Copper Sulfate – Saline Etch for Aluminum – Test 12: Bath Regeneration Test

Name: Nick Osetek & Tessa Chambers                                                 Date: 5/10/2018

Room Temperature: 69*F                                                                    Humidity etc: Dry

Experiment Title: Dead Bath Regeneration Test

Experiment Goal: We exhausted Bath 1 by letting pieces of aluminum eat away in the bath for about 2 days. Once the bath was exhausted it turned clear with all the red copper oxide built up at the bottom. We separated the dead bath into (2) 6 oz  containers.

In one bath we added 1/2 a tablespoon of copper sulfate.

In the other 6 oz dead bath we added 1/2 a tablespoon of citric acid.

We let the baths sit for 9 days until etching to let the baths mix. We’re testing each mixture to see if citric acid or copper sulfate will be more successful in regenerating the bath.

Plate material: Aluminum (5052)

Plate Preparation: We quickly degreased with Bon Ami and soy sauce. We only etched small aluminum strips just to see if either bath would still etch at all.

Evaluation of Plate Preparation: Normal

Etching Bath Notes: The citric acid mixture remained clear, with the copper oxide built up at the bottom.

Our copper sulfate mixture has turned turquoise with its typical white sludge (elemental copper) settled at the bottom.

Time in bath15 minutes

After B

ath Evaluation: Neither bath was very active during etching. The Aluminum test strip in the copper sulfate mixture definitely etched deeper than the strip in the citric acid.

Removal of Grounds: N/A

Inking Methods: N/A

Paper Type: N/A

Soaking Time: N/A

Press, blanket set up, pressure: N/A

Conclusions: Citric Acid Bath: The etch in this mixture was minimal. You could barely even feel anything.

Copper Sulfate Bath: This strip etched much deeper compared to the citric acid etch. We printed this strip to see if we etched black for those 15 minutes, but we got a dark gray tone instead of black. Which still means this bath revived, while the citric acid bath barely revived at all.

The fluid on the left is the dead bath we added copper sulfate to. The bath on the right we added citric acid to the dead bath.

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