Originally Posted by lambofgod121980
Thanks tom - I still have no idea what I'm doing and the blobs of solder are a bit on the super ugly side- if I grind (sand) them down will I mess it up.
I'm not sure how this works. Is the solder filling the gap or just covering it up. Does the flux make it go into the crack, or is it just so it sticks to the metal
The flux helps clean the metal for a better adhesion. But even with it the metal needs to be clean. Sand the areas where you want the solder to flow/stick to so you have clean metal. A stainless steel brush will be helpful for very small, tight areas.
If you're getting "blobs" then the area isn't heated enough. You want the solder to go liquid and flow around the base of that stud to fill any gaps/pin holes/cracks.
I'd suggest a solid core solder as opposed to a flux core which is really made for electrical connections. Nokorode is a brand of soft solder flux that has been around for ages and is still one of the best for use with lead based solder. I'd ask for and use solder termed 95/5 which you might not find at the local hardware store but can be purchased at a plumbing or air conditioning supply outlet. It is harder and less susceptible to vibration than 50/50 or 40/60 (used for stained glass work) but requires a little more heat.
Practice on some scrap metal to get a feel for how much heat to apply to get that magic flow temperature needed.