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Etching Copper & Brass


Catherine Ronan

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Catherine Ronan

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No, This is not a miniature. This is about a technique which could easily be used for a miniature to get any sort of design you want etched on the surface. The design really shows up nicely once the metal work is finished and it has been oxidized and polished.
 
Ferric chloride will etch copper and brass. I buy it at Radio Shack.  It is not dangerous, though it should be done in a well ventilated area and you should wear rubber gloves and eye protection. If I wanted to do this on sterling silver I would have to use nitric acid because Ferric chloride will not etch sterling silver.
 
Any design you can draw, stamp or stencil on metal will work with this technique. You just want to protect the areas you want to be raised in your design with ink. You must use permanent ink for this. Even a sharpie will act as a resist to the acid. You can have a rubber stamp made if you find a black / white design you like. You just want a positive-negitive, not something with shaded areas.
 
I use a shallow plastic container and fill it with ferric chloride. Once you have the design you want on the metal (in ink) you will need wax feet to lift the piece away from the bottom of the container. So you will need a bit of extra metal that can be cut off where your wax will be. You are going to place it in the acid bath upside down so the metal bits can fall to the bottom of the container.  I usually use soft casting wax but bees wax would be fine. You can protect the back of your design with tape.
 
It is wise to do a test piece first. If you are using a very thin gauge of metal. You don't want it to etch all the way through it. It took about 30-35 minutes to etch this design in the copper.
 
I then went on to die form the sheets to see how far I could stretch them without distorting the design. It had to be annealed several times during that process. I won't go into die forming here.
 
The lip at the top of the shield shape was made by twisting two heavy round brass wires together and drawing them several times through a square draw plate. Then the wire was silver soldered on the shield after it was riveted together.
 
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Bill Hudson

Thank you Catherine, Very well done. Very interesting and something I should like to try sometime. I have done photo etching of electronic circuit boards for large scale, self propelled irrigation machines but not just surface etching purpose. I have had others do photo etching for several of my miniature projects including the popcorn wagon.

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ElgaKoster

Thank you Catherine, I am amazed that a sharpie is enough protection against the acid. I watched a live video some time ago where they did this on silver, they also used the sharpie there, as well a special sheet (can't remember now what it was called) that you could print your design on which I would think is probably the easiest for fine miniature designs, if I remember right it has to be a laser printer and not an inkjet printer.

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Debora Beijerbacht

What a gorgeous piece Catherine! Your various metal treatments make it look so sumptuous and rich!

 

As for the ink, that was the same thought as me Elga. Pretty amazing that the ink of a sharpe is sufficient to keep the metal from being affected by the acid/chloride. Needless to say, the etching technique is very suitable for miniature metal objects. Your post makes me wanna have a go at it right away, something i've thinking of doing for a long time now.

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  • 1 month later...
MissyBoling

Elga, micromark has an etching kit that works with ink jet printers.  I haven't tried it, but I know of other miniaturists that have used it.

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I've used the photo etch kit from Micromark to make tiny plaques for my knot board and buckles for my pack basket class and snowshoe classes at the Guild School. I use the ink jet printed transparencies, and add sprues to one side so they don't all fall into the etchant. As long as I take care with each step, I've had success.

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  • 3 weeks later...
bonni.b

In the Micromark etching directions they specify that the marker needs to be a Sharpie, other markers don't work. They suggest using it to touch up where the photoresist is bad.

 

I have the pieces for my teapot basket, but I need to age them so they look more bronze than brass. What's the best way?

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Elga

 

The technique for etching copper and brass is the same process used for making printed circuit boards for electronic devices.

 

You probably have a Ham-Radio club somewhere in your neighborhood and the ham-radio people makes circuit boards a lot and they can both tell you where to get materials, chemicals and howto.

 

google "the south african radio league"

 

/Niels

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MissyBoling

Bonni, will brass black do it, or will that make it too black?  I just spent the evening doing the graphics to etch some copper.  Hopefully I can do it tomorrow around noon with the sun since I'm fresh out of 100W bulbs with reflectors.  These are so delicate, I'll be lucky if they don't etch too much!  Pictures to follow if it works.

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bonni.b

I'm ordering Extended Life Liver of Sulphur Patina Oxidation Gel from Amazon. It looks like it will be easy to use on my tiny pieces. I'll post pictures of the before and after. I'm looking forward to seeing what you come up with, Missy. I've not done copper, only brass and steel, what gauge are you using?

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MissyBoling

Here are my results.  Bonni, I used 0.005 copper.  What thickness brass are you using?  Before I read the comments here, I decided to make a cup of tea, and put a scrap of the copper on the electric burner under the tea kettle thinking it might end up looking like the bottom of the tea kettle.  After it cooled, I polished it with a dry paper towel, bent it and hammered it, and ended up with this. The heating softened it for a really crisp bend, and the hammering hardened it right up again.  I could have used a torch, but the tea kettle method was so easy, with a cup of tea as a by-product.   ;)   I love the look, except I need to find something different to hammer it with for a better hammered texture.  I just used the little hammer that was on the table.  Any suggestions for miniature hammered texturing?

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bonni.b

The gel I've ordered has a longer shelf life than the rock form of liver of sulfate and being a gel, has none of the drawbacks of the powder form. My teapot pieces are already done in brass, not copper. Years ago I took a class with April and Ron Gill of Wildwood Miniatures and the storefront we did had a copper roof with standing seams. We used a mixture of lemon and table salt to verdi gris the roof and 12 years later it still looks great.

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MissyBoling

Cool!  Lemon and table salt sounds tasty too!  Makes me think of a margarita....  I expect your teapot pieces to turn out well, since I hope to be in the class.   :D

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