String trimmers are a great way to keep weeds cut down around the home and create nice yard edges. Use a string trimmer long enough and you will need to replace the trimmer string. Replacement string is available at most any hardware store. The string comes in various diameters, but the average person only needs up to .065 diameter string. Once you have the replacement string it is a matter of removing the spool and adding the string. The key to changing a string trimmer line is to keep the line tight as you wind the line on the spool.
Remove the cap on the bottom of the stringer spool with your hands. Some caps will need to be pressed in and then turned counterclockwise to remove the cap from the locking tab. Spool caps on other models may require that the cap be pulled straight off of the spool.
Pull the stringer spool off of the trimmer shaft and out of the hub. Clean the hub with a rag to remove any grass buildup. Remove any remaining string that is on the spool. If necessary use a pair of needle nose pliers to pull the string off of the spool. Sometimes the bottom layer of string will melt into the spool due to heat.
Measure off 30-feet of stringer line from the replacement spool. Cut the line with a cutting edge of the needle nose pliers.
Insert 1-inch of one end of the line into the hole in the center of the stringer spool. Hold the line to the spool with your thumb. Wind the line even and tight with your free hand in the direction of the arrow on the stringer spool. Continue winding until you have only 12-inches of line remaining.
Set the remaining 12-inches into the cut notch on the outside of the stringer spool. Insert the stringer spool into the hub with the excess string going through the stringer hole in the hub. Set the spool and hub back over the trimmer shaft. Reattach the spool cap by pushing the cap back over the stringer spool and hub.