I have boards with bad HASL application. First they're not even. Second some pad edges have no HASL and still remains bare copper. What's the maximum and minimum HASL thickness required for a good solderability. My boards are about 6 weeks old, I know that HASL thickness dictates the shelf life of the PCB (correct me if I'm wrong) and is my board still considered OK?

Can I manually tin them with solder specially the BGA's. Will that improve the solderability? What about corrosion of the copper? will it be prevented with the above process considering that after tinning of solder the solderability became acceptable (IPC Class 3)?