6 ms·

I've been to Shenzhen and seen (been taught) how they reball BGAs for phones in the markets, none of that futzing about with solder balls - they just clean the

I've been to Shenzhen and seen (been taught) how they reball BGAs for phones in the markets, none of that futzing about with solder balls - they just clean the pads on the chips, re-tin them, lots of flux, then place the steel pad stencil over the top of the pads, spread solder paste over and through the holes, wipe off any excess then hit it with some hot air until you see the balls form, if you do it right the stencil will just pop off (don't push it)

burnte 5y ago
Thanks so much for this, I always assumed I was bad at stenciling but I see I was just doing it wrong. I was spreading the paste then pulling it up, not heating it first as I assumed the sldier would melt onto the steel stencil. Thanks!
- Taniwha 5y ago
  It may if you get the stencil hot enough, you have to watch the solder
jacquesm 5y ago
Any video of this particular trick?
- Taniwha 5y ago
  Here's an example: https://www.youtube.com/watch?v=alQq74uWJJA https://www.youtube.com/watch?v=alQq74uWJJA
  - jacquesm 5y ago
    Thank you, very elegant and nice no nonsense video as well. Great tip!
csdvrx 5y ago
For smaller numbers of connections, you don't even need a stencil if you how to use surface tension and have a fine tipped soldering iron.
- Laforet 5y ago
  Letting people know you could pull this off eventually leads to the inevitable assignment in which you need to solder a dozen of NAND chips in some obscure package that nobody seems to have a stencil for :) Oh and the deadline is 24 hours away.
  - rasz 5y ago
    Sounds profitable, whats the problem? https://www.youtube.com/watch?v=I4m0LoGx7Qo https://www.youtube.com/watch?v=I4m0LoGx7Qo you can also go one ball at a time https://www.youtube.com/watch?v=LrXL1uGs0vU https://www.youtube.com/watch?v=LrXL1uGs0vU
  - csdvrx 5y ago
    Exactly why I'm only saying that anonymously here on HN :) FYI, I also do some SMD by hand. It's not very hard with leaded paste. It's a very practical skill to have when you only use it for yourself and a few select friends (read: not colleagues!)
    - skinkestek 5y ago
      Good thing we can reach you through GitHub ;-) Half joking, if you have forgotten that you added that link here's your chance to remove it B-)
      - csdvrx 5y ago
        And... it's gone now! (Thanks for reminding me BTW) I prefer keeping a low profile. Because I like speaking my mind freely, which I might not do if my account was linked to my name.

burnte 5y ago

Thanks so much for this, I always assumed I was bad at stenciling but I see I was just doing it wrong. I was spreading the paste then pulling it up, not heating it first as I assumed the sldier would melt onto the steel stencil. Thanks!

Taniwha 5y ago
It may if you get the stencil hot enough, you have to watch the solder

jacquesm 5y ago

Any video of this particular trick?

Taniwha 5y ago
Here's an example: https://www.youtube.com/watch?v=alQq74uWJJA https://www.youtube.com/watch?v=alQq74uWJJA
- jacquesm 5y ago
  Thank you, very elegant and nice no nonsense video as well. Great tip!

csdvrx 5y ago

For smaller numbers of connections, you don't even need a stencil if you how to use surface tension and have a fine tipped soldering iron.

Laforet 5y ago
Letting people know you could pull this off eventually leads to the inevitable assignment in which you need to solder a dozen of NAND chips in some obscure package that nobody seems to have a stencil for :) Oh and the deadline is 24 hours away.
- rasz 5y ago
  Sounds profitable, whats the problem? https://www.youtube.com/watch?v=I4m0LoGx7Qo https://www.youtube.com/watch?v=I4m0LoGx7Qo you can also go one ball at a time https://www.youtube.com/watch?v=LrXL1uGs0vU https://www.youtube.com/watch?v=LrXL1uGs0vU
- csdvrx 5y ago
  Exactly why I'm only saying that anonymously here on HN :) FYI, I also do some SMD by hand. It's not very hard with leaded paste. It's a very practical skill to have when you only use it for yourself and a few select friends (read: not colleagues!)
  - skinkestek 5y ago
    Good thing we can reach you through GitHub ;-) Half joking, if you have forgotten that you added that link here's your chance to remove it B-)
    - csdvrx 5y ago
      And... it's gone now! (Thanks for reminding me BTW) I prefer keeping a low profile. Because I like speaking my mind freely, which I might not do if my account was linked to my name.