Loctite 37421 271 Red Heavy Duty Threadlocker

Q: Would this be 2 heavy for gun sight installation or just what i need?

It might be to much for 271. It was designed for larger treads 3/8 + hold, and might make it impossible to remove at a latter time because of inability to apply enough heat and torque to remove from small treads like a scope mount. use Blue which is for small threads

Q: Does this product require a primer? The fourth picture on Amazon suggests it does but the instructions do not mention a primer. Stainless + aluminum

I didn't need to. I used it on steel threads. Didn't even clean them. Applied this product and assembled. Hardened in minutes. I waiyed 24hrs before use just in case. Excellent product. I've used in the automobile repair industry for 30yrs.

Q: Would this be appropriate for the locking nut on a sink faucet, that is always coming loose and making the faucet wobble?

Oh god no! This is for applications of extreme vibration and areas that's could be extremely dangerous if a bolt or nut came loose. All you should need for you faucet is the blue loctite. After using the red, you would need some serious heat and a breaker bar to free that nut if you needed to replace that faucet in the future.

Q: if it is opened/used, how long will it stay fresh/usable?

Unopened/opened shelf life of Loctite 271 is two years from date of manufacture. Since exposure to oxygen is what keeps the liquid product stable, and it is packaged in a "breathable" plastic bottle, there is no change in shelf life once the product has been opened.

Product ID: 1998119

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Details

Brand
Loctite
Specific Uses For Product
Automotive DIY
Material
Metal-based
Item Form
Tube
Special Feature
Strong

🔥Heat-resistant up to 140°F

🔩High-strength bond for heavy-duty bolts

⏱️Sets in 10 minutes, full cure in 24h

Frequently Bought Together

Loctite 37421 271 Red Heavy Duty Threadlocker

Loctite Threadlocker Blue 242 Blue, 0.2 fl oz, 1, Tube

LOCTITE 242 Threadlocker for Automotive: High-Temp, Medium-Strength, Anaerobic | Blue, 6mL Tube (PN: 37418 - 487229)

Description

🔧 Lock it down like a pro — no slip, no stress!

SHOCK VIBRATION PROOF - Engineered to secure components under extreme mechanical stress
FAST SETTING CONVENIENCE - Get your project moving with a quick 10-minute set time and full strength by next day
EASY DISASSEMBLY WITH HEAT - Strong hold that releases with localized heating and simple hand tools
UNIVERSAL METAL COMPATIBILITY - Works flawlessly on stainless steel, aluminum, and plated surfaces—even oily ones
PROFESSIONAL GRADE RELIABILITY - Trusted by OEMs and pros for critical automotive and industrial use

LOCTITE 37421 271 Red Heavy Duty Threadlocker is a professional-grade adhesive designed for securing large bolts and studs (≥1 inch) in automotive and industrial settings. It bonds to all metals, tolerates minor oil contamination, sets quickly in 10 minutes, and fully cures in 24 hours. Resistant to shock, vibration, chemicals, and temperatures up to 140°F, it ensures durable, reliable fastening with easy heat-assisted disassembly.

Specifications

Brand	Loctite
Specific Uses For Product	Automotive, Industrial, DIY, Furniture, Heavy-Duty
Material	Metal-based formulation
Item Form	Tube
Special Feature	Strong
Color	Red
Item Package Quantity	1
Package Information	Tube
Item Volume	6 Milliliters
Viscosity	Low viscosity
Full Cure Time	24 Hours
Water Resistance Level	Water Repellent
UPC	079340374218
Global Trade Identification Number	00079340374218
Manufacturer	Loctite
Model	LOCTITE 271 Threadlocker for Automotive \| Red, 6 ml Tube
Item Weight	0.16 ounces
Product Dimensions	6.5 x 3.81 x 0.8 inches
Item model number	37421
Is Discontinued By Manufacturer	No
Exterior	Packaged
Manufacturer Part Number	37421
OEM Part Number	37421
Special Features	Strong

Have a Question? See What Others Asked

Would this be 2 heavy for gun sight installation or just what i need?

Does this product require a primer? The fourth picture on Amazon suggests it does but the instructions do not mention a primer. Stainless + aluminum

Would this be appropriate for the locking nut on a sink faucet, that is always coming loose and making the faucet wobble?

if it is opened/used, how long will it stay fresh/usable?

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