New Wood Floor Abrasives Are Developed
Alec Stacey, technical manager at Bona, talks rough:
FEW of the flooring contractors who attend our training seminars are excited by the abrasives they use on a day to day basis! I would be the first to agree that abrasives may not be the most riveting topic for conversation but, due to changes within our industry, now is the time to be a little more inquisitive and learn how the new developments can improve your efficiency and quality of workmanship.
One area of significant change is the manufacture of pre-finished floors due to the increase in demand for more durable finishes, particularly for pre-finished sports floors. Modern factory-applied finishes have become more resistant to scratches and often contain ceramic material as part of their formulation.
In many cases this has proved to be very useful, extending the life of the surface. However when the floor requires refurbishment, there can be complications.
The simplest refurbishment for varnished floors is the ‘cut back and overcoat’, where the surface is lightly abraded prior to the application of a compatible finish. This used to be a very straightforward process with few problems.
These days it can be difficult to get varnish to adhere to the surface due to the surface being insufficiently ‘keyed’. The contractor may begin to abrade the surface using a sanding screen grit 150 or similar and find the abrasion effective, the presence of some fine dust indicating the impact on the surface.
However, as the ceramic factory finish contains aluminium oxide, the same material in fact as the abrasive grit, this becomes ineffective after just a few square meters: the abrasive has become blunt. When the furthest part of the room is reached there is still the fine dust, giving the illusion of abrasion, but the finish is un-abraded.
This can be disastrous on a large floor, as sports floors tend to be, when the applied finish begins to peel due to poor adhesion to the pre-finish. Often the simplest response to this would be to sand the floor back to bare wood and re-finish.
Manufacturers have responded by introducing a solution to tackle these very tough finishes, diamond impregnated abrasives. These are 220 grit cloth pads which fit the multi-head drive plates on buffing and sanding machines.
These abrasives are not only hard and sharp enough to effectively ‘key’ the surface but also, due to their construction and grit size, leave virtually no scratches, an important consideration particularly when working with unsympathetic, high-gloss finishes.
Although their primary function is for keying existing aluminium oxide based factory finishes, diamond abrasives are also extremely useful for preparing floors prior to staining – a process which often highlights imperfections in the sanding process.
Tough factory pre-finishes also present problems when it comes to a full re-sand and re-treatment as they are difficult to remove using traditional abrasives, especially aluminium oxide (the base for these ‘scratch resistant’ finishes). This has led to the development of ceramic abrasives which are produced by subjecting the abrasive grit to extreme heat and pressure resulting in highly aggressive abrasives which are designed to take floors back to bare wood as quickly as possible.
When tested against traditional abrasives, what would take three or more passes with a belt sander can now be achieved in just one pass. I believe these new materials will revolutionise the way we think about sanding and refinishing and will maybe even stimulate some renewed interest in abrasives!
This article has been reproduced from the Contract Flooring Journal website. You can find them at www.contractflooringjournal.co.uk.