That looks like lead instead of Solder.
I may be wrong but technically I believe it's solder, an alloy of lead and tin... or at least that's what we used to call it 35 years ago when I did this kind of stuff for a living. Back then I believe the two most common alloys of "body solder" available were 60/40 and 70/30 and I believe we used the 60/40. We even referred to body files as "solder flow files".
But it's been a long time and we weren't sticklers for technical accuracy so I could be completely wrong and if so I stand corrected.
Regardless I'm having a lot of fun and experiencing a lot of déjà vu.
