Corrosion and Scratch Resistance in the Paradigm stainless razor

The most common enemies of stainless safety razors are corrosion and scratching. As those of you who have been following pre-release chatter will know, I had planned to coat this razor with a material so hard that it would not scratch unless by diamond and so corrosion resistant that 1000 hours of salt spray would not faze it. The coating did not happen, on grounds of retail price. It would have driven the price up by some tens of dollars. The coating may appear on a subsequent razor, but for now, I judged it was not worth the expense to the purchaser.

Corrosion and wear in safety razors is a big topic; I will only scratch the surface here. (I know, very bad pun). The real bugaboo, since the razor has a highly polished finish, is scratching. But it shouldn't be much of an issue, even without the coating. The Paradigm stainless razor is machined from 17-4 stainless. Nearly all stainless razors use a 300 series steel. There are big differences between them.

Let's consider ultimate hardness. 17-4 stainless is about 45 on the Rockwell C scale. That's pretty darn hard. 300 series stainless is so soft it doesn't even fall on the Rockwell C scale, which makes apples/apples comparisons difficult. But it's fair to say that 17-4 is about three times harder. We heat treat to the H900 standard, which is as hard as this steel gets. It's aerospace stuff. We machine in the "as annealed" state, which is a bit of a bear. In fact, the steel is about as difficult to machine as Titanium. Manufacturers use 300 series stainless because it has good corrosion resistance and is cheap to machine -- it cuts like butter. But as many will know from experience, it is easily scratched. Moreover, it just will not take the same shine as 17-4. 

Our steel goes through a multi-stage process. It is machined, heat treated, passivated, hand polished, passivated again, then hand polished again to remove the gunk left behind by polishing it the first time. Passivation is a process involving a mild acid bath to remove iron and other surface contaminants from the surface of stainless steel; it leaves behind a thin oxide layer which helps inhibit the formation of rust.

The razor should be quite resistant to corrosion without any special treatment. In order to avoid "tea stains" from galvanic corrosion, remove the blade between shaves and dry off the razor. This procedure is recommended for all your stainless razors as an extra measure of caution; other manufacturers make the same recommendation.