Brass-Loc 2020 Purple.
Pre-applied threadlocker and sealant for brass fittings — formulated to work on brass without corroding it. A microencapsulated activator in the coating is released by thread engagement and initiates the cure, filling thread voids and locking the assembly. Low to medium strength, dual lock-and-seal, 300°F rated. Also suitable for plated finishes.
Standard lead time 1–2 weeks — from receipt at our dock to coated parts back on yours. Rush accommodated on request. Customer pays inbound and outbound freight; F.O.B. St. Charles, IL.
STRENGTH
LOW-MED
VIBRATION-RATED
FUNCTION
LOCK+SEAL
DUAL
SUBSTRATE
BRASS
+ PLATED
TEMP RANGE
300°F MAX
CONTINUOUS
REUSABLE
NO
SINGLE-INSTALL
The threadlocker built for brass — so the fitting stays put without corroding.
Brass-Loc 2020 is the only Loctite pre-applied threadlocker specifically formulated for brass fittings and copper alloys. Where standard anaerobic threadlockers can interact with copper ions to cause inhibited cure, staining, or corrosion on the fitting surface, Brass-Loc uses a different cure mechanism that avoids this problem entirely.
Standard Dri-Loc grades cure anaerobically — the cure is triggered by oxygen exclusion when threads engage. Brass and copper alloys are known to inhibit anaerobic cure and can produce a galvanic reaction that stains or corrodes the fitting surface. Brass-Loc 2020 solves this by using a microencapsulated activator: the activator is contained in microscopic capsules within the coating. When the fitting is assembled and the threads engage, shear forces break the capsule walls, release the activator, and initiate the cure. No copper-ion interaction, no inhibited cure, no corrosion.
The cured film fills all the voids in the thread profile and locks the assembly against vibration loosening. The same film seals the thread against motor oils and water/glycol solutions — the two fluid types most common in automotive and industrial pressure-fitting applications. Low to medium strength means the fitting can be serviced if required, though the coating is consumed on cure and reapplication is needed after disassembly.
Brass-Loc 2020 is also suitable for plated fasteners and fittings — not just bare brass. The microencapsulated activator mechanism is compatible with zinc-plated, chrome-plated, and similar surface finishes where standard anaerobic cure can also be partially inhibited. Application range includes pressure gauges and sensors, brake fittings, pipe fittings, adjustment screws, shower heads, fire sprinklers, and door closure hardware — the same applications where brass fittings are standard.
SPEC AT A GLANCE
Why engineers reach for Brass-Loc 2020
The only Loctite pre-applied threadlocker and sealant formulated to work on brass without corroding it. Microencapsulated activator mechanism. Low to medium strength. Dual lock-and-seal for brass fittings and plated fasteners.
- PRODUCTLoctite Dri 2020 / Brass-Loc Purple
- CHEMISTRYWater-based, microencapsulated activator
- STRENGTHLow to medium
- FUNCTIONLock + Seal (dual)
- SUBSTRATEBrass (primary) — also plated finishes
- VISUALPurple — conventional low/medium signal
- TEMP300°F continuous (-65°F to 302°F full range)
- MECHANISMMicroencapsulated activator — not standard anaerobic
- REUSABLENo — single install
- KEY FLUIDSMotor oils and water/glycol solutions
Loctite Purple Brass Loc by the numbers.
The full datasheet is available below — these are the values engineers most often need before specifying. Anything missing, ask the engineering desk.
PRODUCT
Loctite Dri 2020BRASS-LOC PURPLE
Also marketed as Brass-Loc 2020 and LOCTITE DRI 2020. The Brass-Loc designation identifies it as the brass-safe member of the Loctite pre-applied threadlocker family. Purple color is consistent with low-to-medium strength across the Loctite product system.
CHEMISTRY
Water-BasedMICROENCAPSULATED ACTIVATOR
Unlike standard Dri-Loc grades (which cure anaerobically via oxygen exclusion), the 2020 uses a microencapsulated activator. During thread engagement, the shear force breaks the capsule walls and releases the activator, which initiates the cure. This mechanism is brass-compatible; standard anaerobic curatives can interact with copper ions in brass and cause corrosion or inhibited cure.
BRASS COMPATIBILITY
BrassPRIMARY SUBSTRATE
Formulated specifically for brass fittings and fasteners. Standard anaerobic threadlockers can corrode brass or produce inhibited cure on copper-containing alloys. The 2020 avoids this problem by using a different cure mechanism. Also suitable for plated finishes — confirm specific plating types against the TDS.
STRENGTH RATING
Low to MediumVIBRATION-RATED
Rated low to medium strength — the fitting can be serviced if required, though the film is consumed on cure and must be reapplied after disassembly.
FUNCTION
Lock + SealDUAL
Both locks the fastener against vibration loosening and seals the thread against fluid migration — motor oils and water/glycol solutions. The microencapsulated film fills thread voids on cure, creating both the mechanical lock and the fluid barrier.
TEMPERATURE RANGE
300°F-65°F TO 302°F
Maximum continuous service temperature of 300°F (150°C). Full operating range: -65°F to 302°F (-54°C to +150°C) — the same 300°F ceiling as most Dri-Loc grades.
VIBRATION RESISTANCE
YesPOST-CURE
After the microencapsulated activator cures, the assembly resists vibration loosening. Vibration resistance is a function of the cured film, not the uncured coating.
REUSABILITY
NoSINGLE-INSTALL
Film is consumed on cure. Not reusable — same as Dri-Loc high-strength grades. For reusable brass fitting sealant, see the Vibra-Seal or Dri-Seal family (though those are not specifically formulated for brass compatibility).
KEY APPLICATIONS
Brass Fittings+ PLATED FASTENERS
Rear axle filler plugs, bearing adjuster nuts, pressure gauges and sensors, brake fittings, pipe fittings, compressor pipe plugs, cable connectors, screws for plastic assemblies, adjustment screws, overhead fire sprinklers, shower heads, and door closure hardware.
VISUAL ID
PurpleLOW-TO-MED SIGNAL
Purple is the conventional Loctite color for low-to-medium strength products (standard Loctite 222 is also purple). Provides visual batch inspection in production environments.
MANUFACTURER SPECS