Thread: Crocus finish or Satin?

This is a far better choice than hide glue....

Yep that's the stuff I use & was talking about. I thought it was hide glue ? Maybe not.

Hide glue is made from animal hides and normally comes as crystal that are melted in a glue pot. Total pain in the rear end.

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.

Great Post Peter...I don't know if Naxos emery can be purchased today but I guess I'll be trying to find some. Really good info!

I could not agree more. Awesome Peter.

I got a flint hard felt wheel recently and now am waiting on some synthetic 1 micron iron oxide , curious to see how it will work out.

I also plan on making some wooden wheels with leather . I am not sure if the rough side of the leather should be facing out or the smooth side? My guess would be the rough side.

Originally Posted by mainaman

I got a flint hard felt wheel recently and now am waiting on some synthetic 1 micron iron oxide , curious to see how it will work out.

I also plan on making some wooden wheels with leather . I am not sure if the rough side of the leather should be facing out or the smooth side? My guess would be the rough side.

Iron oxide should work fine. The problem is how to bring it on the wheel! You need to glue it on the wheel or produce a paste that you can use.

The production of wooden wheels with leather is not an easy thing. The connection between the wood and the leather must be very good, otherwise the leather is thrown away when the wheel turns. Could be very dangerous!
The rough side of the leather is glued to the wood. Make sure that you roughen the leather with a file. The wood should have some rills that will be filled with glue for better bonding. Glue the leather stripes to the wood and fix them with nails. The nails are only driven partly in the wood so that they can be removed after the glue is fixed.

Regards Peter

Originally Posted by hatzicho

Iron oxide should work fine. The problem is how to bring it on the wheel! You need to glue it on the wheel or produce a paste that you can use.

The production of wooden wheels with leather is not an easy thing. The connection between the wood and the leather must be very good, otherwise the leather is thrown away when the wheel turns. Could be very dangerous!
The rough side of the leather is glued to the wood. Make sure that you roughen the leather with a file. The wood should have some rills that will be filled with glue for better bonding. Glue the leather stripes to the wood and fix them with nails. The nails are only driven partly in the wood so that they can be removed after the glue is fixed.

Regards Peter

Thanks for the tip Peter, that definitely will take some rial and error to get right

I am pretty happy with this thread. I am undergoing some experimenting too. I have made a couple of wooden wheel. I used MDF for my wheels so there is no grain or grain direction. I have not mounted my leather as of yet and I am planning to use hide glue. I have an old strop that will be used for the leather. I had considered trying to make solid leather wheels but have abandoned that idea.