Wednesday, February 01, 2012

More Sterling Clay Experiments

I ran another course of sterling clay through the kiln last night, technically finishing my Four a Month project on time, although I didn't do the patina until today.


I made a couple of small hollow-form heart pendants or charms.


This first one taught me to remember to protect openings from the carbon, as the carbon wedged inside the piece caused it to crack. I'll have to repair it.


This version utilized fine silver syringe work on top. It's not true that fine silver must be fired in air -- it works well! It IS necessary to remove the binder with oxygen available, for all of the metal clays in fact. But after the binding is gone, sintering takes place either open or buried in carbon. Fine silver and gold were the first metal clays manufactured because the pure metals don't oxidize when sintered in air. However, nothing untoward happens when they are sintered without oxygen, as long as the binder has been removed.


One interesting detail here is that the two hearts were cut from the same templates, but came out different sizes. I assume this is a function of all the fine silver line work, which doesn't shrink as much. I'll have to think about how this could be useful.

6 comments:

  1. Beautiful pieces! Great experiments too!!

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  2. Katie Hanrahan8:25 PM

    Ah, great information about the fine silver line work. These pieces are wonderful! Thanks, Vickie

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  3. Thanks for the information! Will you place the next hollow piece in a stainless steel screen to keep the carbon out?

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  4. I've used the stainless steel screen a couple of times with good success, Janet. I'm also going to try thick fiber paper.

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  5. I used fiber blanket and had some problems with fuming. The blanket turned brown where it was against the sterling silver. The sterling silver and stones also had brown dust. It washes off but if it is under the stones it dulls them. See my last blog posting for a photo.

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  6. Yes, Janet, I've seen the brown fiber blanket. I interpreted it differently. I guess I need to think about that more.

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