Thursday, 28 April 2016 00:00

Etching brass plates with PRP Photoresist/Sodium Hyrdoxide/Ferric Chloride

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Quick (but complete) notes on etching brass using photoresist.
  1. Clean brass with Brasso, and acetone. Dry and polish with lint free cloth.
  2. Spray with Electrolube PRP photo-resist, from side to side with light passes. Press and release can off of the work-piece to ensure an even coat. Dry for a few minutes with a hair-dryer.
  3. Print two copies of the design (mirrored) on to 90gsm tracing paper with as much density as your printer can muster - you might want to add a box around the image to sit a couple of mm outside the brass to help aligning the brass to the design.
  4. Overlay one copy above the other exactly and staple so the images align perfectly (this doubles the light resistivity of the toner).
  5. Place the tracing papers on the bed of a UV box (toner side up) and place the brass on top of it exactly where the etch is to go.
  6. Develop with Sodium Hydroxide (1 teaspoon of the powder to 1 litre at around 25C) for around a minute, agitating the solution until the developers rises off. Rinse.
  7. Heat enough ferric chloride for the etch in a microwave, or make up crystals to 50-60C. Etch for 1-2 hours depending of your required depth of etch. Agitate occasionally.
  8. Rinse and polish as needed. 1500 grit paper may be a good start.
Last modified on Thursday, 28 April 2016 22:55

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