Turning Archive 2007

Subject:
Chemistry and guilding *PIC*

Steve Antonucci
>I've been messing with a form that has been languishing around my shop for years. Instead of tossing them, I tend to use them to experiment with new techniques and processes.

This walnut crotch hollowform has been burned, carved, and textured over a period of many years. I wasn't thrilled with it, so it went back on the shelf. A couple of years back, I sat in on a David Marks lecture on guilding and patination at the Woodworking Shows, and I decided to try it with a twist.

I guilded this form with a copper leaf (twice now, and you'll see why in a second). Now, I have a basic understanding of chemistry, and I know that copper will react in the presence of salt and an acid (I'm using vinegar). The result is very interesting, since the reaction is verdigris. I've read (and tested) that ammonia will produce more of a greenish color (currently, I'm getting a very turquoise blue).

Here's my dilemma: the copper leaf is so thin that it's largely being consumed by the already weak acids in the vinegar and the ammonia. Ideally, I'd have a mostly green and blue pot, but I'm really closer to 50/50. I'm debating cutting the solution again, but I'm looking for a more controlable reaction.

Any chemists out there that can help me out?

Picture of the current state of affairs below. I'm going for an over all green/blue covering. Not quite there yet.

Steve

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