Introduction: “Ultimate Pi Day” T-shirt

About: In a valiant attempt to keep myself from dying of boredom, I create.

Every year on March 14 we get to celebrate “π (pi) Day”, especially here on Instructables, the one day of the year where we can live the first 3 digits of that irrational number pi. This year is something mega special because it is the one day of the century where we can live the first 10 digits of pi. The first 10 digits of pi are: 3.141592653 so we can divide them up into the following way: 3.14.15 9:26:53 or in other words, 3 (month March) 14 (day), ’15 (year), 9 (hour): 26 (minutes): 53 (seconds). This only happens once in a century, twice is you use a 12 hour clock (AM and PM). To me that is something worth really celebrating, so I decided to create a T-shirt to help the world understand and appreciate this epic occasion. So this is how I created my “Ultimate Pi Day” T-shirt. Let’s get started.

Step 1:


  • T-shirt -100% cotton (your choice of color and size, this one is my favorite blue and my size)
  • 12” x 12” piece of heat transfer vinyl in white (Can be bought at craft supply stores or sign supply stores like Regional Supply in Salt Lake City, Utah)
  • Scrap (about 3”x 12”) piece of heat transfer vinyl in gold
  • Personal electronic cutter and computer program it run it
  • Weeding tool
  • Iron
  • Pillow case
  • Parchment paper

Step 2:

Open your desk top program for running your personal electronic cutter. Decide which fonts you want to work with. I chose Lucida handwriting and Book Antiqua. I wrote out the words Ultimate, Day, AM and PM in Lucida handwriting,

Step 3:

the numbers and the phrase “It only happens twice a century” in Book Antiqua. Each word or phrase was in its own text box, so I was able to adjust the placement of each text box and the size of each text box, until I was very pleased with the result.

Step 4:

There was only one thing missing and that was the symbol for Pi. For that I went on line, did a search and found one that I really liked. I copied that on to my desk top then I opened it using the trace image function of the program and looked at it, decided it would work and then copied it onto the mat. Whoops, it covered the numbers, so, I moved the text box holding the numbers aside, put the pi where I wanted it, in the middle with everything surrounding it. I put the numbers so they could be read on top of the pi. And took a long look at it. Yeah that is just the way I wanted it.

Step 5:

Next I selected all the boxes and flipped them over so that when I cut them on the film, and applied them on to the t-shirt they would read right.

Step 6:

Final step before cutting, I “cut” the pi from the mat (screen) and “pasted” it on another mat (screen), for I wanted the “pi” to be in gold and the rest of the writing to be in white.

Step 7:

Place the white heat transfer vinyl gloss plastic side down on the mat. The side I will be cutting is the side that will be touching the fabric of the T-shirt, that is why we reversed the writing. Turn the machine on, and load the mat into the machine. You want the machine to “kiss” cut the vinyl, which means it cuts the vinyl but not the clear plastic the vinyl is attached to. I have the blade length at 4 and the pressure at 3. These work for my machine. You may have to experiment to see what works best for your machine. Click on the cut button and wait while the machine does its job and cuts the vinyl.

Step 8:

Unload the mat and set it aside for a moment. On another mat, put your piece of gold vinyl on and prepare to cut the p symbol. Cut it out just like you did the first sheet.

Step 9:

Get out your weeding tool. For professional sign makers this can be an exacto type knife. Both Provo craft and Silhouette sell weeding tools, if you have one use it. Wedding a vinyl mat is the same process as weeding a garden, remove what you don’t want and leave behind what you do.

Step 10:

When you think you are done weeding turn it over and look at the result. Make any adjustments you may need. Weed the pi piece.

Step 11:

On a kitchen counter place an old pillow case. Turn you iron on to 379.4°F or 193°C or you can put in on the “Cotton” setting. The iron needs to be hot enough to melt the vinyl onto the fabric of the t-shirt. Press the pillow case, so there are no wrinkles. Press the t-shirt to remove any wrinkles. Place the pieces of vinyl, still attached to the clear plastic on top of the T-shirt. Make sure the dull side is against the fabric while the clear plastic is on top. Adjust the placement so that it is just the way you want it. Yes! It looks good.

Step 12:

Remove the white vinyl piece and cover the plastic of the pi piece

Step 13:

with parchment paper, or brown paper sack. Your iron is hot enough to melt the plastic if it comes in direct contact with it, so the parchment paper protects the plastic while allowing the heat to melt the vinyl onto the T-shirt. Press the pi piece for 15-20 seconds.

Step 14:

Put down the iron, remove the parchment paper and lift the corner of the clear plastic, if the gold p is left behind on the fabric, pull the rest of the plastic off. If not, replace the parchment paper and iron another 10-15 seconds. Check it again.

Step 15:

Once the clear plastic is removed, turn the shirt over and press it form the back to make sure it is sealed. Let the T-shirt cool completely.

Step 16:

Place the white vinyl words where you want them and the place the parchment paper over the clear plastic and iron for around 30 seconds.

Step 17:

Test by lifting a corner. If the vinyl has all adhered to the T-shirt, remove the plastic and press from the back. Let cool.

Step 18:

Done, and ready to wear on our epic day! Enjoy!

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