T-962-improvements

If you're using stencils (and as long as your boards are relatively small, there's almost no reason not to with how cheap they are from jlcpcb/oshstencils), I highly recommend buying a jar of Loctite GC-10: it's the best solder paste I've ever used, and it lasts forever. I have a jar that expired 2 years ago and is still great. Also, the T-962 reflow oven is pretty good for its price, with a bit of modding (flashing open source firmware (https://github.com/UnifiedEngineering/T-962-improvements), removing masking tape that melts and stinks, and adding a thermocouple for cold junction compensation).

Works fine for us! Haven't had any issues to date, must have done over 100 different boards. There is third party firmware[0] for better control including an active fan if you run in to issues. Thanks for the tip though. [0] https://github.com/UnifiedEngineering/T-962-improvements

The T-962 and its clones out of the box have temperature so uneven that it can scorch the center of a board while reflowing OK an inch away from the center. With various mods [1] it's marginally usable. I've used TechShop's unmodified clone unit (melted the solder mask at board center and scorched the FR4 substrate) and a used modified Puhui unit (after careful setting of a suitable heating curve, acceptable.) With new firmware, the cooling fan is run slowly during the heating phase, which stirs the hot air and reduces the hot spot problem. You have to pay about $3000 to get a reflow oven that Just Works, unfortunately. The good ones are true convection ovens with uniform air temperature. KiCAD is not bad. The schematic drawing part is mostly OK. The schematic symbol and footprint editors are poor draw programs, and the library manage

Shadowing a variable really ought to be an error. At least, you shouldn't be able to hide a local variable with another local variable. Yes, sometimes you have to write "vv" in the inner loop instead of "v", and not feel as l33t. Deal with it. (A shadow variable problem in C just turned up in firmware for a surface mount reflow soldering oven I have. The variable name is "avgtemp". This may explain why some ovens scorch PC boards.[1] Read the discussion. Note that none of the people writing about the issue understand that "static" would confine the scope to one file, and that uninitialized variable declarations at top level are global to the whole program. That's probably because they came up from Arduino land, where people are not taught to think about that stuff. Arduino land is really full C++ using gcc, but it's not taught that way.