Filter in case of contamination and change as soon as the bath is exhausted. The surface to be blackened is indicated on the product page in m2.
Can I use hydrochloric acid as an activator?
Only where allowed. Verzinkshop Metal Activator is usually sufficient. Follow the instructions for each product.
My black layer rubs off
Cause: treated for too long, too concentrated solution or insufficient activation. Shorten treatment time or dilute. Rinse thoroughly.
Stainless steel chemical blackening
Does standard black oxide work on stainless steel?
No. Use Black Stainless Steel Oxide. Stainless steel must first be activated with acid.
What activation is needed for stainless steel?
400 series: often sufficient with Verzinkshop Metaal Activator. 300 series: use stronger acid such as 32% hydrochloric acid diluted 1:1. Rinse very well and do not let dry.
Do I also have to seal stainless steel?
No, it is oxide repellent in itself. But sealing prevents discoloration and wear and can be applied as extra protection. Use DeepSeal, Acrylic Sealer or any other coating.
The color does not pick up or remains light gray
Surface is not active enough or not cleaned properly. Extend or strengthen activation and cleanse thoroughly.
Galvanize
My copper, nickel coating or other metal is not shiny
Check that there is enough brightener in the bath (never add too much!) Poor gloss is also due to contamination or improper current density. If adding additional brightener does not bring improvement, check other parameters.
Can I store and reuse an electrolyte?
Yes, as long as it is clean and properly sealed. Filter in case of contamination and replenish components. Some baths, such as bronze, are depleted by metal consumption because the metal comes from the electrolyte instead of the anode.
Does it adhere to any material?
Only on well-conductive, cleaned surfaces. Check the metal compatibility list to see which metal can be applied to which metal. First make plastic conductive with Verzinkshop Conserve or Carbon Conductive Paint.
How do I know if the bath is finished (as with bronze)?
Less metal deposits, loss of gloss or color change are signs. Change the bath.
Electroforming
Can I electroform on plastic or other non-conductive surfaces?
Yes, if treated with a conductive lacquer such as Verzinkshop Conserve or Carbon Conductive Paint.
How thick can the layer be?
This is highly dependent on the chosen electrolyte, current and time. V-BRITE 100 copper can build up millimeters. Nickel applies a very thin layer.
My shape is getting bumpy or rough
Cause: too high current density, polluted bath or irregular conductive layer. Reduce current, improve filtration and check the paint layer.
Can I solder or paint the result?
Copper is easy to solder. Nickel or chromium, for example, do not. Painting can be done after good degreasing and light sanding.
Patina
Do I always have to seal patina?
Yes. To preserve the color and prevent wear. Use oil, acrylic, or wax. Apply thinly.
Why does the color get blotchy?
Often due to poor preparation. Clean thoroughly, sand lightly and work in thin layers.
Does patina work the same on every metal?
No. Each alloy gives a different reaction or color. Always test on a test piece.
Sealers and finishing
Which sealer should I choose?
Choose DeepSeal Electrolyte for maximum protection, even outdoors. This oil penetrates deep into pores and displaces water. For indoors and a subtle finish, Verzinkshop Acryl Sealer is suitable: a thin, transparent layer that dries quickly. Alternatives such as wax, WD-40 or clear coat are possible, but usually offer less durable protection.
How do I apply sealer?
Oil sealers can be dipped, brushed or sprayed. Leave them on briefly and remove any excess material. Acrylic Sealers are applied thinly with a cloth or spray method. Make sure the surface is well cleaned and dry, otherwise stains or poor adhesion will occur.
My sealer is streaking or staining
This is usually due to a layer that is too thick or moisture on the surface. Always apply sealers thinly and evenly. Repeat several thin layers rather than one thick one. With oil sealers, short dipping helps to displace remaining water.
Cleanse and activate
How important is cleansing?
Cleaning is crucial for good adhesion and color. Residues of grease, oil or corrosion cause poor deposits, stains or peeling. Degrease thoroughly with a suitable degreaser and rinse carefully in clean water before activating or treating.
What is Activation?
Activate removes the oxide layer of metal with an acid such as hydrochloric acid or phosphoric acid. This makes the surface chemically active for blackening or electroplating. Never allow the surface to dry between activate and the next step to avoid staining and rust.
Can I rinse under the tap?
Not recommended. Rather rinse in an immersion bath or with an overflow system. Direct tap water on the workpiece can lead to irregular rinsing, limescale stains or discoloration. Preferably use demineralised water for the final rinsing step.
Safety, storage and shelf life
How long do products last?
Unopened chemical products often have a shelf life of several years. Conductive paints and water-based products are more sensitive: usually have a shelf life of 1–2 years. After opening, the shelf life depends on storage conditions, such as temperature, light and airtightness.
How do I store liquids and powders?
Keep everything tightly sealed, cool (10–25°C), dry and out of direct sunlight. Protect against frost and label used baths clearly with contents, date and possible consumption. Avoid contact between incompatible substances, such as acids and bases.
What PPE do I need?
Always wear chemical-resistant gloves, safety goggles and appropriate clothing. Work in a well-ventilated area. When using acids or vaping substances, a cooker hood or respiratory protection is recommended.
Waste and regulations
Can I rinse away residual liquids or rinse water?
No. Chemical liquids and rinsing water with metal ions fall under chemical waste. Private individuals hand this in at the recycling center. Companies must engage an approved waste processor or apply for a discharge permit. Don’t let anything run into the sewer without permission.
How do I limit waste?
Work with small volumes, reuse rinse water with cascade systems and filter baths in case of contamination. Use sealable bins, dose carefully and avoid spillage. Keep acidic and alkaline products separate.
Where can I find more information?
Please review the label and the included product manual for specific safety and disposal instructions. If in doubt, you can contact a waste processor or the helpdesk of Verzinkshop.