Loctite Blue vs Loctite Red: For dynamic, vibrating assemblies, blue provides the right balance of holding power and removability. But for permanence in securing studs and presses, red is unmatched.

Loctite Blue vs Loctite Red: What’s The Difference?

As I said, we need to compare different Loctite adhesives to get the difference between Loctite Blue vs Loctite Red.

1. Strength – Loctite blue products are medium strength, while Loctite red products are high strength. The red products offer stronger bonding and locking of threaded fasteners.
2. Disassembly – Loctite blue products allow disassembly with hand tools. Loctite red products require heating to disassemble parts.
3. Viscosity – Loctite blue products tend to have a lower to medium viscosity for wicking into threads. Loctite red products have a higher viscosity or gel-like consistency.
4. Cure speed – Loctite red products generally cure slower than blue products. The red products are better suited for large gaps or passive metals.
5. Temperature range – Loctite red products can withstand higher temperatures (up to 230°C) compared to blue products.
6. Applications – Blue thread lockers are good for vibrating assemblies while red is better for permanently locking studs. Red sealants work well on rigid flanged connections.
7. Color – The color coding helps identify the strength level – blue for medium strength, and red for high strength.

	Loctite 246	Loctite 243	Loctite 515	Loctite 518
Color	💙	💙	❤️	❤️
Description	Medium-strength anaerobic threadlocker	Medium-strength anaerobic threadlocker	Anaerobic flange sealant	Anaerobic gasket sealant
Datasheet	📥Loctite 246	📥Loctite 243	📥Loctite 515	📥Loctite 518
Fluorescence	Positive under UV light	Positive under UV light	Positive under UV light	Positive under UV light
Components	1K – requires no mixing	1K – requires no mixing	1K – requires no mixing	1K – requires no mixing
Viscosity	Medium, thixotropic	Medium, thixotropic	High viscosity	Thixotropic gel
Cure	Anaerobic	Anaerobic	Anaerobic	Anaerobic
Secondary Cure	Activator	None	None	None
Application	Threadlocking	Threadlocking	Sealing flanges	Sealing gaskets
Strength	Medium	Medium	High	Medium
Max Gap Fill	0.25 mm	0.15 mm	0.25 mm	0.25 mm
Temperature Range	-55°C to +180°C	-55°C to +180°C	-75°C to +150°C	-75°C to +150°C
Key Substrates	Steel, stainless steel, brass, zinc	Steel, stainless steel, brass, zinc	Steel, aluminum	Steel, aluminum, zinc
Typical Applications	Heavy-duty bolts, transmissions, rail, construction equipment	Threaded fasteners, gears, hydraulics	Pumps, thermostats, compressors Read More: Loctite 515 vs 518	Machinery casings, gearboxes

💙My Hands-on Test of Loctite 29513 Blue 246

In order to determine which product would be suitable for my specific needs, I reached out to Loctite’s tech support. They recommended this particular product, and I decided to give it a shot. I was working on my water-cooled motorcycle, specifically on the studs that hold the headers to the head. These parts needed to be removable, but I wanted to ensure they stayed securely in place until intentionally removed.

The high-temperature blue Loctite did not disappoint. Once applied, the set screws for my rifle gas block remained perfectly seated without any movement since installation. Its higher temperature rating compared to the standard blue Loctite made it the ideal choice for my application. I was thoroughly impressed with its performance.

Although the bottle size of the high-temperature Loctite is small, it is more than sufficient for numerous applications, as long as it is used properly. The price, considering the size, is reasonable in my opinion. I found it to be a worthwhile investment, especially for applications on engines where high temperatures are involved.

It’s worth mentioning that removing fasteners secured with this high-temperature Loctite can be slightly challenging, as heat is often required for disassembly. While this ensures a stronghold, it’s important to take this into consideration, especially if you anticipate the need for frequent removal.

In addition to automotive applications, this Loctite product also proved to be great for use in transmission and differential plugs. Its effectiveness extends beyond engines, making it a versatile choice for various needs.

💙My Hands-on Test of LOCTITE 243 Blue Medium Strength Threadlocker

✅Pros: Loctite Blue

Now, let’s compare Loctite to other threadlocker companies. Personally, I wouldn’t claim that Loctite is the best, but it works well enough for my task, and I have confidence that it won’t fail. I specifically chose the 243 version because my fasteners occasionally come into contact with oil, and I didn’t want to risk the threadlocker degrading. If you anticipate your fasteners encountering oil, I recommend the 243 version as it offers better durability in the long run compared to the 242 version.

I also used this Loctite Blue Medium Strength Threadlocker on my Magped’s screws.

Three things to check before riding Magped:

1. Check your magnet and ensure screws are tight.

2. Check pins – Hot tip🔥: Add a drop of Loctite 243 during installation to ensure they stay tight.

3. Check spindles, make sure they spin freely and they are tightened to the crankset.

And most importantly… enjoy the ride!

Feature Design

To address a common complaint I’ve seen about the bottle being half empty, I must clarify that it is intentionally designed that way. It’s not a flaw, but rather a feature. The bottle is supposed to be half full to prevent the product from curing inside and to allow you to mix the chemicals properly by shaking the bottle. It surprises me how many people complain without understanding that it’s for their own benefit. So, remember to shake the bottle thoroughly before each use to ensure it works correctly.

Bottle Design

Speaking of the bottle design, I must commend Loctite on their lock-type bottle. It’s incredibly convenient to use. After removing the white cap, the top of the needle applicator simply pushes forward to apply the Loctite, and when you’re done, it pushes closed again. This design makes application easy and mess-free. Furthermore, the needle doesn’t get clogged during application, and the bottle seals tighter, ensuring the Loctite lasts longer.

Value for Money

In terms of value, this larger bottle is a great investment. It offers a significant amount of product at a reasonable price. While it mayseem excessive for small or occasional use, it’s perfect for those who use Loctite frequently or for larger projects. Just make sure to consider the shelf life and purchase accordingly.

❌Cons: Loctite Blue

Now, let me address some concerns raised by other users. Some have mentioned that the bottle doesn’t come full, but that’s actually intentional. It’s not meant to be completely full. As I mentioned earlier, it’s designed to be half full to allow for proper mixing and prevent premature curing. So, don’t worry if your bottle isn’t completely filled.

❤️Test of Loctite 518 (Loctite 518 Gasket Maker Flange Sealant)

✅Pros

One of the standout features is that it dries in the absence of air, making it ideal for any press fit assembly. Fortunately, it worked exceptionally well for my needs, and any excess was easily cleaned up.

In terms of the product itself, it performed exactly as described. The seal it created was excellent, and I was particularly pleased with its size, which was just right for my requirements. The value for money was also impressive.

On a positive note, I have experienced the reliability of this product firsthand. Unlike the blue sealant I previously used on a PTO bolt, which would often let go and require the use of a torch for removal, Loctite 518 holds the bolt securely without the need for excessive heat. It has become my go-to option for such applications.

❌Cons

However, I must admit that I made a mistake when ordering and didn’t pay enough attention to the package size. To my dismay, when I received my order, I discovered that the tube was incredibly tiny. I needed to seal a swimming pool pump flange, and there was barely enough product to apply a very thin coat around it. I debated whether to even give it a try, but because I needed to get the pump back in service, I decided to proceed. At this point, I’m letting it dry overnight, so I’m still unsure if it will hold up. In the future, I’ll be more cautious and ensure I carefully consider the quantity before making a purchase. It’s possible that I’ll opt for a different product next time.

FAQ of Loctite 518