In electroplating, it’s often the chemistry in the plating bath that gets the attention—the shine of nickel, the leveling of copper, or the performance of trivalent chrome.
Bukola AdeyemiBut Bukola Adeyemi of Hubbard-Hall says that focus can be dangerously misplaced. The real key to consistent, high-quality plating starts long before a part ever touches a plating bath. It begins with pretreatment.
In a recent conversation as part of Hubbard-Hall’s Seen & Solved podcast, Adeyemi made a compelling case that cleaning and pretreatment are not just preliminary steps—they are the foundation upon which successful plating is built.
Why Pretreatment Is Critical
“Pretreatment is the foundation of the entire plating process,” Adeyemi said. “I compare it to painting a wall. You wouldn’t paint over grease, mold, or dirt—you prepare the surface first. It’s the same in plating.”
If parts are not properly cleaned and activated, even the best plating chemistry will fail. Oils, fingerprints, soils, and residues can prevent adhesion, leading to blistering, peeling, and inconsistent deposition.
“You can have the best chemistry in the world,” she emphasized, “but without proper and adequate pretreatment, you’re setting yourself up for failure.”
Common Mistakes Shops Make
Adeyemi says shops often make these frequent pretreatment missteps that she sees in the field:
1. Rushing the Process: Many shops are eager to move parts quickly into the plating bath, sometimes skipping or shortening critical cleaning steps.
“Platers tend to focus more on the nickel or copper bath than on pretreatment,” she says. “But if you don’t get cleaning right, nothing else works.”
2. Using a ‘One-Size-Fits-All’ Cleaner: Different substrates require different cleaning approaches. Using the same cleaner for steel, aluminum, brass, and copper can lead to inconsistent results.
3. Poor Bath Control and Maintenance: Inadequate monitoring of cleaner concentration, temperature, and contamination levels can degrade performance over time.
4. Insufficient Rinsing: Rinsing between stages is essential to prevent drag-in of soils and chemistry into subsequent baths. Poor rinsing can contaminate activation and plating baths.
“Most of the time, when shops have plating problems, it traces back to cleaning,” Adeyemi says. “Fix the pretreatment, and the rest usually follows.”
What Happens When Pretreatment Fails
The consequences of poor pretreatment are both technical and financial.
Adhesion failures, blistering, uneven deposits, and high scrap rates are common. Shops may try to push through to avoid downtime, but that often makes the problem worse.
“You end up contaminating your chemistry, making more scrap,” Adeyemi says. “Eventually you still have to stop production—only now it’s more expensive to fix.”
Adeyemi described what she calls a “pre-flight” approach—both mechanical and chemical—before production begins. This includes checking equipment, agitation, piping, bath concentrations, and quality parameters.
If defects arise, you can go back to that checklist and see where things went wrong, she says.
The Three Key Stages of Pretreatment
Adeyemi outlined a typical pretreatment sequence in three broad categories:
- Mechanical Preparation: This includes both equipment checks (no leaks, proper agitation, functioning filtration) and part preparation—ensuring surfaces are free of oils, smudges, and fingerprints.
- Chemical Cleaning: Soak cleaners or electrocleaners must be within specification for concentration and temperature. Regular testing and replenishment are critical.
- Acid Activation: Depending on the substrate, shops may use sulfuric or hydrochloric acid to activate the surface prior to plating. Proper rinsing before and after activation is essential.
“Every step matters,” she said. “You can’t skip any of them.”
How can a shop tell when a cleaner is no longer doing its job? Adeyemi pointed to two key indicators:
- Routine testing and control charts: Daily checks of concentration, temperature, and contamination help prevent problems before they start.
- Visual and quality clues: Excess oil buildup on the bath surface, poor adhesion, inconsistent plating, or quality rejects are signs it’s time to act.
“If you replenish regularly, you can often extend bath life and avoid a full change,” she says. “But if you wait until the bath crashes, you’re already too late.”
The Role of Water Quality and Rinsing
Water, often overlooked, plays a major role in pretreatment effectiveness.
“If your rinse water pH is too high or too low, you can drag that into subsequent baths and alter their chemistry,” Adeyemi warned.
City water versus DI water, rinse overflow rates, and tank cleanliness all affect results. Proper counterflow rinsing and regular water changes help minimize drag-in and contamination.
Residues from soils, oils, and metal fines inevitably accumulate in cleaning baths. Without filtration, these contaminants can redeposit onto parts.
“Filtration helps remove debris while the line is running, extending bath life and improving cleanliness,” Adeyemi said. “Without it, you’re just cycling contamination back onto parts.”
Operator Training: Understanding the “Why”
Even the best process will fail without properly trained operators.
A key challenge, according to Adeyemi, is that many operators focus primarily on the plating bath rather than pretreatment.
“They need to understand why cleaning is so important,” she said. “If they grasp that proper pretreatment prevents downtime, scrap, and customer complaints, they take it more seriously.”
She often uses the painting analogy to make the point relatable: “You wouldn’t paint a dirty wall—why would you plate a dirty part?” she asks.
Balancing Cleaning with Environmental Regulations
Stricter environmental regulations, water usage limits, and chemical controls are reshaping pretreatment.
Fortunately, Adeyemi sees this as an opportunity rather than a burden.
“New chemistries and automation are helping shops use less water, less chemistry, and achieve better results,” she said. “It’s a win-win for production and the environment.”
Looking ahead five to 10 years, Adeyemi expects increased automation, smarter monitoring, and more efficient cleaning systems.
Shops will seek solutions that reduce cycle times, lower energy and water consumption, and improve consistency.
“Platers are asking: ‘How can I cut my process time from an hour to 30 minutes?’” she said. “Innovation is moving in that direction.”
A Real-World Turnaround Story
Adeyemi shared a recent example where pretreatment—not plating—was the root cause of a customer’s issues.
A shop was experiencing inconsistent plating and assumed their plating bath was the problem. Lab testing showed the bath was actually within specification.
When Adeyemi visited the facility, she found a heavily contaminated soak cleaner with visible oil buildup, no filtration, and poor rinsing practices. Parts were even partially air-drying before activation.
Despite initial resistance, she convinced the shop to make new cleaner, replace rinse water, and clean the line properly.
“The result? Beautiful, consistent plating immediately,” she said. “The bath was never the problem—the cleaning was.”
One Piece of Advice Every Plater Should Remember
If she could leave platers with just one takeaway, Adeyemi says it would be this:
“Take quality control seriously. Check your baths every day. Know what’s in them before you start plating.”
A few minutes spent on proper pretreatment and testing can save hours of downtime, thousands of dollars in scrap, and even lost customers.
“You can have the best chemistry,” she concluded, “but without a clean part, you will never have clean, reliable plating.”
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