Plastics can be joined or welded together in many ways. One is with electrical welding leister. Generally the plastics products used in cars, bikes and other vehicles are thermoplastics so they can be easily molded or welded. Some manufacturer marks code for material identification like ABS, PP. Leister 100.726 can easily weld the cracks, working splits in plastic without any loss of strength and quality of plastic.
Hot air welding equipment leister traic can also weld the loss of material. Whereas a steel component of same damage will cost more and is time consuming. This welding does not produce fumes if it is welded in right way.
Generally these steps are followed while welding plastic
Wear gloves so that your hands are not harmed
Firstly clean the surface that has to be welded. Then take a torch which can produce the steady air 60 liter/min for a long time. This torch will show the temperature by the dial on its back or by the amount of air coming out of it.
After that right temperature of blowing air is settled for the welding.
Your weld rod should match with the material that is to be repaired.
Other ways of plastic welding are:-
Hot Gas Welding
In this process a heat gun gives out hot air with the great force on the parts of plastic that is to be welded so that the area becomes soft. This type of welding is used for small items like water tanks, chemical tanks, plumbing fitting, heat exchangers etc.
Free Hand Welding
In this type of welding, jet of hot air is thrown on the parts to be welded and a tip of welding rod simultaneously. As soon as it softens the welding rod welds.
It is much like spot welding but the only difference is that the heat is not given by electrical conduction but by convection of pincher tips. The two parts join when heated tip pinch them causing it to melt and join.
Hot Plate Welding
It is used to weld large parts. The part that is to be joined is attached to a tooling which is further attached to the two opposing platens of a press. A pot plate is of the same material as of the parts that are to be joined and this plate moves between them. The two platens bring the parts in contact to the hot plate when it gets soften by the heat the plate is taken out and the two parts are pressed so that they can join. It remains in that position until it solidifies.
High Frequency Welding
Some plastics like polyvinyl chloride, polyamides and acetates that are chemical dipoles that can be welded with electromagnetic waves of high frequency. This softens the plastic to join. It is also called dielectric sealing, radio frequency (R.F) heat sealing.
Heat is produced by friction in the parts to be joined by high frequency of 15 KHZ to 40 KHZ and low amplitude vibration. Maximum heat is in the interface of the parts.
In this two materials are rubbed together with higher amplitude and low frequency as compared to the ultrasonic welding. This friction produces heat between parts by vibration which causes the material to melt. Now the material starts forming layers which intermingle with each other and are joined. After all this it is left for cooling until it solidifies.
It is much like friction welding but the difference is that only one part is vibrated. When it gets soften it is pressed to the other parts and finally both of them joins.
In this process one part should be transmission and other should be absorptive or have coating which can be absorptive to the beam. With the movement of laser beam at the line of joining both the parts are put under pressure. It passes from one part and absorbed by another to soften the interfaces of the parts for joining.
In this, a solvent is used that dissolve the plastic temporarily. Polymer chains are free and join with other similar chains. Then the two interfaces intermingle and solvent goes in air. Finally chains loses mobility and again changes to solid state after joining.