Your Trusted Black Oxide Plating Shop in Milwaukee, WI

Welcome to L & L Metal Finishing, Milwaukee’s premier metal finishing shop specializing in black oxide plating and a range of industrial, aerospace, and automotive metal finishing services. As a locally owned and operated business with deep roots in the Milwaukee manufacturing community, we pride ourselves on delivering superior quality coatings and metal finishing solutions that are tailored to meet the diverse needs of our clients across the region. From complex aerospace components to automotive parts and delicate electronics, our expertise ensures that your metal parts receive the highest level of protection, durability, and precision.

Milwaukee has a proud industrial heritage that continues to thrive, with sectors ranging from automotive manufacturing to aerospace engineering and electronics assembly. We understand the critical role metal finishing plays in these industries. Whether it’s black oxide for automotive parts exposed to the harsh Wisconsin winters, or barrel plating for electronics destined for high-tech applications, L & L Metal Finishing stands ready to meet and exceed your expectations. Our comprehensive services, including black oxide coating, electroless nickel plating, stainless steel passivating, and barrel plating, are performed with precision and care, adhering to military and aerospace standards to ensure the utmost quality.

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Our Black Oxide Plating Services

At L & L Metal Finishing, black oxide plating is at the core of what we do. This process is a chemical conversion coating that imparts a deep, matte black finish to steel and iron surfaces, providing both aesthetic appeal and functional benefits. It’s a highly effective coating that offers excellent corrosion resistance when paired with appropriate post-treatment oils or sealants, all while maintaining the exact dimensions of the original metal parts.

What Makes Black Oxide Plating Special?
The black oxide coating we apply is a hot chemical process that converts the surface of the steel into magnetite (Fe3O4), a dense and stable compound. Unlike plating methods that deposit layers of metal, black oxide plating chemically alters the metal’s surface without adding thickness or causing dimensional change. This feature is essential for components that require precise tolerances, such as automotive parts, aerospace fasteners, and industrial machinery.
  • No Dimensional Change: Our hot black oxide process ensures the original part dimensions remain intact, which is vital for tight tolerance applications and interchangeable parts.
  • Durability: The finish is highly durable and will not peel, chip, or rub off, unlike paint or powder coatings. This makes it ideal for parts exposed to handling, friction, or repeated assembly and disassembly.
  • Enhanced Corrosion Resistance: While black oxide itself provides some protection, the finish’s true power emerges when combined with oils or rust inhibitors. These post-treatments seep into the porous black oxide layer, creating a barrier that guards against rust and environmental degradation.
  • Retains Surface Characteristics: The finish preserves the metal’s surface hardness, polish, and texture. This means polished parts remain glossy, and hardened parts retain their Rockwell hardness.
  • High Heat Resistance: Black oxide can withstand continuous exposure to temperatures up to 900°F (482°C) before the black coloration begins to fade, making it suitable for automotive and aerospace components subjected to high heat.
Flexibility for Your Production Needs
Whether your project requires small batch runs or high-volume production, we’ve got you covered. Our black oxide plating line is engineered for flexibility, allowing us to accommodate short runs for prototype parts or large-scale orders for manufacturing clients. We strictly adhere to the MIL-C-13924 specification, which is a military standard ensuring consistent quality and performance for black oxide coatings.
In Milwaukee’s bustling automotive sector, for instance, our black oxide coating is used extensively on fasteners, brackets, and engine components to provide corrosion protection without impacting assembly tolerances. For aerospace clients, the non-dimensionally changing finish helps maintain critical clearances while improving component longevity.

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Citric Acid Passivating of Stainless Steel

Passivation is a vital process for stainless steel parts to enhance their natural corrosion resistance by removing contaminants and free iron from the surface. At L & L Metal Finishing, we specialize in citric acid passivation, which is increasingly preferred over traditional nitric acid methods due to its safety and environmental benefits.

  • Meets Industry Standards: Our passivation process complies with ASTM A-967 and AMS 2700B, the current aerospace and defense industry standards.
  • Improved Corrosion Resistance: Citric acid passivation enriches the chromium oxide layer on stainless steel, creating a more passive, corrosion-resistant surface.
  • Safer and Environmentally Friendly: Citric acid is less hazardous than nitric acid, making it safer for workers and easier to dispose of responsibly.
  • Used in High-Tech Industries: Our passivation services are in demand by Milwaukee’s semiconductor and medical device manufacturers who require contamination-free, corrosion-resistant stainless steel tools and components.

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Barrel Plating Services

Barrel plating is a cost-effective and efficient plating method ideal for small, high-volume parts such as electronic components and automotive fasteners. Our facility is equipped with advanced barrel plating lines designed to handle large batches while maintaining high-quality finishes.

  • Superior Burnishing and Descaling: Barrel plating provides excellent burnishing, producing smoother finishes and more uniform plating compared to rack plating.
  • High Volume Production: The barrel plating process allows us to process a significantly larger volume of parts in less time, ideal for manufacturers with tight deadlines.
  • Cost Efficiency: Because barrel plating can be automated and performed in batches, it often results in reduced labor and material costs.
  • Versatile Applications: We plate a variety of metals and apply coatings for different industrial requirements, from corrosion-resistant finishes for electronics to decorative finishes for automotive parts.

Our barrel plating services support Milwaukee’s fast-paced electronics and automotive supply chains, delivering consistent results on time and on budget.

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Specialty Metal Finishing Services in Milwaukee

In addition to black oxide plating, L & L Metal Finishing offers a comprehensive array of metal finishing services designed to meet the demanding needs of industrial, aerospace, automotive, and electronics manufacturers in the Milwaukee area.

Electroless Nickel Plating (EN)
Electroless nickel plating is a highly specialized coating process that deposits a uniform, hard, and corrosion-resistant layer of nickel-phosphorus alloy onto metal surfaces. Unlike electroplating, which requires an electrical current, electroless nickel plating relies on an autocatalytic chemical reaction, enabling even coverage in blind holes, threads, complex recesses, and sharp edges.
  • Hardness and Wear Resistance: As deposited, our electroless nickel plating typically has a hardness of 45-50 Rc, which can be heat-treated to around 60-65 Rc. This makes it excellent for parts requiring abrasion resistance and long service life.
  • Uniform Coating Thickness: Because the process is chemical rather than electrical, the plating thickness is consistent over all surfaces, reducing the risk of thin spots or buildup on edges.
  • Corrosion Resistance: EN plating forms a protective barrier against corrosion, which is especially valuable in harsh environments like Milwaukee’s industrial atmosphere.
  • MIL Specifications Compliance: Our electroless nickel plating meets MIL-C26074 and AMS 2404 standards, ensuring aerospace-grade quality for critical applications.
  • Cost Savings: EN plating can often replace more expensive hard chrome or high alloy materials, reducing costs while maintaining or improving performance.

Milwaukee’s aerospace and heavy machinery manufacturers frequently rely on our electroless nickel plating to improve the durability and reliability of their components.

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Why Milwaukee Trusts L & L Metal Finishing

Milwaukee’s industrial landscape is unique—our location, weather, and manufacturing heritage all create specific challenges and opportunities for metal finishing. L & L Metal Finishing understands these local needs and offers solutions that are both technically sound and economically smart.

  • Harsh Weather Protection: Milwaukee winters bring moisture, salt, and freezing temperatures that can rapidly corrode unprotected metal parts. Our black oxide coatings with post-treatment oils are designed to extend the service life of automotive and industrial components under these tough conditions.
  • Precision Manufacturing: Milwaukee’s aerospace and machinery industries demand tight tolerances and flawless finishes. Our black oxide plating causes no dimensional changes and our electroless nickel plating provides uniform hardness and corrosion protection, ensuring parts perform reliably in critical applications.
  • Local Service and Support: Being a Milwaukee-based company means we can provide fast turnaround times, onsite consultations, and flexible scheduling that larger, out-of-state companies cannot match.
  • Environmental Responsibility: We follow strict environmental guidelines and offer safer processes like citric acid passivation, supporting Milwaukee’s commitment to sustainability and worker safety.
  • Customized Solutions: Every manufacturer’s needs are different, and we tailor our processes to fit your exact specifications, whether you need aerospace-grade coatings or economical finishes for high-volume automotive parts.

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At L & L Metal Finishing, we are proud to serve Milwaukee and its surrounding areas.
Please refer to the map below for our service area.

Frequently Asked Questions

What types of metals can be black oxide plated?

Black oxide plating is primarily used on ferrous metals such as steel and iron. It is not effective on non-ferrous metals like aluminum, brass, or copper. For these metals, alternative finishing methods such as electroless nickel plating may be recommended.

How does black oxide improve corrosion resistance if it is so thin?

The black oxide layer itself is very thin and porous, providing only minimal corrosion resistance alone. However, when combined with oil or other post-treatment dips, these substances penetrate the porous layer, creating a protective barrier that significantly reduces rust formation.

Will black oxide plating affect the mechanical properties of my parts?

No, one of the key benefits of black oxide plating is that it does not alter the surface hardness or mechanical properties of the metal. The coating is a chemical conversion process rather than a deposit, so the part retains its original strength and hardness.

Are your black oxide and other finishing services compliant with military and aerospace standards?

Yes, we strictly adhere to specifications such as MIL-C-13924 for black oxide, MIL-C26074 and AMS 2404 for electroless nickel, and ASTM A-967 and AMS 2700B for passivation, ensuring that our coatings meet rigorous performance criteria.

How quickly can you complete high-volume plating orders?

Our facility is equipped to handle both small prototype runs and large-scale production orders. We maintain efficient processes and flexible scheduling to meet your deadlines, whether you need a few hundred parts or tens of thousands.

Need a Black Oxide Plating Shop in Milwaukee, WI?

If you’re seeking a reliable, experienced, and locally trusted black oxide plating shop in Milwaukee, look no further than L & L Metal Finishing. Our reputation for quality, precision, and customer service makes us the preferred choice for businesses across the automotive, aerospace, electronics, and industrial sectors.
We invite you to reach out today to discuss your metal finishing needs. Whether you require black oxide coating for automotive parts that must withstand Milwaukee’s challenging climate, electroless nickel plating for aerospace components, citric acid passivation for stainless steel tools, or high-volume barrel plating for electronics manufacturing, we have the skills, equipment, and dedication to deliver outstanding results.
Contact us today to experience firsthand how L & L Metal Finishing can protect and enhance your metal parts. Let us show you why so many manufacturers in Milwaukee and beyond trust us as their metal finishing partner. Together, we’ll ensure your parts not only meet but exceed your performance expectations, helping your business thrive in a competitive marketplace.

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