11: trial BATCH 4 etching

Despite the poor quality of the transfers, I decided to run the 4"copper plates from trial: BATCH 4 through the etching bath to see the results because I need a better understanding of the overall process of crafting the discs from start to finish. Before etching, the paper remains were removed from the discs. This was completed in the warm soapy water bath with some fine steel wool and a little elbow grease. The ink was quite robust with good adhesion and the paper eventually pealed away.


trial: BATCH 2. You can see decent adhesion of the trace underneath the paper cover. The flip sides of these discs have inaccurate traces. Adhesion on both sides is a must in order for the sync disc to work properly.

After removing the residual paper, I took a sharpie marker (which acts as etch resist) and filled in the areas of the trace that didn't transfer properly. Once the transfer process is perfected the markup/infill will be minimal.


Prepping discs for etching. The different colors are interesting. The tree disc on the left had a white coloring while the star disc on the right was very much blue in nature. The same toner from the same copier was used on both.
I suspended the discs in the Ferric Chloride solution and monitored the process. I did not heat up the etchant but I did plug in the air pump which kept the liquid agitated.


Filling the tank.


Submersing the discs.

The discs were monitored and checked at key intervals throughout the process. From prior research on etching it figured that the overall etching time would probably be approximately 30 mins. This etch went from start to completion in 32 mins.


12 minutes submerged.


12 minutes submerged.


25 minutes submerged.


25 minutes submerged.

At 32 minutes the discs appeared to be finished and were pulled from the etch bath and placed in soapy warm water to be cleaned up.


The copper not covered in the etch resist is dissolved and reveals a yellowish colored epoxy substrate board and the trace patterns on both sides of the disc. The next steps will be to use alcohol and acetone to remove the transfer ink to reveal the copper traces.