A. There are different grades of Loctite® Threadlockers to refer to different strengths. For example, the purple Loctite® Threadlocker is low-strength, blue Loctite® Threadlocker is medium and red Loctite® Threadlocker is high-strength; the green Threadlocker is a special wicking-grade product that allows faster and deeper penetration through the assembled parts.
A. Loctite® Threadlockers and Loctite® Thread Sealants are designed for specific purposes and applications and should not be used interchangeably. A Loctite® Threadlocker adhesive locks and seals the threaded parts with stronger locking/bonding strength. On the other hand, a Loctite® Thread Sealants seals threaded parts tighter to withstand very high pressure but with lower bonding/locking strength.
A. Loctite® offers a wide range of threadlockers with color-coded packaging to help users understand the different threadlocker grades for different applications. Refer to the Technical Data Sheet for more information.
The following quick guide can be used to narrow down your choice for Loctite® Threadlockers:
- What are the assembled parts made of? Refer to Active and Inactive Materials chart above for examples and decide whether to use the activator/primer or not.
- Do you want the assembly to be removable later for servicing? If so, a low-strength (purple) or medium-strength (blue) Loctite® Threadlocker is the appropriate product, since hand tools can be used for disassembly - with some effort. If not, a higher-strength Loctite® Threadlocker (red) is suggested, but the assembly may still be loosened with heat and hand tools. Careful product selection is needed, depending on each application requirement.
- What is the thermal resistance requirement for the assembly? If the heat resistance in excess of 300°F (150°C) is needed, it is recommended that Loctite® 272 Threadlocker to be used.
- What Loctite® Threadlocker to use if the parts are oily? Loctite® 243 Threadlocker works on slightly oily threaded parts.
- If I have bolts and nuts of different sizes, what Loctite® Threadlocker adhesives to use? The Technical Data Sheet contains the approximate, relevant guideline for the bolt size pertaining to Loctite® Threadlockers. In general, for small bolt/nut assemblies, a low- or medium-strength Loctite® Threadlocker is suggested over a high-strength; otherwise in the process of disassembly later, the small bolts may break if the high-strength adhesive is used.
A. Anaerobic adhesives are not recommended for use in systems that contain pure oxygen or oxygen-rich environments, chlorine or strong oxidizing substances.
A. Threadlockers are thermoset polymers, which means they will not melt like typical thermoplastic (PET-soda bottles, polystyrene-coffee cups, hotmelts, and polyethylene-bags). The first thing to happen when you heat a part assembled with a threadlocker is the thermoset plastic actually gets harder and more dense because the heat drives more cross-linking. As the temperature continues to rise, the plastic eventually becomes brittle, and upon continued heating, the cured material will begin to degrade and char. This weakens the bonds and allows for disassembly.
A. Loctite® 243 Threadlocker can be applied to a slight oily surface, whereas Loctite® 242 Threadlocker needs a surface cleaning.
A. No solvent will wick into the joint to break the threadlocker down. This is either hand-tool removable at room temperature; if not, it requires high temperatures of 450-600°F (212-316°C) to separate parts. The products are thermoset plastics in the cured state that soften at higher temperatures. Thus, you need to disassemble while at the higher softening-point temperature. Do not let it cool down first. Otherwise, it will resoldify. Solvents like methyl ethyl keytone and methylene chloride can be used for clean up of residue only after disassembly.
A. Yes, you can. Traditionally we recommend Loctite® Retaining Compounds like Loctite® 609 or Loctite® 603 but threadlockers are the same base chemistry and could be substituted in many cases. In fact, years ago, Loctite® 271 Threadlocker was referenced as Stud and Bearing Mount. Inversely, you could use retaining compounds to lock threads, so long as you're cognizant of the fact that most will permanently lock the threads.
A. Loctite® does not sell any electrically conductive threadlockers. There are a handful of silver-filled electrically conductive epoxies, but these were formulated to replace solder connections on a printed circuit board. These products are so highly filled/dense that they probably wouldn't fit between threads.
A. For thru-hole applications, such as a nut and bolt combination, Loctite® Threadlocker is applied just to the bolt, coating 3 or 4 threads, going all the way around the diameter, and then assemble. On the other hand, it is critical to apply the threadlocker to both male and female threads for blind-hole applications, such as a bolt going into a closed housing. If it is applied just to the male threads and torqued down, air pressure will force most of the product back out as you assemble. This will result in incomplete coverage and partial cure only, leading to premature failures.
A. Our general statement is that threadlockers will support fungus growth that is already present but will not promote growth otherwise. Many threadlockers conform to military specifications. These specifications (Mil-S-22473E, MIL-S-46163) state that the polymerized compound will not support the growth of fungus when tested to the requirements of the military specification.
A. Loctite® 222 Threadlocker is sold worldwide and is not tested to any military-specification standard. Loctite® 222MS is sold in North America and not ldworwide; it happens to be tested to Mil-S-46163A Ty II Grade M standards for existing designs. Other than this, the formulations are very similar.
A. When we apply a threadlocker to bolt and finger tighten a nut down, we let it sit for 24 hours and allow it to fully cure. We then take a torque wrench and break the bond. The initial reading on the unseated assembly is the breakaway value (remember, this is not torqued to a specified value, such as 11N.m (100 in lbs). This shows us the strength of the threadlocker alone. They then continue turning it; the average of four-quarter turn provides us with our prevailing torque value. This shows us how much friction or drag is left to continue turning the nut. If, on the other hand, we torque the assembly down to 11N.m (100 in lbs), and we use a threadlocker with a breakaway of 6N.m (50 in lbs), the breakloose value initially on this seated assembly is 17N.m (150 in lbs) (100+50). The difference between what you torque this down to - 11N.m (100 in lbs) - and what you breakloose at - 17N.m (150 in lbs) - is 6N.m (50 in lbs). This is referred to as torque augmentation.
The main function of any threadlocker is to maintain your torque. It has been determined that over time, due to various factors, such as vibration and side sliding, you lose up to 30% of your on torque. In order to maintain your torque over time, the goal is to choose a suitable threadlocker that provides a breakaway value equivalent to 30% of the torque you apply to the assembly
A. The Loctite® Threadlocker Stick products are similar but not identical to liquid products. Their chemistry and function is the same but there are some distinct differences. Stick products are not recommended for blind-hole applications. Blind-hole applications require applying product to both male and female threads and this would be very difficult to do with the stick formulations. The stick products yield strength values that vary some from their liquid counterparts. See the TDS's for specific data. Also, the stick products are not tested to any military standards like their liquid counterparts.
A. Loctite® Threadlocker Calculator on www.iLoctite.com can help you with the calculation. You simply plug in the quantity and dimension of bolts and nuts you need to assemble; the Calculator will tell you the volume of Loctite® Threadlocker needed for your job. Or you can do it the other way around: Select the dimension of bolts and nuts you need to assemble and plug in the volume of Loctite® Threadlocker. The Calculator will tell you how many assemblies it can do. Click here for Loctite® Threadlocker Calculator.