Brass etching

In a fit of procrastination this evening, I decided that I would do a brass etching with the brass that appeared in the mail yesterday. I went with the airship pilot's badge from earlier. The transfer was really good, the magazine peeled off in one piece, which was a really good feeling. Here's a picture of the magazine page after peeling, with the brass next to it:












I put it into the tank with my new plate holder (left, lovingly turned down on a school lathe), and switched the power supply on, it drew between 1.5 and 2.5 Amps the entire time, and built crud up on the surface a lot faster than the copper did. Some copper also rose to the surface of the brass. There was no surface pitting either. This etch took about 15 minutes.






In case you're unfamiliar with the difference between copper and brass, brass has zinc as well as copper, and looks gold rather than red. The brass is at the top, and copper at the bottom:

















Here is the finished etching, after being 'inked'. More on inking later.

An experiment in separation

I have found that when I etch, the plate that I'm etching heats up to a point where the toner flakes off the plate, leaving the copper underneath exposed. This evening, I decided to try and change this. in the past, I have put the two plates very close to each other, about a centimetre apart. While this positioning means that it only takes about twenty minutes to etch a plate, I think it contributes to the heat.

Anyway, I transferred this picture onto a piece of copper, and put it into the etching tank. The picture was from the front cover of the first issue of this magazine.
But this time, instead of putting the two plate really close together, I put them on opposite sides of the tank. Because the resistance would be much higher, I knew I would have to leave it for a lot longer than normal. I put it on at 15 volts, and between 1 and 1.25 amps, and came back 50 minutes later to check it and turn it off, as I was leaving the house to ferry lurkers around town.

When I got home again, I turned it back on again, and got to tinkering around the workshop. Another 50 odd minutes later, I turned it off, this time for good. Not as much toner had fallen off as in previous attempts. Success! I got a nice gradation of depths, deeper in the wider lines, shallower in the narrower. Then I cleaned it off, and inked it. Here's what it looks like.

One thing that I have noticed with using magazine pages for toner transfer, is that parts of the image from the magazine sometimes transfer too.You can see this above and to the left of the bird. So sometimes, my etchings end up with words etched into the background and other things like that. At some point, I will attempt a different paper.

An experiment in stainless steel and blue paper

On the weekend I split a packet of Press'n'peel Blue with a mate of mine, because we both wanted to try it out, having only ever used magazine pages. I also bought some stainless steel wall-plates, used for light switches and audio systems etc. For a couple of days I tried to find something that would look good on a stainless steel wall-plate as a replacement for my boring white plastic light switch. I finally stumbled upon the back of a card. After mucking around with it in Gimp for a while, I finally got it scaled to the right size for my wall-plate. I decided then that this would be the perfect opportunity to test out the Press'n'peel Blue. Accordingly, I printed my image onto a sheet of it, and proceeded to align and iron it. FAIL.The bottom picture is my first attempt at the Press'n'Peel, and the top is the second attempt.
My iron was on too high a temperature, it was still on the setting I use for magazine pages. I turned it down to 'Synthetic' and tried again. FAIL. I don't know if it was poor technique, or if P'n'P doesn't work on stainless steel, or if it even works at all, but only about a third of the image adhered to the metal, the bits that I've drawn around were the only bits that adhered. So I went back to magazine pages, and, wha'd'you know, it worked. It wasn't perfect, but about eighty-five percent of the picture was there.

I took it out to the workshop and set up a brand new tank, this time with table salt as the electrolyte. After discovering that yet another fuse was blown in my power supply, I switched to batteries. My smaller battery was too small to have much of an effect, and when I put my bigger one on and tried to measure the current the tank was drawing, the jumper leads exploded. So I hooked it back up, but with three pairs of jumpers instead of one. Much better, and it was pulling about six amps.

After blowing up lots of little hydrogen bubbles, I took it inside and cleaned it off. It's pitted in places, and looks very raw, but it has a certain je ne sais quoi to it, appealingly aged.Here it is installed on my wall, I put some Prussian blue oil paint over it to bring out some of the detail, but the camera doesn't show it.

Intaglio plate

This evening I decided to try and make a printing plate of the airship wings image. Because I wanted the final image, in this case the print, not the plate, to be a positive, I had to reverse a step.

When I printed out the image on the magazine page, it was a positive. This means that the blank spaces (which are supposed to be white) would be etched out, leaving a negative, once you put the ink on and press it into some paper, it becomes a positive image on the page.


I bought some ink in a bottle today with this in mind, as well as a roller. Both came from the art shop in Dickson. The roller is made of plastic, so somehow I had to protect it from the heat that remains in the copper plate during ironing. I found that I had a roll of aluminium tape in my workshop, so I put a couple of strips on the roller, et viola! A protected roller. After heating the toner, I rolled the copper and the paper with the roller, and then soaked the paper off. I was pleased to find that the roller helped in the quality of the transfer, more stuck down than usual. There were a couple of little spots that came off while I was removing the paper, but they were in non-critical spots so I didn't re-do it.

Unfortunately, while I was drilling the two holes in it, my drill slipped and I bent the plate. I straightened it out again, but I think I may have weakened the toner's grip on the copper.

I hooked the plate up to the new and improved power supply that I did yesterday (which works wonderfully, I might add), and etched for about twenty minutes, after which the toner had started falling off. I suspect this was because the plate was getting quite warm, softening the toner up, and also because of the bending I mentioned.

















In spite of this it turned out reasonably well, and I cleaned it off, painted a thin layer of ink on to it, put some paper on it, and went over it with the roller a couple of times.


I think next time I need to etch deeper, and not bend the plate.

I once again apologise for the photos. The lines (particularly in attempts 1 and 4 are actually quite sharp.

Power supplies

I am very fortunate. I have a friend who works for Questacon, who has lots of fantastic electronic junk. One prime example of this is a trio of variable linear power supplies, each having a range of 9-18 volts DC. In my annoyance at having to recharge my SLA batteries after etching, I finally broke one of the power supplies out in the place of the battery. It's a wonderfully simple device, you just put mains in one end, and a preset and adjustable voltage comes out the other end. Because I had no proper electronics enclosure on hand, and lacked the motivation to build a nice box to put it in, I had decided to mount it in an abandoned lunchbox. This was necessary, because otherwise there would have been bare, live mains wires sitting on top of my workbench, which is both permanently covered in crap, conductive and non-conductive alike, and is within easy reach of my two lurkers. I wouldn't want to zap them, now, would I? Anyway, I set the voltage to about 10VDC, zip tied it in, put a switch and some connectors and a fan for ventilation in as well, and closed the lid. That was my power supply until today, when I mounted it up in a nice box, with adjustment knobs for voltage and the current limiter, and all the connectors. Still to come is an ammeter and a polarity switcher, which will allow me to plate with this supply.



















You, however, may not be as fortunate in your friends as I am. Never fear. All is not lost. You can use other power supplies. As I mentioned before, SLA (Sealed Lead Acid) batteries work very well. They're basically car batteries, but they don't spill, and you can get them in different strengths. You will, however, also need to shell out for a charger, and keep the battery charged. What a pain. But, that's not the only alternative. Do you have a phone that's broken? (A land line, hands free phone that is.) Or a broken scanner? How about some dead computer speakers? Most of these devices are powered from a 'plug pack', a step down transformer that plugs straight into the wall. One of these plug packs will suffice as a power supply for etching. Just make sure the output is DC, and at least three volts. You may want to solder some alligator clips onto the end of the wires (after lopping the plug off), to help you identify +VE and -VE, and to make your connections easier.Pictured above are a 7 Amp/Hour SLA battery and some plug packs

Etching

Now that the toner is on the copper, we can etch it.
This means that you have to have made the tank, and found a suitable power supply.

The power supply needs to be at least three volts, and absolutely has to be DC, or direct current. According to my friend, who is doing second year engineering at the ANU, you need three volts for the copper to start coming off the plate. Much more than three volts is overkill, but it does no harm. However, the higher the voltage, the more leeway you have (theoretically) with the size of the plates and the distance between them, as well as the concentration of the electrolyte solution. If you measure the voltage across the two plates while they are etching, it reads higher the further apart they are. This is because of Ohm's law, which states that Voltage=CurrentXResistance, or V=IR. If you move the plates close to each other, the resistance between them drops, causing the voltage to go up. The same goes if you put more copper sulphate into solution.

The procedure for etching is this: Figure out some way of suspending the plate as close to parallel as possible with the cathode. I drilled two holes, one near each of the top two corners. Then I put some fencing tie-wire through the holes and hung it from a bit of aluminium stock so that it would hang below the water line.


Connect the positive of the power supply to your piece, and the negative to the plate in the tank, and turn the juice on.












Every fifteen minutes or so, turn the power off and scrape the crap that forms on your piece off with a toothbrush. Return it to the tank and continue.















This particular piece only took about half an hour to etch, but that's because it's so small. The bigger it is, the longer it takes. This is because the current will spread out pretty evenly over the surface of the copper. Because there is only so much current, if you have a large plate, there will be fewer amps per square centimetre. I once etched a card box with a picture about 5X7 cm, which took about two hours.






Here's the badge that I etched, based on the picture in the second post. The lines were about 0.5mm deep, and very clean. The only problems with the etching quality are the parts where I failed to transfer the toner properly, i.e the wing tips, and three parts of the zeppelin. The other flaw is that there is some pitting on the wings, but I suspect that that is due to the large spaces of black. It might work better if that part of the picture were made up of lines.











If that is where you're going to leave it, then now is the time to ink it. This can be tricky if you don't have the right stuff, but it's not all that bad. If you're going to do something else, you shouldn't ink it yet.

Interesting fact: I touched the back of the plate before etching, and was left with an etched fingerprint on the back. The back does etch, but not deeply.

Toner transfer

This is a technique that I used to use to manufacture PCBs (Printed Circuit Boards), but I realised when I read this that it could be used for other things too. The basic concept is this: A laser printer melts stuff called toner onto the page, if you're careful, you can then re-melt the toner, onto something else! The wonderful thing about toner, is that it's both acid resistant, and electrically non-conductive. This allows you to use it for a mask on either electro etching or acid etching. If you want to create your own one-of-a-kind, hand drawn plate, you can use a soft ground, which is a thick oil based ink (the one I've got is at least). You paint it on, wait a couple of days for it to dry, then just scratch your picture on. But I'm using the toner transfer method.

Here's what you need:
As pictured, you need an ironing board, with a cloth on it so I don't burn the cover, a sheet of copper, which I'm using for practice, a nibbling tool, steel wool, isopropyl alcohol, scotchbrite, an iron and a block of wood.

Print your image onto a page from a glossy magazine (I used New Scientist), make sure the image that you are etching is printed in black and white (the colours on the magaine page don't matter at all) , and the exact opposite of the picture you want to have at the end. Ergo, the colours (all two of them) are inverted, and the picture is mirrored.

Cut out your image, and a piece of copper that the image will fit on. That's what the nibbling tool's for, but you can use anything that works. Now you have to clean it REALLY well. Scrub it with isopropyl and steel wool until it gleams, you can use the scotchbrite instead of the steel wool if you want. Make sure there is no dust, dirt or oil on the surface, that includes fingerprints.

Once it's clean, wrap your image around it, with the picture over the cleaned surface, and the edges of the paper behind it. Now iron it. Put the iron on its highest setting, dry of course, and press hard, moving the iron around a little. It sometimes helps to rub it with a roller or the back of a spoon or something. This can take around 2 minutes, but practice will tell you exactly how long. Because ironing boards are padded, I always put a block of wood under the copper, but if you're ironing on your workbench, there's probably no need. But it might still help.

Once the ironing is done, put the copper and paper in some hot or warm water. Let it soak for about 10 minutes, then gently peel the top layer of paper off. Soak it again, and take more paper off. Continue this until there's almost no paper left, then you can rub the rest of the paper off. You want tho be left with a piece of copper with only toner and empty space on it. Nothing else. And that's the toner transfer method.

You should be left with something like this:


My technique wasn't great on this one. Decent, but not fantastic. I missed the wing tips and the bottom tooth of the gear, and I think that I accidentally ironed some of the blue from the magazine page onto the copper too. If you have an etch resist pen, sold in electronics stores, you can go through and touch up bits that are missing, and you can carefully scrath lines out of the toner when bits that shouldn't be there are there. (By the way, don't be fooled by the shaky lines, they're actually very sharp, my camera's not great is all.)

Aims and materials.

When I'm done with this particular set of experiments, I want to be able to get good quality etches, with nice straight lines, I want to be able to 'etch machine' as well, which is where you etch right through the plate, causing a bit to come off. I want to minimise surface pitting, and master toner transfer, which I'll explain at some point.



The project I'm going to be making for this is a badge, the image I'm using for the badge comes from a web comic called Girl Genius that is quite amusing, and it's an airship pilot's badge. I think it's quite a striking image.




The materials I'll use are:
Large Tupperware container
Copper Sulphate
Plates of brass and copper (Obtained from A&E Metal suppliers )
Variable power supply
Laser printer New Scientist magazine
An iron and ironing board
A Roller
Isopropyl alcohol
Black paint
Steel wool
Scotchbrite
Brass brooch findings, also from A&E



You might also find one of these useful at a later date.














The first couple of steps I have had completed for a while now. They're as follows: Make an etching tank. I had some old float valves, enormous ones, and the float on one of them was bashed in and useless. Or so I thought when I got it. It was made of copper, so I cut a bit out of it for my cathode. I drilled a couple of holes in the side of the Tupperware container and in the copper scrap, then bolted the copper to the inside of the tank. That's the cathode done.

The next step is the electrolyte (the salt solution). I went to the hardware store and got some copper sulphate, a blue crystal used for killing plants, or you could 'acquire' some from the school's chemistry dept. Dissolve some of the copper sulphate in water in the tank. Obviously, you want to keep the water level below the holes in the sides of the tank. If you're not going to use it straight away, put the lid back on and put it out of the reach of lurkers (A.K.A fiendish sisters)

Lurker #1

Galvanic Etching

I have been interested in making etchings in brass and copper for some time, and in fact made a card box out of copper, with a scene from Alice's Adventures in Wonderland Galvanically etched into the front. Once I had finished that, I lent my etching tank to a good friend of mine, and I only recently got it back. But now that it's back on my workbench, I am going to improve the quality of my existing etching skills, and broaden my repotoire of techniques. I'm going to start with a brief history of Galvanic etching first though. The benefit of the ability to etch images and words into various metals was twofold. They were used in printing, where the plates would be of the Intaglio variety, where the raised part of the image were the lines desired on the final piece, a negative of the final image if you like. As well as this, etched plates can be quite aesthetically appealing. Galvanic etching, also known as electrolytic, or electro etching, is a process that has been known since the 19th century, the original description of the process having been published in 1855 under the name electro-etching. Prior the widspread use of electrolytic etching, acids had been used in their place, these acids included nitric acid, hydrocloric acid, or ferric chloride. None of which are particularly pleasant chemicals (http://www.greenart.info/galvetch/advan.htm). The basic theory of Galvanic etching is this: If you suspend two plates of metal (both based on the same metal, that is, if you have a copper plate, you can couple it with brass, copper, or bronze) parrallel to each other in a solution of the same metal (in a salt form usually), and pass an electric current from one to the other, particles of one plate will become dissolved in the solution, and will then be dposited on the other plate. Electro-etching is essentially the polar opposite of electroplating.

In this diagram, sorry for its low quality by the way, the brass plate is on the left, and the copper is on the right. The plate connected to the negative supply is always the cathode, or K, and the positive is always the anode, or A. When you etch, your piece is always the anode, and a bit of appropriate scrap is the cathode. Reverse this for plating.