4 ms·

Thanks! This is super useful. I had a QFN solder failure on one of my last boards. I mistakenly tented the center vias on the bottom, forgot to clear them be

• lgeek 13y ago
  > You reflow the whole board with a hot air station? I've been using an oven. How big a board can you do that way? Yep. It's not really by choice, but because I have limited space. That being said, I like being able to watch the process and to correct minor issues like a 'tombstone' passive, so I think I'd prefer a hot plate over an oven. My SMD boards are small, the largest one by length is 7 cm and the largest one by area is 25 sq cm. You could definitely do larger ones, but you'd probably get significant temperature gradients - bad for manufacturing, probably ok for prototyping and one-offs.
• EChrisDenney 13y ago
  cottonseed, Chris from Worthington Assembly here. We've actually reflowed proto boards here with a hot air station. The trick is to get the whole board warm first and then target the gun (or pencil) at the joints. You can use a hair dryer to get the whole board warm and then use the hot air gun to quickly reflow each joint. It's pretty fast and works well. If you bump the pads like you mentioned with a little solder, you can then flatten the joints very carefully with a flat piece of metal (but end of a small screwdriver or something similar) and then apply a little flux, and then warm the whole board and reflow as mentioned before. Works like a charm!