Instructables

Make 10 Etchants for Copper Printed Circuit Boards

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video Make 10 Etchants for Copper Printed Circuit Boards
We show 10 ways to make PCB etchants using easy to access chemicals

1. Hydrogen Peroxide (5mL of 3%) and Hydrochloric Acid (5mL of 37%)
Loses strength in storage but makes copper chloride that can later be used as a fully recyclable etchant.

2. Hydrogen Peroxide (10mL of 3%) + Sulfuric acid (1mL of 98%)
Loses strength in storage but can be electrochemically recycled back into copper and sulfuric acid.

3. Hydrogen Peroxide (10mL of 3%) + Sodium Bisulfate (5g)
Loses strength in storage but can be electrochemically recycled back into copper and sodium bisulfate. Extremely slow but easier to make since sodium bisulfate is easy to obtain as pH control for swimming pools.

4. Ferric chloride
Stable in storage. Somewhat complicated to recycle.

5. Copper chloride (1.6g) + 6mL water + Hydrochloric acid (5mL of 37%)
Stable in storage. Extremely easy to recycle as bubbling air through will regenerate the etchant to full capacity. Eventually will need more hydrochloric acid but nonetheless easy to do.

6. Copper sulfate (3g) + Hydrochloric acid (10mL of 37%)
Stable in storage. Functionally identical to copper chloride and hydrochloric acid. Sulfate contamination does not interfere with activity. Easy to make due to availability of copper sulfate.

7. Bleach (2mL of 6%) + Hydrochloric acid (10mL of 37%)
Loses strength in storage. Produces toxic chlorine gas so must be used outside or in a fume hood. Very easy to make but not economical to recycle.

8. Manganese dioxide (0.5g) + Hydrochloric acid (10mL of 37%)
Loses strength in storage. Produces toxic chlorine gas so must be used outside or in a fume hood. Very easy to make but not economical to recycle.

9. Nitric acid (20%)
Stable in storage. Produces toxic nitrogen monoxide gas so must be used outside or in a fume hood. When depleted can be boosted once by addition of sulfuric acid. after which copper sulfate waste can be electrochemically recycled.

10. Potassium nitrate (3g) + Hydrochloric acid (12mL of 37%)
Loses strength in storage. Produces toxic chlorine, nitrogen monoxide and nitrosyl chloride gas so must be used outside or in a fume hood. Not economical to recycle.
Orngrimm1 year ago
What a wonderfull instructable and summary!
Especially a big thanks for the shown link from my favorite H2O2+HCl (instable) to the stable CuCl2+HCl and (especially) for answering my unasked (here) question if i can regenerate the CuCl2+HCl by bubbling normal air or if i have to use the "liquid air" H2O2 which would dilute the solution more and more...