Using sealant for car headlights

Many do not know which is the best sealant to use for car headlights if a repair is necessary. It is impossible to use plumbing and other options. It is necessary to choose a special composition, it will provide high-quality bonding or repairing damage. There are several varieties on sale, so it’s worth understanding their features in order to determine which type is suitable in a given situation.

Types of sealants for headlights

The compositions differ primarily in what raw materials they are made of. This determines their properties and provides certain characteristics. Most often, there are 4 types of options in stores, it is worth disassembling each of them separately.

The composition must be specially designed for gluing headlight glasses.

Polyurethane compounds

Polyurethane provides high strength after curing. Most often it is used to seal cracks and damage. Some even glue whole pieces of glass if you need to go urgently.The main features of this variety are:

1. High adhesion to smooth surfaces. The sealant perfectly adheres to glass and does not fall off under the influence of vibrations, temperature changes and other adverse factors.
2. The composition does not allow moisture to pass through, therefore it protects the headlight from its penetration and prevents fogging of the glass from the inside.
3. The service life is at least several years. And with high-quality application, polyurethane sealant can retain its properties for decades.
4. Repair can be carried out even at not the highest air temperatures. Thanks to this, if necessary, it will not be difficult to seal the headlight right on the street if there is no garage or the glass was damaged on the road.
5. After polymerization, the polyurethane mass is not afraid of oil, fuel, alcohol-containing liquids, road chemicals, etc.

The polyurethane version is very strong and durable.

Due to the fluidity, even small parts can be glued with high quality.

The main disadvantage is the low heat resistance.. If the headlights get very hot, then you should not use polyurethane sealant. It is also unsafe for human health before solidification, as it emits dangerous fumes.

Anaerobic Options

Anaerobic formulations are ideal for emergency repairs.

This group of products has its own characteristics and is used in some cases when its properties are suitable:

1. The tool has a liquid consistency, which imposes certain restrictions on its application.
2. It is used in minor damage, when other types of compounds simply will not penetrate. You can carefully fill the crack and thereby strengthen it or seal a tight joint.
3. Protective equipment is not required during operation.The composition is carefully applied to the right place, after which the elements must be pressed tightly against each other and held for a while.

High turnover creates problems during repairs. It is necessary to dose the liquid very accurately and make sure that it does not leak and does not spoil the reflector or other elements of the headlight.

Heat resistant sealants

Heat-resistant compounds withstand any temperature.

This solution is distinguished by high strength; after polymerization, the composition can withstand temperatures up to 400 degrees or even higher. Such extreme resistance is needed for headlights that get very hot during operation and turn on very often. But in addition to heat resistance, this type has other advantages:

1. The hardened mass is characterized by high strength and long service life. It does not lose plasticity for years and provides a reliable connection of both the same and different materials.
2. Does not exfoliate under constant vibrations, well withstands moderate deformation loads. Technical and other aggressive liquids do not spoil the mass and do not impair its properties.
3. Most often it is a two-component composition, which is prepared before use. It can be both plastic and hard enough. Due to this feature, the shelf life of the sealant is long, since it does not harden until a hardener is added to the composition.

By the way! After application, leave the headlight for at least 8 hours so that polymerization takes place and the finished mass sets well. Therefore, repairs are best done at night or when there is a margin of time.

Silicone compounds

The basis for the manufacture of this group of products are natural or synthetic rubbers.Due to this, the mass is plastic and resembles dense rubber after solidification. Most often, the composition contains additives for protection against ultraviolet radiation. But such options do not tolerate the effects of technical fluids, especially alcohol-containing ones. When choosing, you need to pay attention to this moment. The features are:

1. This is the cheapest type of composition, so they are used most often. Silicone-based sealant can be bought at any auto shop.
2. The adhesive properties are high, and the consistency is quite thick, which allows you to securely fasten the headlights to the body. Silicone is easy to apply, it does not spread and does not set immediately, which allows you to set the optimal position and fix the glass.
3. Temperature resistance is different, usually it ranges from 100 to 300 degrees. It is better to select an indicator with a margin in order to exclude any problems.

Silicone options fill all the voids and securely glue the elements.

The advantage of silicone can also be called the fact that, if necessary, it is much easier to separate it than other types. It does not harden too much and cuts well with a sharp knife, making it easier to remove the glass if required later.

What to look for when choosing

Not all sealants are equally reliable. When buying, you need to remember a few tips to choose a quality option suitable for a particular type of work. The following factors should be taken into account:

1. Adhesion to certain types of materials. You need to know which surfaces will be glued in order to choose the solution that will provide reliable fastening and prevent damage to the adhesive layer.
2. Vibration resistance. During the operation of the car, its elements vibrate.Therefore, the sealant after hardening should become not only durable, but also elastic.
3. Heat resistance. This is especially true for headlights that have xenon or other very hot bulbs. There must be a certain margin for resistance to temperatures, otherwise the layer will dry out over time and does not provide the necessary reliability.
4. The volume of the composition in a container. Here it is worth proceeding from how much sealant is required for the normal execution of the planned work. You need to take it with a margin, since the actual consumption is almost always more than planned.
5. Ease of removal from surfaces. This applies both to cleaning parts that have been exposed to the sealing compound and to dismantling the headlight if this may be required later.
6. Composition color. If you need to repair a crack or damage on the glass, then a transparent option is suitable, it will be invisible after hardening. For gluing glass to the body, the color does not really matter, since the junction is hidden.

For bonding glass, only a transparent composition is suitable.

It is better to give preference to products from the middle and high price segment. Its quality corresponds to the declared and the marriage is almost never found. In the cheap segment, there is no guarantee that the sealant will provide the necessary reliability.

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How to use the composition correctly

Even the highest quality option will not provide proper reliability if the work technology has been violated. Therefore, you need to follow a few simple tips in order to achieve a good result:

1. The remnants of the old composition, if present, are sure to hit.This is done mechanically using a degreaser or other means.
2. The surfaces to be bonded should be well cleaned of dust and dirt and degreased. If they are smooth, sanding may be required to improve adhesion.
   Before gluing, the surface must be cleaned and degreased.
3. Instructions for use of the sealant must be carefully studied before starting work. Follow the manufacturer's recommendations to rule out any problems and get the desired result.
4. After gluing, the parts must be fixed with clamps or other devices so that the parts do not move during the polymerization of the sealant. The manufacturer's recommended curing time must be followed.

To speed up the hardening of the composition, you can use a building hair dryer or any other source of heat.

Popular headlight sealants

There are many options, but some of them are in high demand, as they have been repeatedly tested in practice and proved their quality:

1. 3M PU 590. Polyurethane mass from a serious manufacturer. Suitable for gluing headlights and any other elements in the car. It is packaged in tubes of 300 and 600 ml, can be used as a sealant anywhere. Polymerizes in just 40 minutes.
2. Dow Corning 7091. Clear silicone based compound best suited for bonding glass to body. Creates an elastic strong seam which does not pass moisture and is resistant to an ultraviolet. Available in different packages, odorless, which simplifies application. Freezes fairly quickly.
3. Abro WS 904. This sealant is not available in a tube, but in the form of a thin bundle rolled into a roll.In order to glue the glass to the case, you need to degrease the surface, tear off a piece of a suitable length and heat the elements well with a hairdryer. After cooling, a strong seam is obtained, resistant to adverse effects.
   This option is easy to use and does not stick to your fingers.

In order to glue headlight glass well or repair cracks on the surface, it is necessary to choose a high-quality and safe composition. It is equally important to read the instructions on the packaging in order to do the job correctly.