Body repair in its arsenal has many methods of car restoration. It is not always advisable to repaint the entire part as a result of a dent or chips. Using a solvent for transitions, you can achieve the same effect as when painting the whole element. The task of the auto-painter is to use the modern materials to restore the car to its original form.
In which cases a solvent is used for transitions
Unforeseen situations on the road leave their mark on the paintwork of cars. To restore it, sometimes you have to repaint any elements of the body, which, accordingly, reduces the market value of the car. How to determine that a repair has been made? There are certain signs according to which you can establish which part has been repainted:
- Different tone of paint on various details. If you look closely, the part that has been repaired has a different shade of paint from the whole. This is especially noticeable on machines painted with enamel without a metallic effect.
- The texture of the varnish is different. The skill of an auto painter is to obtain the same surface structure on enamel or varnish as on a factory part. To achieve this, vast experience is needed.
- Traces of polishing. It is clearly visible in the sun. If polishing artifacts are noticed, then it should be examined more carefully, perhaps previous defects will be discovered.
In order to minimize these disadvantages, the machine is painted using a solvent for transitions. This will help to make the intervention visually invisible. In addition, it will reduce the cost of work and materials. Such large elements of the body as the roof, hood, it is impractical to repaint the whole because of a small chip or dent.
Types of Transitional Diluents
Modern cars are painted both with homogeneous enamel and nitro-paint with subsequent varnish coating. For the transition to nitro enamels or varnish, different methods with solvents for transitions are used.
To make the difference in shades of paint on one part invisible, a binder is used. It removes dust from the transition and smoothes the border between old and new enamel.
To make the difference invisible when applying a new coat of varnish on top of the old one, a solvent is used to move through the varnish. Its action is that it partially dissolves the factory paint, and a new layer of varnish penetrates into the old, mixing with it. Conventional solvent or diluent used with the paint system, this effect is not available. One of the inexpensive and commonly used products is Novol Transition Solvent.
Why is it difficult to paint perfectly
Despite the fact that there is a computer selection of paint, it is rarely possible to get ideally “in color”. Many factors influence the final result:
- colorist qualifications;
- air pressure in the spray gun;
- temperature and humidity in the spray booth;
- the distance from which the enamel is applied;
- number of layers applied;
- the angle at which the part is painted.
To understand how the shade of the base enamel changes, the painter must have rich experience.
How to make the transition to base enamel invisible
To minimize the difference between the repair and factory enamel helps painting transition. It is performed as follows:
- The first layer is applied tint primer. This is done so that it is not necessary to paint in several layers of enamel. Some varieties of paint do not cover the repair soil well, and they have to be applied in more than 3 layers, which significantly darkens the color. If for dark tones this is not critical, then for light cars it is not permissible.
- The first base coat is applied. He must close the primer. Then it is dried for 5-10 minutes.
- The second layer should overlap the first by 15-25%. If you paint only the primer, then there will be a significant difference in shades.
- The third layer is final. It overlaps the second by 10-15% and should completely equalize the transition in color from repair enamel to factory.
- The last layer is applied binder. Its task is to smooth out the dust from staining and eliminate the “standing stake” metal enamel grain, which did not lie exactly on the border.
In addition, it should be noted that between each layer it is necessary to wipe the surface of the part with a sticky gauze. She removes enamel that has settled in the form of dust from the surface.
How to use a solvent for transitions on varnish
Sometimes you need to paint only part of the part. And accordingly, there is no need to completely coat the part with varnish. In this case, on an inconspicuous place, a transition is made on the varnish from new to old. The method of using the solvent for transitions on varnish is different.
In order to make the transition, the surface in this place must be sanded with 2500 grit sandpaper or ginger tape with a matting paste.
The border will remain anyway, but the point is to minimize it. Subsequently, using polishing, you can reduce it to zero. To make the transition to varnish, you must:
- Wait until the base dries.
- Wipe the part with a sticky cloth.
- After mixing the varnish with diluent in a ratio of 1: 5, apply the first coat of varnish. This layer should not be plentiful. It is needed only in order to ensure adhesion of the surface to the second layer, which will be the main one.
- After exposure for 10-20 minutes, depending on the temperature and properties of the varnish, a second coat is applied. Here you need to find the middle between the fact that the varnish creates a shine and does not drip on a vertical surface.
- The final step is to use a solvent for the transitions. It is also applied with a spray gun to a small area between fresh varnish and the rest of the surface.
It should be noted that in the absence of a transitional solvent, you can simply mix the varnish remaining in the spray gun with the usual solvent or diluent included in the kit, to a consistency of 1: 1. This mixture will be more liquid and can smooth the transition.
Subtleties of the transition to alkyd and acrylic enamel
Alkyd enamels are used for painting bodies on automobile conveyors. For repair, these enamels are rarely used. Most often use acrylic paint. In order to make the transition of acrylic enamel to alkyd, a transitional solvent will not work, because it has a different basis. In this case, another means is used. The solvent for the transitions provides the diffusion of one material with another.
Therefore, in order to achieve the desired effect, it is necessary to make the transition with nitro enamel, followed by coating the entire part with a varnish layer.
In order to make the transition, it is important to polish the entire painted element with sandpaper. Gloss should not be visible anywhere on the surface.
If you decide to make the transition with acrylic enamel followed by varnish, in this case, the paint should be applied by dry spraying. To do this, the spray gun is configured to minimize the flow of material at high air flow. Then the paint will lie in a dry layer without gloss. The layer dries quickly and can be varnished. If the enamel was laid by the “wet” method, then it will be possible to cover it with varnish after the final drying and subsequent grinding.
Polishing transitions
Polishing machines is not only used to give shine to old paint and eliminate scratches from the surface of the machine. It is used by car painters to visually reduce defects that have arisen after painting.
As mentioned above, it is impossible to completely remove the border between old and fresh varnish. Although a solvent is used for transitions, the technique for completely eliminating traces involves polishing. It is performed as follows:
- After the varnish has completely dried, the transition place and partially the old surface are sanded out with 2000 grit sandpaper. Do this by pre-moistening the place with water. It is necessary to skin until the dust from the varnish disappears and the surface becomes homogeneous both to the touch and to the look.
- Using a polishing machine, you need to give shine to polished places. First, polishing paste No. 1 is applied. After rough processing, the process is repeated with paste No. 2.
If the machine is dark in color, then traces of polishing remain on it, and to remove them, use a finishing paste and special towels.
In some cases, the transition on the varnish is done under the moldings, at the boundaries between the planes. This visually masks the transition. Therefore, neither polishing nor a solvent for the transitions in this case is required.
What materials to use for self-painting
You can fix the defects of the paintwork yourself. But not all, but only some of them. It should also be understood that there will be no professional result, no matter how manufacturers of paints and solvents for transitions in cans assured.
Details that can be tinted by yourself should be in places hidden from sight. For example, automobile thresholds, lower parts of wings and bumpers.
These places often suffer from stones flying from under the wheels, and it is not necessary to paint them in a car service. You can do it yourself.
To do this, you need to acquire the necessary materials:
- Degreaser or gasoline.
- Aerosol primer.
- Paint in the spray can. It is bought in accordance with the number indicated on the special plate on the body.
- Sandpaper. To work on the ground, you need number 240, 320. For grinding under the base - 600. For coating with varnish - 800, 1200.
In addition, you will need scotch tape, a couple of bottles of solvent No. 746, a solvent for transitions on the varnish in the spray can, aerosol varnish, and a cover film.
Self-painting process
Before painting a defective place, it is necessary to prepare it. To do this, wash the part with water and dry it. Then use gasoline to remove traces of tar, particles of engine oil, degrease the place of work.
Before priming, the defect must be sanded with 240 grit sandpaper, then 320 grit. After that, degrease again.
After that, the entire place that is supposed to be painted should be sanded with 800 grit sandpaper.
So that the sprayed primer does not get on other parts of the body, with the help of adhesive tape and material for covering, isolate the working area.
Now you can primer. This must be done in several passes, between which there should be a time interval. If you put a thick layer of soil at a time, then it can leak, which will cause difficulties with its subsequent processing.
After the soil has dried, it is sanded with 600 grit sandpaper. The entire area where the application of the base enamel is supposed to be sanded is polished. The area to be varnished should significantly overlap this area and be sanded with No. 800 sandpaper.
Well, the final stage of preparation is the grinding of areas where solvent-aerosol will be applied for transitions. For this, sandpaper No. 1200 is used.
After the part is again pasted over and degreased, you can start painting. If there is no experience in using paint in spray cans, then first you need to practice on the wall or fence. Enamel should be sprayed evenly. To do this, the hand must be driven at the same speed, without jerking, and the can valve should be open by one amount. Begin to apply the base before the hand reaches the area to be painted so that no prominent spots appear. You need to paint in several layers until the soil layer ceases to shine through with a dried base.
After the enamel has dried, varnish is applied. The spraying technique is the same as for enamel. Aerosol varnish hardens much faster than a professional repair varnish, therefore drying time between layers is shorter. Depending on the ambient temperature - 5-10 minutes. However, this varnish has a high fluidity, so you do not need to apply it a lot at a time.
After applying the last layer of varnish, you need to wait until it partially hardens, then spray a spray solvent for transitions on top of it. It will even out the texture of the varnish and make the transition uniform.
Work safety measures
All paints and varnishes, including solvents for transitions in spray cans, contain highly toxic compounds that cause damage to the respiratory system when they are poisoned by vapors. Solvents also easily penetrate the skin and are absorbed into the bloodstream, causing weakness, dizziness, and nausea. If the degree of poisoning is large, then convulsions and a coma can occur.
Therefore, when working, it is necessary to use personal protective equipment:
- Gloves. They must be resistant to chemical solvents.
- Respirator for respiratory protection. Gas masks with an open mask and a charcoal filter are best suited. 3M respirators also worked well. They go by numbers, depending on the size of the face. The filter elements that are installed on them must be protected against organic solvents.
In addition, it is advisable to carry out work in well-ventilated areas. After finishing work, tighten containers with paints and solvents.