In January I decided to try out acid etching. Having never tried it before my first attempt which I documented in this blog wasn’t a complete success.  The etching was good but the silver was slightly marked in places and definitely not good enough to sell. I said at the end of the post that I would try different techniques and put up some photos when I thought I had it cracked! So here’s the story of my extensive testing and the results.

If you want to see my previous posts on acid etching click here.

The problem I had with the etching was that the acid was eating through the resist in certain areas leaving me with little marks on the parts of the silver that I wanted untouched. Rather than waste silver sheet, I began doing a series of tests on the different resists using some scrap silver. This way I could figure out which resist wasn’t doing it’s job.

The technique I used was to transfer a photocopy on acetate onto a clean silver sheet using heat so the printer ink acts as a resist. When I tested this on it’s own it worked perfectly but only when the image was transferred without gaps or marks. This meant controlling the heat when I was transferring the ink. Too little heat and the image would not transfer completely. Too much heat and the ink would run into the design blurring the fine detail. Once I resolved the heat problem, the ink held up in the acid so at least I knew the printer ink worked.

The next thing I used on the silver to patch up any gaps left by the photocopy transfer was a red Staedtler permanent marker. I had read on a few acid etching websites that this was the best to resist the acid. Unfortunately it didn’t work for me, after a few hours in the acid it began to break down and let the acid attack the silver. I tried putting extra layers of it on the silver but it made very little difference so the red marker has been relegated to the office.

The final thing I tested was the nail varnish as I used this to cover the sides and the back of the silver for etching. This was by far the best. I left it in the acid bath for eight hours and I still had to scrub it with nail varnish remover when I took it out.

Since then I’ve ditched the marker and am using the photocopy transferring which I’m touching up with nail varnish. While previously I only used the nail varnish for the edges and back, I now use it to touch up any areas of the printer ink that haven’t transferred. I use a bright opaque colour nail varnish so I can see clearly what areas have been covered and make sure it doesn’t run into the design.  I’ve tried it on a number of different designs and it hasn’t let me down. The great thing about this is the level of detail I can achieve. Here are a few photos of some of the pieces I’ve done recently.

This is part four of a series on acid etching silver. Click on the links to see Part one, two and three.

The silver was immersed in the ferric nitrate solution. I checked the piece every hour, I had initially decided to check it every 30 minutes but it proved a bit pointless since it took six hours to etch. I was able to test the depth of the etching with a cocktail stick. The point of the stick catches on the edges of the lines so you can feel how deep the etch is, if it slides across the design you know it hasn’t etched deep enough.

When I thought it was deep enough I removed the piece from the etching bath and put it in a mix of water and baking soda to stop the ferric nitrate from continuing to eat into the silver. It starts fizzing when it reacts with the baking soda, this is a good thing! When it stops fizzing you know the ferric nitrate has been neutralized, I took it out and rinsed it in water. When I took off the tape and cleaned off the nail varnish here’s what I got.

When I polished up the silver the areas that the etch had eaten through was easier to see. It only ate away the area that had been masked with the red marker, so at least now I know not to use Marker as a resist in future. I was really happy with the texture of the etched area, it’s a great contrast to the polished silver.

I finished by doming the disk and giving it a final polish. And here’s the finished piece, not as perfect as I would have hoped but not bad for a first attempt at acid etching. Test pieces like these obviously should never see the light of day. When I have an acid etched piece I am happy with, I’ll be sure to post pictures of the finished product.

This is part three of a series on acid etching silver. To see part one click here and to see part two click here.

Having prepared my silver I then make up my ferric nitrate etching solution. This is done in a plastic container with a tray under it in case of any spills. The ferric nitrate needs to be stored in plastic or glass with plastic lids as it will rust and corrode metal.

In my acid etching area I have the etching bath plastic container and tray, a measuring jug, distilled water and a weighing scales.

I start by measuring the distilled water. The guide I got from the Goss Design Studio website on silver etching is to use 200ml of distilled water to 150grams of ferric nitrate. It  says you can also add nitric acid to kick start the solution but I don’t like working with neat acid if I can avoid it.

I then weigh my ferric nitrate crystals and add it to my distilled water. I use a plastic spatula, you can also use a wooden spoon. Although the ferric nitrate isn’t a pure acid you need to wear protective clothing and gloves. It doesn’t give off fumes but I still did all my preparation in a well ventilated area.  The most important thing to remember when mixing the solution is to always add the ferric nitrate to the water and not the other way around.

Once the solution is mixed I’m ready to immerse my silver pieces for etching. The piece has to sit face down in the bath so the corroded silver particles can fall away and not clog the design. The best way I’ve found to do this is to tape the silver onto a square of Styrofoam so it floats.

Once the piece is put in the ferric nitrate I set my alarm so I can check the piece every thirty minutes.

You can see the results in of the etching in Part 4.