Thread: Crocus finish or Satin?

Originally Posted by hatzicho

Really an interesting thread! Thanks for bringing that up.

During the last 5 years or so I searched for - and spoke to - maybe a dozen old german grinders about polishing of blades. Traditionally the polishing process on blades and razors in Solingen is done on wheels of either wood surrounded by leather, felt or cork. The choice of the material depends on what you are polishing. For example if you polish a hollow grinded blade or razor, a felt wheel might be too soft, so that the edges get rounded, therefore cork or wood is the better alternative. Of course there are different grades of hardness of felt and harder felts may also be used, so every grinder has his own experiences.
The surface of the wheels are covered with emery, traditionally Naxos emery, which is glued with bone glue to the wheel. Nowadays also so-called red-glue is used, but a lot of the old grinders swear on the usage of bone glue.
For different stages of polishing, different grades of Naxos emery is used. The pre-polishing is done with coarser emery and is getting finer during the process, which can consist of 5 stages or even more . Last stage before the black- or mirror polishing is the so-called blue polishing. Here the finest emery is used, typically Naxos grade 5/0. During the blue polishing, the surface of the steel is densified. Polishing does not only mean to cut the peaks of the metal surface but also to fill the valleys with material. After the blue polishing process, the surface of the steel shines blueish if turned into the light, hence the name. The surface of steel is somehow sealed after this stage of Polishing, therefore the knifes made of carbon steel don't oxidize too much and too fast. The blue polishing of knifes in Solingen was very famous in the past and still is today, of course it doesn't make the steel inoxidable, but somehow inactive to rust.

The mirror or black polishing is one stage further. Normally the same wheels are used that already did the blue polishing, means, no finer emery is used. Additional pastes help to do the special polishing effect. Nearly all of the grinders I spoke too, have their secrets, what to use, how long, which formular, etc.
Traditionally in Solingen Vienna chalk mixed with rape oil was applicated on the wheels. Vienna chalk is very soft, so depending on the hardness of the steel and the steel itself, also other materials have been used. Sometimes special polishing mops do the final polishing process.

Sorry to revive this old thread, but I have been wondering something about vintage Solingen razors. The semi-polished or satin polished razors have a special pattern of grinding or maybe polishing Whee marks l that you can not achieve that mark pattern with a belt grinder or buffing felt. Maybe I cannot express my idea well enough because my English is not good. If you kindly look at the pictures below I am sure you will understand easily. The marks or trails of grinding or polishing Wheel is very neat and even. there is no up and downs between marks. You can see this pattern even on the razors of these days producers like dovo and wacker, but not on böker razors or french razor producer thiers issard razors. Do you know how can they do this pattern.