> i'm soldering a lot, using a cheap 5$ iron. i'm some problems:
A Cheap $5 iron can be a problem but they can work.
If you have a copper tip it is expected for the tip to wear, and can
be reshaped with a file, a grinder might be a bit too much as it is
just copper
If you have a tip that is iron clad coated you do not want to file
or grind as you do not want damage the iron coating. These tips
will last a long tip if maintained.
The Black can be cleaned off, I use a wet sponge, it is best to use
the sponges sold for soldering irons that come with alot of the
soldering iron stands. Keep the tip clean and apply solder right
after cleaning, do not leave excess solder on tip just needs to be
coated not a blob.
Also be sure the tip is tight so that there is good heating of the
tip.
Be sure and use rosin core solder, most commonly use is the 60/40
rosin core.
Also some of the off brand solders do not work very well, Kester is
one of the most popular brands.