One of my hobbies is electronics design. Because of logistics issues it is highly
impractical for me to order circuit boards at one of the common board houses,
so I'm spinning my own. To improve solderability, I'm tin coating the boards,
using an electroless process.
The tinning solution consists of 5g of SnCl2, 50g of thiourea and 10ml of H2SO4
in 1l of distilled water, and can be reused multiple times. Unfortunately it has a
relatively short shelf life of just 4-6 weeks.
Other that cool, air-tight storage, is there any way I can extend the shelf life?