Screws, bolts, and other fasteners – without them, machines would literally fall apart. But what’s the best way to keep these critical components tight and secure? Engineers face a deadly serious choice between two adhesives: Retaining Compound vs. Threadlocker.
Join me on an adhesive adventure to settle this stick-off once and for all. We’ll weigh the pros, cons, and best uses of retaining compounds vs Threadlockers. Get ready for some bonding action as we face off against these threaded titans to see who will reign supreme! Whether you’re team blue or red, you’ll gain insider knowledge to find the perfect solution to keep your fasteners fabulously fastened.
❓ Retaining Compound vs. Threadlocker: What’s the Difference?
The main difference between Retaining Compound vs. Threadlocker is that: Retaining compounds create robust, gap-filling bonds between components while Threadlockers focus on sealing threads to prevent loosening and corrosion. Retaining compounds excel in high-load applications thanks to their strength and stress distribution, but Threadlockers allow for easier disassembly. Retaining compounds are preferred for permanent bonds with high loads, tolerance of gaps and dirty surfaces, and longer cure times. Threadlockers work best for accessible threaded connections needing vibration resistance and quicker curing without complete permanence.
Here is a basic application table for them
|Retaining Compound Use Cases||Threadlocker Use Cases|
|Bearings and Bushings: install bearings, bushings, and other cylindrical parts onto shafts and housings. The compounds fill tiny gaps between surfaces and create a strong, uniform bond that reduces slippage and fretting corrosion. They allow for stress-free assembly and ensure proper load transmission.|
Pulleys and Sprockets: ideal for securing pulleys, sprockets, gears, and other rotating power transmission components onto shafts. The compounds absorb shock loads, dampen vibration, and evenly distribute stresses.
Rotor and Stator Assemblies: Using a retaining compound when assembling motor rotors, stators, armatures, field coils, and other electrical components improves load transfer and protects against vibration damage.
Threaded Fasteners: Applying retaining compound onto threaded fasteners increases their load-carrying capacity and vibration resistance when assembling machines, vehicles, structures, and other high-stress applications.
Press and Shrink Fitted Joints: Retaining compounds augment press fit, shrink fit, and slip fit assemblies by enhancing bonding, especially in rough, dirty, or damaged component surfaces.
|Aerospace and Aviation Fasteners: Applying Threadlockers on bolts, screws, nuts and other threaded fasteners in aircraft and spacecraft provides resistance against vibration loosening and ensures critical connections remain intact.|
Industrial Machinery Maintenance: ideal for securing threaded fasteners in industrial machinery and equipment. They prevent the self-loosening of bolts and screws in high- vibration environments.
Appliance and Electronics Assembly:
Threadlockers securely fasten bolts, screws, and other threaded components in appliances, consumer electronics, computers, and other devices while remaining adjustable.
Outdoor Equipment and Recreational Products: Applying a Threadlocker during the assembly of outdoor, sporting, and recreational equipment helps secure connections and tolerates temperature extremes and chemical exposure.
We are going to take Lotite 680 (Retaining Compound) and Loctite 243 (Threadlocker) as an example to dive deeper into their difference.
Loctite 680 (Retaining Compound) is better for permanent, high-strength bonding of cylindrical parts with larger gaps, while Loctite 243 (Threadlocker) is preferred for accessible threaded fasteners that may require disassembly. The choice depends on the specific application requirements.
Read More: Loctite Vs. Permatex Threadlocker
📝 My Hands-on Test of Loctite 680 (Retaining Compound)
I found that this retaining compound works great when used correctly. Thoroughly cleaning both parts with brake cleaner or acetone is crucial before use. Additionally, Loctite 680 works even better when used with the appropriate primer for slip-fit applications. However, it sets quickly, so it’s essential to plan on assembling immediately.
One thing to keep in mind is that Loctite 680 sets up very quickly, especially if used with primer beforehand. I’ve used it with primer and found that it starts to cure within 60 seconds or less. I have yet to attempt to disassemble anything that I’ve used it on, but from what I have read online, it’s worse than trying to take apart stuff with red Loctite. I use 680 over red 271 only in situations where I never want to take two things apart, such as mounting studs that form part of an adapter or sleeves that will never need to be pressed out, etc.
It’s essential to work fast with Loctite 680, primarily when using primer before using it. This liquid sets up quickly and hard in a very short time. However, it works great when used to retain bearings. I used it for sleeving a wheel cylinder in brass, and the 680 setup instantly. The bond has never failed even once over many different repairs.
I was impressed with how Loctite 680 worked for me. I used it to replace a loose pusher button on my Chronograph watch, and it worked great. It also helped me attach a sling swivel and front sight barrel band to a Ruger No.1-A barrel. However, it’s important to note that it can be pricey, but it’s worth it, considering the money it saves you in repairs.
💬 FAQ of Loctite 680 (Retaining Compound)
Q: Can this be used to secure M2 taper chucks or arbors in place?
A: I have seen it used for that purpose, but for a more secure hold, I recommend using a clean shrink fit with a heated chuck and cooled arbor tapped together with a lead hammer. I have never had issues with slippage using this method.
Q: Is there a specific primer to use with this retaining compound for non-ferrous metal?
A: I have used this retaining compound successfully on plastic, aluminum, and all types of steel without a primer. It works well on these surfaces without one.
Q: Will this retaining compound provide a strong enough bond between a steel electric motor shaft and a bronze press-fit gear?
A: This retaining compound is quite strong, but I cannot confirm its suitability for this specific application. I have only used it for a small mounted micrometer that is moved manually.
Q: Does this retaining compound produce foam?
A: No, it does not foam.
Q: Is the bottle completely filled or partially filled?
A: The bottle is only partially filled, leaving some air space. This is because Loctite products need to cure in the absence of air.
Q: Can this retaining compound prevent metal roof screws from backing out?
A: Unfortunately, I don’t believe this retaining compound is suitable for your needs. The lock tight, threads on the bolt/but, and pressure are what create the bond. It only fills gaps of up to 0.015 inches, and it may be difficult to achieve such a small gap with sheet metal screws.
Q: Should I use this retaining compound for an AR-15 barrel extension to mate with the upper receiver, or stick with 620?
A: I recommend sticking with 620, as this retaining compound can be difficult to remove once the object is installed.
Q: I am interested in purchasing Loctite 680 for aircraft assembly. Can you tell me the expiration date?
A: I have only used Loctite 680 and cannot speak to the differences between the two products.
Q: What is the curing time for this retaining compound?
A: This retaining compound typically sets up within 5-10 minutes but should be allowed to set overnight, around 10 hours, for a solid bond.
Q: Is this retaining compound conductive?
A: While this retaining compound is made of plastic and is not inherently conductive, it could conduct electricity if there are voids or uneven surfaces, especially if high voltage or contact is made.
Q: I am looking for a product to repair a cold solder joint on a double-barrel shotgun. Can this retaining compound be used for that?
A: Unfortunately, you cannot repair a cold solder joint. It needs to be reheated, the proper flux used, and then cooled slowly.
Q: Can this retaining compound, along with a primer, hold a 15mm bicycle lug nut permanently, even against breaker bars? I plan to use heat to remove them for theft protection.
A: I have only used this retaining compound for precision work, so I’m uncertain if it can withstand the pressure of breaker bars. It’s designed for slip-fit applications, so it may not be as strong as red or blue Loctite.
Q: Can this retaining compound handle the high temperatures of an AR-15 barrel, or will it cook off?
A: Loctite 680 is primarily used for slip connections and is very strong, but it may not be ideal for threaded connections. If you plan to use it on the flash suppressor, compensator, or sound suppressor that is threaded on the end of the barrel, or to attach the barrel to the upper receiver, I recommend using Loctite 271 instead.
Q: Can this retaining compound work as well as Loctite 638 for bushings?
A: This retaining compound actually works better than Loctite 638 for bushings.
Q: Can this retaining compound be used to glue a hand-cranked meat grinder to a surface?
A: No, this retaining compound is not an adhesive glue and is only designed to fuse metal to metal through a chemical etching process.
Q: My retainer is broken. What kind of glue can I use to fix it?
A: Without knowing the specific details of your retainer, it would be best to consult Loctite’s application guide to determine the appropriate product for your needs.
📝 My Hands-on Test of Loctite 243 (Threadlocker)
One of the things that I appreciate about this product is that it works in almost all applications, and the blue Threadlocker is a bit softer, allowing for removal but keeping bolts tight. It does the job as it says and delivers great quality every time.
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Many times, I need to use a blue Threadlocker on something that I just can’t get all the oil off of, and the Loctite 243 has so far worked ok, but I’ve heard that it is better. Additionally, this material works great with grease’s presence, making it perfect for those who work on their cars.
I have used many Loctite products over the years, and I really like the locking spout under the cap of this one. The spout itself slides up and down to “seal” the bottle and prevent air from entering and curing the Loctite. The spout itself is graduated, and the opening is small enough that it makes metering out Loctite easy to do as opposed to the regular little tube where you get too much or nothing at all.
The container of Loctite 243 is a lot larger than I expected, and most of my Threadlockers are in really tiny tubes, but the stuff does go a long way, so this batch will likely last me a lifetime. Although the price seems high, considering how much product you get, the price seems fair.
I wanted to address some of the negative reviews I have seen on this product. Some people seem to think that this is somehow a ripoff when they receive the bottle and see that it’s about half full. I can guarantee that if you weigh this item, it will be just as described. This is enough Loctite to last most people a very long time even with a decent bit of regular use as you only need a couple of drops per application.
Read More: Blue Loctite 242 vs 243
Loctite 243 cures slightly faster and is less sensitive to surface cleanliness than Loctite 242, making it a better choice for medium-strength applications. Unlike Loctite 242, which requires a clean, dry, non-greasy surface on both items being connected and only works with ferrous materials, Loctite 243 works with any material and is more versatile while offering similar functional characteristics to 242.
💬 FAQ of Loctite 243 (Threadlocker)
Q: What are the benefits of using Loctite 243 over Loctite 242 for medium-strength applications?
A: Loctite 243 cures slightly faster and is less sensitive to surface cleanliness than Loctite 242, making it a better choice for medium-strength applications. Unlike Loctite 242, which requires a clean, dry, non-greasy surface on both items being connected and only works with ferrous materials, Loctite 243 works with any material and is more versatile while offering similar functional characteristics to 242.
Q: I’m interested in purchasing the product you have listed for sale, but the price difference between your listing and the usual market price seems suspicious. Can you explain this?
A: There is nothing suspicious about the price difference. You can order the product and see for yourself that it is 100% authentic and made in the United Kingdom. The product is being sold at a lower price due to our current promotion.
Q: Is it possible to remove fasteners using ordinary hand tools with Loctite 243?
A: Yes, ordinary hand tools can be used to remove fasteners that have been treated with Loctite 243. This threadlocker is designed to offer similar functionality to Loctite 242, but with greater versatility as it can work with any material and does not require a perfectly clean surface.
Q: Do you know the expiration date of the current stock being shipped?
A: While I cannot confirm the exact expiration date of the current batch of Loctite 243, I can attest to the freshness of the product I received from a previous order. The bottle I received was manufactured in April 2021 and had an expiration date of October 2022. It remained effective even after the expiration date.
Q: Is this Threadlocker safe for food use?
A: To my knowledge, Loctite 243 is not safe for food use.
Q: What is the break strength of Loctite 243? Is it suitable for use on zinc-plated nuts and non-plated bolts?
A: Loctite 243 is a medium-strength Threadlocker that can withstand a breakaway torque of 19ft/lb. It is suitable for use on threaded fasteners between 1/4″ and 3/4″ made of any material, including zinc-plated nuts and non-plated bolts.
Q: Can Loctite 243 be used to stop diesel leaks from threaded joints?
A: Loctite 243 can be effective in stopping diesel leaks if the threads are cleaned properly before application.
Q: Would Loctite 243 be suitable for holding copper tubes carrying hot water?
A: Loctite 243 is designed for use on threaded fasteners only and is not suitable for holding copper tubes together. Soldering is the recommended method for joining copper tubing.
Q: What is the temperature range for Loctite 243? Is it waterproof?
A: Loctite 243 has a service temperature range of -55 to +180°C. It is waterproof and effective for locking and sealing threaded fasteners. For greater security, Loctite 638 green can be used for permanent fastening, and Loctite red can be used for fastening that can be undone with heat.
Q: Is it necessary to reapply Loctite 243 after unscrewing and tightening a fastener?
A: Loctite 243 is a Threadlocker, not a sealant. If a fastener is disturbed, it should be re-applied.
Q: What is the drying time for blue Loctite?
A: Blue Loctite is a medium-strength Threadlocker that takes approximately 24 hours to fully cure.
Q: I ordered a bottle of Loctite 243 listed as in stock, but it now shows as on order and will take a month to arrive. Why is this happening?
A: Unfortunately, the discrepancy between the stated availability and actual delivery time may be due to unscrupulous merchants.