Why Brush Sanding?
Brush sanding is commonly used to sand mouldings and products with profiles. It is also used on products with sharp edges and to remove fibres from the wood before lacquering.
Examples of brush sanding
Brush sanding is used for kitchen cabinet doors, raised panel doors, mouldings, MDF etc. for the preparation of flat or profiled wood. Brush sanding removes the loose fibers to improve the surface quality before lacquering. It is also used to optimize lacquer adhesion in sharp edges or to open the wood surface after moulding to allow a better penetration of stain or even to intermediate sanding of primed/lacquered parts.
Note that brush sanders cannot calibrate, so you need to combine the brush sanders with a wide belt sander to get an even surface.
Type of Sanding
What is the difference between AO and AOC sanding?
There are two different kinds of brush-sanding: AO sanding (Wood) and AOC sanding (Sealer)
In a general brush sanding setup, wood would first be measured, cut and then processed in a wide-belt sander before being brush-sanded with AO abrasives. Then sealer would be applied whereafter it would be brush-sanded with AOC. This last part of the process is often repeated a couple of times.
AO is an acronym for Aluminum Oxide.
AO is used for what is known as pre-sanding, as it is applied before stain, primer, sealer, lacquer etc.
Sanding with a sanding disc or sanding wheel, using AO, is for sand mouldings and profiled parts, to remove fibres from the surface before lacquering.
To achieve the perfect finish it is crucial to choose the right sanding cloth. The primary choice, as we would recommend, for AO sanding grit is between #120 – #400. The right sanding grit depends on the profile and material as well as the previous processing of the wood. If your product needs sealing on the wood such as stain, primer, lacquer etc. you may use AOC as described below.
AOC is an acronym for Aluminum Oxide Electro-Coated.
AOC is used for what is known as intermediate sanding; when sealer has been already applied to the surface.
After initial AO sanding, you can progress to AOC sealing. The AOC abrasive is a special sanding paper that is coated to ensure that lacquer does not stick to the sanding cloth and ensures a longer lifetime. For AOC sealing we recommend to use grits between #240 - #600. The grit you should use depends on your profile and material and the previous processing of the wood. If you are unsure which grits you should use, you can read more in our grit guide.
Which height should I choose?
To determine the heights of the brush, we need to know which depth the profile has.
- For flat profiles no deeper than 10mm. we recommend a brush height of 46 mm.
- For deep profiles, which means profiles between 10 mm. and 25 mm., we recommend brushes with height 61 mm.
Be aware that we do not recommend brush sanding in deeper profiles than 25 mm. due to the risk of oversanding the top. If you have a deeper profile than 25 mm. please contact us to get our recommendation.
Length of the Abrasive
Which length should I choose?
If you have an abrasive or brush strip we recommend you to use the same length. At AbrasiveNow we offer customized length, so you can choose inbetween 30 – 1600 mm. in length.
Which grit should I choose?
To insure the use of the right grit in your sanding process, you should consider which type of sanding you are doing. Further more, you should consider the previous process of the wood. You can read more about AO sanding and AOC sealing in the section above regarding "Type of Sanding".
What is the abrasive grit?
Grit determines the roughness of the abrasive. The grit size of the abrasive is stated as a number inversely related to the particle size. A small number such as #40 or #80 indicate a coarse grit, while a large number such as #600 indicates a fine grit.
First, you want to remove the fibers before the lacquering process. We always recommend a grit between #40 - #100 for calibration (AO sanding) and between #120 – #240 for fine sanding. For wood sanding we provide these grits: #120, #150, #180, #240, #320 and #400
A common error that we find is skipping grits. For example, we see some who go from grit #80 to grit #180 or from grit #180 to #320 in the same machine. We definitely do not recommend skipping grits to ensure maximum fiber removal.
What happens if I skip grits?
If you skip more than one grit you will not remove all the fibres, and that means that you will have to use more lacquer in the next AOC sealing process.
If you skip more than one grit in the process the fine sanding paper is not unable to remove all the scratches of the rough sanding paper. Skipping more than one grit will give you a rough surface and the lacquer may remove easily because it will be on top of the wood rather than sinking into the wood.
Which cut should I choose?
At AbrasiveNow we provide four cuts of abrasive: 3, 5, 10 and 20 mm.
- For flat products or for products with wide profiles, we recommend a combination of 5, 10 and 20 mm.
- For narrow and deep profiles, we recommend a combination of 3 mm. and 5 mm. cuts for optimal results
We always recommend to use two or three cuts in each wheel to get the best sanding process.
Changing of Abrasives
How often should I change abrasives?
We recommend changing the abrasive once a week. However, that does not mean changing all the abrasives at once; change 1/3rd of the abrasives each week to get the best results.
Changing in part or in full?
A lot of manufacturers change all the abrasives in the wheel at the same time, and that is a big mistake if you want the best result of your sanding. If you change all the abrasives in the wheel at once, you will have a much more unstable sanding process. This is due to how the sanding effect will be at its maximum when all of the abrasive has been changed and then at its minimum when it is time to change it again, rather than a more stable middle-ground if only partly changed.
Direction of the Wheels
Should I use differing directions?
When working with profiles, it needs at least two brushes working in opposite directions. Without it, one edge will be sharper while the other will be rounder.
To achieve the best result you should have multiple sanding brushes that drive in each direction, which makes it possible to sand into even the smallest details in the wood. This way you can ensure that all the edges in the wood are sanded and not only the surface. It is the best way to prepare wood for lacquer.
Be aware that if you use more than one head you have to recalculate the rotation speed of the heads. See our speed guidelines, when having 1, 2, 3 or 4 heads in use, below.
Speed of the Wheels
Why is the speed important in the brush sanding system?
The right speed it critical to the sanding process in obtaining the best possible results. Therefore it is important that the motor is frequency-controlled in the sanding system.
Should I use another speed if I change to AbrasiveNow?
If you consider using the AbrasiveNow solution, you should ideally not have to change your rotation speed. We recommend that you use the same speed as your current abrasive system, provided that it is set up correctly.
How does the speed affect my sanding?
A low speed performs better sanding in the profile, and breaks the edges better, while also ensuring a longer lifetime for the abrasives. If the speed is too high, there is less sanding effect, and the sanding can be rough on the corners. This also makes the lifetime of the abrasives lower.
To obtain the best result, try always to use the biggest possible head and the lowest possible RPM (rotation per minutes).
We have calculated the rotation speed your brush sanding system should use depending on how many heads you’re using:
|2||0-65 ft/min||Rotate opposite direction|
|2-3||65-130 ft/min||Depending on the quality and wood/profile|
|3-4||130-290 ft/min||Three along the fibres and one against the fibres|
Remember, the rotating speed also depends on the diameter of the head, in which case you can refer to the table with speed guidelines for just one head. You can find it just below.
Speed guidelines for one-head sanding systems:
|Hubs core diameter||RPM|
|35 mm.||1200 - 1500|
|50 mm.||1200 - 1500|
|80 mm.||700 - 900|
|100 mm.||600 - 900|
|120 mm.||450 - 700|
|180 mm.||250 - 400|
|280 mm.||50 - 280|
The AbrasiveNow Solution
The AbrasiveNow solution consists of three components: an abrasive, silicon carbide/aluminium oxide and a Tampico support brush. The difference between the traditional brush sanding solutions and the AbrasiveNow solution, is that the Tampico brush can be changed separately from the abrasive since it has a much higher durability. Thus, you do not need to waste perfectly good brushes.
We recommend reusing the brush five times while only changing the abrasive. This is not only better for the environment, with the big reduction in waste, but it is also much more cost-effective.