Having completed the main part of my amp build, I wanted to finish the amp off with a brass name/logo plaque. I had originally thought about engraving it and searched for companies that could do this for me, using custom artwork. Turns out this isn’t a cheap process! Then I found an excellent guide for etching brass using ferric chloride at instructables.com. The technique is known as the Toner Transfer process and effectively you print a reversed design with a laser printer and then use heat to transfer the toner to the brass. This acts as a mask, to resist the etchant.
I started with a brass door fingerplate and cleaned the surface.
Printed my design on an OHP transparency sheet and ironed it on to the brass.
Peeled off the OHP and…
Hmmm. Ok clean it off with acetone and wire wool and have another go, this time using paper instead of an OHP transparency.
Now this looks a lot more promising. I touched up some areas of the mask with a permanent marker and then masked the back and edges of the plaque with tape. I also added a tape “handle” so simplify getting it in and out of the bath of ferric chloride.
Unfortunately after about 20 minutes, part of the mask started lifting off. I fished it out rinsed it off to see what had happened.
Almost there but the etch was just not deep enough to stand out, unless you just happen to catch it at the right angle.
I bought a couple of thin brass sheets from ModelZone in Manchester for my next attempts.
And again the mask started lifting after about 20 mins.
This time I decided to simplify the design and, instead of etching the lettering itself, to etch away everything that isn’t the text.
Heat up the brass plate with the iron to transfer the toner.
And then etch.
Much happier with the result of this.
Now to mount it on the amp. First off I measured up to centre the plaque on the panel and marked it with tape.
Keyed the back of the plaque to give the glue something to grab on to and then applied a coat of Araldite.
Mount the plaque to the amp and weigh it down with a couple of heavy books (I knew those Next Directories would come in handy eventually).
After a couple of hours I removed the books and marking tape, cleaned up a couple of areas where I had applied too much Araldite, and finally, my amp is finished.