Sealing Function : discover our data sheet!

Pre-coating is an innovative and economical technique that advantageously replaces many sealing systems such as flat seals, O-rings, sealing pastes, anaerobic resins and Teflon strips.

Our special machinery allows us to produce small series (1000 pieces) as well as large series (1 million pieces) on a very wide range of applications.

New data sheet available! Download it here :

Sealing under blind nut heads – Precote 200

 Under-heads sealing

of screws & crimped parts

Sealing of threaded joints – Precote 5

Sealing of threads

on all types of parts

Sealing of tubes – TB2353

Sealing of tubes and

stocketed parts

Sealing under M2 screw heads – Precote 200

Sealing combined

with locking function


The sealing function is often both complex and costly to obtain in mechanical assemblies. The pre-coating of fasteners makes it possible to ensure a completely reliable, easy-to-use seal with no installation costs.

The product we apply to your parts is dry, non-sticky and completely localized.

During assembly, whether by screwing, press fitting or crimping, fills in spaces in the
assembly to ensure an immediate sealing

A variety of fluids can be sealed using the pre-coating technique:

  • Compressed air and gas
  • Oils and hydrocarbons
  • Cooling liquids and brake liquid
  • Water for spraying or immersion
Sealing of engine stud threading – TB2353


  • Elimination of costs for workshop or construction site assembly
  • Replaces O-rings or flat seals as well as difficult-toapply
    pastes and liquid resins.
  • Perfect seal: 100% sealing with no leakage.
  • Flawless quality: the sealing system is guaranteed and visible
  • Immediate sealing after assembly, up to 50 bars for certain assemblies.
  • High admissible pressures
  • Sealing level of up to IP67
  • Control of technical parameters
  • High resistance to chemicals
  • Works on all types of metal as well as on plastic parts


Pre-coating involves applying a bead of product under the heads of screws for an immediate seal following assembly. Their re-use depends on the shape and profile of the interface.

Sealing of screwed parts :

  • M2 to M4 electronics screws
  • Screws for plastic
  • Standard screws
  • Threaded plugs

Sealing of crimped parts :

  • Blind rivet nuts
  • Clinch studs
  • Small head rivet nuts
Sealing under heads
precote-200 crimping nut
Sealing under heads of threaded screws for plastic – Precote 200


  • Tension is maintained in screwed assemblies as the metal-to-metal contact is maintained.
  • Compact sealing function design
  • No added parts (washers, paste, etc.)
  • Streamlined industrial process: automatic assembly using a vibrating bowl, etc.
  • A lower overall cost than traditional solutions


Sealing on automotive plug threading – TB2353


  • Screws, axis, studs
  • Stoppers and connections for fluids
  • Sensor and contactor plugs
  • Special parts
Precote 15 - special sealing part

Pre-coated parts can be used for a variety of applications including electronics, automobiles, motorcycles, household appliances, electric motors…


  • A more effective substitute for flat seals and O-rings
  • Prevents loss of clamping force due to vibration
  • Simplified industrialization in air, water or oil circuits
  • Good heat and chemical resistance


Soprima has developed special expertise in the pre-coating of socketed parts.

Our pre-coating technique for tubes, axis and other smooth parts offers superior technical performance and substantial savings in a variety of sectors


  • Pump outlet cannula and rigid pipes
  • Press-fitted socketed smooth nozzles
  • Grit removal plugs
Sealing on grit removal plugs – TB2353
Sealing on fitted connectors – TB2353

This type of sealing is primarily used in the automotive sector to seal many engine components.


  • Robust sealing for automobile fluid circuits
  • 0 ppm application quality on large series
  • Replaces Banjo-type threaded connections
  • Effective on aluminium, steel or stainless steel bar-turned tubing or seamless drawn tubing
  • Replaces in-line bonded grit removal caps


Fasteners to be sealed can also be secured to prevent loosening by adding a locking product to the threading: a micro-encapsulated adhesive such as threadlock or polyamide resin for repositionable parts.

Under some conditions (fluid, pressure, assembly design), locking products can also provide the sealing function on the threading.


We offer a wide range of products to meet a wide variety of sealing needs.

*Datasheet upon request

Sealing under heads of clinching inserts – Precote 200
Sealing under heads of countersunk screws – Nyseal
Sealing of cannulas – TB2353


Our sites are all ISO 9001 certified and our quality systems meet the specific requirements of the automotive and aeronautics industries.


Our products have been certified by a variety of automotive standards:

  • Renault CDC 39.02.010
  • PSA B14.12.35
  • Volvo STD 1262.2
  •  Ford WX 201


Discover our new data sheet on the sealing function of parts!

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