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Epoxy Coating

Paint, powder & polymer coatings · Spray applied

Epoxy coating is a crosslinked protective film valued for adhesion, chemical resistance, and barrier protection.

CNC machiningSheet metalPremium cost $$$Insulating
Quote a part with Epoxy coatCompare paint, powder & polymer coatings
Epoxy Coating on a machined part

What is Epoxy coat?

It is commonly used as a primer, industrial topcoat, tank lining, or heavy-duty metal coating.

How it works

A liquid two-component epoxy mixes resin and curing agent immediately before application, then crosslinks at ambient or elevated temperature. The prepared substrate must be free of oil, rust, salts, and loose oxide; abrasive blasting is common for steel. Multiple passes build the specified dry-film thickness. Epoxy forms a dense barrier but its aromatic binder can chalk and lose gloss under ultraviolet exposure, so outdoor decorative systems normally add a UV-resistant polyurethane topcoat.

Why specify it

  • Strong adhesion to correctly prepared metal
  • Typical v1 dry-film range is 50–200 µm
  • Good barrier resistance to water and many industrial chemicals
  • Useful as a primer beneath polyurethane topcoat

Where it falls short

  • Unprotected epoxy can chalk and fade in sunlight
  • Rigid films can chip at impacts and flexing edges
  • Poor blasting or surface contamination causes delamination
  • Thick film obstructs threads and close fits

Epoxy coat at a glance

Epoxy coat is strongest on corrosion protection (83 of 100), at a premium cost.

Corrosion protectionVery good83 / 100
Surface hardnessLow15 / 100
Cosmetic qualityGood55 / 100
LubricityLow15 / 100
Relative costPremium40 / 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.

Epoxy coat key numbers

Typical values from the governing specifications and shop practice; bars are this finish against the highest value among paint, powder & polymer coatings finishes.

Thickness50–200 µm2–7.9 mil
Salt spray500–1,000 h
Max service temp.120 °C248 °F
Thickness
50–200 µm depending on primer, topcoat, or lining duty
Hardness
2H–4H pencil hardness (ASTM D3363) — two-component epoxy, fully cured
Corrosion (salt spray)
500–1,000 h per ASTM B117 scribe creep, 100–200 µm two-component epoxy over blast-cleaned steel (typical) — System and film build govern; zinc-rich primers extend the figure.
Electrical
Insulating
Colours
  • gray
  • black
  • white
  • custom color
  • clear
Appearance
Smooth to orange-peel, usually gloss when new; outdoor exposure can produce chalking without a UV-stable topcoat.

Where Epoxy coat 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. Epoxy coat 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 26Copper plate — corrosion 32, hardness 39Decorative 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 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 & POWDERPowder coatWet paintType II anodizeZinc plateZinc-nickelHard chromeDLCTiN PVDTin plateCadmium plateE-coatCerakoteHot-dip zincNitridingHVOF coatingEpoxy coat — corrosion 83, hardness 15Epoxy coat
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 26Copper plate — corrosion 32, hardness 39Decorative 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 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 & POWDERPowder coatWet paintZinc plateEpoxy coat — corrosion 83, hardness 15Epoxy coat
Anodize & conversionPlatingPaint & powderHard coatings

Specifications for Epoxy coat

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

Drawing call-out

2K EPOXY COATING, LIGHT GREY, 100–150 µm TOTAL DFT; VERIFY ADHESION PER ASTM D3359, 4B MIN; MASK THREADS, SEALING FACES, AND WELD ZONES

Which materials take Epoxy coat?

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

Material familyVerdictNotes
Aluminum
YesUse an aluminum-compatible pretreatment or primer.
Steel
YesAbrasive blast preparation is commonly required.
Brass
With careAdhesion and tarnish bleed-through require a qualified primer system.
Copper Alloy
With careTarnish and adhesion must be validated; pretreat immediately before coating.
DMLS / SLM
With careMetal AM parts can be coated after powder removal and suitable pretreatment.
Magnesium Alloy
With careUse a validated conversion pretreatment and coat promptly.
Stainless Steel
With careAbrasion and compatible primer improve adhesion.
Titanium
With careNeeds mechanical profile and a compatible pretreatment.
Zinc Alloy
With careOutgassing and pretreatment must be controlled.
FDM
LimitedLayer lines and low-temperature polymers limit conventional oven-cured films.
MJF
LimitedPorous nylon can be coated after blasting and sealing.
Polymer
LimitedCure chemistry, stiffness, and solvent compatibility must be validated.
SLA
LimitedFully post-cure first; many oven schedules exceed resin limits.
SLS
LimitedPorous nylon can be coated after sealing; film build fills texture.

How Epoxy coat is applied, and what it does to the part

  1. 1Degrease
  2. 2Abrasive blast or pretreat
  3. 3Remove dust and salts
  4. 4Mask
  5. 5Mix components
  6. 6Spray
  7. 7Recoat within specified window
  8. 8Cure
  9. 9Inspect
DimensionsAt 50–200 µm per side, epoxy must be excluded from precision bores, threads, and mating faces unless allowance is designed.
Build-up per side50–200 µm — Dry film adds its full measured thickness on each exposed face.
MaskingUsually needed. Mask threads, fits, gasket lands, electrical contacts, and weld areas.
ElectricalInsulating
Temperature limit120 °C (248 °F) continuous
AppearanceSmooth to orange-peel, usually gloss when new; outdoor exposure can produce chalking without a UV-stable topcoat.
Added lead time3–7 working days on top of the bare part

Design rules for Epoxy coat

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

  1. State the surface-preparation grade separately from the coating.Epoxy adhesion depends on cleanliness and blast profile.
  2. Specify total dry-film thickness.Wet-film thickness does not equal cured buildup.
  3. Add a UV-resistant topcoat for exposed cosmetic service.Many epoxies chalk and lose gloss outdoors.
  4. Mask every threaded or sealing interface.A 50–200 µm film can prevent assembly or sealing.

Epoxy coat versus the alternatives

Finishes engineers weigh against Epoxy coat, and when each wins.

FinishCorrosionHardnessCosmeticCostThicknessChoose it when
Epoxy coat
this page
831555$$$50–200 µm—
Powder Coating
Epoxy coat vs Powder Coating →
831485$$50–150 µmwhen an oven-cured decorative metal finish is preferred
Wet Painting
Epoxy coat vs Wet Painting →
591090$$20–80 µmwhen broad cosmetic color and thinner film are primary
CorrosionHardnessCosmeticLubricityEconomy
Epoxy coatPowder Coating

The radar overlays Epoxy coat with Powder Coating, its most common alternative — chosen when an oven-cured decorative metal finish is preferred. Scores in the table are 0–100 across every finish in the catalog.

Cost, lead time and compliance

Relative cost

Epoxy Coating is a premium-cost finish ($$$): cheaper than about 55 % of the finishes FabDigit quotes.

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

Lead time and compliance

Added lead time3–7 working days
RoHSCompliant
NotesConfirm exact pigments, curing agents, solvent content, and intended chemical exposure.

What Epoxy coat is used for

  • Industrial tank exteriors
  • Pipeline components
  • Structural steel
  • Marine equipment
  • Machinery bases

Epoxy coat — frequently asked

epoxy coating vs powder coating

Epoxy can be applied as a liquid at ambient or moderate cure conditions and is strong as a chemical-resistant primer or barrier. Powder coating usually needs an oven and commonly produces a 50–150 µm decorative film.

how thick is epoxy coating

This catalog uses 50–200 µm as the typical range for industrial epoxy coating. Linings and multi-coat systems can differ, so total dry-film thickness must be specified.

is epoxy coating UV resistant

Many aromatic epoxies chalk and lose gloss under sunlight. Outdoor cosmetic systems commonly cover epoxy with a UV-stable polyurethane topcoat.

does epoxy coating stop rust

It is an effective barrier when the steel is correctly blasted and the film remains continuous. A scratch or poorly coated sharp edge can expose steel and allow underfilm corrosion.

can epoxy coating be used on threads

It should normally be masked from functional threads. Even 50 µm on each flank can tighten fit, while a 200 µm film can bridge thread detail.