Both red and green Loctites are strong and well-respected threadlockers and adhesives that can be used around the house and with automotive repairs. But is there any real difference between the two?
While both red and green Loctite form fast and strong bonds on materials, red tends to be better on high-vibration jobs such as automotive work, whereas green Loctite works great around the house. But there are some places where you should not be using one or the other, and some contexts in which neither is suitable.
Keep reading to learn more about the differences between these two Loctite categories, and where they can best be implemented.
Red Loctite is a Threadlocker
Red Loctite is first and foremost, a threadlocker. This means that it’s specifically formulated to help seal threading on metal components such as automotive parts and metal piping.
If you need a water-proof or gas-leak-proof bond, red Loctite is your friend. It’s incredibly tough and does great as a long-term solution for automotive parts as well as sensitive and potentially dangerous gas lines.
Red Loctite is primarily a sealant for metal threading and works well against leaks, vibrations, and even moderate shock to a system or threaded bond.
Green Loctite Does a Bit More
Green Loctite is also classed as a threadlocker, but it can do a bit more and works well in very delicate as well as larger jobs. It works great with preassembled components such as electronics, radio-controlled hobby items, and helps protect against rust and corrosion.
It’s a medium-to-high-level threadlocker and works well in settings where the maximum hold in the most extreme conditions is not a variable. For example, it will work just fine for basic home repairs, hobby items, and electronic parts. It works well on metal as well as plastic and threaded PVC piping.
Green and Red Need Both Heat and Torque
Both red and green Loctite, however, have an incredibly strong bond. They set very firm, and will likely require a combination of heat as well as torque to remove. This means you’ll need to get the bonded material pretty hot, and then use a wrench to help loosen the components.
This makes them ideal for jobs that are going to be more permanent, and won’t need to be disassembled any time soon. It also makes them ideal for jobs where human safety is paramount, such as personal vehicles, bikes, safety equipment repairs, and scaffolding.
Liquid vs. Anaerobic
While Red Loctite comes in a liquid or an anaerobic form, Green Loctite is available only as a liquid. Anaerobic adhesives bond especially well to steel in the absence of oxygen, but don’t do as well with plastic, rubber, or other metal materials. Liquid adhesives, on the other hand, often perform well on a variety of surfaces.
So if you need a bond that will work on any material, go for a liquid adhesive or threadlocker. Red and green both come in liquid forms, but the existence of red Loctite as an anaerobic indicates that red is specially formulated for metal bonds.
The curing time for both of these materials is 24 hours. They should take 15-20 minutes to set, but allow 24 hours to fully cure before starting up your machinery or resuming water or gas flow within a pipe.
You can use an activator on both materials to help improve drying time or improve bonding to porous surfaces, but the curing time will still need to be respected for safety reasons.
Vibration and Shock
Both red and green Loctite do very well in situations where the components are facing moderate levels of vibration and shock.
Red Loctite is especially prized for its suitability in high-vibration elements, and for handling things like bumps, jolts, and rough driving. Green performs very well but is better suited for projects that won’t take as much punishment as a Jeep or an ATV.
So if your threading job is going to be subjected to continual punishment and fact a lot of jarring, rough maneuvers, go with red Loctite. It’s best in the long run and can handle rough driving.
Red is Great for Metal
While both red and green Loctite types work great on metal, Red is superlative at very permanent bonds on metal. As mentioned earlier, its anaerobic form is great for sealing metal bonds and keeping all liquid or gas inside of a metal piping.
Red Loctite also does great for structural bonds such as bolts and threading used in home construction. Need the hold to last a lifetime? Need your house to stay upright? Use red Loctite. It’s great for construction and any sort of truly permanent bonding.
Green is a Wicking Sealant
Green Loctite is actually classed as a wicking sealant as well as a threadlocker. This means that it works very well with pre-assembled threaded components, and can penetrate especially well into tiny cracks, porous holes, and dimples in a material.
This makes it especially well-suited for creating a waterproof or vapor-tight seal within metal, as it is adept at filling in even the tiniest cracks or gaps in metal threading.
This makes it a great choice for anything you may need to be truly watertight. So if your threading job needs special protection against the elements, or needs to be especially leak-proof, green is a great choice. It also tends to adhere very well, and can even be applied post-assembly.
Green is Great for Smaller Projects
If you’re doing smaller tasks around the house or putting together radio-controlled electronics, green Loctite is a great choice. It’ll hold fast, but won’t be so firm that it could cause materials to be excessively brittle or inflexible.
Red Loctite is amazing on tougher projects, but more delicate jobs where a bit of flexibility may be needed would benefit a bit more from green Loctite. Green Loctite also does well on everyday repairs and maintenance work on items like bicycles, mopeds, and even fishing equipment.
It’ll keep your metal parts secure and protected from loosening and give you years of protection. It can also help you with medium-intensity bonding jobs, including small structure assembly (such as storage sheds or cabinets), and garage repair.
Both Are Best for Permanent Jobs
The thing to keep in mind is that both red and green Loctite types are going to be suited for metal threading jobs that don’t need to come apart any time soon. If you need to hold to be tough, strong, and last a while, both will work.
They are going to be a bit of a pain to remove in either case, and if your job is going to require a lighter hold, or you’d like to be able to undo the adhesive hold with just a wrench, go for blue or for purple Loctite. Those color categories can give a stronghold but require no heat to undo.
When to Not Use Either
There are certain contexts where neither red nor green Loctite is going to be a good option. Never use Loctite in place of threading. If your metal threading is worn or rusted, no amount of Loctite will compensate for the extra strength of metal threading.
Any bolts that you’ll have to remove frequently aren’t a good match for Loctite. Loctite is too permanent to be used on temporary jobs, or on light-duty bolts.
Tips and Tricks
Whether you use red or green Loctite, here are a few things to keep in mind. Cold temperatures can increase the amount of time needed to fully cure the threadlocker, so if you’re working in cold temperatures or outdoors in the Winter, give your Loctite at least 48 hours to fully cure.
Using anaerobic red Loctite? Use it with iron, but not with “inactive” metals like zinc or stainless steel. Liquid red or green Loctite can be used on any metal, but check all material handling instructions to be extra sure.
If you’re re-locking components, get all of the old threadlocker off first. This will help keep your job smooth, and safe, and avoid any dangerous leaks or gaps in the sealant. Simply brush off the old, dried threadlocker with a metal brush before applying the new adhesive.
Both red and green Loctite types work well for a secure and long-lasting bond. Green Loctite is a wicking formula and can be applied post-assembly. It works great on bikes, mopeds, and fishing equipment, too. Red Loctite in its anaerobic form is best with steel, whereas liquid red and green can be used on a variety of metals.
Red Loctite is best for bonds that will take the maximum amount of punishment, such as ATVs, Jeeps, and other vehicles likely to see intense and life-long jolts and vibrations. Neither red nor green Loctite is well suited for projects that will have to be disassembled soon after, or often. Both need 24 hours to cure, or 48 hours in cold temperatures.
Neither is a substitute for strong or safe metal threading. If the metal threading on your job is worn, corroded, or inadequate, invest in new hardware. It’s worth the expense to keep you safe and keep your equipment running well.