If you’re going to use a whiteboard to teach a group of people, you’ll need at least one whiteboard eraser at your disposal. A whiteboard eraser will quickly wipe away the dry-erase ink that you use to write down notes for your classroom. So, what size does an eraser come in?
The standard whiteboard eraser will roughly measure 2 inches wide, 5-1/8 inches long, and stand 1-1/4 inches tall. It can easily sit on the whiteboard marker tray or slip inside of your desk’s cabinets.
In today’s guide, I’ll go into greater detail about the size of a whiteboard eraser, what you can do to increase its longevity, and how you can fashion a whiteboard eraser on your own.
What Is the Whiteboard Eraser Size?
The size of a whiteboard eraser, which is used to wipe away dry-erase ink, might not seem too important, but if you value convenience, then you’ll want to pay close attention to the size of the eraser.
Most erasers will measure 5-1/8 × 2 × 1-1/4 inches (L × W × H). If you pay close attention to the whiteboard tray—the metal portion of a whiteboard that is used to store markers and erasers—you’ll notice that it’s just wide enough for the eraser to sit on comfortably.
What Are Whiteboard Erasers Made of?
There are two main components that go into every whiteboard eraser—the fabric bottom that is used to erase dry-erase ink, and the plastic holder that keeps the eraser portion in place. Some whiteboard eraser models have cylindrical grooves in them for dry-erase markers.
The fabric bottom is typically made of felt. However, underneath the fabric is a hard center that gives the eraser structure. Generally, that hard center is made of foam, though there are porcelain and EVA (a type of plastic) centers, which can cost more but do not break down as easily as foam.
What Makes Dry-Erase Markers Erasable?
Whiteboard erasers are used exclusively to erase the ink in dry-erase markers. So, what makes dry-erase marker ink erasable?
If you compare permanent markers to dry-erase markers, you’ll find that their inks contain very different chemical ingredients and proportions. Permanent ink contains an acrylic polymer, which helps the ink adhere to surfaces permanently.
As for dry-erase markers, they contain silicone polymer, which makes the ink slippery on smooth, non-porous surfaces. The oily polymer also contains alcohol to help it dry almost immediately, but it never permanently sets on whiteboard melamine or porcelain surfaces.
If you’re like me and are annoyed by how permanent markers and dry-erase markers look almost identical, you can use colored tape to distinguish one from the other. Simply add a strip of tape to your permanent marker or the dry-erase marker, making sure that you know what the tape represents.
How to Make a Whiteboard Eraser?
The fact of the matter is that the felt surface of a whiteboard eraser isn’t the only thing that will get rid of dry-erase marker ink. You can use virtually any piece of cloth you have on hand. If you’re in a pinch, just use a tissue to wipe the ink off your board.
However, if you want to construct a whiteboard eraser, here’s how you do it.
- Purchase your supplies. You’ll need a sheet of felt, a cardboard box (a crayon box will work just fine), some glue, a block of foam, a utility knife, and a pair of scissors.
- Using the scissors, carefully cut the cardboard box so that it measures 2 inches wide, 5-ish inches long, and 1-ish inch tall. Make sure the box is hollow.
- Using the utility knife, carefully cut the block of felt until it is slightly smaller than the cardboard box. Just subtract 1/8 of an inch from the dimensions of the cardboard box to get the dimensions of the foam block.
- Apply a generous layer of glue on the exterior of the foam block, making sure not to get any glue on one of the wider faces.
- Stick the foam block inside the cardboard box and let it sit for 5 to 10 minutes until the glue has hardened.
- Using the scissors, cut the sheet to size. It should measure at least ¼ of an inch wider than the face of the foam block.
- Stick the felt sheet inside the cardboard box, making sure to tuck the sides of the sheet inside the box.
Alternatively, you can wrap a sponge with a sheet of felt and use rubber bands to keep it in place. Just make sure that you never use the rubber band to wipe your whiteboard since it might cause streaking and possibly lead to permanent staining.
Can a Whiteboard Eraser Get Rid of Permanent Ink?
Unfortunately, no, it cannot. A whiteboard eraser’s felt surface is designed to swiftly wipe away the oily ink of dry-erase marker, not a permanent marker. At the very best, the eraser will smudge the permanent ink, which will do nothing but further stain your board and make it virtually impossible to clean.
However, before you think about purchasing a new white surface for your whiteboard, you can try out this nifty trick.
Take a dry-erase marker and trace over the portion of your whiteboard that has been stained with permanent ink. The more dry-erase marker ink you use, the better. Now, let the erasable ink sit on the whiteboard for 10 to 15 seconds before using a whiteboard eraser and erasing the ink. You will notice that the permanent ink will also get wiped off with each stroke of the eraser.
This is due to the chemical properties that I talked about earlier. When you introduce the oils and silicone in dry-erase marker to permanent ink on a non-porous surface, such as a whiteboard, the chemicals will blend with the permanent ink, causing them to break down and become more easily erasable.
However, this trick doesn’t work 100% of the time, especially if you let the permanent ink sit for extended periods of time. In this case, your only option might be to resurface your whiteboard with a new sheet of melamine or porcelain.