Anaerobic Thread Locking Systems

Last edit date: 9/12/2023

Each Caltrans-authorized anaerobic thread locking system requires 3 components:

  1. CLEANER - to clean lubricant and oils from the threads of the stud and nut.
  2. PRIMER - to promote rapid curing of the anaerobic compound and to minimize migration of compound on threads.
  3. ANAEROBIC THREAD LOCKING ADHESIVE - to secure nut onto stud by filling the gap between nut and stud threads. Note: Anaerobic thread locking adhesive compounds will set only where no oxygen is available.

All components used in a single thread locking application shall be from one of the systems below and from the same thread locking adhesive manufacturer, following the Manufacturer’s Application Instructions for Caltrans-Authorized Anaerobic Thread Locking Systems.

Manufacturer Information Component Trade Name Part Number Expiration DateBABA Act Information*
Permabond International
480 South Dean Street
Englewood, NJ 07631
Adhesive Permabond HH120 HH120 6/9/2028Unconfirmed
Cleaner & Primer Perma-Lok Anaerobic Surface Conditioner ASC10 6/9/2028Unconfirmed
300 Eisenhower Lane North
Lombard, IL 60148
Adhesive Adhesive T77 High Strength Permanent Thread Locker 6/9/2028Unconfirmed
Cleaner & Primer Primer T 19166 6/9/2028Unconfirmed
Hernon Manufacturing, Incorporated
121 Tech Drive
Sanford, FL 32771
Adhesive Hernon Nuts N' Bolts Anaerobic Adhesive 429 3/1/2023Unconfirmed
Cleaner Hernon Cleaner 62 EF-62 3/1/2023Unconfirmed
Primer Hernon EF Primer 49 or 50 EF-49, EF-50 3/1/2023Unconfirmed

  1. Follow Manufacturer’s instructions for use.
  2. For any special requirements, consult with an engineer.
  3. Part numbers may vary based on amount of product purchased.

Caltrans contact: Structural Materials Testing Lab,

*As attested to by the supplier.

The California Department of Transportation (Caltrans) is implementing statutory changes required by the Bipartisan Infrastructure Law – Build America, Buy America Act (BABA), which expands Buy America to additional construction materials, in addition to steel or iron materials and manufactured products.