// FINISHING — BARREL PLATING
Barrel Plating High-Volume Small Parts
The efficient finishing method for fasteners, bolts, and small hardware at volume — up to 350-lb barrel loads, clear and yellow zinc, with stainless passivation available.
Barrel plating is the production method for finishing large quantities of small parts at low per-piece cost. Parts tumble freely in a perforated rotating barrel immersed in the plating solution, receiving uniform coverage on all surfaces without the labor of individual racking. It is the standard process for fasteners, bolts, screws, washers, pins, and similar hardware wherever the volume is too large and the parts too small for cost-effective rack plating.
When barrel plating is the right choice
The tradeoff with barrel plating is contact marks: parts tumbling against each other will show small cosmetic contact points on the plated surface. For fasteners and hardware this is entirely acceptable — the functional and corrosion-resistant properties of the coating are not affected. For precision parts where surface contact marks cannot be tolerated, or for parts with delicate features that cannot withstand tumbling, rack plating is the correct approach.
- High-volume small parts — fasteners, bolts, screws, washers, pins
- Uniform plating coverage on all surfaces without individual fixturing
- Low per-piece cost at production volumes
- Up to 350 lbs per barrel load
- Barrel dimensions: 14" diameter × 42" long
Available finishes
Clear and yellow zinc are the standard barrel plating finishes, providing sacrificial corrosion protection to steel fasteners and hardware per ASTM B633. Clear (trivalent chromate) is the RoHS-compliant standard; yellow provides a distinctive gold-iridescent appearance and a slightly higher baseline corrosion-resistance rating. Stainless steel hardware can also be passivated in barrel quantities through NorTex for customers sourcing stainless fasteners alongside their machined components.
- Clear zinc (trivalent chromate) — bright, RoHS-compliant corrosion protection
- Yellow zinc — gold iridescent, higher salt-spray baseline
- Stainless steel passivation available for small stainless hardware lots
Capacity
NorTex runs barrels up to 14" diameter × 42" long with load capacity up to 350 lbs. This accommodates the large fastener lots common in production machining programs where hardware is sourced and finished alongside machined components.
| Process | Barrel electroplating |
|---|---|
| Finishes | Clear zinc (trivalent) · Yellow zinc · Stainless passivation |
| Barrel size | 14" dia. × 42" long |
| Max load | 350 lbs per barrel |
| Best-fit parts | Fasteners, bolts, screws, washers, pins, and small hardware |
| Standard | ASTM B633 (zinc) · ASTM A967 / AMS 2700 (passivation) |
Barrel plating is commonly combined with our production machining programs where hardware requires finishing at volume. For larger steel components, see rack zinc plating. For stainless machined parts requiring passivation, see our dedicated passivation page.
// FAQ
Frequently asked questions
Small, robust parts that can tumble against each other without damage: fasteners, bolts, screws, washers, nuts, pins, clips, and similar hardware. Parts with delicate features, tight tolerances on all surfaces, or requirements for zero contact marks should be rack plated instead.
Thickness is controlled to the specification — typically 0.0002" to 0.0005" for standard decorative/protective zinc per ASTM B633. Heavier deposits are available if required. For threaded fasteners, the deposit must account for thread class, which is standard practice.
Up to 350 lbs per barrel load, in a 14" diameter × 42" long barrel. Contact us with your part geometry and quantity and we can estimate how many runs your lot requires.
Yes — stainless steel hardware can be passivated in barrel quantities through NorTex. This is a common request when customers source stainless fasteners alongside their machined components and want consistent, documented passivation on the whole hardware kit.
Clear zinc with trivalent chromate passivate is RoHS compliant and is the standard specification for customers with RoHS requirements. Yellow zinc with hexavalent chromate is NOT RoHS compliant; trivalent-process yellow is available and compliant — confirm the chemistry with us at quoting if RoHS is a requirement.
Send us the hard one.
Upload your drawing or STEP file and we'll come back with pricing and lead time — from a single high-mix part to full production runs, held to exacting tolerances.