We have been annealing these shells between 500C and 650C, with a warm up time of 30 minutes and 2 hours at peak temperature. We have also been opening the oven door fully at peak temperature.

By adjusting the annealing temperature you can respectively change the patina and the hardness of the steel. Mostly it goes that the higher the temperature, the harder the material. Lower temperatures will rather give a golden like color and higher dark purple. The temperature you will choose to anneal your instruments with will also depend very much on your own shaping and tuning process. Between the different batches you will also want to vary your temperature as the hardness differs as well as the possible colors to be achieved.

When you oil the shell the color changes a lot! We use phoenix oil. See below a photo of four different shells unoiled:

As there is so much to explore in temperatures per batch, this is a great place to all share our experiences.

2 months later
4 days later

Ralf van den Bor thank you for the long and detailed answer.
Than must be it, somehow I should have mistaken the shell thinking it was other batch.
I normally clean with soap solvent and acetone and didn’t had problems, but maybe at high temperatures acetone starts staining, so I should also use alcohol.
Ok I’ll also make the gap between shells bigger.

Find attached the tools I used for polishing.

It’ll be nice to see how you polish the shells before sending them to the customers, so if 1 shell out of 4 in the oven get stained we could repolish the same way you do and have similar annealing colors of the other 3



    This is the result street polishing with the tools of the pictures and annealing up to 600C and oiled with 🥥 oil

    I find that using a double action polisher, the surface get much smoother and the scratches are almost erased, the con is that you cannot polish near the rim because as it doesn’t make a circular movement it hits the rim is you get too close

      8 days later

      Vikram

      Between rounds we cook at 325C for 2 hours at peak temperature and open door completely when the two hours are finished. Our warm up time is 30 minutes.

      • Giah replied to this.
          2 months later

          Hola, yo acabo de estrenar mi horno y he horneado dos conchas de ember steel a 600 grados durante 3 horas, anteriormente he limpiado con disolvente varias veces incluso con un disco de lana para profundizar mas en la limpieza pero aun asi el resultado no ha sido como yo esperaba y siguen saliendo manchas y diferentes colores, no se porque, algun consejo?
          Hello, I just new my oven and I have baked two shells of ember steel at 600 degrees for 3 hours, previously I have cleaned with solvent several times even with a wool disk to deepen the cleaning but still the result has not been As I expected and stains and different colors continue to appear, I don’t know why, any advice?



            Roy_Ayasa_Instruments No, ese lo limpie con disolvente y despues con alcohol, pero parece que la mancha de aceite penetra mas en el acero y aunque parece limpio aparece despues, he probado a pulir con el scoch britte ultrafino y ha dado muy buen resultado, apretar muy poco para no arañar y queda muy bien
            No, I cleaned that with solvent and then with alcohol, but it seems that the oil stain penetrates more into the steel and although it seems clean it appears later, I have tried to polish with the ultrafine scoch britte and it has given very good results, press very little so as not to scratch and it looks very good

              Aceton works quite well for me, with a very clean fabric.
              But as I find it very difficult to have a perfectly clean shell, I decided to use those marks in an aesthetic way. This with some other ideas and it makes something quite cool

              But I’m using a torch, not oven.
              By the way, could anyone give me a quick feedback about the annealing time ? The torch makes a very quick warm up, and I only fire for a 3 or 4 minutes. It then cools down pretty quickly, I’d say the whole process may take 15 minutes. I like the way I work now, and I won’t be able to get an oven before a while, but I’d be curious to know the consequences of such a a controlled and long annealing 🙂

                2 years later

                Giah We tune the first round everything to zero so that the note is in tune and try to get it as strong and stable as possible. By heating in between rounds your are allowing the molecules to find their place again. This results in less brittle material, allowing you to work on it again in the second round. Then in the second round you can also see how far the notes detune. If a note is detuned a lot it often means that it was not tuned properly. This means you can work on it again to make it tighter and ore more balanced. Hope this helps!

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