Fengfan KCL Zinc Plating Process Rack And Barrel Plating Additives CLZN-10

Product Overview

This is a two-component brightener system for potassium chloride acid zinc plating. The zinc chloride, potassium chloride and boric acid make the electrolyte; this pair of liquids controls how that electrolyte behaves at the cathode, which is why the colour, the gloss and the bath's tolerance to contamination all come from the same two drums.

Plating shops buy it for mixed production. A barrel of fasteners in the morning and a jig of pressed brackets in the afternoon both come out white-bright, and the deposit is fine enough to go straight into colour, blue-white or white passivation without mechanical polishing in between. Because the components are dosed separately, a line that needs more gloss can be fed more gloss without over-treating everything else in the tank.

In the process of electroplating zinc from a chloride bath, the additive sits between pretreatment and passivation: degrease, descale, activate, plate, rinse, passivate. Nothing exotic is needed on the line beyond a lined steel tank, good rinse discipline and a normal analysis routine. Most plants run it on steel parts that need a decorative, corrosion-protective zinc layer before assembly, packing or dispatch.

As metal plating chemicals go, this acid zinc system is the general-purpose member of the family rather than a specialist. It is not built for continuous wire, strip or high-speed sheet lines, and it is not a zinc-nickel, alkaline or ammonium system. It is aimed at job-shop and in-house rack and barrel lines that want one pair of additives to cover both. If you are unsure whether your bath is a match, send us the current make-up and we will tell you plainly.

Performance in the Tank

• White-bright colour straight out of the bath. The deposit leaves the tank bright rather than grey, so a part that waits a shift before passivation still looks like a plated part.
• Gloss comes up early in the cycle. In a normal metal plating process the colour develops before the end of the plating time, which gives the operator room to pull thin work early without losing the finish.
• Fine, even grain. A fine-grained zinc layer reflects light evenly, and that is the difference between a bright part and a milky one once it reaches the passivation tank.
• A predictable bath through the shift. Additions take effect the way they did at the start of the day, so nobody is chasing colour with extra brightener in the last two hours.
• Low brightener consumption. The additions hold instead of fading, which matters on an electro plating line that runs every day and budgets by the drum.
• One tone across a mixed load. Jig work and barrel work come off the same bath with the same white appearance, so a mixed day's production can go through a single passivation sequence.

Two-Component System

Two liquids, dosed separately. ClZn-10A and ClZn-10B are supplied as a matched pair and are meant to stay a pair. They go into the bath independently, which is the whole point of a two-component design: as the bath consumes brightener, you replace the part that has actually been used up instead of tipping in a fixed blend and hoping the balance still holds.

Why that matters on a working line. A single-drum additive forces every correction through one addition. If the work dulls, you add more, and the rest of the bath chemistry takes the overshoot. With the pair, the correction is narrower and the response is easier to predict, which is what lets an operator hold colour across a long shift without fighting the tank.

Keep the pair together. Do not top up one component with another supplier's equivalent, and do not let one drum run dry while the other is still half full — the ratio the bath was set up on is the thing that makes it predictable. Order the two in matching quantities so they finish together.

Dosing discipline. Measure the additions, write them down, and tie them to analysis or to ampere-hours rather than to how the work happens to look. Two people each adding a little more on a Friday afternoon is how a stable bath becomes an unstable one.

Most plating chemicals of this type go into an electro plating bath as supplied, with the order of addition and the quantity for your tank volume stated on the make-up sheet that comes with the order.

Iron Contamination Control

• Where the iron comes from. Pickling acid dragged in on the work, steel that rides in the barrel without being plated, and parts that drop off a jig all put iron into a chloride zinc bath. Some of it is normal; what matters is how the bath copes over a week.
• What iron does to a bright deposit. Iron co-deposits with the zinc and the colour goes first: the part reads slightly grey or patchy, and the passivation film darkens or takes an uneven shade instead of the one the customer asked for.
• What this system does about it. The pair is built to hold brightness in a bath that is carrying iron, so a line keeps producing saleable work between purifications rather than going dull on the second day after a weekend shutdown.
• Signs it is time to act. Brightener additions that no longer bring the colour back, an analysis that shows iron climbing, a hazy or cloudy solution, or passivated work with a colour that varies across the load.
• Practical control. Rinse properly after pickling, keep parts on the rack rather than in the barrel bottom, manage drag-out, filter the bath, and purify on the analysis instead of on the day the work goes wrong. Settling iron out of an acidic zinc bath costs far less than a week of rejects.
• Iron is a maintenance problem, not a formula problem. No brightener will compensate for a bath that receives a litre of acid every hour. Fix the drag-in first and let this additive do the job it was bought for.
• When to call us. Send the iron figure alongside zinc, potassium chloride, pH and working temperature, and we will say whether the process of electroplating needs a purification step or a make-up correction before anything else is changed.

Rack, Barrel and Part Types

Rack work. Jigged parts are usually the larger, heavier or more visible ones — brackets, housings, pressed components, anything that would tangle or mark itself in a barrel. On the rack the variables are jig position, contact points and how evenly current reaches the far side of the part. Put the contact on a face that will not be seen, leave enough space that neighbouring parts do not shield each other, and the deposit comes up white-bright across the visible surface.

Barrel work. Small parts in volume: fasteners, stampings, clips, small fittings. Inside the barrel each part acts as its own cathode for part of each rotation, so load size, barrel speed and solution exchange through the perforations decide the result as much as the additive does. Overloading a barrel is the usual reason a bath that ran well on Monday looks dull by Thursday.

One pair of components, two sets of settings. The same two liquids serve both line types. What changes is current density, agitation and time, and those figures come with the make-up sheet for your line. A shop that runs rack and barrel metal plating does not need two additive systems in the chemical store.

Parts that sit between the two. Long thin parts, parts with deep blind holes, and parts too large for a barrel but too few for an economic rack load all need a judgement call. Send the drawing and the quantity and we will say which way to run it.

Where this system is not the answer. Continuous wire, strip and high-speed sheet lines run sulfate zinc chemistry rather than this chloride system. That is a different process of electroplating with a different bath composition, and the sulfate products in our range cover it.

Bath Make-Up and Operating Control

1. Send us the tank volume, the line type (rack or barrel) and the zinc chloride and potassium chloride figures the bath runs at today.
2. We send back the make-up and replenishment sheet for that bath, together with the working temperature, pH and cathode current density to run it at.
3. Clean the tank, pipework and filters before the first fill. If you are converting an existing bath, drain it rather than pouring one additive system on top of another.
4. Make up at working temperature, add the two components in the order given on the sheet, then run a short electro plating trial on scrap parts before the line goes live.
5. Analyse on schedule and replenish on the results — brightener, pH, zinc and chloride — rather than on how the work happens to look at the end of the shift.
6. Log additions, drag-out and rinse condition week by week and compare the log with the deposit. Drift shows up in the numbers before it shows up in the barrel.

Product Data

Passivation and Sealing

• Colour passivation. The familiar iridescent yellow-brown film, used on fasteners, brackets and general hardware where the part will be seen and handled.
• Blue-white passivation. A cooler, almost colourless film that keeps the part looking like zinc rather than brass; common on decorative fittings and on work that will be lacquered later.
• White passivation. The brightest of the three and the closest to a silver appearance, and also the one most sensitive to how fine the zinc layer underneath is.
• The deposit does half the work. Passivation only reveals what is already there: a fine, bright zinc layer takes an even film, while a coarse or dull layer shows through as patchiness that no passivation can hide.
• Rinse discipline. Carry-over of zinc bath into the passivation tank drags iron and zinc with it and shortens the life of the passivation; a clean rinse between the two tanks protects both.
• Sealing and salt spray. Where the drawing specifies a salt-spray figure, a sealer over the passivated film is the usual way to reach it. The hours actually achieved depend on coating thickness, passivation type and sealer, so test the combination on your own parts rather than assuming a number transfers from another shop.
• The last wet stage. On most metal plating lines passivation is where the part stops being a workpiece and becomes a product, and a good zinc deposit is what makes that stage easy.

Documentation, Storage and Handling

1. Ask for the SDS for the product and for the market you ship to before the first delivery. These are acidic plating chemicals, and the sheet tells your team what PPE, first aid and waste handling apply.
2. Store both components in the closed original containers, under cover, off the floor and away from acids, oxidisers and direct sunlight.
3. Keep them labelled and physically separate from other suppliers' additives. A mis-poured drum is the most common reason a bath suddenly stops behaving.
4. Dispense with dedicated measures for each component, and never return unused additive to the drum.
5. Wear gloves and eye protection, and keep the tank edge ventilated while additions are made.
6. Note the batch number on every drum you open, so a problem can be traced back to a delivery if one ever appears.

Ordering and Delivery

Wider Fengfan Range

Few plants need only one additive. If you run more than one finishing process, the same range covers the neighbouring steps: SZ-30B brightener for sulfate zinc, ZN 50 bright alkaline zinc and ZN-500 brightener for cyanide-free alkaline zinc where a line plates a different chemistry; the Phoenix EB 204A-204B divalent tin salt electrolytic colouring additive plus Phoenix Seal 149-L and 149-T sealing agents for anodising; FI-970 bright acid copper; FF-4219 nano-protective for wood, stone and concrete; Nickel Purify P3 for nickel baths; and the FF-116 chrome mist inhibitor for chrome lines.

Ordering several steps from one place means one set of paperwork, one batch record and one contact when something on the line misbehaves. In a metal plating process, that continuity is usually worth more than the small difference between one supplier's price and another's.

Switching From Another Additive

1. Start with an analysis of the bath you are running now. Zinc, potassium chloride, boric acid, pH, iron and a note of which brightener system is in the tank tell us more about the risk than the tank volume does; most switchovers that go wrong were decided before anyone looked at those figures.
2. Choose between converting and rebuilding. A bath that is low in iron and still in balance can often be converted by dropping the old brightener out and treating the solution. A bath that is cloudy, heavily loaded with iron or years old is better drained, with a fresh make-up built in the cleaned tank. Send the analysis and we will say which route your tank suits.
3. Clean what the solution touches, not just the tank floor. Pipework, filter housings, anode bags and the walls all hold residues of the outgoing additive, and a new make-up on an uncleaned tank contaminates itself within a shift. Rinse to clear, neutral water and change the filter element at the same time.
4. Inspect anodes and lining while the tank is empty. Heavily passivated anodes, bags full of sludge or a lining that has begun to lift will spoil a fresh bath whatever brightener goes into it.
5. Make up to your own volume and your own water. The quantities of zinc chloride, potassium chloride, boric acid and both components for your tank are on the make-up sheet issued with the order; those figures are set for this pair of acid zinc plating chemicals and are not interchangeable with a sheet written for another chloride bath.
6. Plate scrap before you plate orders. Run a rack load and a barrel load of the actual parts at the temperature, pH and current density on your operating sheet, then judge colour, coverage in recesses and passivation response before anything goes to a customer.
7. Log additions in millilitres against ampere-hours for the first two weeks. A new bath moves faster than a settled one: brightener demand, pH drift and iron pick-up all calm down only after several production days, so correct on the log and the analysis rather than on one dull barrel.
8. Keep a route back. Hold a drum of the outgoing additive until the new bath has run a full production cycle and the passivated work has passed your inspection; if a customer rejects the finish during the trial, you can return to the old chemistry without stopping the line.

Bath Control and Deposit Checks

• Analysis on a fixed day each week: zinc, potassium chloride, boric acid and pH, written down beside the additions made over the same period. The log and the analysis read together show whether the bath is drifting; either one on its own does not.
• Brightener consumption per kA·h as an early warning. Rising demand usually means iron or drag-in is building up, and it shows in the numbers before the deposit dulls.
• Filtration and circulation kept running: continuous filtration holds suspended solids down and keeps the two components evenly distributed through the tank. Check and change the element on a schedule rather than when the solution turns cloudy.
• Anode condition checked at each shutdown: clean zinc anodes, bags in good order and anode area matched to the load. A sludged anode set raises the voltage and changes what arrives at the cathode.
• A reference sample from the first good production load, plated and passivated, bagged and labelled. Compare new work against it dry and under the same light, so a colour shift is judged against a fixed standard instead of yesterday's memory.
• Thickness readings with a magnetic gauge on steel, taken at points agreed with your customer — a recess, a flat face and a high-current edge — recorded as a minimum and a maximum rather than a single average.
• Corrosion results filed with their conditions: hours in neutral salt spray, coating thickness, passivation type and whether a sealer was applied. A number without those details cannot be compared with the next batch or with a customer specification.
• Batch numbers from each drum entered in the bath record and matched to the inspection certificate issued for that delivery, so that a question about a shipment can be answered from paperwork and not from memory. When something does go wrong, send the analysis, the settings, a photo of the part and the batch number together — that combination is what lets us find the cause quickly in a plating process that has otherwise been running well.

Technical Support & Model Matching

Choosing the right match is where most sourcing decisions stall. As a trading supplier, we keep one point of contact from first enquiry to after-sales: tell us what you are making and the conditions you work under, and we shortlist the closest matches from our supplier network, compare specifications and arrange samples before you commit to a bulk order. If something does not behave as expected, we work with the supplying partner on the cause and a practical fix, and stay with the case until it is settled. Email, WeChat or WhatsApp enquiries get a reply within 24 hours.

FAQ