Spray machines bring immeasurable benefits to many projects in the building industry. As such, they have become invaluable, particularly in the plastering and rendering world. Many of our installers use spray machines to speed up the application of render and basecoat. Therefore, we have decided to compile a guide to spray machines. In this guide, expect to find a ‘how to’ for using spray machines, their various components and benefits, and some helpful tips. Through our partnership with EWI Pro, we have a unique insight into these tools. The EWI Pro Technical Team delivers Spray Machine Training courses throughout the UK. Therefore, the tips we provide come directly from Messrs. Harris and Christmas, who possess over 55 years of industry experience.
What are spray machines?
Plaster spray machines are innovative tools engineered to speed up the plastering process dramatically. They are specialised pieces of equipment designed to mix and spray plaster onto various surfaces in a continuous, controlled manner.
These machines utilise a motor and a pumping system, capable of handling different types of plaster (from the traditional cement-lime mix to ready-mixed products), to deliver plaster from the machine to the wall or ceiling. It replaces the need for manual plaster mixing and application. This is labour-intensive but also requires a degree of expertise to ensure consistency and smoothness.
By automating the process, plaster spray machines also address the issue of quality. When applied manually, plaster’s consistency can vary depending on the mix and the applicator’s skill. With a plaster spray machine, the mechanical mixing and application process ensures a uniformly mixed plaster and consistent application, resulting in a smoother, more even finish.
Plaster spray machines come in different shapes and sizes. Some advanced models even offer features like adjustable spray nozzles for control over plaster volume and spray pattern.
Components of a spray machine
Most spray machines share the same components as they all work on a similar system.
- Hopper: The hopper serves as the reservoir for the plaster mix. It can be filled manually or mechanically, depending on the machine’s design. In some advanced models, the hopper may also include a mixer or agitator that keeps the plaster mix at a consistent viscosity, preventing the separation or settling of materials.
- Pump: Often referred to as the heart of the spray machine, the pump is responsible for creating pressure. This pressure is necessary for moving the plaster mix from the hopper through the hose. Depending on the model, a plaster spray machine might utilise a piston pump, diaphragm pump, or screw pump. The pump’s power and performance also significantly influence the overall capacity and effectiveness of the machine.
- Hose: This is the critical link between the pump and the spray gun. The hose must be sturdy and flexible enough to withstand high internal pressure while allowing ease of movement for the operator. Hoses also come in varying lengths to accommodate different worksite conditions. The inner surface of the hose is typically designed to reduce friction and prevent clogging, ensuring smooth and uninterrupted flow of plaster.
- Spray Gun: The spray gun is part of the machine where the velocity and direction of the plaster spray are controlled. It is typically equipped with a trigger or lever that, when pressed, releases the plaster onto the surface. Advanced models may have adjustable nozzles to change the spray pattern, enabling the user to customise the finish based on the project’s requirements.
How to use it
First, the plaster mix is poured into the hopper. Depending on the machine, you can pour in pre-mixed and also dry ingredients. The machine’s pump then pushes the plaster up the hose under high pressure. At the spray gun, the operator pulls the trigger to release the plaster. The force created by the pump ensures the plaster then leaves the spray gun at high velocity, covering the wall or ceiling evenly. As the force created is significant, the mixture becomes atomised. As the plaster is sprayed onto the surface, a trowel or similar tool may be used to further smooth out the plaster, ensuring a uniform, high-quality finish.
This process is continuously repeated, allowing large areas to be plastered quickly and efficiently, saving both time and labour costs. The mechanical nature of the process also ensures a consistent finish that can be difficult to achieve with manual methods.
The benefits
One of the most significant advantages of using plaster spray machines is the speed at which they operate. Unlike a manual application, which requires multiple layers and waiting time in between for drying, these machines can cover vast surfaces in a fraction of the time. This speed is not just beneficial in terms of project completion time but also allows for better project planning and management.
Plaster spray machines provide a level of efficiency superior to manual plastering. The even, controlled distribution of plaster results in a smoother finish, reducing the need for sanding and additional finishing work. It also ensures uniform drying, which can improve the structural integrity and appearance of the plastered surface.
Plaster spray machines can bring substantial savings in labour costs due to the reduced time taken to complete a project. Furthermore, they minimise material wastage as the machine delivers the plaster directly where it’s needed. This efficient use of resources makes them a cost-effective solution, particularly for large-scale projects.
The ability of plaster spray machines to handle different types of plaster – from cement and lime mixtures to gypsum-based ones – adds to their utility. This versatility means they can be used in a wide range of projects, accommodating various environmental conditions and aesthetic preferences.
Manual plastering is labour-intensive, and extended periods of such work can lead to physical strain and fatigue. Plaster spray machines mechanise the process, significantly reducing the physical exertion required from workers. This reduction not only boosts productivity but also helps improve worker morale and reduce the risk of work-related injuries.
With their uniform application and consistent mix, plaster spray machines often deliver a higher quality finish compared to manual methods. This leads to aesthetically pleasing results and structurally sound surfaces, which can enhance the overall quality and value of the construction project.
Guide to spray machines – tips
As aforementioned, we have gathered some tips from our Technical Team.
Tip 1 – Take a clear bin bag, poke a hole through the bottom, and then tape it to the inside of the hopper. By doing this, you won’t need to clean the inside of the hopper at the end of the day. You can use any sort of tape to attach it. Just ensure that the bag does not drop down into the mechanism below.
Tip 2 – Always spray into an empty bucket or back into the hopper initially as the initial burst of material is usually lumpy.
Tip 3 – When spraying, avoid unnecessary pauses that can allow the plaster in the nozzle to dry and possibly cause clogs.
2 thoughts on “A Guide to Spray Machines”
The tips are good but how do you clean all of this? Even the hopper might get dirty if the bag rips
Hi Andy, the bag can rip but you can also cover the inside of the whole hopper with something like our orange tape, which will be more durable. The best way to clean out the delivery hoses and nozzle is whilst the render is still wet; use the foam balls and water to run it through the system and empty into a bucket.