Dri-Loc 204 Red.
High-strength, dry-to-touch pre-applied thread locker for plated and stainless steel fasteners. Inert in storage, cures on assembly, seals while it locks. The only standard Dri-Loc SKU with NSF approval for potable water — specified into water-system, marine, and heavy-duty automotive prints where plated or stainless is the fastener finish.
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
HIGH
VIBRATION-RATED
TEMP RANGE
300°F MAX
CONTINUOUS SERVICE
CURE
ROOM TEMP
ON ASSEMBLY
SUBSTRATE
PLATED
+ STAINLESS
REUSABLE
NO
SINGLE-INSTALL
High-strength hold on plated steel, stainless, and potable water joints.
Dri-Loc 204 is the broadest-substrate member of the Loctite Dri-Loc red film family — the answer for assemblies where the fastener is plated or stainless, the joint cannot back out, and the application may include a potable water or NSF-regulated environment.
The 204 formulation is a water-based film engineered to bond on plated and stainless steel substrates — the two most common surface conditions in precision automotive, marine, and industrial plumbing fastener programs. Stored on the shelf, the film is dry to the touch and dimensionally stable; it does not migrate, does not pick up dust, and does not activate prematurely.
On assembly, mechanical compression between mating threads excludes air from the film and triggers cure. The resulting joint resists loosening from cyclic loading, thermal cycling, and high-frequency vibration. It is not designed to be serviced. Removal is possible with extended torque or applied heat, but the film is consumed in the process; reinstall calls for reapplication. Full cure occurs within 72 hours at room temperature — no oven step required.
204 Red carries NSF approval for potable water applications — the only standard SKU in the Dri-Loc line with this designation. That makes it the default callout for water-system hardware, food-equipment fasteners, and any print where an NSF-listed thread locker is a procurement requirement. The red pigment reinforces the message: red is the assembly line’s universal signal for a permanent, high-strength bond that the next tech should not disturb without cause.
SPEC AT A GLANCE
Why engineers reach for 204 Red
Three reasons it shows up on plated and stainless prints — works on both substrates, NSF approved for potable water, and the red pigment is a universally-understood permanent-lock cue.
- FAMILYDri-Loc 204
- CHEMISTRYWater-based film
- STRENGTHHigh · Vibration-rated
- VISUALRed · Inspectable
- TEMPUp to 300°F
- SUBSTRATEPlated & stainless steel
- NSFPotable water approved
- SERVICESingle-install
The 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 204RED
High-strength member of the Dri-Loc dry-film family for plated and stainless steel fasteners. Distinguishable on inspection by red pigment. NSF approved for potable water applications.
CHEMISTRY
Water-BasedDRY FILM
Anaerobic-cure resin in a water-carrier film. Inert until air is excluded by mating thread compression. Water-based carrier evaporates on shelf; film is dry to touch.
STRENGTH RATING
HighVIBRATION-RATED
Designed to maintain preload under sustained vibration loading. Removal requires extended torque or applied heat. Not intended for field service.
TEMPERATURE RANGE
Up to 300°FCONTINUOUS
Continuous-service ceiling to 300°F. Short-duration excursions higher are tolerated; consult engineering for sustained service above 300°F.
CURE MECHANISM
AnaerobicRT · ON ASSEMBLY
Cure begins when air is excluded by thread engagement. No oven step. Initial cure within minutes; full cure within 72 hrs.
SUBSTRATE COMPATIBILITY
Plated & StainlessSTEEL
Formulated for both zinc-plated and stainless steel fasteners — broader substrate range than Dri-Loc 200 (P&O only) and 201 (plated/bright). See substrate section for detail on brass and P&O surfaces.
NSF APPROVAL
YesPOTABLE WATER
NSF approved for potable water applications. The only standard Dri-Loc SKU carrying NSF approval. Required callout on water-system fastener prints.
VIBRATION RESISTANCE
YesSUSTAINED
Validated against industry-standard cyclic-load tests. Maintains preload through extended duty cycles under thermal and mechanical loading.
REUSABILITY
NoSINGLE-INSTALL
Film is consumed at install. For reusable mechanical lock, see Bradley Nylon Patch.
VISUAL ID
Red PigmentQA-INSPECTABLE
Red is a universally understood permanent-lock color cue. QA tech can verify coating presence across an entire batch with a glance. Pigment is consistent across the fastener length.
FASTENER SIZE RANGE
M3–M36#4 – 1.5 IN
Coatable across the standard fastener-size envelope. Larger or specialty sizes — consult engineering.
MANUFACTURER SPECS