Yes, the radiator block is not made of aluminium. If you are not yet familiar with liquid metal, make sure you watch a video on youtube beforehand. You don't want to cause a short circuit on your mainboard.

Here is an example:
https://m.youtube.com/watch

I also have the conductonaut. I am very satisfied with it. You will need the "cotton sticks" that come with it to spread the liquid. the liquid metal behaves a little differently than normal paste ;)

Oh yes! It may well be that the syringe resists a little at the beginning when you press it and then it suddenly goes plop. It happened to me. That's why I would operate the syringe with both hands. That way you have more control. Excess drops can easily be sucked back in.

Attention! I just looked in the data sheet of the Pure Rock (BK009). It says "Cooling surface material: aluminium". I would therefore not use this fan with liquid metal.