Sunday, July 29, 2018

Carbon Steel needles

When I started all this, I was pleasantly surprised that my carbon steel (spring) steel needles did not rust nearly as much as I expected.  When I sold carbon steel needles, I included a bit of crocus cloth to polish corrosion off of the needles, but I find that I do not need it nearly as often as I would expect.

Recently I was sitting by a pool, knitting.  The ground under me was rocky, and I dropped a needle. It clattered and bounced some yards. And then I noticed that the needle was scratched until it was distinctly rough. At home, I would have gone into the shop and buffed it. On other trips, I would have swapped another needle out of the knitting bag, but all I had was a very limited sock kit. So I kept knitting with the scratched needle. In a couple of hours, the roughness disappeared, no buffing or polishing with crocus cloth. The yarn was certainly NOT harsh enough to polish steel that fast. What happened?

My yarns have lanolin on them, and it leaves a film after knitting. As the steel starts to rust, the lanolin gets into the rust, forming a patina that protects the metal.  However, sitting next to the pool, I was using hand lotion, suntan lotion, and a commercial yarn with no lanolin on it.  I think the hand lotion and suntan lotion was enough to allow the metal to form a patina that protected the metal, but was "soft enough" to be scratched on the rocks. In fact, I notice that the patina on those needles is soft enough to be polished off by a few hours of knitting, but will reform in a couple of days.

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