mojo wrote:PS. Using a brass sponge to clean the tip instead of a wet sponge makes them last 20x as long and perform consistently throughout their lifetime, as well as doing a better job of actually cleaning them. Wet sponges also cool the tip a little.
Wet sponges and brass pads serve different purposes. Brass pads are used to remove excess solder and larger contaminants from your tip. A wet sponge (actually damp- not wet) is used to remove smaller contaminants and chemicals like flux which, especially in the case of an RA flux, can definitely eat up your tip. You should use the wet sponge any time you think the brass pad is not properly cleaning the tip. As soon as you use the wet sponge you should tin your tip. If it is the last cleaning of the day then you should use tip tinner and not solder as it does not contain flux which can corrode a tip.
A wet sponge should not cause any degradation in your tip if you use distilled water (or other source of very clean water). You should wash your sponge from time to time to remove any chemicals like fluxes that can build up.
The temperature drop from using a sponge is negligible for a good iron- the recovery time is so fast that by the time you're a couple of inches from the sponge, the tip has completely recovered. Don't use cold water, or let the sponge get too wet. Doing so can cause the temperature to drop more than necessary, and can even cause thermal shock that damages the tip.