One cool thing that happened last week was the acid etching workshop. First time I’ve played with a CuSO(4) solution since… well a long time ago. We used Zn as the etching plate, although we also have access to Cu & Al plates. (Cu is obscenely expensive though now, Al is cheap but the etch is a bit messier).
This was the process:
Pick up Zn plate, and using Brasso, give it a good polish
Use cream cleaner to get rid of the grease
Rinse with water - there should be no surface resistance
Place Zn plate on the hot surface
Apply hard wax (can also use soft depending on the desired etch)
Use roller to provide smooth, even coating onto the Zn surface, moving the Zn to the cooler surface when necessary to aid process
Get a sharp implement, and etch away at the wax until you’ve obtained the desired image
Apply tape, or some other protectant to the back of the plate (to prevent it from corroding)
Place the plate in the solution/etching bath for the desired time (wearing appropriate protection - in this case full-face goggle mask & thick gloves)
Remove, rinse off etching solution, check etching depth.
Repeat process if necessary, adding “paint-out” or “block-out” (basically varnish) to areas of the etch which do not require further oxidation.
Use white spirits & methylated spirits to clean the plate post-etch.
Afterwards, Georgia (another student) kindly showed me how to create a print out of the etch.
Chamfer the edges of the plate to a 45 degree angle (etch up)
Apply sparingly a coat of block ink, then wipe off the excess
Place onto the press, followed by the print paper, then then a layer of thinner paper, and then the mats.
Gently turn the handle.
Remove the print.