2UUL Black Skull Solder Paste for Repair 50g (BS148 / BS183)

Not every rework job should use the same solder. Reballing a CPU that sits on top of another chip calls for a lower-temperature paste, so the parts underneath don't reflow too. Standard jobs are fine with the usual eutectic melting point.

The 2UUL Black Skull is a 50 g jar of solder paste. The product text and other retailers list two versions: BS148, which melts at 148 °C, and BS183, which melts at 183 °C. According to the listing, the powder size is 20–38 μm, it wets pads well and gives off little smoke, and it leaves clear residue that is easy to clean.

When each version suits

• Stacked or heat-sensitive chips that could be damaged at higher temperatures. Use the 148 °C version.

• General BGA reballing and chip soldering. Use the 183 °C version.

• Cold or dry joints that need reflowing.

• FPC connector repairs and pad rework.

Working with it

Stir the paste before use. Spread a thin layer over the stencil or pads, then reflow with hot air until the joints turn bright. Clean off the flux residue afterwards if needed.

Seal the jar after use and keep it at about 10–25 °C. Too much paste causes bridges, so use a thin layer.