Fillers are an essential tool of the trade for painters and plasterers. Whether it be bare brickwork or a renovation project: walls or ceilings almost always need to be filled first. In this guide, we have put together the reasons why filling compound is needed, how you can spray it with a spray device from WAGNER, and what you need to be aware of.
Walls need to be filled in order to prepare a substrate for further processing. The surface is evened out with filling compound, while holes and other uneven areas are filled and smoothed out. Provided this is what the customer is looking for, a very fine, smooth finish can be achieved. For smaller holes such as those caused by dowels, nails or similar, renovation filler will suffice. For larger uneven areas, wall filler is used. From a functional perspective, even filling is importance since tiles and wallpaper can only stick long-term if there are no gaps or irregularities in the bonding surface. Design trends are heading clearly towards a smooth and flawless wall design. Even with tiles, modern tastes are demanding as seamless a design as possible. This can be achieved in several stages with a fine, paste-like filling compound that is sanded down between layer applications.
Filling the substrate not only achieves an even surface, but also creates a further positive effect: depending on which filling compound is used, it can also be used as a primer. The differences between building materials are compensated and there is just one surface with constant properties, on which wall paint, for example, produces an even finish. This is not the case with synthetic or synthetic resin fillers: the surfaces is too smooth in many places, and in this case we recommend following the filling process with a spray of primer.
You can save time and material when spraying large surfaces by using a WAGNER airless device. We show you how to do it in 5 simple steps:
In most cases, large surfaces are filled in the shell - masking is rarely necessary. The surface should be clean. Dust and dirt should be carefully removed beforehand with brushes and sponges.
If you use ready-mixed filler, you only need to hang the suction hose in the container or fill the filler into the material container. Powder filler must first be mixed according to the manufacturer's instructions before it can be used. Make sure that you either connect the sprayer to a power supply with the appropriate capacity or have filled the tank with petrol to avoid unwanted interruptions in the working process. Small tip for more comfortable and faster work: Instead of direct suction, use a large-volume container with a bag squeeze-out table to be able to apply large quantities of ready-mix filler more quickly and easily!
First set the spraying pressure. Depending on the viscosity of the putty, the pressure must be adjusted to achieve an optimal spraying result. If the spray pressure is set too low, the spray jet will collapse, too high a pressure will increase overspray and stress the longevity of the machine and its individual parts. Test the spray jet. If it is still uneven, smooth it with a squeegee and adjust the pressure.
Start moving and only then pull the trigger of the gun. Avoid swivelling movements and always keep the spray gun at the same distance from the wall if possible. Then smooth out the filler with a flat trowel. It is best to work in pairs so that the filler does not dry in the meantime. During breaks in the work, operate the respective lever to relieve the pressure in order to protect the machine. Also cover the material container.
Cleaning an airless device is not as complicated as it may seem. The important thing is to clean the unit immediately, before the putty hardens. Fill warm water and, if necessary, a special cleaning agent into the material container, switch on the unit and spray into a collecting vat. You can take apart the small parts, such as the gun or the nozzle, and clean them in warm water as well. The respective cleaning modes per unit can be found in the corresponding operating instructions.
Filler is one of the highly viscous substances and you should pay attention to a few things when working with it:
Filler is one of the highly viscous substances and you should pay attention to a few things when working with it:
Use the right device! If you use a conventional airless device to spray high-viscosity materials, you run the risk of damaging the device because it cannot transport the material. As listed below, our HeavyCoat and PlastCoat devices are ideal, along with the ProSpray 3.39.
Carry out filling at room temperature. You should therefore place the material you are going to fill in a room at a similar temperature so that it is not too cold.
Equally important is the choice of nozzle. For spray putties, you can use a nozzle that has at least a hole diameter of 0.035 inches, which means that the number ends with 35 and up. The first number of the nozzle number, i.e. 5 for nozzle number 543, refers to the spraying angle and therefore the width of the spray jet.
Ensure that you have the correct power connection for the device. Check whether a high-voltage connection is needed for your WAGNER spray device.
You will also need a suitable gun filter. For spray putty, a green filter with a 30 mesh is needed. For especially fine fillers, use the white filter with a 50 mesh. For especially heavily filled materials with a large grain size, you may need to leave the filter off altogether.
Tip: More detailed information on the right settings for the device and the right choice of accessories for the material being used can be found in our SprayGuide!
The process of spraying filler with a WAGNER device, as it can look in the real world, can be seen in our video from the Unstoppables. We show you not only the HeavyCoat 750 in more detail, but also how you can upgrade the device.
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Even if you are spraying filler, the material needs to be smoothed with the surface spatula. This is however only the final step and serves merely to achieve a completely smooth surface. With the airless device, you can apply the filling compound evenly and therefore achieve uniform distribution of the material much faster and more ergonomically than applying it by hand. While one person is using the airless device, another or several people can be smoothing and filling the wall at high speed.
Spraying with a WAGNER device therefore allows a much faster working pace to be achieved easily than if you were having to fill the same area by hand. Working with an airless device is also convenient and, thanks to the upright posture, easier on the back, allowing low-fatigue working. When filling ceilings especially, the material application process is made much easier. The long spraying hoses, which transport the filling compound to the spray gun, especially help with this. They give you a particularly wide working radius without having to constantly carry the material around.
Finally, you have perfect control over the thickness of the layer you want to apply. A fine layer of dispersion filler is very simple to apply with a spray device, and if you want a thicker layer, then you can allow the spray jet to overlap more generously.
Although you already know, we've summarised them here again just as a reminder: Filling compounds are divided primarily into mineral fillers (such as gypsum filler) and paste-like dispersion fillers.
Mineral fillers (usually powdered filler) is generally coarser and is used to fix layers of very different heights, as well as for filling gaps and holes.
Paste-like filling compounds, known as dispersion fillers, are usually used in a thin layer to smooth and even out surfaces. This smooth, even surface can then be used as the substrate for further work. Dispersion fillers, due to their chemical composition, require more time to dry. On absorbent materials such as filled plasterboard especially, a primer should therefore always be sprayed on first. Otherwise, too much water (and therefore volume) would be drawn in too quickly and it would collapse. Filling compound that has been optimised for spraying is known as spray putty or airless filler.
Furthermore, they are classified according to the primary base component: Mineral fillers are either gypsum-bound or cement-bound. Synthetic resin fillers are always ready-mixed with the help of solvents and are therefore always dispersion fillers.
Furthermore, they are classified according to the primary base component: Mineral fillers are either gypsum-bound or cement-bound. Synthetic resin fillers are always ready-mixed with the help of solvents and are therefore always dispersion fillers.
Cement-based filler is used in outdoor areas, as well as in wet rooms and for flooring. Cement-based filler can withstand moisture and wetness without damage. Thanks to various compositions, there is a suitable cement-based filler for every application: Floor filler for evening the surface of screed and concrete flooring or repairing steps, or fabric filler for integrating reinforcement fabric and attaching insulating panels.
Plaster-based filler is the classic mineral filler for indoor use. Since chalk-based filling compound is pH-neutral, it can be used with all coating materials. Here too, there are various compositions available to suit the area of application. Interior filler, for example, is particularly good for filling mineral plaster and filling gaps and holes, while adhesive filler is ideal for smooth surfaces and for filling plasterboard.
Synthetic resin filler is ideal for all surfaces, both indoor and out. As already mentioned, the package is already immediately ready for spraying. The synthetics are dissolved with binding agents in water. Synthetic resin fillers harden through the evaporation of water, resulting in a longer-than-average drying time for the same layer thickness.
You can find out more about the spraying properties of individual types of filler and the right equipment in our WAGNER SprayGuide: we have tested all of the possible materials and manufacturers for you and provide recommendations for you, such as regarding device settings.
Filling compound is a highly viscous, i.e. very thick and solid, material, which is why paint spray systems for small projects or airless devices are not suitable for it. The WAGNER ProSpray 3.39 is ideal for use with fine and airless fillers. If you are using fillers with a higher viscosity, WAGNER HeavyCoat or PlastCoat products are the best choice.
The ProSpray 3.39 is the ideal device if you want to apply both airless filler and emulsion paint. It is the most powerful piston pump in the ProSpray family and is supplied with the corresponding accessories so that you are directly equipped for both application possibilities.
ProSpray 3.39
The HeavyCoat products are equipped with a hydraulic piston pump. This makes them the most powerful piston pumps from WAGNER and, with a maximum delivery rate of 12.0 litres per minute, they are suitable for use on large construction sites. Optionally, the HeavyCoat units can be equipped with an electric motor or petrol engine to ensure supply for every possible application. If large quantities are processed, the large-volume container is recommended for HeavyCoat units.
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With the PlastCoat HP 30, we at WAGNER have developed another equipment technology that is ideal for large-scale use of highly viscous materials: the new, valveless high-pressure screw pump that combines rotor-stator pump technology with airless technology. The 230 V connection allows it to be used on any construction site. Thanks to HEA technology, it can additionally process emulsion paint. Yet light and compact, it is a manoeuvrable and easy-to-operate unit. With its pneumatic tyres, the PlastCoat HP 30 is also easy to transport and move around the construction site.
PlastCoat HP 30