Whizzing What is it? How does it work?

Conclusions:

Brushes: The choice of brushes was critical to the results. The softest brush (404) caused little more damage than would abrasive polish on a cloth. The only steel brush I used (443) was far more savage than expected. The effect, when I first applied the brush to the coin, was quite startling - ripping off the toning instantly, and leaving a finish which appeared to the casual glance (naked eye) to exhibit a magnificent, mint-state lustre. It was, in fact, hopelessly damaged by an overlapping network of scratches. The 405 nylon brush did far less damage to the coin, removing the toning and applying a fine polish without discernable scratching.

The LHS whizzed by the steel brush. Note the filings on the mat.

Technique: Pressure of application made little difference with either of the two nylon bristle brushes. Neither of them produced significant scratching despite heavy pressure applied. Gentle pressure was certainly called for with the steel brush. Heavy pressure removed large amounts of metal quickly. Scratching could not be avoided, even with the gentlest of pressure. In order to simulate "cartwheel lustre", I applied gentle strokes from the centre to the rim of the coin, in a "spoke-like" pattern. To a certain degree, this did produce a sort-of "radial" pattern, but it did not behave like true cartwheel lustre when the coin was tilted. It was in no way convincing.

Some attempts were made to produce "raised ridges" near devices, a diagnostic symptom of "moving metal". None were produced (or observed) on the florin, nor on the contemporary coin when this effect was sought in earnest. "Ridges" were indeed produced, but it was easy to show that these were below the original surface of the coin, and hence were products of abrasion, not of the plastic deformation of metal.

Hairline scratches were obscured by the whizzing process, but by a process of abrasively covering them with a field of more scratches, deeper and more disfiguring to the coin. They were not "filled in" by metal being "pushed" into them. Two hairline scratches inbetween the the "1" and the "9" of the date were mostly obscured by this process, but remnants of them still remained visible after the whizzing process. The significant feature of this is that they (the original scratches) are visible only in the ridges (the high areas) left by whizzing, and have been removed from the valleys (the low areas, removed by whizzing). This effect was most noticeable when viewing the coin in stereo at high power (20x). This certainly suggests that the removal of scratches is by the process of abrasion, not by "filling".

(Added 16 April) The illustration at right shows the mechanism by which "ridges" or "crests" can be produced by whizzing. This is a macro view, and is intended to illustrate the effect seen on the 2001 coin, and between the "1" and the "9" of the florin (above).

The illustration at left shows the hypothetical raising of ridges during the process of abrasion. I have neither demonstrated nor recorded this method, but I acknowledge its existence. Maybe I will update this site later with a a high-power photomicrograph which illustrates it. The "magnification" of this illustration is many orders of magnitude greater than the one above. It depicts a single scratch.