We're going to learn how to make a sphere out of insulation foam (extruded polystyrene). What you do with that sphere is your own business.

Step 1: Materials 'n Such

You're going to need:

Insulation foam - found at you local home supply store. I used 4'x8'x2" sheets. around 4 of them for this sphere. (sorry i don't know exactly how many, i was also working on another project simultaneously

Spray Adhesive - Make sure it's compatible with foam. I recommend Loctite High Performance Spray Adhesive , that stuff worked great, I was surprised how well it worked.

Cutting Tools - Sure, you could use a serrated bread knife, in fact that will come in handy later, but for the major cutting, do yourself a favour and buy a hand Jigsaw! I spent way too much effort cutting out large circles with a knife when I realized that tools had been invented to make life easier, and it did. My jigsaw cost about 30 bucks, and it was so worth it.

Large Chalkboard Compass - I found mine at a school supplies shop. this was a real life-saver. I first tried a string on a nail, but it was inaccurate and a real pain to use. The large compass made drawing large circles a breeze. I know, imagine that, tools made for our convenience.

Shaving/Sanding tools - get a hand rasp like the one pictured, It was the most efficient and least blister inducing. also get a couple different grades of sand-paper, coarse and fine. Use smaller electric sanders if you like.

Measuring Tape

Sharpies - Sharpies are the best.

Tunes! - get some good tunes goin! ask for me for recommendations, go ahead.
<p>I used the same technique to make large jack-o-lanters for my Halloween display.</p>
<p>Thank you so much for posting this, I used it for a Pokemon costume (Gengar) that I made for my son this year. Gengar was a little more egg shaped than perfect sphere so I modified the cross section template a bit. Also, I had a lot easier time using a hotwire cutter for the big cuts (to smooth out the edges). His principle at his elementary school loved it :) Thanks again! </p>
<p>Thakyou for sharing this. You helped to realize one of my instrutables. I realy apresiate the clear instructions and the work you do. Thankyou again. </p>
<p>If I need to make 22&quot;, 20&quot; and 12&quot; would it be better to purchase the 3/4&quot; foam board?</p>
<p>This may help as well. This ball would be just over 44 inches tall. These would be the radius of each ring.</p><p>:) Steph</p>
<p>Thanks dude! This is an awesome instructable!</p>
<p>clever clever. . . </p>
This is great! I want to make my sweetie a death star for xmas and even tho mine won't be quite so big, the concept is similar. I was thinking of decoupaging a childs rubber ball and then popping it inside and threading lights inside but wasn't sure if it would be stable enough. This gives me great ideas. Thanks for sharing!
Thanks for posting this. It's the kind of thing I'll probably end up making at some point, for whatever reason, and you shared some good tips here. (Specifically how you laid out the measuring circle to help get all the layers the right size--very clever.)
Thanks, and You're Welcome. Hope it comes in handy some time.
Spheres are difficult to make, yours looks good!<br />So...what are you going to do with it?
Thanks! <br>Mine was turned into a costume, a globe of sorts. It was for a commercial someone was making.

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