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.
- 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
- Beaker or flask (graduated) to mix the ingredients
- Small weighing scale
- A magnetic stirrer is handy...
- Tray (tupper)
The substances are irritating, use gloves.
- Pour water in the beaker
- Weigh and add the chemicals one by one while stirring
- 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.
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