Introduction: Masking & Painting Globes on Spheres of Any Size.
As the Paint Booth Master of the Invention Studio, I try to come up with new and exciting ways to use the resources at our disposal - with the end goal of engaging and inspiring our users to make neat things.
As I was designing another project that's in the works - and also globe related - I wondered if it would be possible to spray paint designs on a sphere cleanly, with no image distortion. As it turns out, yes. It can be done, and it can look super clean when you've finished.
I'll be showing you all how to make and apply a globe stencil to a cheap 15" ball I bought at Target. I'm still trying to work out an easy way to make your own pattern, so hopefully I'll get an Instructable up about that soon.
Step 1: Bill of Materials
- Well-ventilated area
- X-Acto Knife
- Cutting mat
- Any sized sphere
- Spray paint
- Masking tape
- Printer paper
- Any vector graphics software - I'm using Illustrator
Step 2: Understanding Spheres & 2D Patterns.
If you've ever compared a map and a globe, you may have noticed that the geography looks different between the two. This is because:
Spheres are magical and deceptively simple.
Vox does a great job of explaining why maps are all weird, so if you're curious, I'd watch the video here. Essentially, it's mathematically impossible to get the visuals from a globe to lie distortion free in a rectangular 2D pattern. That's why globe makers use a series of weird, identical slivers to position landmarks on their products. (PS. These are called sinusoidal projections with 30 degree gores.)
Fortunately for us, we don't have to mathematically calculate out the shapes of these slivers, because we have the Internet and people have already done it for us.
To start, you'll need to download one of the templates from this helpful website! I downloaded the "colour globe template".
Pic from Amazon.
Step 3: Design Your 3D Stencil As a 2D Net.
I imported the map template in Illustrator, and then I image traced the map to reduce it down to simplified paths that I would later cut out.
Note: Image tracing will mean you won't have an entirely accurate globe, but it's the quickest and easiest way to make a traceable path for later. If you're chill with a slightly inaccurate globe, you can download my Illustrator file.
Step 4: Size Your Stencil Appropriately for the Size of Sphere That You Have.
Now it's time to do some math, cause this is where the magic happens.
Because the stencil goes from north to south pole, we know that it represents 1/2 of the circumference of the sphere. We also know that the circumference of the sphere is 2*pi*radius.
Therefore, we know that the height of the stencil should be scaled up to:
(1/2)*2*pi*radius = pi*radius
Since I have a sphere with a 15" diameter, that means that my stencil had to be 23.5" tall.
So, in Illustrator I made sure the aspect ratio was locked, and then I set the height of the stencil to 23.5" tall.
Editors Note: I got cocky here and listened to the Target description of the ball rather than measuring it myself. It was actually 14" in diameter - meaning that my math was wrong, so my stencils were a little off.
Step 5: Print Out Your Net & Setup for Cutting.
I planned on using the Invention Studio's vinyl cutter, in order to save me from hand-cutting my stencils, but, after about 2 hours total of fighting it to cut something 24" long, I decided it wasn't worth the fight.
Print out a b/w tile copy of all of the pieces of your globe, making sure that it stays scaled correctly.
Lay all of your papers out like a giant puzzle and tape them into place.
Then, cut out a large sheet of vinyl that's the same size as your paper.
Step 6: Cut Out Sections of the Mask With Your Sad, Sad Hands.
Using utmost care and a significant amount of time, trace every edge of the stencil. Since we're going to use the mask to cover all of the bodies of water, you'll need to trace the landmasses, in addition to the outlines of the wedges.
Take care to make sure that the paper doesn't shift during your cuts. Sometimes, I'd put a blob of masking tape down underneath the mask for more stability.
Step 7: Apply Your Stencil to the Sphere.
It also turns out that I didn't have transfer tape for this project, but I discovered something more exciting! Masking tape works as transfer tape.
Using a strip of masking tape, peel off one section of masks one at a time. Because you're applying to a globe, it's a good idea to place all of your stencil, and then peel off the landmasses later.
Slowly and meticulously align your masks as you work your way around the ball, making sure that the top corners and the continent outlines all touch. (Since I wrongly assumed a diameter, I had to fudge it a bit.)
This is an extremely tedious process. You at least need somewhere that you can place the ball where it won't roll around, and the ideal case is having a friend there to help you out.
Step 8: Compensate for Mistakes and Tomfoolery.
On the conclusion of Stencil-palooza, there were some gaps in alignment for the stencils. Part of that is attributed to my sizing mistake but another reason for that is I am not a robot, and alignment is challenging.
Use masking tape to quickly patch up any gaps in your mask, because if you don't - the paint is going to get all up in there.
Step 9: Paint.
Before spraying, you should test your paint on another item with the same material properties.
But then, you should spray that paint, yo. I used green because duh, but it really didn't matter.
Step 10: Peel & Enjoy!
Peel off all of your stencils, and you're done! Peeling stencils may be challenging, but you can gingerly use the tip of an X-Acto knife to get the peel started.
Finish it up with a clear coat.
You should now have a globe!