Frequently asked questions
Here’s a list of queries with responses that might help you.
We need to reopen the fastener. Can Loctite threadlockers be removed?
Yes, LOCTITE threadlockers can be removed as and when needed. The low strength grade of LOCTITE threadlockers can be removed by giving a loosening torque which is higher than the tightening torque. The medium and high strength LOCTITE threadlockers can be removed by applying localised heat (250 degrees celsius) to the part, for disassembly.
How can we visibly determine whether LOCTITE threadlocker has actually been applied to the nut and bolt or not?
All LOCTITE threadlockers have the property of fluorescence. When you disassemble, you can easily find out by white powder on the bolt, that whether LOCTITE threadlocker has been applied or not. In uncured form, LOCTITE threadlocker can be identified by its color (Purple-Low strength; Blue-Middle Strength; Red-High Strength)
Our bolting locations are such that it is difficult to reach for application of threadlocker. Is there a LOCTITE threadlocker that can help?
Yes. With LOCTITE 290, which is the wicking grade LOCTITE threadlocker, you can lock the nuts and bolts that are difficult to reach for application otherwise. You can just apply a few drops near the joint where the bolt head meets the part, and LOCTITE 290 will wick inside the nut-bolt interface due to capillary action.
Can LOCTITE threadlockers migrate to and jam other parts?
No. LOCTITE threadlockers are thixiotropic in nature and hence don't tend to flow to other parts. Also, LOCTITE threadlockers only need to be applied on the nut-bolt interface and once the nut covers the area where LOCTITE threadlocker was applied, the adhesive will get cured in the absence of air and presence of metal, thereby turning into a thermoplastic, which cannot flow.
LOCTITE threadlockers being liquid, will create a mess during application to which our operators will object. How can we deal with that?
LOCTITE threadlockers come with a nozzle for precise drop-by-drop application. Hence, there is no scope for a mess. In case of any spillage, you can wipe it off easily because as long as LOCTITE threadlocker is in contact with air, it will remain a liquid and not cure at all.
The fasteners used to hold our machinery are big and there is constant load and vibration exerted. Is there a LOCTITE threadlocker that can help?
Yes. There are some high strength threadlockers that can lock fasteners that are big and resist extreme vibrations. Please refer to the product selector tool.
If LOCTITE threadlockers cure in the absence of air, why don’t they cure inside the bottle?
The anaerobic bottles are specially formulated. Air-permeable polyethylene bottles allow air to pass through the wall. There is also some air gap over the product inside the bottle to maintain stability of the product. Thus a 50 ml pack of LOCTITE contains 50 ml adhesive in a much larger bottle.
What is fixture time?
The fixture time is the time taken by the adhesive to provide initial handling strength to the locked/sealed components. Once the fixture time gets over, you can take the assembled component for further processing on the assembly line.
What is cure time?
The cure time is the time taken by the adhesive to completely become a tough structural solid (thermoset plastic).
Can I use a threadlocker for non-threaded assemblies like locking bearings on bushings in housings or on shafts?
Yes, you can. Normally we recommend retaining compounds like LOCTITE 638 for such applications, but threadlockers and retaining compounds both are same in terms of chemistry i.e. they are anaerobics. Inversely, you can use retaining compounds to lock threaded assemblies but the locking would then be permanent.
Can I use anaerobics where one or both parts are made of plastic?
Anaerobics are generally not recommended for use with plastics as they might result in stress cracking or softening. In such cases, cyanoacrylates are recommended.
Do I need to use a primer with LOCTITE threadlocker?
We recommend the use of primer where both the parts come under the category of 'inactive surfaces'. These metals lack the iron or copper content and thus the metallic ions are required to fully cure the product within 24 hours. These inactive surfaces include plated parts, stainless steel, galvanized steel and anodized aluminium to name a few. On the other hand, in case both or at least one part is an active metal, then there is no need to use a primer to ensure full cure which is typically within 24 hours at room temperature.
Can LOCTITE threadlockers be used on oil impregnated parts?
Yes. LOCTITE 243 can be used on oil impregnated parts, as it can cut oil effectively and lock properly. Just clean the part once before applying the product.
What is breakaway torque?
When we apply a threadlocker to a bolt, we hand tighten a nut down and let this sit for 24 hours to get fully cured. Now we take a torque wrench and break the bond, the torque needed to break the bond is the breakaway torque. Note that we haven't given any additional tightening torque to the parts. Thus, the breakaway torque gives us the strength of the threadlocker alone.
What is prevailing torque?
When we apply a threadlocker to a bolt, we finger tighten a nut down and let it sit for 24 hours to get it fully cured. Then we take a torque wrench and break the bond. After breaking the bond, we continue to turn the nut around by four quarters(360°), which provides us with the prevailing torque value. This shows us how much friction or drag is left to continue turning the nut.
What is breakloose torque?
When we apply threadlocker to a bolt, we tighten it by giving a tightening torque. The torque at which the nut can entirely be taken off is the breakloose torque. The main function of the threadlocker is to maintain the torque. It has been determined that over time, due to various factors like vibration, side sliding etc., there is a loss of upto 30% of the torque given to the parts. The goal is to select a threadlocker that would give you a breakaway value equivalent to 30% of the initial torque in order to maintain your torque over time. For eg: Let's say that a tightening torque of 10 Nm was given to the assembly. The breakaway torque (strength provided by the threadlocker) is 5 Nm. Now due to vibrations, there is a 3 Nm loss in tightening torque. So if you do not apply a threadlocker, your assembly tightened at 10 Nm will open at 7 Nm. Whereas, by applying a threadlocker, your assembly tightened at 10 Nm will have the total torque of (10+5) 15 Nm and even on 30% loss, it will open at 12 Nm, which is higher than your tightening torque. This is what is known as torque augmentation with LOCTITE threadlockers.
What is the proper way of applying LOCTITE threadlockers for blind hole applications?
In order to ensure complete coverage and cure, apply LOCTITE threadlocker to both the male and female threads for blind hole applications such as a bolt going into a closed housing. If it is applied only to the male threads and torqued down, air pressure will force most of the product back out as you assemble.
Can the curing process of anaerobics be accelerated via heat?
Yes, heat can help achieve faster cure. Typically one can heat cure LOCTITE threadlockers at 125 degrees celsius for 1 hour, or go as low as 66 degrees celsius for 3 hours. The trade-off here is that there will be a reduction in strength to a certain extent. Please refer to the Technical Data Sheet of the selected product for testing the suitability.
How do I determine how much threadlocker I need to apply?
We have developed a calculator to help you with the amount of LOCTITE threadlocker you need for your application.
How do I select the right threadlocker to suit my requirement?
To make the job of selecting the right product for your requirement easier, we have developed a product selector tool. Just enter your requirements and the tool will get back to you with the best solution.
Will LOCTITE thread sealant be able to withstand pressure >200 bar?
Yes. LOCTITE thread sealants can take pressures upto 689 bars on a conservative basis and with dimensionally stable threaded assemblies, LOCTITE thread sealants can be used at upto 1000 bar.
Do Loctite products contaminate the fluid media?
LOCTITE products when cured, harden into a thermoset plastic which does not mix with the fluid media that is flowing through the pipe. Hence there is no contamination. If some materials remain cured, they get dissolved in fluid media.
How do I know whether LOCTITE thread sealant is compatible with the fluid or not?
LOCTITE thread sealants are compatible with a wide range of fluid. Please check the Fluid Compatibility Chart for the concerned fluid.
Can I use LOCTITE thread sealant on pipes that carry oxygen or other strong oxidizers?
We do not recommend the use of LOCTITE anaerobic thread sealants for fluid media like oxygen. However, we do have a special variant which is compatible with such media. Please contact us for more details.
Can the curing of LOCTITE thread sealant be expedited?
Yes. In case you need immediate testing, use LOCTITE 55 which once wrapped around the joint, gives instant sealing.
How to disassemble a joint which has been sealed with LOCTITE thread sealant?
It is easy to disassemble joints sealed with LOCTITE thread sealants with standard hand tools. In case that is not sufficient, use localized heat upto 250 degrees celsius, and disassemble while hot.
When is a LOCTITE thread sealant fully cured?
The cure speed of LOCTITE thread sealant depends upon the thread material, thread size and temperature. For fine thread sizes, full cure can be obtained within 24 hours. For faster curing requirement, use of Primers 7649 or 7471 is recommended. Please refer to Technical Data Sheet of the chosen product for further details.
Since the LOCTITE thread sealants are liquid, will they create a mess during operations?
LOCTITE thread sealants are thixotropic in nature and hence will not flow to other areas. Also, LOCTITE thread sealants come with a nozzle for precise application on the joint engagement area. Hence, there is no scope for a mess. In case of any additional amount coming out of the nozzle, you can wipe it off easily because as long as LOCTITE thread sealant is in contact with air, it will remain a liquid and not cure at all.
When should a Primer be used with LOCTITE thread sealants?
It is highly recommended to use Primers 7649 or 7471 with inactive thread surfaces like stainless steel, aluminium, plated surfaces etc., to ensure complete seal. Also, use of Primers is recommended in case you need faster curing.
Which thread sealant is best for plastic joints?
LOCTITE 55 Pipe Cord is the best for sealing plastic joints.
What is the difference between a threadlocker and a thread sealant?
LOCTITE threadlockers and thread sealants have each been developed for specific applications and purposes. Threadlockers lock and seal threaded parts to provide higher locking strength, Whereas, thread sealants seal threaded parts so that they can withstand higher fluid pressures.
Some thread sealants are liquid while others are in thick paste form. Are liquid thread sealants good for sealing?
Yes. Liquid thread sealant is used for hydraulic and pneumatic systems that normally have filters inside. These liquid sealants contain no fillers or particles and therefore there is no need to be concerned about clogging the filtering system or contaminating system fluids with the filler particles. Hydraulic and pneumatic threads are very fine and have a tight fit. Liquid sealants provide an excellent sealing in this case.
We require a gasket that can withstand very high pressures. Can we use Loctite Gasketing solutions?
Yes, LOCTITE Anaerobic Gaskets can resist pressure upto 34.47 N/mm2.
Our design uses the pre-cut gasket as a shim. Is there any way to use Loctite Gasket in case the gaps between the flanges are large?
Yes, in case the product design specifies the use of pre-cut gasket as a shim, LOCTITE Anaerobic Gasket Dressing can be used in conjugation with the pre-cut gasket. Just clean the flange surfaces and apply LOCTITE Anaerobic Gasket Dressing to both the sides of a fresh pre-cut gasket. Make sure to use a primer on both the sides of the pre-cut gasket before application of the Gasket Dressing.
What type of materials can LOCTITE gasketing compounds be used on?
LOCTITE gasketing sealants can be used on many different materials including metals, wood, rubber, plastic, ceramics, glass and even concrete. The type of sealant selected for a specific application depends on the material to be sealed, environmental conditions, temperature and operating pressures in the system.
There are some traces of the old gasket left on the parts. What can be used to remove them?
In order to remove any old gasket parts, you can use LOCTITE SF 790 Chisel Gasket Remover.
We have to seal a fuel system. Would LOCTITE gasketing compounds be effective?
Yes. LOCTITE has two types of gasket technologies - one is anaerobic and the other is high performance Silicones. LOCTITE Anaerobic Gaskets are resistant to gasoline and Fuel oils. LOCTITE High Performance Silicones are 8 times more oil resistant than standard RTV silicones and hence perform well when used to seal hot oil systems like oil pans. They are both definitely superior to ordinary silicones as the latter swell and loose their sealing ability when used to seal fluid systems.
How can we disassemble a part sealed with LOCTITE Gasketing Compound?
In order to disassemble the flanges sealed with LOCTITE Gasketing Compound, just use hand tools, and clean the flange surfaces with LOCTITE SF 790 Chisel Gasket Remover.
What is the optimum fit for using anaerobic retaining compounds if I want to maximize the shear strength?
The optimum fit for thinner products (low viscosity) like LOCTITE 603 and LOCTITE 609 is 0.025 mm to 0.08 mm, and for thicker products (high viscosity) like LOCTITE 638 and LOCTITE 648 it is 0.05 mm to 0.1 mm.
What is the recommended surface roughness for cylindrical components being fitted with LOCTITE retaining compounds?
The recommended range for surface roughness of the cylindrical parts is 0.8 micron to 3.2 micron. You can also go for surface roughness as high as 50 micron if eccentricity is not a concern.
What is the correct procedure for applying LOCTITE retaining compounds?
For slip fit assemblies, apply to only one of the parts and assemble with a twisting/turning motion. For tight/close fitting assemblies with minimum clearance, apply to both parts.
We need to lock bearings in place but there will be exposure to oils. Will LOCTITE retaining compound also seal the joint?
Yes, all LOCTITE retaining compounds offer the dual benefit of lock and seal.
Can LOCTITE retaining compounds migrate to and jam other parts?
No. LOCTITE retaining compounds are thixotropic in nature, which means that they are quite viscous unless a shear force is applied. Hence, LOCTITE retaining compounds will not flow to other areas of the machinery.
Do I need to use a Primer with a LOCTITE retaining compound?
We recommend the use of primer where both the parts come under the category of 'inactive surfaces'. These metals lack the iron or copper content and thus the metallic ions that are required to fully cure the product within 24 hours. These inactive surfaces include plated parts, stainless steel, galvanized steel and anodized aluminium to name a few. On the other hand, in case both or at least one part is an active metal, then there is no need to use a primer to ensure full cure, which is typically within 24 hours at room temperature.
How can a cylindrical assembly fitted with LOCTITE retaining compound be disassembled?
To disassemble an assembly fitted with LOCTITE retaining compound, just pull the assembly apart mechanically. If necessary, apply localize heat (230 degrees celsius for 5 mins) and pull while the assembly is hot.
We need to retain a worn shaft and also lock it into a housing or bearing. Are there any solutions for this?
Yes. With LOCTITE 660 retaining compound, shafts with radial gaps less than 0.5 mm can be locked. In case of badly worn shaft, the repair can be done with LOCTITE Superior Metal.