Thursday, September 24, 2009

Stuff rolls down hill.

So apparently my math class did not do so well over all, with our class average being 8 out 9 classes.

This appeared to have bothered my math professor as she managed to deliver in an hour 19 (by my count) passive aggressive NASTY slurs about our class while delivering them in a chipper cheerful voice.

I was a little flabbergasted.

For the record I did okay, not great.


  1. Just checked out your April etched coins and box post. Good stuff. I'm doing some similar work right now with copper. I'm making challenge coins. Currently I'm making my own impression dies, but would like to experiment with etching for more detailed work. My books recommend ferric acid or nitric acid for copper. Any thoughts on this.

  2. Regarding the etching. For the copper and brass I used Ferric Chloride. The copper etched pretty good and the brass etched really well.

    For the bronze and the Shibuichi (the silvery ones) I used Nitric.

    Nitric etches really really fast. For the dilution you'd use for silver it etches almost to fast for copper, brass and bronze.

    If you compare these two links (sorry no imbeded images in blogger comments)

    Both of the two above were in the nitric for the same amount of time and whereas I got a solid etch on the Shibuichi the detail was very nearly obscured on the bronze.

    So if you use nitric, you'll almost certainly want to dilute it.

    If you are just etching copper it's also easier to get ferric chloride, as it's use to etch circuit boards and is available at Radio Shack and the like. It's also less dangerous to handle (merely requiring nitrilte gloves to avoid staing the skin as opposed to hazmat gloves...)

    Basically, if you aren't etching silver (or an alloy thereof) I don't see a reason to use nitric.

    For image transfer We were using PnP blue transfer paper like this.

    It allowed for some pretty fine details.

    Any more questions? I'm happy to answer them.

  3. Thanks for the response. I picked up some ferric this weekend. But I want to pick your brain some more. I've built a pair of dies and pressed an image onto my "coin" on both sides. With different density between he image(high relief?) and the rest of the coin, even if I put a resist on it, will I have trouble with the acid eating the relief somewhat. And yes I'm only etching copper at this point. 1/4" thick and I have no Idea about the alloy. It was used copper piping.

  4. Anywhere the etchant can reach... it will etch.

    I will write up a little how-to etch primer and post it separately and if you have more question you can post them there, that way I can tag it appropriately for later searching.

    Should be up by tomorrow afternoonish at the latest.