I feel a little silly about posting to the beginner's section as I am actually a professional in the field, however I certainly qualify as beginner level when it comes to soldering.
I recently took up a project that requires building a board with a microcontroller. I chose an AVR with USB in a TQFP-44 package. Designing the board was delightfully simple but actually constructing it is turning out to be deviously hard.
I knew I needed to upgrade my tools, so I got myself a Weller WES51 with a nice small screwdriver tip, some Kester 245 at 0.020", a good flux pen, thin desoldering braid and some nice Wiha ESD tweezers. Combined with the excellent tutorials that can be found on YouTube (including Dave's), I thought I couldn't lose. After all, I mastered through-hole soldering many years ago...
In a way I feel like I was tricked. Everywhere I was told that surface mount soldering is no trouble at all... anyone can do it... it's a breeze! Well it isn't, it's difficult.
No matter what I do I seem to leave far too much solder on everything, even knowing that I'm doing so. Simply tacking a 0603 resister in place to start soldering it is a task that my hands do not seem steady enough for. I seem to short every fifth lead on my TQFP-44, and desoldering braid is unable to pick it up even after using so much heat that entire part is oxidized and useless. On the tutorials I watched, the solder reflows perfectly and the parts seem to magically settle on to the pad once heat is applied. Well that doesn't happen for me, it doesn't happen at all.
Most frustratingly, these fancy new tips oxidize so quickly that I'm at a loss to understand how they could be used professionally. I tinned my tip as I've been doing for years, but after only one use (about 30 mins), the tip has become useless. I only used it at about 450-550 degrees. When I took it out for the second round, attempts to re-tin the tip only result in a ball forming at the end of my solder strand. It doesn't look so bad but it is obviously oxidized. These are genuine Weller tips, what on earth is going on? I can't afford to keep buying these at 4-7 bucks a pop, and SMD soldering is futile if I can't hold solder at the tip. I ordered some tip tinner that hasn't arrived yet. Will that clean it enough to let me keep using it?
Please tell me what I'm doing wrong! Thanks for any help.
-d