Use a preheater for soldered RAM upgrades.

Yes, you should remove the motherboard and use a preheater. Trying to do it with just a hot air station is asking for trouble.

The problem is simple: the PCB soaks up heat like a sponge. A hot air station alone will heat the chip unevenly, and the surrounding board stays cold. That’s a recipe for cold solder joints, lifted pads, or cracked solder balls under the BGA. A preheater brings the whole board up to temperature so your hot air only needs to finish the job — not fight a giant heatsink.

Removing the motherboard isn’t optional either. You can’t preheat the whole laptop, and you don’t want to cook the screen, battery, or plastic parts. Take it out, set it on the preheater, and work on a stable surface.

Can a skilled person pull it off without a preheater? Maybe. But you’re gambling on a board that costs a lot more than a cheap preheater. Don’t.

Future you will appreciate not having to re-ball a dead laptop.