www.925-1000.com

At some point (by the 1960s I think), WMF (Württembergische Metallwarenfabrik) of Geislingen, Germany, was marketing is silver-plated flatware as "patent hartversilbert." Does anyone know when this occurred? Does hartversilbert imply a different/new process over its "Patent 90," or is it just a new name?

Hi,
Right, it seems to be just another name for the patent we have already discussed: double layer of silver was applied to exposed areas of cutlery to prevent wear of plating.
It is still used under the name 'Perfect-Hartversilberung', WMF being the only manufacturer of cutlery applying the method.

auch heute noch findet dieses Verfahren unter der Bezeichnung 'Perfect-Hartversilberung' bei WMF als einzigem Besteckhersteller Anwendung.

Regards

``Patent 90`` seen on WMF
Patenting 90 grams of silver for plating two dozen of spoons and forks (marked ``90``) makes no sense, because many manufacturers used 90 grams, some even more, i.e. 100 or 150 grams.
http://www.925-1000.com/a_platenumbers.html
So, ``Hartversilberung`` cannot be 90 grams, but reinforced areas, as patented.