Adafruit tells you How to make 3D Printed molds for custom stamps!

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Adafruit’s Guide to 3D Print molds for custom Stamps

Hey guys, Any printing ideas going? Well, I was diving in some of my favorite blogs and luckily found this tutorial on how to make custom stamps using 3D Printed molds! This means you can basically use any design to authenticate your objects with ink and be free to get as many custom stamps as you want from your 3D printer. The detailed guide popped up two weeks ago as a contribution from Phillip Torrone, Ruiz Brothers and Lady Ada.

In fact, it started as an initiative of stamping Harriet Tubman’s face onto $20 bills

Torrone (founder of Hackaday) and Fried (founder of Adafruit Industries) decided to act putting their 3D printing skills to work in order to speed up the distribution of the pieces, since the official version with the civil rights hero on it wouldn’t be released until 2020, according to United States Treasury’s announcement.

“We have this technology,”explains Fried. “We know how to 3D print stamps. Instead of just making birthday card stamps, I thought it would be neat to make something a little more countercultural—something that would help people see, here’s what technology can do.”

After creating the 3D printed molds with Tubman’s face, Torrone and Fried dipped them in ink, and began stamping the bucks. That’s basically how Andrew Jackson became Harriet Tubman.

custom stamps
Harriet Tubman was an American abolitionist, humanitarian, and an armed scout and spy for the United States Army during the American Civil War.

“If you see these faces every day, they gain power. They’re on the most powerful currency in the world,” Says Fried. “It’s hard to tell some girl, ‘Hey, you can grow up to be a founding father.’ No, you can’t. But you can learn about Sally Ride or Harriet Tubman and be like, ‘This person had strength in adversity and was able to do something amazing.’”

Now, here is a summary of the guide’s most relevant points to create your own 3D Printed Molds

You will basically need the next tools and supplies along the process:

  • Scale
  • 3D printer
  • flush cutters
  • play-doh
  • Amazing mold putty

Designing the mold

First step is using an image editing program to resize the illustration of your choice to fit the stamp size. Then, go to and convert the image into a 3D model; once there you can create the negative parts for the mold by editing some of the model settings, which include:

  • Changing the thickness to 3mm.
  • Setting the thinnest layer to be 1mm and.
  • Changing vectors per pixel to 2.
3D printed molds
Before converting Harriet Tubman’s image into a 3D mold, they scaled it to a dollar note by measuring the image in the example to 35mm x 45mm; Source: Adafruit.

Note: Remember to reverse your design in order to get the right orientation once you print it.

Next step is adding walls for the putty to fill in the mold part and using meshmixer to align and combine them in one single object:

3d printed molds
Note: If the meshmix has errors creating a union between the two objects, you’ll need to first select each object and then use the “make solid” option. Source: Adafruit.

You can find the editable version of the wall design in the STL files of the official Guide. It also includes a handle to attach to your stamp mold.

Once you get a solid model you can import it into the slicing program to generate the tool paths for the 3D printer.

3D printing stage

Printing parts up right will give you much more detail for the mold part

Printers have a much higher resolution on the X and Y axis then z; with the purpose of getting a higher resolution, send to print the design vertically. Orientate the mold so it can print on the flat edge of the wall to achieve the quality desired.

3d printed molds
Printing parts up right benefits from a (theoretical) resolution in the x-y-plane of 12.5 micrometer; together with a layer height of about 0.15 mm will give you much more detail for the mold part. Source: Adafruit.


Note: To adhere the edges to the printing bed, authors added 4 skirts outlines (2mm brim) to the bottom of the part. This ensures parts properly attach to the bed while printing.


You can find the links to STL files and plenty of instructions for the 3D printing stage HERE.



Build the stamp from the 3D printed molds

Making the actual stamp involves using casting putty to create the stamp mold

Why using this material? Well, the putty is silicone base, so its able to transfer ink really well.

3d printed molds3d printed molds

First of all, you’ll use play-doh to know the exactly amount of putty you need to fill the 3D printed molds. Just apply the doh into all of the voids in the design; Employ the 3D printed lid part to help press the doh into all of the corners and remove any excess that doesn’t fit in the negative.

Use the weight of the doh to measure the two part putty mixture for the 3D printed molds

Use the weight of the doh to measure a 1:1 mix ratio. To weight the doh, they used a general mailing scale for envelopes. Set the units to grams and make sure to measure on a level surface; Stamps in the example weighed in at 8g, so authors measured two 4g parts.

3d printed molds

Now mix quickly and evenly both parts into a ball and then use your thumbs to work the putty into all of the details and corners of the mold. Reuse the lid to help compress the putty into the part.

3d printed molds

If the putty feels fully cured, you can go ahead and carefully peel the 3D printed mold off the part. Remove all the excess on the mold with a pair of sharp scissors.


Note: It takes the putty about 20 minutes to fully cure. After that time, press on the edges with your fingernail to see if the putty has turned into a solid piece. CLICK HERE to find the full instructions.

3d printed molds

Glue the stamp to the printed handle. Apply small drops of glue on the flat side of the handle and press the mold consistently against it to adhere.

Note: Allow to glue to cure for about 15 mins before using the stamp for the first time.

Testing pressure and ink on the custom stamp

It’s finally time to check the results! Test the stamp with a bigger ink pad so all the stamp’s edges can fit in. Then you’ll need to try the amount of ink to put on the mold according to the level of detail you want.

3d printed molds

3d printed molds
A harder pressure with less ink achieves the most detail for this design. Source: Adafruit.

I consider this one a very useful tool whenever you need to stamp anything (including $20 bills, which for me is surprising, since it is all legal in the USA). Plus, I’m pretty sure these are really easy to make with most common home desktop 3D printers out there.

Stay tuned with, more posts like this coming up soon!

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  1. Daniel F says

    Great Work!!

  2. Tom Baxter says

    The project itself shows a novel way to use 3D printed parts. The power and the message conveyed is immeasurable. Great job!

  3. Adam Davis says

    Wow! That’s Really Kool.

  4. Richard Bynum says

    So proud of these guys! 2020 is a long wait from now for the new bills to be rolled out! It would be so cool to come across one of these stamped bills! I would frame it!

  5. PIPE says

    a good example of what can do a 3d printer!!!

  6. Michael Champlin says

    My project involves a picture (3 to 4 of them) being applied to a Coffee Mug. I’m using to make my curved lithophanes. just have to figure out how to merge them with the mug

  7. Richard Bynum says

    I came back to re-read how to do this and to copy the helpful links. I’m going to try this in a few weeks after I get my 3D printer. I know it’s going to take me a few tries to learn how to use the software and to get the hang of my new printer. But I think it will be fun. It’s over my head right now so it might take way more than a few times!..haha. But I think there’s no better way to learn something than to jump in head first! Thanks for sharing this! I can’t wait to make some cool/funny/neat stamps!

  8. Oleg says

    I would like to see as it will be working with architecture modulation things

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