How to thin the paint for a spray gun?

The spray gun is a special device that allows you to quickly and evenly apply paintwork. However, it is impossible to pour undiluted viscous paint into it, and therefore the question of diluting paintwork materials remains quite relevant.

Painting surfaces with the help of spray guns makes it possible to obtain an even and beautiful coating, free from defects and smudges, as well as significantly reduce the duration of painting work. However, not all paintwork materials are suitable for use with a spray gun due to their very high viscosity.

• Too thick enamel is difficult to apply evenly on surfaces, it will begin to lay down in a thick layer and will dry for a long time. This will significantly increase the consumption of paintwork and painting time.
• Undiluted paint is unable to effectively fill pores and penetrate into narrow cracks, which noticeably affects the quality of work.
• Modern spray guns are a rather sensitive technique. and quickly become clogged from too thick paintwork. Most household models are equipped with nozzles with a diameter of 0.5 to 2 mm, which are difficult to spray thick enamel. As a result, they have to be constantly disassembled and the internal channels cleaned. By the way, when working with large professional spray guns, the nozzle diameters of which reach 6 mm, there is another problem - too liquid enamel will break into large drops and form smudges on the objects to be painted. Therefore, before proceeding with the dilution of paintwork materials, it is necessary to get acquainted with the technical characteristics of the spray gun.

In order to properly dilute the enamel, you need to read the instructions on the can. Usually the manufacturer specifies which solvent to use and how much to add. It must be remembered that for each paint and varnish material it is necessary to use its own dilution means. But sometimes it happens that the information on the bank is written in a foreign language or the text is hard to see or is covered with paint. In such cases, it is necessary to use the advice of experienced craftsmen, whose recommendations are presented below.

These two-pack paints, made from polyester resin, are used on wood, plasterboard and metal surfaces.

These one-component paintwork materials are made on the basis of alkyd resins and, after drying, require varnishing. Alkyd enamel is used for working on concrete, wood and metal surfaces, as well as a primer with anti-corrosion properties. It is inexpensive, dries quickly and does not fade in the sun. As a diluent, you can use xylene, turpentine, white spirit, Nefras-S 50/170 solvent or a mixture of these substances.

These paints are based on nitrocellulose varnish combined with coloring components. Nitro enamels used to paint metal objects are fast drying and have a pungent odor.

Water emulsion is the cheapest paintwork and is made from polymers, dyes and water.It is used in all types of repair and painting work. When diluting, it is allowed to use ether, alcohol or distilled water. It is not necessary to dilute it with ordinary tap water, since, due to its low quality and a large amount of impurities, it often causes a whitish coating to appear on painted surfaces.

Such paints are based on a combination of drying oil and coloring pigments. Oil enamels are distinguished by bright, rich colors, which is why they are often used as facade enamels in the repair and construction of housing. There are varieties designed for metal work. Such enamels contain red lead and are quite toxic.

These paintwork materials have a porous structure and are represented by persistent polymer dyes dissolved in a chemical reagent. They are often used for metal processing, are very durable and skillfully mask surface defects. Thinning hammer paint requires the use of toluene or xylene.

Such paint is often used as a facade paint, and it is also used to paint metal structures, metal tiles, profiled sheets, slate, drywall, chipboard, fiberboard, concrete, plaster and brick. To dilute it, take distilled water, but only not more than 10% of the total volume.

It is not difficult to dilute paintwork materials for a sprayer at home. This requires choosing the appropriate solvent, strictly observing the proportions and adhering to a simple algorithm.

1. First, you need to thoroughly mix the paint in the jar in which it was purchased. To do this, you can use any tool with a spade end that can reach the bottom of the can. You need to stir the enamel until there are no lumps and clots left in it, and in its consistency it does not begin to resemble thick sour cream. In a similar way, you need to mix the paint in all cans that you plan to use for painting. Then the contents of all cans must be drained into one large container and mixed again.
2. Next, it is recommended to rinse the empty jars with solvent and drain the residues into a common container. This must be done, since a sufficient amount of paintwork remains on the walls and bottom, and if it is not collected, it will dry out and be thrown out along with the cans. It is very important to remember that when using expensive branded enamels, dilution should be carried out with solvents of the same brand as the paintwork materials.
3. Then they proceed to the most important event - the addition of the solvent. It should be poured in a thin stream, continuously stirring the paint. From time to time you need to pick up the mixing tool and look at the flowing enamel. Ideally, the paint should run off in an even, uninterrupted stream. If it drips in large drops, it means that the enamel is still very thick and needs a solvent addition.

Professional builders determine the consistency of paint "by eye", and for less experienced craftsmen, a simple device has been invented - a viscometer. On domestic samples, the unit of measurement is seconds, which is very convenient and understandable even for those who encounter the device for the first time. The viscometer is made in the form of a container with a volume of 0.1 l, equipped with a holder. There is an 8, 6 or 4 mm hole in the bottom of the case. Budget samples are made of plastic, and metal is used for the manufacture of professional devices.

Using this device is very simple, for this you need to follow these steps:

• close the hole with your finger and fill the reservoir with paint;
• take a stopwatch and start it by simultaneously removing your finger from the hole;
• after all the paint runs out in an even stream, you need to turn off the stopwatch.

Only the flow time of the jet is taken into account, the drops do not need to be counted. The obtained result is checked against the table, which is included in the set of the viscometer, and the viscosity of the enamel is determined.

If the table is not at hand, then you can use the data below, which are valid for a device with a 4 mm hole:

• the rate for oil paint varies from 15 to 22 s;
• for acrylic - from 14 to 20 s;
• for water-based emulsion - from 18 to 26 s;
• for alkyd compositions and nitro enamels - 15-22 s.

The viscosity must be measured in the temperature range of 20-22 degrees, since at lower temperatures the paintwork thickens, and at higher temperatures it becomes thinner. The cost of viscometers varies from 1000 to 3000 rubles, and the device can be purchased at any hardware store.

This must be done in order to dissolve grease or oily stains inside the spray gun, which may remain there from the previous paint and turn out to be incompatible with the new paint. Then diluted enamel is poured into the working tank of the spray gun and the quality of staining is checked. The composition should come out evenly from the nozzle and be sprayed with a finely dispersed stream.

If paintwork material flies out in large splashes or drops, then a little more solvent is added to the tank, mix well and continue testing. With an ideal ratio of enamel and solvent, the air mixture comes out of the nozzle as a directed mist and falls on the surface in an even layer. Sometimes it happens that when the first layer was applied, the enamel formed a beautiful and smooth layer, and when the second was sprayed, it began to look like shagreen. This happens with quick-hardening formulations, therefore, before applying the second coat, it is necessary to carry out a control test and, if necessary, add a little thinner.

If, after dilution, the paint has become much thinner than it should be, then a number of measures must be taken to return it to a thicker consistency.

• Top up with undiluted enamel from a jar and stir thoroughly.
• Let the liquid enamel stand for 2-3 hours with the lid open. The solvent begins to evaporate and the paintwork quickly thickens.
• Place the container with liquid enamel in a cold place. The lower temperature will cause the material to thicken quickly.
• When using white enamels, you can pour a small amount of chalk or plaster into them and mix well.
• Use a spray gun with a small diameter nozzle and thus apply several coats at once.