FabDigitFabDigit

Copper Plating

Electroplating & electroless plating · Electrolytic bath

Copper plating is a conductive, ductile undercoat used for leveling, adhesion, shielding, and build-up.

CNC machiningSheet metalInjection molding3D printingStandard cost $$Conductive
Quote a part with Copper plateCompare electroplating & electroless plating
Copper Plating on a machined part

What is Copper plate?

ASTM B734 covers electrodeposited copper for engineering uses.

How it works

After cleaning and a substrate-specific strike, the workpiece is made cathodic in an acid copper or other copper electrolyte. Copper ions reduce onto the part while soluble anodes replenish the bath. High-throwing-power strikes establish adhesion; acid copper then levels and builds thickness efficiently. Current density produces thicker edges and thinner recesses. Nonconductive plastics first need etching, catalysis, and electroless copper or nickel before electrolytic build.

Why specify it

  • High electrical conductivity
  • Ductile 5–30 µm underlayer
  • Levels polishing marks under nickel-chrome
  • Provides EMI shielding on metallized polymers

Where it falls short

  • Tarnishes rapidly without topcoat
  • Diffuses into gold and tin unless barrier plated
  • Poor direct adhesion on passive metals
  • Electrolytic thickness is nonuniform

Copper plate at a glance

Copper plate is a middle-of-the-range finish; its best score is cosmetic quality (65 of 100), at a standard cost.

Corrosion protectionLow32 / 100
Surface hardnessFair39 / 100
Cosmetic qualityGood65 / 100
LubricityLow22 / 100
Relative costStandard22 / 100
CorrosionHardnessCosmeticLubricityEconomy

Each score is 0–100 against every finish in this catalog. Corrosion comes from salt-spray life (ASTM B117, log scale) and hardness from the finish layer's Vickers or pencil hardness; cosmetic, lubricity and cost are FabDigit's engineering assessment. Economy on the radar is the inverse of cost.

Copper plate key numbers

Typical values from the governing specifications and shop practice; bars are this finish against the highest value among electroplating & electroless plating finishes.

Thickness5–30 µm0.2–1.2 mil
Hardness50–250 HV
Thickness
5–10 µm as a strike or underplate; 10–30 µm for leveling or conductive buildup
Hardness
50–250 HV — Varies widely between soft ductile and hard additive-controlled deposits.
Electrical
Conductive
Colours
  • copper
  • rose
Appearance
Bright salmon-pink to matte red-brown; tarnishes darker in air.

Where Copper plate sits among all finishes

Surface hardness (Vickers, log scale) against corrosion protection (salt-spray hours, log scale) for every coating FabDigit offers, one cloud per finish group. Copper plate is highlighted; hover a dot for its name or open the full map.

02550751000255075100Corrosion protection (0–100)Surface hardness (HV, log scale, 0–100)Plating — 19 finishesHard coatings — 17 finishesAnodize & conversion — 8 finishesPaint & powder — 7 finisheshard, low corrosion protectionhard and protectiveprotective, softsoft, little protectionType II anodize — corrosion 71, hardness 54BSA anodize — corrosion 71, hardness 52Type I anodize — corrosion 71, hardness 49Hard anodize — corrosion 71, hardness 61PTFE hard anodize — corrosion 71, hardness 61Nitriding — corrosion 55, hardness 73PEO — corrosion 70, hardness 74Sherardizing — corrosion 83, hardness 56Brass plate — corrosion 35, hardness 44Bronze plate — corrosion 40, hardness 49Cadmium plate — corrosion 70, hardness 26Decorative chrome — corrosion 64, hardness 71Electroless copper — corrosion 20, hardness 41Electroless nickel — corrosion 70, hardness 68Nickel plate — corrosion 51, hardness 55Gold plate — corrosion 68, hardness 39Hard chrome — corrosion 40, hardness 73Hot-dip zinc — corrosion 90, hardness 42Nickel-PTFE — corrosion 72, hardness 57Silver plate — corrosion 55, hardness 39Solder plate — corrosion 42, hardness 9Tin plate — corrosion 34, hardness 0Zinc plate — corrosion 60, hardness 30Zinc-nickel — corrosion 86, hardness 60Cerakote — corrosion 83, hardness 27E-coat — corrosion 83, hardness 15Epoxy coat — corrosion 83, hardness 15Powder coat — corrosion 83, hardness 14Wet paint — corrosion 59, hardness 10AlCrN PVD — corrosion 58, hardness 93AlTiN PVD — corrosion 52, hardness 94CrN PVD — corrosion 62, hardness 83DLC — corrosion 55, hardness 93MoS2 PVD — corrosion 20, hardness 26TiAlN PVD — corrosion 50, hardness 93TiCN PVD — corrosion 40, hardness 92TiB2 PVD — corrosion 40, hardness 94TiN PVD — corrosion 45, hardness 87WC/C PVD — corrosion 48, hardness 77ZrN PVD — corrosion 52, hardness 90CVD alumina — corrosion 70, hardness 85CVD TiCN — corrosion 38, hardness 92CVD TiN — corrosion 45, hardness 87Multilayer CVD — corrosion 62, hardness 88HVOF coating — corrosion 78, hardness 77Plasma spray — corrosion 60, hardness 68Plastic chrome — corrosion 72, hardness 71Electroless plastic — corrosion 58, hardness 39Clear coat — corrosion 20, hardness 12Soft-touch — corrosion 20, hardness 5PLATINGHARD COATINGSANODIZE & CONVERSIONPAINT & POWDERElectroless copperNickel plateType II anodizePowder coatZinc plateZinc-nickelHard chromeDLCTiN PVDTin plateCadmium plateE-coatCerakoteWet paintHot-dip zincNitridingHVOF coatingCopper plate — corrosion 32, hardness 39Copper plate
02550751000255075100Corrosion protection (0–100)Surface hardness (HV, log scale, 0–100)Plating — 19 finishesHard coatings — 17 finishesAnodize & conversion — 8 finishesPaint & powder — 7 finishesType II anodize — corrosion 71, hardness 54BSA anodize — corrosion 71, hardness 52Type I anodize — corrosion 71, hardness 49Hard anodize — corrosion 71, hardness 61PTFE hard anodize — corrosion 71, hardness 61Nitriding — corrosion 55, hardness 73PEO — corrosion 70, hardness 74Sherardizing — corrosion 83, hardness 56Brass plate — corrosion 35, hardness 44Bronze plate — corrosion 40, hardness 49Cadmium plate — corrosion 70, hardness 26Decorative chrome — corrosion 64, hardness 71Electroless copper — corrosion 20, hardness 41Electroless nickel — corrosion 70, hardness 68Nickel plate — corrosion 51, hardness 55Gold plate — corrosion 68, hardness 39Hard chrome — corrosion 40, hardness 73Hot-dip zinc — corrosion 90, hardness 42Nickel-PTFE — corrosion 72, hardness 57Silver plate — corrosion 55, hardness 39Solder plate — corrosion 42, hardness 9Tin plate — corrosion 34, hardness 0Zinc plate — corrosion 60, hardness 30Zinc-nickel — corrosion 86, hardness 60Cerakote — corrosion 83, hardness 27E-coat — corrosion 83, hardness 15Epoxy coat — corrosion 83, hardness 15Powder coat — corrosion 83, hardness 14Wet paint — corrosion 59, hardness 10AlCrN PVD — corrosion 58, hardness 93AlTiN PVD — corrosion 52, hardness 94CrN PVD — corrosion 62, hardness 83DLC — corrosion 55, hardness 93MoS2 PVD — corrosion 20, hardness 26TiAlN PVD — corrosion 50, hardness 93TiCN PVD — corrosion 40, hardness 92TiB2 PVD — corrosion 40, hardness 94TiN PVD — corrosion 45, hardness 87WC/C PVD — corrosion 48, hardness 77ZrN PVD — corrosion 52, hardness 90CVD alumina — corrosion 70, hardness 85CVD TiCN — corrosion 38, hardness 92CVD TiN — corrosion 45, hardness 87Multilayer CVD — corrosion 62, hardness 88HVOF coating — corrosion 78, hardness 77Plasma spray — corrosion 60, hardness 68Plastic chrome — corrosion 72, hardness 71Electroless plastic — corrosion 58, hardness 39Clear coat — corrosion 20, hardness 12Soft-touch — corrosion 20, hardness 5PLATINGHARD COATINGSANODIZE & CONVERSIONPAINT & POWDERNickel platePowder coatZinc plateCopper plate — corrosion 32, hardness 39Copper plate
Anodize & conversionPlatingPaint & powderHard coatings

Specifications for Copper plate

The documents a drawing cites to define this finish, with the Type / Class rows that apply. Each links to a page explaining the standard.

StandardType / ClassThicknessRequirement / testStatus
ASTM B734
Standard Specification for Electrodeposited Copper for Engineering Uses · ASTM
Class 5≥ 5 µmEngineering copper, 5 µm minimum. · Thickness and adhesion.Active
Class 12≥ 12 µmEngineering copper, 12 µm minimum. · Thickness and adhesion.
Class 20≥ 20 µmEngineering copper, 20 µm minimum. · Thickness and adhesion.
Class 25≥ 25 µmEngineering copper, 25 µm minimum. · Thickness and adhesion.
Class X—Thickness stated by the purchaser. · Specified thickness and agreed tests.

Drawing call-out

COPPER PLATE PER ASTM B734, 25 µm MIN, DUCTILE ENGINEERING DEPOSIT; PLATE SIGNIFICANT SURFACES SHOWN; MASK M6 THREADS

Pattern: COPPER PLATE PER ASTM B734, CLASS <5|12|20|25|X>, <THICKNESS FOR X>, <SIGNIFICANT SURFACES>

Which materials take Copper plate?

Verdict per material family, with the grades that behave differently. Each family links to its datasheets in the material library.

Material familyVerdictNotes
Brass
YesCommon decorative and electrical substrate after cleaning.
Copper Alloy
YesReadily plated after cleaning.
Steel
YesCommon after a suitable strike.
Aluminum
With careRequires zincate or equivalent activation plus a strike before the functional plate.
DMLS / SLM
With careMetal AM parts can be plated after density, powder, and porosity review.
Stainless Steel
With careNeeds activation and a nickel or other strike over the passive film.
Zinc Alloy
With careRequires a protective strike before acid copper.
Magnesium Alloy
LimitedHighly reactive; needs a qualified pretreatment and is rarely plated this way.
Polymer
LimitedNeeds plateable resin and electroless metallization.
  • Plateable ABS is common.
SLA
LimitedOnly if the resin is qualified for metallization; most SLA parts are not.
Titanium
LimitedPossible only with specialized activation; not a routine job-shop sequence.
FDM
NoFused-filament polymers are not a standard plating substrate.
MJF
NoPorous nylon powder-bed parts are not a standard plating substrate.
SLS
NoPorous nylon powder-bed parts are not a standard plating substrate.

How Copper plate is applied, and what it does to the part

  1. 1Clean
  2. 2Activate
  3. 3Apply copper strike
  4. 4Build acid copper
  5. 5Rinse
  6. 6Polish if decorative
  7. 7Apply topcoat or inspect
DimensionsAllow 5–30 µm per exposed side and all later nickel, chrome, tin, silver, or gold layers.
Build-up per side5–30 µm — Edges receive more copper than recesses; total stack includes subsequent coatings.
MaskingUsually needed. Mask final contact, fit, and solder areas when copper is only an undercoat.
ElectricalConductive
AppearanceBright salmon-pink to matte red-brown; tarnishes darker in air.
Added lead time3–6 working days on top of the bare part

Design rules for Copper plate

What to decide on the drawing before the part goes to the finisher.

  1. Specify whether copper is final or an underplate.Bare copper tarnishes and may not survive service.
  2. Add a nickel barrier under gold or tin where needed.Copper diffusion degrades thin top finishes.
  3. Provide electrical rack contact.Electrolytic copper cannot initiate on an insulating surface.
  4. Avoid sharp edges.Current crowding creates excessive buildup and nodules.

Copper plate versus the alternatives

Finishes engineers weigh against Copper plate, and when each wins.

FinishCorrosionHardnessCosmeticCostThicknessChoose it when
Copper plate
this page
323965$$5–30 µm—
Electroless Copper Plating
Copper plate vs Electroless Copper Plating →
204142$$$0.2–5 µmwhen initial conductive coverage on plastic or inside through-holes is needed
Electrolytic Nickel Plating
Copper plate vs Electrolytic Nickel Plating →
515578$$5–25 µmwhen a harder diffusion barrier is required
CorrosionHardnessCosmeticLubricityEconomy
Copper plateElectroless Copper Plating

The radar overlays Copper plate with Electroless Copper Plating, its most common alternative — chosen when initial conductive coverage on plastic or inside through-holes is needed. Scores in the table are 0–100 across every finish in the catalog.

Cost, lead time and compliance

Relative cost

Copper Plating is a standard-cost finish ($$): cheaper than about 76 % of the finishes FabDigit quotes.

Finishing is priced per part with a lot minimum, from FabDigit's own China-side rates cross-checked against US job-shop pricing. The exact figure appears on the instant quote once the part is uploaded.

Lead time and compliance

Added lead time3–6 working days
RoHSCompliant
NotesCopper is RoHS compatible; cyanide strikes and copper-bearing wastewater require controlled treatment.

What Copper plate is used for

  • Plating undercoat
  • EMI shielding
  • Grounding straps
  • Decorative hardware
  • Dimensional buildup

Copper plate — frequently asked

why use copper under nickel plating

Copper improves adhesion, ductility, and leveling before nickel. A 5–30 µm layer can fill polishing texture, while nickel supplies hardness and diffusion resistance.

how thick is copper plating

Underplates are often 5–10 µm, while leveling or engineering buildup commonly uses 10–30 µm. Edge thickness will exceed deep-recess thickness unless tooling corrects current distribution.

can you copper plate plastic

Yes, but plastic must first be etched, catalyzed, and covered with conductive electroless copper or nickel. Electrolytic copper then builds the layer to roughly 10–30 µm.

does copper plating prevent corrosion

Copper is not sacrificial to steel and tarnishes when exposed. It is usually an underlayer in a multilayer system, not the sole outdoor corrosion coating.

electroless copper vs electrolytic copper

Electroless copper starts uniformly on catalyzed nonconductors and through-holes without current. Electrolytic copper deposits faster and thicker but needs conductivity and has edge-to-recess variation.