[quote name='icastle' timestamp='1365701809' post='2043255']
A little bit late, but for future reference:-
You can't solder directly to a pot casing, you need to 'rough up' the surface you intend to solder on with a little bit of sandpaper or the like before you start.
Once you've done that, you hold the soldering iron flat against that prepared area and melt the solder onto it.
That'll give you (hopefully) a neatly flown pool of solder.
Tin the wire you want to connect, reheat the pool and push the wire into it.
Hold it perfectly still and don't be tempted to blow it to cool it down artificially.
A 15W iron is a little small for the job and LF solder isn't what I'd use from choice, but it's not impossible.
[/quote]
tried to do exactly that after having watched several youtube vids. roughed it up ok, but just couldn't get the solder to melt.
i gave up before i did any damage as it was stressing me out too much!
charlie turned it around in a day for £25 which was money well spent i reckon!