Save Battery replacing problem

[NBaco]

After noticing my copy of Mario Land 2 for the Gameboy no longer saves, I decided to replace the battery and used a CR1616 battery with tabs and solder the battery back in. I had no problem removing the old battery, but now the problem is getting the new one in. For some reason, I can't get the solder to stick to the tip of my iron, which is posing a problem. I even tried "dripping" the solder onto the tabs but this doesn't work as the joints get cold and break. Does anyone have any suggestions for this? As of now, my assumption is that it's the iron. I used a cheap radioshack iron.

I can save now after using the tape trick to keep the battery in place, but I don't like the idea of using tape to keep a battery in place. It seems to me that after a year (or one good bump) the tape will loosen. I'm most likely going to have a guy here in NC I know do the replacement for a few bucks since he has the equipment to do it. But I figured I would at least ask about it since the people here on this forum probably know far more about this type of thing than I do.

Thanks in advance!

[Gamereviewgod]

Is the tip of the iron clean?

[NBaco]

Yeah, it's brand new. After it failed, I even took the liberty of wiping the tip off. A friend of mine suggested using sand paper to clean the tip, but that didn't work either.

[APE992]

Sand paper will just remove the protective oxide coating they put on during manufacturing, not all is lost though.

Get some decent flux, put it on when the iron is hot and tin the tip. FYI when you're soldering you're supposed to heat up both joints to be soldered and flow the solder into the hot joint. Solder is not supposed to be on the iron and shoved into the joint.

[NBaco]

I was unaware I needed flux, I wonder if that could be the problem? I tried heating up the joints (without flux since I dont have any) and that didn't help. At this point I've mangled the battery up so badly it's a little embarassing...

[APE992]

Flux to clean the tip.

If there is solder on both parts to be joined flux isn't needed. BTW, heat up that battery enough and lithium will shoot a little flame out the side. Has happened to me before and I'm quite seasoned.