One Dollar Rubber Stamp

I wanted a rubber stamp that looked good and didn’t cost much. I am not much of an artist with an X-Acto knife so I tried something I haven’t seen done before. The premise is to print a mold and squeeze a rubber eraser into the mold. Nothing outlandish. Fortunately this method doesn’t require anything sharp so it is safe for kids.

You will need:

• 3D printer or laser engraver and media
• Polymer eraser
• Sturdy clamp
• Block of wood at least as large as the eraser

Erasers cost less than one dollar at the art stores but I had perfect results with a four pack of polymer erasers from a dollar store. Printer filament isn’t free but even then the rubber stamp should not cost more than one dollar. Plus, after you have a mold printed you can make unlimited stamps from it for $0.25 each. You can make an entire alphabet for $6.50.

Some images are animated.

Download the files from this step or from Dropbox.

For this example I have included a stamp with my emblem.
I have also included an OpenSCAD file for rendering the Instructable’s robot as a stamp mold. This should help anyone who wants to make a custom stamp.

The OpenSCAD file, robotStamp.scad, imports an image, robotCropped.png*, with the surface() function and sizes it with the scale() function. It is important that the files be saved in the same location. The Dropbox file puts them in the correct order for you. Add your own PNG image by copying the file in to the same folder then changing the file name to match. Now you have a custom mold.

Print the file at a size no larger than the eraser.

*I got this image from here.

Boil two cups (0.5 liters) of water. Add a pinch of salt if you are heating water in the microwave.

We want to be able to completely submerge the eraser. Use more water for more erasers.

Heat the eraser for at least five minutes. The water doesn’t have to be boiling during this time.

1. Shake water off the eraser. Use chopsticks, or better yet, tongs.
2. Place the hot eraser on a table.
3. Place the mold on the eraser so that the mold will make an impact on the eraser face.
4. Place a piece of wood over the mold.
5. Clamp the pieces together as tightly as possible. The hot eraser will flow into the mold and take its shape.
6. Allow the eraser to cool while clamped. This make take some time, I recommend letting it cool overnight.

Remove the clamp and reveal your new rubber stamp. You are ready to test.

Cheap stamp pads can be found at dollar stores which are little more than ink soaked pieces of cheap foam. But they work.

If your eraser bulged over the edge of the mold it will be problematic and leave marks on the paper. Fortunately erasers can be shaped just by rubbing paper on them. You still don’t need a knife. Just rub paper over the offending bulge and it will erode the way erasers are meant to erode.

Thank you for reading. I write incessantly at my blog, 24HourEngineer.com

You can find this project there including the parts I messed up and how I mistakenly printed the mold backward thinking it was a good idea. There are some projects with 3D printers and some without. There are some projects with programming and some without. There are some projects with only simple tools and some without. All of them have lots of pictures, even the parts I mess up.