I am a beginner at soldering and am trying to assemble a number of these small pcbs. In the process, I have to solder SK6812 MINI-E LEDs and am struggeling to get that right. My problem is that the LEDs tabs are almost exactly as large as the solder pads on the PCBs and if I apply solder and flux to the pads and try to use hot air to settle the tabs into place, they tend not to stick to the pads and if I try to put them in “dry” and solder them with the soldering iron (like a through hole connection), I have trouble getting solder between the tab and the pads. Any advice? Any video that shows how to solder this kind of joint?
I’ve no experience using hot air, but I do have a method for soldering parts like that with an iron that’s worked well for a few keyboards now.
- Melt a small blob of solder onto one pad
- Use tweezers to line up the part on the board
- Reheat the presoldered pad, use the tweezers to align the part and make sure it’s flat on the board
- Solder the remaining tabs
I’ll usually do step 1 for every board/part I’m assembling, then 2, etc. to avoid switching tasks a ton of times. Try one part a time until you get the process working for you.
It’s important to apply the step 1 blob quickly to avoid drying out the solder. I usually carry a small ball of solder on the tip of the iron and briefly touch the pads with it. Apply more solder as needed. Clean the iron if it starts drying out.
Thank you for the advice, I also tried that way but ran into problems because, the LED is supposed to sit in the hole in the pcb which requires the LED’s tabs to be more or less in contact with the pads. If I put a blob of solder on beforehand and then insert the LED into the hole, it is difficult to do and/or the tab bends upward.
If you only put a blob on one of the 4 pads then you should be able to line up the led, melt the blob, and then gently set the led into the mounting hole. One soldered pad is plenty to hold it in place while you solder the rest normally.
