That's a pretty rubbish argument
My lead free solder does not take long at all to melt. Time for some maths, I think!
1 watt = conversion of 1 joule of energy per second.
My iron = 18 watts.
Assuming lead free solder takes one second longer to melt than lead solder, (just a guess, though - my lead-free solder is quick to melt, but clearly, others are not),
10 seconds X 18 watts: 180 more joules of energy converted.
100 seconds X 18 watts: 1800 more joules of energy converted.This
site says 100g of McVities digestive biscuits contain 470KCal, or 470 000 calories.
470 000 calories = 1 966 480 joules
(1800/1966480) X 100 = 0.915 grams of digestive biscuits. So, for 100 joints with lead-free solder, using an 18 watt iron, and the solder taking 1 second longer to melt than lead solder, you use the same amount of energy as you could get out og less than 1g of biscuit!
Now that is something to think about....