I made a few transparencies when I made the first Zentangle sheet for Decals, and rubber stamps so I thought I'd give it a try.
I have Copper stampings (from Thompson Enamels and from Metaliferous) that I use for my enamelling so I got a few of those out, some steel wool (0000), exacto knife, and my iron.
You want to take your steel wool and clean one side of the copper/silver - you need to clean off any oils - including those from your hands -
You will do it one more time or wait till after you cut out your transparency - but long as you do it just before putting the transparency on the copper and ironing it on.
Cut out your piece
Heat your iron up on about medium - you do not want too hot to melt the transparency
You may have to play with this part as everybody has a different iron - no steam
Place the flatest part of the iron right on the piece and push down for about 30 seconds. This should make it adhere to the copper.
Keep the heat on it and pushing down. let sit 30 seconds pushing down and use the edges almost like burnishing. WAIT FOR IT TOO COOL- ITS HOT
The first attempt I think my iron was not high enough and I did not push down or burnish enough - so you can see all the toner did not stick.
In my second attempt I did all above - pushed down, burnished and let sit on top for 30 seconds at a time and kept the iron moving over and burnishing with the edges.
This one is nice and dark - couple of spots that look light but I'll show how to fix next time.
Here is what the transparency looks like after you peel off
Then I prepared the copper by putting a strip of packing tape on the back - running my nail around the edge so that it would stick and then put into a bath of Ferric Chloride (Radio Shack in U.S.A I have access to chemical company here in Canada and got samples ) Once you see it is deep enough take out - and I would suggest using gloves take the copper piece and rinse under cold water. Take off the tape and dip the piece in a mix of water and baking soda to neutralize the acid. Use goo gone to take off the sticky backing from the tape. Clean with steel wool - you can also pickle to clean it up.
Both are in the etch - I'll visit in about 1 hour to see how they are doing. Depending on the strength of your etch it can take a short or a long period to etch - you just have to keep watching how deep you want it.
So far been 3 hours - its etching but its not as deep as I want yet. So I'll keep going till its deep enough