RocketRob40's advice was straight on. I bought the 60/40 solder, some flux and this $9 40w iron, all from Radio Shack:

http://www.radioshack.com/product/in...entPage=search

And had no further problems. We mowed through all 8 batteries.

Thanks to everyone for advice. It feels good to be able to solder so quickly. We'd managed a few deans a month ago, but it took forever and was frustrating.

Hans