Sanding Tools

There are several usage cases for deciding which is most suitable for the job in hand.

Electric sanders - are ideal for use on light-to-medium workloads and are quieter than air sanders, however the operator does need to be near a power socket to be able to operate the sander. If the operator requires an electrically powered sander but doesn't have access to a power outlet, then a cordless (battery powered sander) would be most suitable. We always recommend having one than one spare rechargeable battery though, to ensure that there is minimal downtime when sanding, through batteries running out of power.

Air powered sanders - require compressed air to be nearby. However they are lighter than electric or battery powered sanders, which reduces operator fatigue, and can be used for extended periods of time because they are less prone to over heating. Pneumatic sanders are popular in professional workshops, such as in automotive, woodworking or manufacturing environments.

The operator should always sand in a well ventilated area, whilst wearing the appropriate personal protective equipment (PPE). This includes safety glasses to protect the eyes from debris and dust, a dust mask to protect the lungs from inhaling fine particles, as well as using a dust extractor if the sander is able to accommodate one, and also protective hearing equipment. 

When the sander is in operation it should always be held with a firm grip, but do not apply excessive pressure. It should feel like the sander is doing the work.

When sanding pads need changing, always ensure that the sander is turned off and disconnected from its power source, and ensure the new sanding pad is fitted correctly and securely.

The grit required depends on the type of sanding job at hand, however most jobs fall between P40 - P400. For example, if paint is being removed from a wall then coarse sandpaper will be required, but as ther operator gets closer to finishing the job, they should move to a sandpaper with finer grit to ensure there is a smooth and finished surface. The below shows what types of grit are used at each stage of sanding -

• Coarse (P40 – P60 grit) - Used for heavy material removal, stripping paint and also shaping rough surfaces. This grit level is very aggressive and leaves a rough finish.
• Medium (P80 – P120 grit) - Ideal for general sanding, smoothing surfaces and preparing materials before finishing. Sandpaper in this grit range is one of the most commonly used ranges.
• Fine (P150 – P220 grit) - Used for final surface preparation before painting, staining or sealing, and produces a smooth finish.
• Very fine (P240 – P400+ grit) - Used for finishing touches or when sanding between coats of paint. This grit range is ideal for achieving a polished surface.

Variable speed sanders offer better control over the finish, because they allow the operator to tailor the sanding aggression and are particularly useful when switching between different materials or sanding stages. For example, lower speeds are ideal for improved finishing and sanding delicate surfaces like soft wood, veneers or between coats of paint. Slower speeds help to prevent burning, gouging or swirl marks, whereas higher speeds are better for rapid material removal, such as stripping paint or smoothing rough surfaces.

Ultimately, variable speed sanders allow the operator to have enhanced control, improved finish quality and greater flexibility over single-speed sanders.

Wet sanding is normally done with fine-grit sandpaper to smooth a surface and the liquid acts as a lubricant to reduce friction and carry away debris, which prevents the sandpaper from clogging. Wet sanding reduces dust in the atmosphere in comparison to dry sanding, and is ideal for achieving ultra-smooth finishes on paint and clear coat, as well as on delicate surfaces like acrylic or metal.

The operator would commonly carry out wet sanding with very fine grits, between P400 to P2000+ grit, depending on what type of finish is required, and it is generally used for -

• Finishing stages after initially dry sanding.
• Between coats of paint or varnish, in order to remove imperfections. 
• Polishing paint or blending repairs for automotive detailing.
• High quality finishing, such as when a very smooth or glossy surface is required.

The millimetre (mm) measurement on a random orbit sander refers to the orbit diameter. So if the number on the random orbit sander is 5mm then it would mean that the sander moves in a 5mm elliptical pattern from its central point. Essentially, it rotates as a circle but is moving in an irregular overlapping elliptical pattern, so that one point doesn't get over sanded, with the furthest point of the elliptical pattern being 5mm from where the sander would be if it just moved in a constant circular rotation. The same principle applies for any other measurement, such as 2mm, 4mm, 10mm etc.

The operator should be aware that the larger the number is, the more material the sander removes with each pass.

Yes, sanders can be used across many different materials and the most important factors to consider to get the best results are sandpaper type, grit and the speed setting of the sander.

• Sandpaper type - Different materials require different types of sandpaper to smooth them down effectively. For example wood is best sanded with an aluminium oxide sandpaper because it is long lasting, whereas metal is best done with zirconia or ceramic because they are both quite durable and suffer less from heat build up.
• Grit type - As a rule of thumb, coarse grits are from P40 - P60 and remove material quickly, whilst finer grits from P150 - P220+ are better for finishing.
• Sander speed - Variable speed sanders enable the operator to have slower and faster speeds. Lower speeds are better for sanding delicate materials like plastics or when finishing, whilst higher speeds suit sanding tougher materials like wood or metal, or when sanding for rapid material removal, such as stripping paint or smoothing rough surfaces.

To avoid swirl marks or uneven sanding, ensure that the right grit progression is chosen. This means that sanding should start by using sanding pads with coarser grits to remove material, and then progress to finer grits to ensure that the desired finish is attained. Skipping grits can leave visible scratches.

There are also some tips we can provide to ensure the correct sanding technique is used - 

• Don’t apply too much pressure to the sander. The sander should be doing the work and putting excess pressure on it can cause uneven sanding and swirl marks, especially with random orbital sanders.
• Keep the sander moving because if it is stuck in one spot for too long it will create uneven areas or swirl marks, so ensure that the sander is held flat and is continually moving in slow and steady passes.
• Worn or low-quality abrasives will cause inconsistent results, so ensure that sanding pads are regularly replaced, properly aligned to the tool and clean from any dust or debris.

Yes a sander can be used continuously, but there are some caveats. For example an electric sander can run for extended periods of time but this can lead to the motor overheating, especially if the tool is under heavy load. To prevent this, let the tool have a break occasionally to cool the motor down, and also ensure that the air vents are always kept clear. We would always recommend using an air sander if the tool is going to be used for extended periods of heavy use, because they run cooler due to the fact they don’t have an electric motor running inside them that is generating heat. This is why air sanders are commonly found in workshops for woodworkers and metalworkers, where they are used heavily throughout the working day.