Just discovered your channel. Excellent video. Super informative. I will use those information for my coach,s then I will move on the loco after some experience.
It's a question with a multi-faceted answer. You should use a temperature that suits the solder you are using, the iron, in terms of both its power and the shape and size of its tip, the parts and board you are soldering to, and when working in SMD, the flux you are using. It should be hot enough to melt solder instantly on the iron, and to get the joint made in a second or two, but not so hot that it shocks the part or the board. Many MERG pcbs have unnecessarily fine tracks that can be induced to shrivel up with a slight overheat. If you want starting numbers I currently use an 80W Weller MSP iron and/or a 60W chinese TS100 running off an RC battery. I set these to about 320 -340C. I use Amtech BGA rework flux for best, certainly for rework, or flux out of flux pen for day to day. Additional solder is usually 28ga multicore from RS/Farnell/Rapid or 5micron solder paste. A good way to 'get your eye in' is to solder SMD ( 1206 or 0804 ) resistors/caps between adjacent tracks of a piece of veroboard. My technique is to tin both tracks, then remove the solder with a solder sucker or braid, this leaves the areas on both sides tinned, but flat. I can then place the part. I often use tweezers or the finger of God to hold it in place while I reheat/reflow it into place with the iron. I then backfill solder into the connection on either side. I use a webcam feeding a 28 inch monitor as a soldering microscope, though the adonstar 'dashcam' type microscopes are good too.
i don't have any of these problems, i run my locos on internal batteries and hm7000 sound decoders which i buy for £60 (the batteries are free). It doesn't matter what points i use or whether i have a reversing loop thingamyjig. Also i have no need for a track cleaner as my track does not supply power to my loco via the wheels and then through a contact made of a conducting material that must be kept clean. My locos work everytime and never stutter or stop, oh and i nearly forgot i don't need a stay alive, my locos are alive.🙂
The reason stay alives are successful in DCC is that the power is a constant voltage supplied all the time. The storage capacitor in the stay alive is therefore always charged, even if the loco is standing still. With a DC system the track is only powered when the loco is moving, and then only at a fraction of the ~12V supply. The storage capacitor therefore cannot build sufficient charge to be of much use.
