The Art of Floor Sanding Part 7


Good day and Happy New Year from the Floor Bore !

In today’s instalment we are going to begin to talk about the wonderful world of finishes and how to perfectly prepare our floors for the various treatments.
In the previous chapters we talked about rough sanding and the various techniques to bring your floors through the gateway to smoothness ! (60 grit ).
At this point the floors should look flat and smooth with no trace of the previous grit scratches.
What we do now in terms of further sanding depends upon the finish required .
We need to remember that all machines and abrasives create scratches on the floors.
Our job is to sand the floors to a point where the the scratches appear invisible to the eye once the particular finish is applied.
Different finishes require that you take the floors to different levels of smoothness to achieve this .
For example if we are applying a water based sealant the floors will generally only need to be taken to 80 grit with our buffing machine and edger sander .
This is because this type of finish sits on top of the wood easily masking scratches made with our 80 grit buffer .
Conversely oil tints are worked into the wood and actively show up any imperfections in the floors! so we need to finish on a finer grit of 120 or more.

There are 4 main variables to keep in mind here
1.The type of finishing machine.
2.The finish
3.The wood species
4,The Abrasives

1.Finishing machines
We are basically talking about some sort of rotating buffing machine.
(The first of this type made specifically for sanding was the Lagler Trio.)
More recently we have the Bona Flexisand and many other different makes of buffing machines.
Different machines will have different weights and aggresiveness so it’s important to work out how best to
use your particular machine.

2. The finish .
As mentioned the finish that will be used greatly effects how finely the floors need to be sanded.
Below is a general table ranging from the coarsest grits to the finest.

  1. Water based sealant

  2. Hardwax Oils

  3. Lye white Oils

  4. Spirit based stains/Sealant

  5. Colour OIls.

3. Wood species
As a general rule scratches will show up more on darker woods such as Mahogany Teak and
Walnut .

Abrasives come in many forms and are made of different minerals from very tough (Zirconia, Ceramic) to gentler less scratchy (Silicon Carbide, Diamond ) for fine finishing.
The brand and mineral will greatly effect how fine you need to sand the floor.

In the next chapter we will look at particular finishes and how best to achieve the perfect look !
Bye for Now .

julian moore