My son wanted to be Emmet from LEGO MOVIE for Halloween so I looked all over for the costume @ every retailer imaginable, after I had run out of options I decided that I would try to make his costume at home. The head and hair are just a sheet of dense foam. I cut out many of the needed diameter and glued them all together. after that had died I used a coarse wood file to start shaping the foam to my desired shape. I then coated it in resin and painted it. The whole body is nothing more than precisely cut junk cardboard scraps taped together and covered in resin.
Step 1: Measurements of the Person That Is Going to Be Wearing It Are "key"
First thing you need to do is get some measurements. You want the costume to fit the person you are building it for. You can't expect to build it and just hope they can fit in to it. Get measurements of head, shoulders, chest, mid section, waist, legs, feet, etc.. I took every measurement I made and added one inch to it. That way the costume would fit "snug". I found a flat piece off cardboard and started drawing out my measurements. I decided how wide the waist needed to be to look the most "lego like", then based everything from the waist down off of those measurements. Having a lego figure with you will really help with this step. I drew it out with tabs so that it didn't have gaps on the corners after I cut it out and folded the cardboard.
Step 2: Drawing Out and Cutting Your Foam for the Head.
I got a dense sheet of foam to use for the head and hair. I figured out my measurements by comparing the little lego guys proportions in my hand vs. the mid section that I had just drawn out on the cardboard. To make the circles on the foam you can either use a protractor or the ol' nail on one end of a string and marker on the other end. Depending on your thickness of foam you will need to determine how many circles you will have to cut out to reach your desired height. keep in mind that one of the circles you need to cut out are for the neck so it will be about 2 inches narrower than the others but should be figured in to your overall height. Use either a thin steak knife or an old hack saw blade wrapped in tape like I did to cut out the circles. Make sure to keep your blade squared up with your sheet of foam while cutting out the circles so your circles don't end up having angled edges.
Step 3: Gluing the Circles of Foam Together.
To glue the circles together I found it best to use either wood glue or Loctite G02 Glue (which dries like rubberish foam) First choice would be wood glue though. When you glue the circles together you should line them up as flush as possible and keep the glue back away from the edges about half an inch. Also keep in mind that there will be a head in the middle of this so glue where the head will be is a waste of glue. After glueing them all together including the neck, I flipped them over upside down and found the heaviest object to sit on top of them till they dried. In my case I used a car battery for a weight.
Step 4: After a Day or So Its Time to Shape and Hollow Out the Head
Using a coarse file and 80 grit sand paper I smoothed up the head and curved the edges to make it look more like a lego head. after you're done with shaping its time to add the lego tab to the top of the head. Again I figured out my measurement by comparing the foam head to an actual lego head. After glueing the lego tab on top of the head you'll need to let it dry the same way you did the rest of the head. When it's dry you'll just need to slightly sand and roll the edges of the tab to make it look right. After that I drew my sons head measurements on the bottom of the neck with a marker and started carving out the foam until I reached my desired size. make sure to carve out a little extra for their nose to sit comfortably.
Step 5: Test Fitting the Head and Chest.
Just try it on at this point and make sure it all fits like it should. Now is the time to make changes if needed.
Step 6: Drawing Out, Cutting, and Building the Rest of the Body
To make the legs and crotch (which holds the legs) I used cardboard and a cardboard concrete form for the radius at the top of the legs. Tape it all together and test fit the costume again to make sure they can move around freely in it.
Step 7: Making the Hair.
I forgot to take pictures of this but what I did was set the head out and pretty much made half moon pieces of foam that fit around the head all the way to the top then cut out the pieces like doughnuts to go around the head for the bangs and top of hair then topped it off with a smaller circle. I glued it all together and held it together with toothpicks and wedges till it dried. I then shaped it with my file and sand paper.
Step 8: Covering Everything With Primer.
After everything was were I wanted it I covered all of it in fiberglass resin to give it a rock hard shell then coated all of it with very heavy coats of primer.
Step 9: Painting...
I then very heavily coated everything it's desired color using spray paint. Notice the AMAZING thick shiny finish. You get that from taking your time and applying many many even coats.
Step 10: Detail!!!
The white and blue of the shirt are spray paint that I taped off and sprayed. The reflective stripes are glitter duct tape that I found in the arts and crafts section of a local store. All of the black is Sharpie marker (make sure to get a bunch of brand new markers because they crap out pretty quickly on here) The red and black on the face are Sharpie marker and the white teeth was done with spray paint.