Pre-Applied Thread Coating
Color Coding Guide
Pre-applied thread coatings — microencapsulated threadlockers, nylon patch coatings, and thread sealing coatings — use color coding for quick visual identification of coating type and function. This guide explains frequently used color conventions across leading coating manufacturers including Precote, ND Industries, 3M, Nylok, Vibra-Tite and APET, organized by strength grade and function, for automotive, industrial, and engineering fastener applications.
Important — Color Does Not Determine Coating Performance
Coating performance is determined by the coating chemistry and applicable standards — DIN 267-27 (microencapsulated adhesives), DIN 267-28 / IFI-124 (nylon patch coatings), and OEM specifications — not by color. Color is used primarily for visual identification and quality control on assembly lines. There is no ISO or ASTM standard that mandates specific colors for pre-applied thread coatings. Color selection is entirely supplier- and application-dependent.
No International Standard Mandates Coating Colors
While certain colors are commonly associated with specific coating types across major suppliers, color selection ultimately remains supplier- and application-dependent. OEMs frequently specify completely custom colors for their fastener programs. As Precote explicitly states: "specified color is not a primary product feature."The conventions below reflect frequently used industry practices — not binding standards.
Frequently Used Color Conventions
Common color conventions used by major pre-applied coating manufacturers, organized by coating type, function, and strength grade.
Supplier Color Reference
Default colors used by major global suppliers, alongside APET's own standard range. Colors may vary by product grade, customer specification, or regional preference.
| Supplier | Medium Strength | High Strength | Very High / Torque | Thread Sealant |
|---|---|---|---|---|
| Precote / Nylok | Yellow (#FFD600) | Pink (#E91E63) | Turquoise (#00BFA5) | White |
| ND Industries | Yellow TA300 | Red TA800 | Turquoise TA850 | White / Orange ST-3 |
| 3M | Blue 2353 / Yellow 2353Y | Orange 2510 | — | Clear / Light Blue 4291 |
| Nylok Patch | Blue (default) | Red (default) | — | — |
| Vibra-Tite | Blue VC-3 | Red VC-6 | — | White (PB Thread Seal) |
| APET (India)★ Our Standard | Blue / Yellow | Red / Pink | Turquoise / Orange | White |
How to Select the Right Coating — Decision Guide
Do you need sealing against fluids or gases?
Is frequent disassembly required?
What locking strength is required?
Technical Notes on Coating Colors
Pigments are Chemically Inert
Color pigments used in thread coatings (iron oxides, titanium dioxide, ultramarine) do not affect adhesive chemistry or cure performance. Precote explicitly confirms: color does not alter locking or sealing function.
No Heavy Metal Pigments
All major suppliers, including APET, comply with RoHS and REACH regulations. No cadmium, lead, or chromium pigments are used. Pigments are selected for chemical stability and compatibility with the adhesive or nylon matrix.
Custom Colors Available
Most suppliers — including APET — can provide custom colors on request for OEM applications. Custom colors help brand identification but do not alter coating performance. Minimum order quantities typically apply.
Color Used for QC Verification
Color is used as a visual QC indicator (AOI) on assembly lines to verify coating presence and coverage area. Slight color variation between batches does not indicate performance variation.
Green & Purple — Less Common
Green and purple are less common in pre-applied coatings but may be used in proprietary or customer-specific formulations. They appear more frequently in anaerobic liquid adhesives than in factory-applied coatings.
Color is Supplier & Application Dependent
While certain colors are commonly associated with specific coating types, color selection ultimately remains supplier- and application-dependent. Always verify coating type and performance specification — not just color, even against this guide.
APET Typical Color Options
APET follows commonly used industry color conventions aligned with major coating suppliers. Custom colors are available on request for OEM customers — including yellow nylon patch, custom microencapsulation colors, and special thread sealant shades.
* Nylon patch coatings may be supplied in blue, red, yellow, green, or custom colors depending on application requirements. Contact APET to discuss your specific color requirement.
Need a Specific Color or Custom Coating?
APET provides custom color pre-applied thread coatings for OEM and industrial applications. Share your fastener spec, coating type, strength requirement and preferred color. Our engineering team responds within one business day.