Patina

For the last few days I’ve been applying oil to the SET chassis. It now has four coats of oil, cured and buffed out. There’s only one decision left for the chassis.

It’s been a tense couple of days waiting for the patina to set on the 6AS7 SET top plate. But I just placed the copper on the chassis and it looks great!

Regardless of how much planning you do and how many test runs you accomplish, sometimes things simply don’t go as planned.

With the return of some more normal weather here I got the chance to work on the SET chassis today. Specifically I got the bare copper plates chemically treated for the patina for which I was looking. They look good. Or, more accurately, they look just the way I imagined when I first thought of doing this. I’m very happy with the results.

So I’ve been playing with the copper tarnish/patina process and I think I’ve got it figured out. After doing lots of small parts with various approaches I’ve learned enough to start the amp pieces. Among the things I’ve learned is that the washing process both before immersion in the chemical bath and after tarnishing while washing off the chemicals is very important. I’ve also learned that an even buff with a steel wool is better than taking the copper to a high gloss shine. And finally, the initial tarnish is very fragile. After doing the bath and letting the piece dry, it really should be left sitting in the open air for between three and five days. After this, the oxide layer toughens up and it can be handled and clear coated.

I’m now just shy of ten weeks into my new routine and there are a lot of projects vying for my time and attention. This situation has made it difficult to make serious progress on my 6AS7 SET project.