Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. It only takes a minute to sign up.
Sign up to join this community
I've read in numerous places that an ordinary wet dish sponge can be used for cleaning the solder iron tip. I've taken a photo of what the sponge looked like after I cleaned by solder iron tip and shown it below.
The tip burns the sponge, small amount of smoke comes out and tiny black ashes can be seen on the sponge. Is this normal, or am I using the wrong sponge/wrongly?
I'm sure nobody cares about the sponge, I just want to keep my solder iron tip clean properly without damaging it.
Basically what you have there is a standard household cleaning sponge. These are made from either Polyurethane or Polyester (most likely the latter). Neither of these materials hold water very well because of their structure and material. This means the material will not be cooled by the water and so will be exposed to the high temperatures of the soldering iron tip. They are not designed to withstand the heat of soldering - for example polyester sponges will melt at 250*C.
Sponges used for soldering are made from compressed cellulose. This is much denser and critically will hold water and stay damp (you want the sponge damp, not wet!). If it is kept damp the sponge will withstand the temperature of soldering because the water inside it cannot be heated above boiling point - it turns to steam if you try. Now if you were to hold the soldering iron on it for an extended period of time, the water would eventually evaporate away and the sponge would melt, but you don't normally hold it there long enough to do that.
Googling "Compressed Cellulose Sponge" or "Soldering Sponge" will find you many results of where to buy the correct sponges.
First, I would make sure you have a synthetic sponge and not a organic one. Those are more durable to stand up to the heat, when your wiping off your soldering tip. Organic sponges seem to burn and smell when they are used for soldering. They do make sponges that are specifically for soldering. Those are probably a good synthetic material that are durable enough to handle the heat from the tip. They also come with or without holes, which can help get the tip clean faster.
Also if you are using lead-free solder, using a wet sponge will crack the plating on the tip, causing it to oxidize faster, and shorten the life of the tip. In this case, I would recommend using a wire sponge. You can use them dry and are becoming more common since they last longer.
If you aren't sure what kind of sponge you have or what kind of solder you are using, I would recommend using either a dry metal sponge or one specifically designed for soldering. This way it saves you money on tips.
