Silver Blues wrote
If you're going to use MG solder then I would recommend trying the #4860, it's a no-clean 63/37 that I think you may enjoy. I used to use this really nice 3% silver solder that was so awesome but it's become nearly impossible to find anymore so I started to use this and it's almost as good. I just find the eutectic composition solders to have much better working properties.
I picked up the MG because my local store (there's only one in all of Mpls-St. Paul that sells decent electronic supplies - Micro Center) was out of my preferred brand - NTE (part #83-6337-0027). That solder just seemed to work brilliantly.
The MG I have is 60/40 (#4894), and I'm starting to regret I didn't get the 63/37 when I was there. Didn't get a chance to try it with the flux pen last night, but if I'm still having issues, I may just bite the bullet and order a roll of the NTE Kester from Amazon after Xmas.