Pads can lift if you heat them for too long, and you may be heating them for too long because the board or component is contaminated.
I clean boards before soldering. I use Isopropyl alcohol. Meths would probably also be OK.
Also, I use flux or multicore solder containing flux.
I have a stock of quite old components and oxidation on component leads is also a problem, I sometimes use light abrasive on the leads.
Finally, the problem of pad lifting can be because the PCB is poor quality.
I had trouble when I first started too. One thing that helped me was using a (small-ish) chisel tip and getting the temperature set properly (it has been reliable how than I thought it needed to be --I think I’m on 750°F/400°C.
Flux has been a huge help. I use a paste flux with tiny applicators (about 1mm, but it could even be smaller, used for automotive touch up paint) I found on Amazon. The flux in solder is intended to do the same thing as separately applied flux–it cleans the joint which helps the solder stick better. I’ve found that old solder didn’t work as well for me. I don’t know if the flux core dried out or what, but getting new solder helped.
I have had pads lift on me, but almost always on cheap strip board where the Holes aren’t through-plated. I’ll see if I can find a picture. It’s not an absolute disaster when this happens. If the pad stays connected to the trace, and you get the component to solder to it despite it lifting, you can reinforce the joint with CA glue. DO NOT hear the glue with your iron, it can produce nasty fumes.
I’ll see if I can find an example of a lifted pad. I’m sure I still have a board with one.
The biggest thing is to not give up! Troubleshooting this problem is just like troubleshooting a malfunctioning circuit. Proceed logically and methodically and the answer will appear eventually. I would recommend going as far as buying some boards to practice with and just trying to solder short bits of wire. Remember: logically and methodically.
Good luck!
Here’s a picture of a lifted pad. You can see the gap between the (kind of) successful solder joint and the board. The pass will appear to peel away from the board, like a sticker peeling off its backing paper.
This one may have happened sure to me using solid core wire to make the connections. The more copper you have connecting to the joint, the more thermal mass, meaning the more heat you will need to apply to the joint. Not a higher temperature, but holding the iron to the joint longer, which increases the chances of lifting a pad. Someone else mentioned ground planes causing issues–this is the same kind of thing.
I think I mentioned that boards with through-plated holes are less likely to lift on my experience. I don’t know if it’s because of the extra metal in the pad, or just that they’re just generally higher quality boards.
