Grey Flash 2751

The history and restoration of a Vincent HRD Grey Flash

Much debate has ensued about the finishes racing Vincents left The Works with, and no more so than that of the brake drums and especially the brake plates. The consensus is that GFs left Stevenage with drums and plates painted/enameled black (as per BL) or grey but I would like to challenge this latter notion.

Firstly, let’s look at blow-ups of period shots of 2751.

Well, the drums definitely are black – and the plates are definitely not black.
Yup, black drums for sure – the plates could be grey though…
Hang on…
WTF…?
Yeah, GREY!
Huh??

Well, the brake drums seem to be enameled black, no ambiguity there.

The brake plates, however, appear in some shots to be black and in other shots almost grey. I would suggest that this is because they are one of the following:

  1. Left in the raw – or as-cast. They would have been machined and the machined areas would have initially appeared as any freshly machined alloy. Over time all exposed surfaces would have oxidised resulting in a grey “skin” that gradually darkened over time.
  2. Finished with a chemical process to prevent deterioration by oxidisation and damage from external elements such as water and salt. The most well known of these processes is the Dow#7 dichromate process which appears to produce a dark grey/black finish.
  3. Finished with a protective coating of black paint.
These are the plates that I acquired from Paul Woelbing.
The visible finish seems to cover all fittings and fasteners.

This matte finish appears to closely match that in the period shots of 2751. The plates appear to have either been subject to some kind of treatment or blown-over with a protective layer of paint/sealant.

After I acquired the plates, and on the advise of those far more learned on the subject than I, I sealed them with black paint to prevent further deterioration. This paint has been stripped off and al surfaces cleaned. The rear plates are probably original to the bike and had been painted grey.

The rear plates after paint removal and cleaning.
All four plates.

I rue the fact that original finish has been lost but the cold fact remains that these Elektron magnesium components needed properly cleaning to prevent further damage by oxidisation. The front plates, in particular, were quite pitted whilst the ones on the rear were in much better external condition having been protected by paint. A uniform finish for all plates is desirable and this can be achieved by either leaving them to darken over time or covering them with a suitable protective sealant – any comments much appreciated.

Other blow-ups of period shots:

These appear painted black.
As do these but with unpainted air scoops.
Black seems more common though.
Shot of the Ehret BL whilst in the ownership of Franc Trento.

At no point have I seen bulletproof evidence that plates were ever painted grey. What appears to be a grey painted finish in some period shots (such as the group of GFs in Brazil) is in fact one of the above listed finishes.

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