PCB tinning

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This is a simple (acid bath) method for tinning your DIY PCBs. The tin layer prevents the copper from oxidising and it also looks quite nice.

Pcb before and after tinning.JPG


Materials

  • Thiourea (Thioharnstoff) – 12,5 grams
  • Tartaric acid (Weinsäure) – 8,8 grams
  • Tin(II) chloride (Zinn(II)-chlorid) – 1,3 gram
  • Tap water – up to 250 ml

You can get the chemicals in a chemist's shop, a good source is Gehrig, Lucerne: http://www.gehrig-ag.ch/content/index.php/werkstoffe/chemikalien


Tools

  • Beaker or flask (graduated) to mix the ingredients
  • Small weighing scale
  • A magnetic stirrer is handy...
  • Tray (tupper)

Pcb tinning shedhalle 20190331.JPG


How to

The substances are irritating, use gloves.

  1. Pour water in the beaker
  2. Weigh and add the chemicals one by one while stirring
  3. When everything has dissolved, pour the solution in the tray

Clean the PCB before tinning. Remove any oxide on the copper using a soft abrasive sponge or polishing paste.

Leave the PCB in the solution for a few minutes. The longer, the thicker the tin layer will become.

Rinse and dry.

Dispose of the solution properly.


Credits

The idea for this came from Jo Grys (frgmnt) in Berlin. He uses this method and provided a link to Robert Gawron's article: https://robertgawron.blogspot.com/2016/04/galvanic-pcb-tinning-by-using-home-made.html