What are thread lockers and how to use them
Content
All screw connections in the vehicle are tightened with the calculated angular momentum during installation. The weakening of this tightening is unacceptable, both because of the risk of further self-loosening under various types of loads, and due to a violation of the operating mode of the assembly.
Therefore, critical connections, and the overwhelming majority of them are in the means of increased danger, must be equipped with means to prevent untwisting.
Why you need thread sealants
There are all sorts of mechanical devices to protect the thread from loosening. These are spring washers, wire or thread locking, plastic inserts. But it is often more convenient to use compounds that are a cross between glue and sealant. They simultaneously fix the thread and prevent its corrosion.
Thread sealants, they are also retainers, are applied to bolts and nuts before mounting parts, after which, under the action of tightening force or termination of contact with atmospheric oxygen, they polymerize and lock the thread. Moisture and atmosphere no longer enter the gaps, which contributes to the safety of fasteners.
The adhesion of the composition to the metal is high, and its strength is sufficient to create significant resistance to turning away. This creates an additional static moment, which external forces and vibrations cannot overcome. The fastener will remain in its original stress state for a long time.
Types by color
For the convenience of users, the clamps are painted in different colors according to the degree of connection strength. This division is conditional, and not all manufacturers adhere to the accepted rules.
This is not regulated by the standards, but with a high probability it is possible to determine the scope of the product by color.
Blue
Medium-strength fasteners are blue. For not very tense and critical connections, this is enough, but dismantling during repairs is simplified, there is less risk of damage to parts. It is customary to indicate precisely their detachable nature.
Red
Red thread sealants are the strongest. On their labels they write that the connection becomes one-piece. In fact, even stuck, rusty and welded nuts can be disconnected, the only question is the time spent.
If we talk about the experience of using red clamps, then unscrewing the fasteners treated with them resembles a rusty thread. The nut hardly moves from its place with a large moment on the key, and then it goes hard, with a creak and the release of dried sealant powder.
It is also believed that red substances can withstand significant temperatures. But the color does not affect this parameter at all.
Thermal resistance should be specifically stated in the accompanying documentation, but this is usually highly overestimated for marketing reasons. In reality, just increasing the temperature of the connection is used to loosen the hold of the retainer.
Green
Green compounds are the softest and weakly hold threads. They are used for small diameters, when a stronger grip can help shear the bolt at the time of an attempt to break away. But precisely because of the initial diminutiveness of such threaded connections, the force of the green lock is quite enough.
What to look for when choosing
Almost all compositions are made according to the same principles of action. These are acrylic compounds with a complex composition and chemical formulas, long names of components, but united by the property of quick setting in the absence of oxygen. Therefore, they are always stored in their container with the presence of a certain amount of air.
The choice consists in agreement, first of all, with the manufacturer's pricing policy, reputation, specialization of a particular composition and individual characteristics for the intended purpose.
Moment of resistance
Loosening resistance can be determined as the reading of a torque wrench at the moment the bolt or nut is displaced to loosen.
It is difficult to specify it for a specific product, since it is different in thread sizes and tolerances that determine the amount of compound in the gap.
Serious companies, however, are not limited to reports of non-detachable connections or unrealistically high operating temperatures. Several very specific characteristics of the polymerized composition are indicated. The size of the test thread is also given.
The most important moment characteristics:
- adhesion to steel, that is, the moment of failure of an initially loose thread;
- stall moments for different preload values;
- the moment of unscrewing an already connected connection after turning through a certain angle.
These data will clearly determine the strength properties of the polymerized composition and will allow you not to be guided by color, which does not really matter.
Liquid resistance
Fasteners can work in various environments, including quite aggressive ones. It is advisable to find out from the technical description how the product will behave after exposure to petroleum products, organic solvents, water or other penetrating substances.
The plates contain data on the decrease in strength as a percentage of the original after being in aggressive environments for hundreds and thousands of hours.
State of aggregation
The product must be easy to use. The compositions can have different consistency, liquid, gel or paste. If it is convenient to process small and medium-sized threads by dipping into a liquid, then it is difficult to keep it on large ones, gels or pastes are preferable. This does not affect the strength in any way, which cannot be said about the price.
Reaction time
The description indicates the polymerization time, after which the fasteners will gain the required strength after tightening. It is convenient to represent this graphically, with several polymerization curves depending on the surface material of the fasteners.
They can be made of different grades of steel, non-ferrous alloys or have an applied anti-corrosion coating.
Exposing the assembly to workloads is permissible only after complete polymerization, which can be achieved in tens of hours or faster.
TOP best thread lockers
There is no definite answer which of the thread sealants should be used, as a rule, the price-quality ratio works here. When buying an inexpensive brand, you should not count on its phenomenal characteristics.
Loctite
The name has become almost a household name in domestic practice to refer to various auto chemical goods. Produced, including, and high-quality sealants. It is impossible to single out a specific product here, all commercial formulations are highly specialized for specific conditions of use.
Goods have their own catalog number, under which there is a description of the properties and the area of optimal use. The products are of very high quality and work well, but like all similar products, they have a high price.
Open
Abro's widely used thread sealants are low priced yet provide reliable joint locking. The most popular is TL371, which is a universal red fixative in a convenient small package.
Holds the thread well, dismantling is possible, albeit with considerable effort. It protects against corrosion poorly, but in most cases this is not important, high-quality fasteners have galvanic protection.
I'M G
The red "heavy duty" composition under this brand really works great, justifying the promised performance. Others are much weaker, but apparently they are not designed for this.
What to use instead of thread sealant
After an approximate study of the composition of the fixatives and the principle of their action, it becomes clear that in simple or emergency cases, more "folk" remedies can be used.
The closest in properties are all kinds of cyanoacrylate "superglues", which have the same principle of operation - setting and rapid polymerization after compression and cessation of oxygen.
You can apply other paints and varnishes. For example, nitro varnishes and nitro enamels, even nail polish or silicone gasket sealant.
Naturally, it will not be possible to obtain such strength as that of industrial designs, but it is still better and more reliable than a completely defenseless thread.
