Abrasives. What to use and when to use it.
One of the most essential things to bear in mind when you are sanding the floor is the choice of abrasives. Whether it’s for your belt sander or your rotary machine, it is important to not only choose the right grit. But to select the correct grit material. Essentially what you are doing is scratching the floor. The aim of the game is to prepare the floor to a point where the grain is open enough for a finish to be applied, but the wood appears smooth. So, where do you start?
Your first sanding cut is the course cut allowing you to remove the existing finish, flatten the floor and remove any damage on the floor. The second cut removes the deep scratch from the first cut and replaces it with a shallower scratch. And so on until you get to the preferable grit needed for the finishing. Usually, in the floor sanding world, either 100 or 120 grit. The below table shows the grits from coarse to fine.
As well as this, it always depends on what material type of abrasive you use.
Ceramic -Ceramic abrasive is classed as a coarse abrasive. They have many attributes, including long life expectancy and a faster cutting rate. The reason for this is the structure of the grain and the way the grain breaks down. When this abrasive is used, the grains break down into small sharp pieces, giving the abrasive a new cutting edge more frequently. This abrasive is to be used to its best ability when it is under pressure. On your belt sander, if possible, the pressure is best to be high. On your planetary machines, it is best to use a heavier machine or if the option is available to add more weight. We here at Ultimate Floor Care offer a great 150mm Ceramic disc to be used for finishing with tools such as the 150mm Festool Rotex that can be here. Nitro Ceramic Multi-Hole Discs
Zirconia – This type of abrasive stands in the category of course to medium. It works similarly to the ceramic as it breaks down as it is used. But the way this grain breaks down is in large shards. When the grain fractures, the new part of the grain resharpen. Although it breaks down and resharpens as it fractures, it does not have such a high life expectancy if you compare this to ceramic.
Aluminium Oxide – This type of abrasive stands in the medium to fine cut. The way this abrasive is formed is by lots of small rock particles. As the abrasive wears, the rocks break down, not giving this abrasive the best life expectancy but has a great cutting power without leaving a deep scratch pattern.
Silicone Carbide – This type of abrasive is for fine sanding. The form of this abrasive is lots of tiny sharps of grit that break off and reshape, giving that fine sand required for finishing. This scratch pattern is much less aggressive making this a great material to finish with.