Especially competition skis are structured for better gliding performance. After the ski base grinding process has been highly automatised, the structuring is booming. There are various structures for any snow conditions and temperature range. Each parameter of the structure to be grinded can be set up, endless shapes, depths, pitches, angles are possible. Structures become more and more complex and highly specialized. Any detail, any parameter is important and counts...
Is it really true?
It is true that the modern grinding machines can produce almost any structure form and shape which you can even imagine. The grinding machines are extremelly precise and fast. Fine and high-quality stones are formed with diamant pins with accuracy to hundredths, pressure, feeding and revolutions can be controlled and regulated so precisely and stable that structures can be perfectly cut.
On the other side each ski base material is a bit different even if it was produced in the same production batch, but these differences are quite small.
After ski waxes - in multiple layers - have been applied on the structured ski base, a new story beginns to be written. Frist ski waxes and ski base material connect or are mixed on the molecular level to a new material which is a mixture of both wax and ski base material creating a new layer which can be called “gliding surface”. This new gliding surface is created on the molecular level chemically but in daily ski service reality it is created on macro or micro level. Thin wax layers in different forms are applied on the ski base, ironed, excess wax is scrapped off and brushed out of the structure...
Excess wax is brushed out of the structure, structure is restored by brushing, original grinded structrure is revealed again with help of brushing...
Is it really true?
Let us analyze a common case: grinded linear grooves with the pitch distance 0,5 mm which is normally called fine to middle coarse structure.
The pitch distance 0,5 mm which is 500 microns will correspond to ca. 50 microns deep structure, the ratio width / depth is ca. 10 due to technological reasons. Standard linear grooves are V-form grooves, the pitch distance between the tops amounting to 500 microns will correspond to a width amounting to few microns in the bottom (depth ca. 50 microns).
If excess wax is removed, it is first scrapped off by scrappers, later brushed out of the grooves (V-form of grooves is restored by brushing again. Which brush is used to restore the structure / grooves filled with wax?
Standardly steel or bronze brushes are used to clean the wax out of the structure. Both steel and bronze brushes consist of bundles of bristles. Bundles have normaly circle-shape with diameter ca. 5 mm. Each bundle consist of equally long and thin bristles. Standard steel and bronze brushes used to reveal structures have bristle length of ca. 20 to 25 mm and diameter of 100 microns (0,1 mm).
Let us have a look at the situation when the excess wax is brushed out of the grooves a bit more detailed: we have grooves 500 microns wide and 50 microns deep, we have brush with bundled bristles 25.000 microns long and 100 microns wide.
Conclusions: standard steel brush will remove the excess wax out of the upper half of V-shape grooves with pitch distance 500 microns. The bottom area of V-shape grooves with pitch distance 500 microns and depth 50 microns will remain “filled” with wax. In addition the bristles with the diameter of 100 microns will work as a rammer and will compact the wax inside the bottom area of the V-shape grooves resulting in shallower and more rounded groove forms.
Application of ski waxes does change the ski base structure, waxes make the structure shallower and more rounded compared to the status after fabrication.