Once the powder has been dissolved at 50°C and allowed to cool it will plate copper
boards with a thin layer of tin. The solution is such that it will plate tin on tin and so by leaving a board in the solution longer, a thicker layer is built up. 0.2 micron after 20 seconds, 0.8 - 10 micron after 5 min etc. A tin plated circuit protects the board from oxidisation and greatly improves solderability. Working solution has a shelf life of 6 months, unmixed powder has an unlimited shelf life.
