Loctite Red Vs Blue: (The Ultimate Strength Battle)

Workers face a common issue at automotive maintenance, and that is the vibrational loosening of the fasteners. And the solution to this common problem is a Loctite threadlocker.

The old mechanical initiatives for solving the problem are not that fruitful. In contrast, the Loctite adhesive can offer you much more without breaking your bank. These threadlockers are separated by colors, and among them, blue and red are vastly used.

However, there are dissimilarities between Loctite red vs blue.

Loctite blue – the general-purpose threadlocker is ideal for fasteners up to 20mm. And Loctite red will be suitable for up to 27mm. If you are looking for a permanent assembly, the red one will be an ideal choice.

Check out the in-depth comparison to choose the right one for you!

What is Loctite Red?

The Loctite red refers to methacrylate-based threadlocking adhesive with high strength. It offers permanent fix for the fasteners.

There are various types of red adhesive, and some salient features are given below –

Red 262:

This one is a permanent strength thread locker for fasteners up to 3/4″, beneficial for holding tight Grade 5 and 8. As it is designed for extreme conditions, it protects threads from rust and corrosion.

Localized heating and hand tools are required for disassembly. The temp range is from -65 to 300 degrees F. Take full 24 hrs for curing.

Features –

  • Chemical Type: Anaerobic
  • For Fastener Dia: Up to 3/4 in
  • Begins to Harden: 10 min
  • Gap Fill: 0.005 in
  • Flash Point: Greater Than 93.3 Degrees C
  • Specific Gravity: 1.05
  • Viscosity: 1800 to 5000 cP

Red 272:

Loctite 272 adhesive is another high-strength threadlocker for extreme duty applications. It is suitable for fasteners up to 1-1/2 in diameter. It takes 60 minutes to get hardened, and the cure time is 24 hours.

Loctite 272 fills a gap around 0.01in. and can tolerate the temperature to -65 degrees to 450 degrees F. It is ideal for applications where any migration of the adhesive must be prevented. The flash point is greater than 93.3 degrees C. The specific gravity is around 1.11 and comes with 9500cP viscosity.

Features –

  • Chemical type: Anaerobic
  • Shear Strength: 2900 psi
  • Tensile Strength: 200 psi
  • Fixture Time: 40 min.
  • Fixture Time Temperature: 104 °F
  • Full Cure Temperature: 77 °F
  • Thread Size (Maximum): M80

277 – Red:

This one comes with high strength for locking fasteners up to 1 1/2″. The temperature ranges from -65 to 300 degrees F. The cure speed is around 60 min and takes full 24 hrs. It is suited to large threads.

Features –

  • Breakaway torque on M10 bolts: 32 Nm
  • Chemical Type: Anaerobic
  • For Fastener Diameter: Up to 7/8 in
  • Gap Fill:01 in
  • Flash Point: Greater Than 93.3 Degrees C
  • Specific Gravity:12
  • Viscosity: 7000 cP

What is Loctite Blue?

Loctite Blue comes with a medium strength which is enough to place the nuts in the spot without becoming too tough to remove.

There are mainly two types of liquid – Loctite blue 242 and Loctite blue 243 –

Loctite 242:

The Loctite Threadlocker 242 is utilized for valve cover bolts to carburetor studs. It is suitable for less active substrates such as stainless steel and plated surfaces. It requires normal disassembly with standard hand tools.

Features –

  • Cure Time: Up to 24h depending on the substrate used and temperature.
  • Full Cure Temperature: 77 °F
  • Specific Gravity:07 g/l
  • Specific Gravity Temperature: 25 °C
  • Temperature: -65 – 300 °F
  • Thread Size (Maximum): R3/4″
  • Torque Break on M10 Steel: 110 in./lb.
  • Torque Prevail on M10 Steel: 43 in./lb.
  • Viscosity: 800 – 1600 mPa.s (cP) Brookfield
  • Cure System: Anaerobic
  • Flash Point: >93.3 °C

Loctite 243

The Loctite threadlocker 243 is also a medium-strength adhesive that is based on acrylic technology. Don’t worry if the threads are a little dirty, as this one can withstand high temperatures, oil contaminations, varied fluids, and anti-corrosion.

Above all, the plated fasteners won’t need a primer if you apply this upgraded version.

Features –

  • Fixture Time: 5 – 10 min.
  • Full Cure Temperature: 77 °F
  • Specific Gravity:08 g/l
  • Specific Gravity Temperature: 25 °C
  • Chemical Type: Anaerobic
  • Temperature: -65 – 360 °F
  • Thread Size (Maximum): R3/4″
  • Torque Break on M10 Steel: 230 in./lb.
  • Torque Prevail on M10 Steel: 40 in./lb.
  • Viscosity: 1300 – 3000
  • Viscosity Temperature: 77 °

Ultimate Comparison Between Loctite Red vs Blue

Loctite thread lockers with different colors come with various aspects. Let’s check out the comparison chart of Loctite Red And Loctite Blue and choose the right one –

Type   Typical color code Torque to break free

(38-16 size bolt)


     Torque to continue turning
Medium strength Blue 115 in-lb (12 N⋅m) 53 in-lb (6 N⋅m)
Medium strength surface insensitive Blue 180 in-lb (20 N⋅m)           62 in-lb (7 N⋅m)
High strength Red 230 in-lb (25 N⋅m) 225 in-lb (25 N⋅m)
High temperature Red 180 in-lb (20 N⋅m) 270 in-lb (30 N⋅m)



Loctite blue are medium strength thread lockers, and medium strength is great for fasteners up to 20 mm. It can easily be disassembled by hand tools.

In contrast, Loctite red is a high-strength one and has a strong bond that cannot be removed easily. It will fluoresce under UV light to allow for quality control and monitoring. Threading up to 27 mm in diameter can be secured by this thread locker.

However, the full cure time is 24 hours for both of them, and they are suitable for all metal fasteners.


Loctite locker blue 242 or 243 can simply be removed by the bolt and nut with normal hand tools.

On the other hand, as the Loctite red thread locker is a high-strength thread locker, they will require more than 550° F or 220°C localized heat to weaken the bond.

For this, you will need a blowtorch and a wrench. Wear heat resistance safety gloves and safety glasses for protection. Heat the fastener with the blow torch for 2 to 3 minutes. Make sure to move the torch around to heat all sides evenly. Now turn off the blowtorch and remove the nut with the wrench.


If you want a hold that can be easily removed, use the blue one. It can handle minor contamination to industrial oils. So, it’s perfect for motorized and non-motorized parts that need occasional servicing like car parts (oil pans, water pumps), or motorized yard equipment, bicycle, furniture, etc. This is great for fasteners like oil or coolant drain bolt, motorcycle front fork bottom bolt, and more. It can be used on any material.

On the other side, if you want the bolt never to come out, go with the red one. It has many applications, particularly for safety, such as steering components. This is great for heavy equipment, suspension bolts, motor, and pump units, bearing cap bolts, and studs.

As mentioned before, it can only be removed with heat greater than 500° F. So never use it on plastic parts because the plastic will melt at this temperature.


There are four types of Loctite blue thread lockers. They are Loctite 242, 243, quick tape 249, and blue stick thread locker. Loctite 242 and 243 are all-purpose thread lockers. The latter one is recommended as it is the upgraded version of 242 with better features.

In contrast, Loctite 262, 263 271, 272, 277 are red ones. Here, Loctite 271 has low viscosity, 272 had medium, and 277 has the highest consistency. So the latter one can secure thicker fasteners than the former one. Use the Loctite 271 red for securing the tiniest gaps.

Some Recommended Products –

Products Name Features Price
Loctite Threadlocker 242


·       Removable grade up to 3/4” bolts

·       1200/6000 thixotropic viscosity

·       Torque In. ibs – 115/53

·       Specific gravity – 1.07

Loctite 1329467 243 Blue 


·       up to 3/4” bolts with light oil contamination

·       2250/12000 thixotropic viscosity

·       Torque In. ibs – 180/62

·       Specific gravity – 1.08

Loctite 231926 Red 262


·       Permanent locking up to 3/4” bolts

·       1800/5000 thixotropic viscosity

·       Torque In. ibs – 190/275

·       Specific gravity – 1.05

LOCTITE 272 HIGH Strength


·       High temperature applications

·       9500 viscosity

·       Torque In. ibs – 200/220

·       Specific gravity – 1.11

Loctite 277 442-21434


·       High strength for large bolts

·       7000 viscosity

·       Torque In. ibs – 275/275

·       Specific gravity – 1.12



Which One To Choose – Loctite Blue or Red?

There are many Loctite products to cater to a broad array of applications. These various products are color-coded to help you distinguish one threadlocker from another.

The red adhesive comes with the highest strength and available in both a liquid and a semisolid anaerobic configuration. In contrast, the blue bond comes with medium strength and also available in liquid and semisolid ones. You will need heat to disassemble the red adhesive parts but the blue adhesive can be removed by hand tools.

Loctite red will fluoresce under UV lighting to offer quality control and monitoring. It is for heavy equipment, motor, and pump mounts, suspension bolts, bearing cap bolts, studs, and so on.

The medium strength adhesive needs 100 ft Ibs of torque to break the seal. In contrast, the highest strength one requires 275ft Ibs to break the seal.

So the main difference between Loctite red and blue is their strength and removability. Blue ones are easily removable with medium strength, while red ones are strong and more permanent.


Does Blue Loctite work on plastic?

You should not use Loctite blue around any plastic components. The “gases” break down the plastic at the time of curing when it’s close.

Is Loctite waterproof?

All threadlocker is waterproof. They are applied as a liquid. And in the absence of air in contact with an active metal, they turn to a solid thermoset plastic.

Final Words

So, which one is the winner of the battle – Loctite red vs blue, according to you? Always keep in mind the caveats while using the products. And focus on the preferences before choosing among Loctite purple vs red vs blue vs green.

Are you getting confused about Loctite 277 vs 272? Let me know in the comment section!

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