How to Use A Chalk Box or Chalk Line | Engineer Supply - EngineerSupply

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How to Use A Chalk Box or Chalk Line

How to Use A Chalk Box or Chalk Line

What You Need To About How to Use A Chalk Box or Chalk Line

One of the simplest tools for marking a straight line on a flat surface is a straightedge, but these tend to have limited functionality when you are marking long lines. The chalk box solves this problem by efficiently marking a straight line between two points. Those in the construction industry appreciate how simple it is to use this tool yet still achieve accurate markings.


What Is a Chalk Box?

A chalk line or chalk box is a small tool used for marking a straight line on a large flat surface, like a wall, the floor or a rough piece of timber. Sometimes called a chalk reel, the tool is a plastic or metal case containing powdered chalk and a string line inside. The string can range in length, with some of the longer residential-use models reaching up to about 50 ft.  Depending on the size, the case can hold about one to two ounces of chalk.

There is a hook on the end of the line outside the box, and there is a crank that winds the string back into the case once it’s been extended. The case itself generally has a pointed end on the side so it can double as a plumb bob. There are different sizes of chalk boxes as well as different colors of chalk that can be used.

Chalk Powders

It’s important to choose the right color when working with a chalk line. Not all colors will show up well within a particular setting, and some colors could be permanent.

Black Chalk

Black chalk powder is formulated for high visibility and superior adhesions. It tends to resist clumping and is waterproof, so it’s good for outdoor use. It contrasts well against light-colored surfaces, and the line is permanent.


Fluorescent Chalk

If you are needing high visibility, fluorescent-colored chalk is the way to go. It contrasts well on a range of surfaces, and it won’t wash away if it rains. This is another great choice for exterior projects. However, this chalk is semi-permanent so don’t use it on a surface that will be visible later.

White Chalk

If you are working on an interior project, a white powder has less bleed-through with coverings like paint or wallpaper. It’s extremely visible on a dark surface and you can easily blow it off after you are through.

Yellow Chalk

This is great color marking surfaces of metal, plastic or brick, but it doesn’t show up well when working with wood. Yellow is a permanent color, so it’s best used in outdoor areas where you don’t want the elements to wash the line away.

Red Chalk

This highly visible chalk color works well on all different materials and surfaces but it is a permanent color. Although it won’t wash away when applied, be very particular where you plan to mark lines in red.

Blue Chalk

This is considered the best color for general use, as it contrasts well on metal, plastic and wood surfaces. It’s also a temporary color, making it ideal for indoor use where the surface will later be visible.

How To Use a Chalk Line

Step 1 – Pull Out String Line

After preparing the surface for the line, gently grasp the hook on the end of the string and pull. Don’t expand it all the way; just get the line started.

Step 2 – Attach the Hook

You will want to secure the hook on the farthest end of the object where you are chalking the line. You can hook it using the claws or loop it around a nail, screw or tack at the end of the object.

Step 3 – Extend the String Line

Once the hook is secure, extend the string to the side of the object nearest you. Make sure to keep the line taut while you are pulling the string.

Step 4 – Hold the String Line in Place

While you are extending the string, press down on the tip of the chalk line to hold it in place. This will keep it taut while you put it in position and give you the best chalk line.

Step 5 – Pinch the String Half Way

When you have the string in position, grasp it between your pointer finger and thumb. Select a point that is halfway between the chalk box and the hook.

Step 6 – Lift the String Line

Once you are securely holding the line, lift it about four to six inches off of the surface of the object getting the line. Keep the line taut.

Step 7 – Release the String Line

This part is also called snapping the line. When it is taut and off the object, quickly release the string and it will snap down to the surface. As the string hits, it will leave the chalk residue in a straight line on the object.

Tips for Using a Chalk Line on Your Own

Even though it’s an easy tool to use, it can be difficult to get a straight line if there isn’t a way to secure the line and you are working on your own. Make it easier on yourself by putting a pin or a nail in the object to give the hook a landing place. You can also make a small slit in the side of the workpiece as a groove to hold the line in place. If you would rather not make a permanent mark on the surface of the workspace, you can also use tape to hold the hook in place.

If you find that the line is blurry, you may have too much chalk on the line. Stretch the string out in the air and give a pluck or two to help remove any excess chalk. This will lead to a sharp line. You can also snap the line two or three times in succession to get a clear but heavier line in the same spot.

Purchasing a Chalk Box

For a great selection when shopping for a chalk box, browse the products at Engineer Supply. We carry everything you need for measuring a straight line, whether you are working on an indoor and outdoor project.

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Frequently Asked Questions

How Do You Maintain a Chalk Line?


Using the line carefully will keep excess tension from causing the string to break. Also, storing the box inside a toolbox can help keep the dry chalk from getting damaged by moisture.

Are All Chalk Lines the Same?

Although the colors of a chalk line can vary, you could also see differences in how thick or clear the lines are. This could have to do with how much tension you held on the line or having too much chalk in the line. The more expensive your chalk box, the more sturdy and durable the box will be.

How Do You Know if the Chalk Line Is Straight?

The best way to keep the line straight is by pulling the line tight and keeping a strong tension on the line prior to the snap. This is why it’s important to have something stable on which to secure the hook.

Can a Chalk Line Be Permanent?

Depending on the color of chalk you use, your chalk line might be visible for a very long time. If you aren’t using a permanent color and want to ensure the line doesn’t get smudged or blown, you can spray a thin coat of aerosol hairspray over the top.

How Do I Know If I Need New Chalk?

If your box and the string get wet, you can let the string dry before reeling it back in but you may have wet chalk inside. It’s best to open the box and clean out any caked chalk before refilling it with fresh chalk.
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