The Polish Doctor

Theory vs practical of polishing and sanding works

Joemon Thekkaekurikattukunnal

      There are thousands of cars are produced on a daily basis all over the world. And in the production line sanding and polishing are very important tasks. Anything that goes wrong in that section will reflect on the external quality of the car. So the following theoretical and practical suggestion and advises of this process will help the workers in every company.

The most critical situation faced by every polisher is that, he or she is not spending enough time to polish the spots. In the general and advised understanding a person has to polish a sanded spot 15 seconds to repair it and bring back the surface looks normal.  But according to my observation at least  50 conditions have to be fulfilled if you want to apply the famous “15 seconds theory” for polishing. This theory could be applied if all the required norms are applicable and available. Otherwise it is the experience of the person who is handling the polishing air tool that helps better in solving the faults of sanding and polishing of a car in the production line in a factory.

    1.     Colour of the paint

Not all the colours react to the sanding and polishing in the same way.  Some of them are easily visible and some others are a bit shallow. The person who does the sanding is happy when the sanded spot is visible, clear and has a good round shape. In dark coloured cars the sanding spot is very visible  and in white and other light coloured surfaces the sanding spot is not very visible. This visibility problem of the faults and the sanded spots are influential factors in the quality of polishing.

     2.     Quality of the paint

It is not only colour but also the quality of the paint is a deciding factor in the polishing. When a high-quality paint is sanded, it doesn’t get damaged so much but a low-quality paint is easily affected by sanding and polishing. Sometimes it is easy to polish but at times it is difficult. The theory of 15 seconds may not be applicable in every case.

    3.     Thickness of the paint

Sometimes cars come to you after a few resprays. In such situations, the sanding and polishing have different effects. Optically they all look same but in reality, the effect of sanding and polishing are different than the normal situations. When the car is fully mounted a customer who looks at it has no idea whether it underwent resprays! 

    4.     Time when it is sprayed

Sometimes cars reach you directly after the spraying and cooling process.  Sometimes they are delayed for a few extra hours and sometimes even days due to technical problems. When they come in a later stage, the sanding and polishing have different effects on the body of the car. Even the climatic conditions at the time of spray can cause differences in the effectiveness of sanding and polishing.

    5.     Dryness of the paint

If the paint is not properly dried, it will both affect the sanding and the polishing even it may be a cause for a new repair process. unexpected results occur in such situations.  The polisher is not in control of the situation or not aware of such situations.

     6.     Type of the paint

There are different types of paints are used in the car factory.  Each one reacts differently towards sanding and polishing. So colours cannot be taken for granted always.

     
    7.     Quality of the spraying robot arms

Not all the spraying robots function in the same way. Their spraying quality is different or they may have technical problems. In such cases when it comes to sanding and polishing sections even if people do the polishing in the same way, it may not have the same result.

    
     8.    Temperature at the time of spraying

Temperature at the time of spraying is very important to keep the quality of paint. If there are any variations it will result in quality of spray. And in the later stage it will also affect the sanding and polishing.

     
     9.     Humidity at the time of drying

Humidity is very also important at the time of drying of the paint. If it is too humid it will show negative results on the surface of the car and later in sanding and polishing.

    10.  Duration after the spray before it is sanded

If the car reaches to the sanding and polishing sections according to the time assigned to it, the sanding and polishing will show a good result. Otherwise it may have a poor result.

    11. Type of the sanding spot

Not all the sanding spots are of the same category. There are different types of sanding spots. It is recognizable from experience and the computer coding. But once the spot is sanded it is difficult for the polisher to recognize it immediately. Therefore, polishing become difficult and the result of the polishing would not be right.

1  12.   Size of the sanding spot

Not all the sanding spots are at the same size. Some people have good control of the sanding machine and they are able to keep up the size in control. Others will be sanding all various shapes which make it difficult for the polisher.

    
     13. Shape of the sanding spot

In a normal flat location, the shape of the sanding spot should be round. It always depends on the handling of the sanding machine. If the shape is round and it is the size of a 2-euro coin, the normal polishing should be right effective. But if it has a very rare huge shape the finishing of the polishing wouldn’t take place at one go.

14.   Location of the sanding spot

Not all the locations are easily accessible to the polisher. Some are in a very complicated locations, and it will immediately reflect in the result of polishing.

     15.   Depth of the sanding spot

From experience one can recognize if the sanding spot is mild or hard. Some people sand the spot very hard and in such places the effect of the polishing is negative.

    16. Times of the scrape paper usage

A scrape paper could be used for more than one sanding spot. But if the person who does the sanding is not careful and not using enough water in time the sanded spot will be damaged and the polishing will have a negative effect.

    17.  Quantity of the water used for sanding

Sander should be using enough water but not soaking wet. If it is too dry the sanded spot will be left with scratches and if it is too wet the sanding may not be effectively done which will all negatively affect the polishing.

    
     18. Quality of the water used for sanding

The water used for sanding should be clear and pure. If it is contaminated it will damage the paint while sanding and will have a negative result for polishing.

     
    19. Quality of the cleaning cloth

Both the sander and the polisher use some type of cleaning cloths. These cloths should be clean, smooth and sand free. If there are sand particles left on the cloth it can scratch the surface of the paint.

    20.  Humidity level after the sanding

A spot is easy to polish immediately after the sanding. It shall not be too wet or too dry when it comes for polishing. If the place is too wet the polishing paste will be diluted and the effect of the polish is negative. If it is too dry the polisher may have difficulty in removing the sanded spot.

     
    21.  Quality of the air tool

If the quality of the air tool both for sanding and polishing should be of good standard otherwise the effect of both sanding and polishing will be negative.

     22.  Speed of the air tool

Speed of the air tool is a critical factor in both sanding and polishing. If the speed is too low both the sander and the polisher should spend longer time in their process and even it may have a negative effect.

     23.                        Size of the air tool

There are different types of  polishing machines. Each one functions in a different way. The size of the air tool is also a deciding factor in better sanding and polishing.

     24.    Handling style of the air tool

Each person has their own style of handling of the air tool. Some people hold on the head of the air tool and press the liver with back of the palm. Some people hold the machine just like holding a hammer and press the liver with the thumb. There are also others who hold the machine with thump and fingers around and press the liver with the forefinger. Whichever manner it is held, the priority is to give the right pressure on the machine that keep the sponge in its right position.

     25.  Pressure on the air tool

Even after long years of experience in polishing many people still don’t know how much pressure should be used on the air toll. Use of pressure on the air tool is a skill. The air tool has more that 12000 rpm. This is effective only when you use the right pressure on the tool. If you are very loose in holding the machine the polishing may not be effective. In the same way if you are giving extreme pressure on the machine, it can damage the sponge, machine head and the polishing will be adversely affected.

    26.                        Positioning of the air tool on the spot

Positioning of the air tool on the spot is important too. If the air tool is not positioned just above the sanded spot the polishing may not take place as expected. If it is improperly placed after finishing the polishing you will still be able to see unpolished sanding spots which we call “cleaning stains”.

     27.                        Movement of the air tool over the spot

The movement of the air tool over the sanding spot is very important in polishing.  If a person is not attending to the spot the polishing may not take place properly. The basic rule of the movement is as follows: After placing the air tool when the liver is pressed for the rotation of the head, it has to be in the same position without moving for a few seconds until it is warmed up. Then make a few up and down movements and then left and right movement, then make a light clockwise movement and later make an anticlockwise movement.  Slowly release the liver and raise the air tool. All these movement have to be done very gently. No wild movements will help a proper polishing.

     28.                        Type of the sponge pads

There are different types of sponge pads used for polishing. Not all of them are effective in all situations.

     29.                        Quality of the sponge pads

Quality of the sponge pads also is a factor in finishing the polishing in the expected time frame.

     30.                        Size of the sponge

There are different sizes of sponge used in polishing. The result varies according to the size of the sponge.

     31.                        Times of usage of the sponge

There is a limit in the usage of the sponge in polishing. One cannot go on using the same sponge for many polishing. It has to be changed when it feels soft  or too wet with cream.

     32.                        Quality of the cream used for polishing

The cream used for polishing should not be too thick or too thin. It has to have its right consistency.

     33.                        Quantity of the cream used for polishing

The usage of the cream should be well controlled. Not too much and not too little. If too much cream is used it will spoil the sponge in a single use and the dried up cream particles will spread all over the surface of the. And if it is too little the polishing may not be effective.

     34.                        Location and the application of the cream

The cream should be placed almost in the center of the sanded spot depending on the depth of the spot. It is better to be applied in a drop form rather than drawing on the sanded spot.

    35.                        Attentiveness of the polisher

A polisher can be distracted by external factors. When the polisher is distracted he or she may not be able to concentrate on the work and it will affect the polishing.

     36.                        Temperament of the polisher

If the polisher is not in the right temperament, the polishing will be affected. When one is angry, irritated or agitated, the work is affected by it.

     37.                        Mood of the polisher

People have mood changes. When a polisher is not a good mood. It will show in the result of the polish.

     
     38.                        Health situation of the polisher

If the polisher is not in good health, the polishing wouldn’t be perfect.

     39.                        Food habits and hunger situation of the polisher

When people are hungry don’t expect them to perform in the same way as they are not hungry. Hunger has always negative effect on the performance of a worker

     40.                        Speed of the car on the belt

Cars run on the belt not all the time at the same tempo. When the cars run on the belt or the moving platform at a higher tempo the polishers act differently and it will reflect on the quality of the polishing

     
     41.                        Type of the Co-workers

If you have annoying co-workers next to you it will have a bad impact on the performance of the polishing.

    42.                        Lighting of the polish tunnel

Lighting in the tunnel is very important. Poor lighting will affect the quality of polishing. If the polisher cannot assess the type of polish spot don’t expect a quality polishing. shades and poor lighting will negatively affect the finishing of  polishing.

     43.                        Space in the tunnel

A polisher should have sufficient room in the light tunnel for polishing. There should be nothing hindering him in concentrating his work. Air tool should be easily moved around according to the need of the polishing situation

     
     44.                        Availability of the materials

A polisher should have sufficient materials for his polishing. He/she should be able get enough materials for polishing while on the line. So there will be no panic in the shortage which will affect the polishing quality. Sponge, cream etc.

     45.                        Accessibility of the materials for polishing

Materials should be easily accessible. It should be arranged in an orderly manner that at the time of shortage things can be easily picked up

     46.                        Interference of the overseers in the tunnel

When there are too many overseers moving around during the work will affect the quality of the work. The polisher will be distracted by the strangers who move around in the tunnel and the performance will not be up to the maximum.

     47.                        Height and weight of the polisher

Height and weight of the polisher is an important factor when it comes to polishing. A short person with a difficult position polishing a spot will have a negative effect.

    48.                        Analytical capacity of the polisher

Analytical capacity of the polisher is important when it comes to polishing a spot. Polisher should be able to make decision; how much pressure should have needed for a particular spot.

    49.                        Experience and age of the polisher

A polisher who did polishing for many years will be easily polish a spot because of the experience. In the same way age of the person will have an influence on how he or she finishes the polishing.

     50.                        Speed of the polisher

Speed of the polisher is also important when it comes to apply the 15 seconds theory. You can be very slow in the handling of the air tool or you can do it faster.  You can do it extremely fast and it may not be possible to continue for 8hrs per day. So, it is better to apply an appropriate speed that will keep the polisher functioning in a relaxed manner with effectively completing his or her task.

     51. Length of polishing time
     (15 Seconds in theory: but it all depends on all the above factors)

To be continued at the request of the readers....!