Thread-locking fluid primarily comes in three different colors which are used to help distinguish their locking strengths as well as their differences in viscosity. Two brands of threadlockers were researched for this week’s Tech Tuesday article, Palm Labs Threadlockers and Loctite. All three standard variations available from the companies had a common curing time of 24 hours and an operating temperature range of -65°F to 300°F.

Blue Threadlocker:
The lowest locking strength comes as the color blue. The blue thread-locking fluid is considered to be a medium-strength threadlock which prevents the loosening of metal fasteners by vibration. The blue threadlock is recommended for use on nuts and bolts that are frequently removed and reinstalled for normal operation and routine maintenance. This compound is developed so that the nut of bolt that it is applied to can be removed with use of regular tools without added heat. Blue threadlocker should be applied above 50°F and sets in 10 minutes.

Green Threadlocker:
The next level of thread-locking fluid is the green threadlocker. The green thread-locking fluid is considered to be a medium-to-high strength compound which also prevents the loosening of metal fasteners by vibration. Green threadlocker is also a less-viscous compound, allowing for it to be used on smaller fastener ranging in size from 2.2 mm to 12.7mm in diameter. This compound also has a faster setting time, hardening in just six minutes. Due to its medium-to-high locking strength, localized heat may require for the removal of the threadlocked nut or bolt.

Red Threadlocker:
The strongest thread-locking fluid by both Palm Labs and Loctite is the red threadlocker. This is considered to be high strength and is used for permanent locking and sealing of a bolt. Red thread-locking fluids are recommended to be used on a bolt up to 25mm in diameter. To remove a bolt that is held with red locking compound which has fully cured on the bolt or nut, it is recommended that the joint be heated to between 260°F to 500°F, depending on the specific type of thread-locking fluid. A recommended note of caution is to be aware of the area and location where you are heating. The set time of red thread-locking fluid is 10 minutes. For nuts or bolts requiring higher temperatures, there are high-temperature red thread-locking fluids that will give a higher temperature yield of close to 450°F.

We spoke to John Fontana of Palm Labs and asked him some general questions about their products:

Q: DO I HAVE TO CLEAN THE SURFACE BEFORE APPLYING THE THREADLOCKER?
A: It’s always best to clean the surface before applying. Be sure to remove all grease, dirt and rust. For best results in removing rust, use a wire brush.

Q: CAN I REMOVE PERMANENT RED THREADLOCKER IF I HAVE TO?
A: If necessary, the best way to remove a Permanent Red Threadlocker is to apply heat with a torch (260oF) and then use a wrench.

Q: WHAT IS THE HEAT RANGE A HIGH TEMPERATURE THREADLOCKER WILL TAKE?
A: Our Turbo-Lock RED High Temperature has a range of –65 to 450oF.

Q: WHAT IS THE CURE SPEED?
A: Most threadlockers have a fixture time of less than 10 minutes and full cure time of 24 hours. Please see the individual Technical Data Sheets for more information on cure speeds

Q: WHAT KIND OF MATERIALS CAN I USE THREADLOCKERS ON?
A: Generally they are recommended for use on metal surfaces. Some materials are more active than others and the curing speed may be faster or slower.

Q: HOW DO ANAEROBIC THREADLOCKERS WORK?
A: Anaerobic threadlockers need metal ionization and the absence of air to cure, such as when a nut is screwed onto a bolt, squeezing out the air – and hence, the Anaerobic drying and locking.

Q: CAN I USE THREADLOCKERS WITH OXYGEN?
A: It is not recommended.

Q: WHY SHOULD I USE A THREADLOCKER INSTEAD OF A METAL WASHER?
A: During vibration, metal washers can shave and come loose.

Q: WHAT IS THE SHELF LIFE OF THREADLOCKERS?
A: 15 months if unopened.

Q: HOW DO I KNOW WHICH THREADLOCKER TO USE?
A: Whether it should be removable or permanent, the size of the bolt, and the temperature, are all determining factors.

Q: HOW DO I STORE THREADLOCKERS?
A: Store product in a cool, dry location; refrigerate to improve shelf life. Bring to room temperature before using.