Chalk lines are used to draw straight lines across large surfaces from about 2 feet to over 20 feet. But it is not always easy to see the line, especially if you are working in the sun, or your saw has a dusting action that blows the chalk away.
Phil from Ottawa sent in the chalkline tip that to get a long chalk line to show up well, push down in the middle and snap each half separately. Remember to streatch the string fairly tightly and then pull directly away from the surface to be marked -- drawing the line away at an angle will cause the line to curve to the other side. It is also a good idea to draw the line back into the reel after every marking, and bang the reel into your palm to get fresh chalk on the line. Setting the crack handle into its socket freezes the line and allows you to pull the reel itself to put tension in the line.
Did you know that the red and florescent colours are permanent markers that may even show through paint.
The blue is permanent on porous surfaces.
The only really "erasable" chalk line is white.
Yes you need to buy seporate chalk line reels for each colour as mixing colours in the reel makes a real mess.
You may want to shop around for a chalk line as they are not all alike. Some have transparent panes that allow you to see how much chalk is left. Some require you to unscrew the lid where the line comes through to put more chalk into the reel, some have side hatches for refilling. Some have gear mechanisms for reeling in the line fast when you are using the line on large areas. Most are shaped like a tear drop so you can use it as a plumb line as well. And some have belt clips so you don't have to search for it when you need it.