Dri-Loc 203 Silver.
Low-strength, dry-to-touch pre-applied thread locker and sealant for assemblies where the joint needs to be locked and sealed — but also accessible when the time comes. One dry film handles both functions. Inert in storage, cures on assembly, seals while it locks. The Dri-Loc grade for smaller fasteners, instruments, and serviceable assemblies.
Normal lead time 1–2 weeks — from receipt at our dock to processed parts back on yours. Rush accommodated on request. Customer pays inbound and outbound freight; F.O.B. St. Charles, IL.
STRENGTH
LOW
CONTROLLED TORQUE
TEMP RANGE
300°F MAX
CONTINUOUS SERVICE
CURE
ROOM TEMP
ON ASSEMBLY
FUNCTION
LOCK
+ SEAL
REUSABLE
NO
SINGLE-INSTALL
Lock and seal in one film — at a strength the joint can come apart.
Dri-Loc 203 is the low-strength, dual-function member of the Loctite Dri-Loc film family — the answer when the assembly needs to resist vibration loosening and seal against fluids, but the fastener also needs to come out cleanly without heat or impact tools.
The 203 formulation is a water-based film that bonds to the fastener thread and cures anaerobically on assembly. Where high-strength grades like 200 Yellow and 204 Red are engineered for joints that should never back out, 203 Silver is engineered for a different brief: provide enough holding force to prevent vibration loosening, seal the thread against fluid migration, and still release cleanly under normal hand-tool torque when the time comes.
On assembly, mechanical compression between mating threads excludes air and triggers cure. The joint resists vibration and seals simultaneously — one process step replacing both a thread locker and a separate liquid sealant. The film is consumed at install. Removal does not require extended torque or heat, but the coating is gone after the first disassembly; reinstall requires reapplication.
The silver pigment gives the line a clear visual distinction from the yellow (200/201) and red (204) grades — essential in production environments running multiple Dri-Loc SKUs simultaneously. A QA tech can confirm the correct low-strength grade is applied without touching the fastener. 203 Silver is the go-to callout for carburetor and fuel-metering screws, small instrument fasteners, and any threaded joint where the service manual will eventually call for disassembly.
SPEC AT A GLANCE
Why engineers reach for 203 Silver
Low strength with dual lock-and-seal function — the Dri-Loc grade for smaller fasteners, instruments, and assemblies where controlled removal matters more than permanent hold.
- FAMILYDri-Loc 203
- CHEMISTRYWater-based film
- STRENGTHLow · Controlled removal
- FUNCTIONLock + Seal (dual)
- VISUALSilver · Inspectable
- TEMPUp to 300°F
- SUBSTRATESee substrate section
- SERVICESingle-install
The Loctite Dri-loc 203 numbers, plainly.
The full datasheet is available below — these are the values engineers most often need before specifying. Anything missing, ask the engineering desk.
PRODUCT FAMILY
Loctite Dri-Loc 203SILVER
Low-strength member of the Dri-Loc dry-film family. Dual function — thread locker and thread sealant in a single pre-applied film. Distinguishable by silver pigment.
CHEMISTRY
Water-BasedDRY FILM
Anaerobic-cure resin in a water-carrier film. Inert until air is excluded by mating thread compression. Film is dry to touch in storage.
STRENGTH RATING
LowCONTROLLED TORQUE
Low-strength grade. Provides thread locking without the high break-loose torque of 200 or 204. Removal possible with hand tools without heat — film is consumed; reinstall requires reapplication.
FUNCTION
Lock + SealDUAL
Unlike single-function thread lockers, 203 seals against fluid and gas leak paths simultaneously with the locking action. One film, two jobs.
TEMPERATURE RANGE
Up to 300°FCONTINUOUS
Continuous-service ceiling to 300°F. Short-duration excursions higher are tolerated; consult engineering for sustained service above this limit.
CURE MECHANISM
AnaerobicRT · ON ASSEMBLY
Cure begins when air is excluded by thread engagement. No oven step. Initial cure within minutes; full cure within 24 hr at room temperature.
VIBRATION RESISTANCE
YesSUSTAINED
Maintains preload against vibration despite low-strength classification. Recommended for assemblies that see vibration but require periodic service access.
REUSABILITY
NoSINGLE-INSTALL
Film is consumed at install. For reusable mechanical lock, see Bradley Nylon Patch.
VISUAL ID
Silver PigmentQA-INSPECTABLE
Silver color allows visual batch inspection. Unique in the Dri-Loc line — no other SKU uses silver, making 203 immediately identifiable in mixed-SKU production runs.
FASTENER SIZE RANGE
M3–M36#4 – 1.5 IN
Application across the standard fastener-size envelope. Low-strength grade is particularly well suited to smaller screw sizes (M3–M8). Larger or specialty sizes — consult engineering.
MANUFACTURER SPECS