Can you solder without a soldering gun?
Then, what can I use instead of a soldering gun?
Steel wire, screwdrivers, nails, and Alan wrenches are all potential tools for your emergency soldering. Just heat your wire or other steel tool over some open flame for 20-30 seconds and then proceed to solder as you normally would.
Also to know is, can you use glue instead of solder?
As others have said super glue is not conductive. You can buy conductive adhesive which is used when normal soldering is not practical. It can come in numerous styles (in a syringe, tube, or other type container). It is an option when a normal solder job can't be done.
A classic reason solder won't stick to something is because you're not getting it hot enough. Touch some solder on it, and it should melt almost instantly. Put a nice little blob of solder on the tip of the iron. Press the blob of solder into the metal to be soldered.