Thermoseal™ 400 is an ND pre-applied process in which a hybrid microencapsulated high-pressure sealant with medium strength threadlocking capabilities is applied to fasteners. Thermoseal self-locking and self-sealing fasteners are able to meet the demands of high temperature, high pressure applications where other thread sealing materials would fail. Thermoseal processing may also provide a lower coefficient of friction than other thread sealants to help with ease of installation.

ND Thermoseal 400

How it Works

Thermoseal processing involves the application of two-part, dual-encapsulated dry film adhesives to male or female fasteners. Upon installation with a mating part, shear forces cause the microsphere capsules to rupture, mixing the two components, initializing the reaction and curing to form a strong chemical bond and effective seal.

Thermoseal 400 processing creates a fastener with exceptional sealing properties and the ability to withstand pressures up to 40MPa. In addition, it prevents loosening due to vibration, shock, and thermal effects. Thermoseal fasteners can replace the need for PTFE tape due to its better reproducibility and speed of installation.


Versatile Application

Thermoseal pre-applied fasteners provide excellent protection from pressure, heat and loosening due to vibration, shock, and thermal effects. Thermoseal processing creates both a self-locking and self-sealing fastener through its reactive curing technology.

High Pressure Seal

Thermoseal processed fasteners are able to withstand high sealing pressures with burst pressure in excess of 5800 psi (40MPa) under challenging conditions.

Chemical Resistant

Upon installation, the adhesive in Thermoseal fasteners create a cross-linked molecular structure making it one of the most resistant types of adhesives. Oil, gasoline, salt spray, acids, solvents, and water have virtually no effect on parts when introduced after final cure.

Surface Insensitive

Thermoseal processing is compatible with most fastener sizes, configurations, materials and finishes. The use of an epoxy based microsphere adhesive ensures that a strong reliable lock and seal are formed.

Secure Lock

Once cured, a medium strength lock is formed which helps prevent loosening under vibration or reversal of stress and greatly reduces the need to re-tighten fasteners.

Long Shelf Life

Thermoseal processed fasteners have an on-part life of 1 year and will remain inert until a cure is activated by engagement with a mating thread.


  • Saves Time: ND’s Thermoseal Pre-Applied service utilizes custom build in-house equipment to coat your fasteners at extremely high rates. In addition, our rapid turn around time and fast customer service lead to significant time savings.
  • Saves Money: Bulk Thermoseal fastener pre-application to fasteners is less expensive than hand applying bottled thread sealing compounds at the point of assembly. It also eliminates the need for costly lock washers, cotter pins or castellated nuts.
  • Quality Control: The Thermoseal Pre-Applied process is strictly controlled by ND to meet and reduce variation between parts. Fasteners are coated to specification, insuring consistent performance from fastener to fastener and lot to lot.


  • Breakaway Torque: M-10 bolt. Zinc Test Nut @24 hr: >20 Nm
  • Fixture time: 8 minutes @ 72°F
  • Full cure time: 24 hours @ 72°F
  • The adhesives used in Thermoseal are normally applied one to three threads back from the end of a fastener to assure ease of starting.
  • It is recommended that Thermoseal fasteners are not reused.
  • *Shelf life of un-activated part is 12 months when stored in a dry, cool environment.

Thermoseal Competes With

  • N/A – Thermoseal 400 is a ND Industries exclusive process.


Ring gear bolts, Head Bolts, Chassis Hardware, Intake Manifold Bolts, Military and Defense, Large Appliances, Off Road Equipment, Farm Equipment, Construction Fasteners, Aerospace, Agricultural Equipment
Thermoseal 400 detail

Compatible Fasteners

External Threads:Internal Threads:Rivets:
Banjo Bolts, Hex Bolts, Flange Bolts, Wheel Bolts, Machine Screws, Cap Screws, Wood Screws, Sheet Metal Screws, Self Drilling Screws, Shoulder Bolts, Fully Threaded Studs, Double Ended Studs, Singled Ended Studs, Press-In Captive Studs, Carriage Bolts, Lag Bolts, Socket Screws, Set Screws, Eye Bolts, Eye Lags, J-Bolts, U-Bolts, Elevator Bolts, Hangar Bolts, Perforated Base Studs, Through Hole Weld Studs.Flange Nuts, Hex Body Clinch Nuts, Prevailing Torque Nuts, Floating Nuts, Hollow Bolts, Insert Nuts, Lock Nuts, Weld Nuts, Barrel Nuts, Chicago Bolts, Jam Nuts, Wing Nuts, Square Nuts, Self-Locating Projection Weld Nuts (WN/WNS), Spot Weld Nuts, Projection Weld Nuts, Bridge Spot Weld Nuts, Tab Spot Weld Nuts, Square Projection Weld Nuts, Flange Weld Projection Nuts, Stamped Flange Weld Nuts, Spot Weld Cage Nuts.N/A

Don’t see your parts on this list? We process thousands of different types of fasteners and depending on the quantity will gladly look at whether we can accommodate yours as well.

Technical Data

ProcessColorPrimary UsePrevailing On TorqueBreakaway TorqueTemp MinTemp MaxLubricityPressure Resistance**
Thermoseal™ 400TurquoiseHigh Pressure Seal, Medium Strength Lock<2.5 Nm> 20 Nm-40°F (-40°C)428°F (220°C)0.19<= 40 MPa

**Coated parts assembled into aluminum block and submersed in the test fluid and heated for 30 days then tested at temperature for sealing and tested for breakaway torque when cooled. Assembled parts tested at 40MPa (5801 PSI).

Safety, Technical & Process Data Sheets

Process NameMaterialSafety Data Sheet (Applied)Technical Data Sheet (Applied)Process Data Sheet
Thermoseal400Thermoseal™ 400 - SDS (Applied)Thermoseal™ 400 - TDS (Applied)Thermoseal™ PDS
Increase product quality while saving time and money with Pre-Applied adhesives and sealants.