In the last few years, when considering what to make for a halloween costume, I've begun with characters which have had a strong, positive effect on popular culture. Strong, popular characters which aren't really human. I have a really good idea for Halloween 2009, simple in concept with just a couple of engineering challenges.
|
The first thing I did was to have Stacy take a photograph of me standing up. Lately I've started my design with a photo composite of myself behind an image of the character I'm transforming into. Concept photo composites from previous years:
|
The primary challenge this year was where to hide my face. Generally, the first thing people look at is your face, so if you want them to look at your costume, particularly if your costume already has a face, you've usually got to obscure your own face. This year's costume would need to sit high on my shoulders. |
Lately I've abandoned the backpack frame in favor of just bending some PVC pipe with a heat gun. PVC pipes are about a dollar each, and I can usually avoid buying connectors by bending up the shapes I need. I suggest bending PVC outside, because there is some fume and fire danger. You could probably use a hair dryer if you don't have a heat gun. You could probably use a space heater. I used to use a charcoal barbeque, so don't think you need the ideal equipment to pull this off. Bending PVC is really easy. Don't let the length and complexity of these instructions concern you, I'm just trying to deliver as much information as possible. Basically you just heat up a section of pipe until it gets soft, then you bend it. |
To bend PVC pipe:
|
|
A few people have suggested that I try filling the pvc with sand before I bend it, but I'm pretty comfortable with my method, so I haven't tried that yet.
|
Usually I try to make compound bends in separate steps, heating, bending and cooling, then re-heating, re-bending and cooling. Never even once has my pvc pipe become too hot and melted into a globby puddle. I was engineering this as I went. I needed a long rectangle sitting on my shoulders like a table.
|
Next I added a support bracket for the front and a giant rectangle surrounding the whole thing with the final size I needed. Finally I added a rear support bar and screwed the whole thing together. Walking around with this lightweight, well-balanced rig, the potential struck me. I could build up a massive structure on top of this. I could drop a skirt around it, anything. Unfortunately, the main rectangle needed to be a bit higher, just below my eyes, so I re-bent the rear bracket and moved the screws on the front. I also added a little foam padding to the shoulder yoke. Success! |
Next I started building two low boxes for the main structure of the costume. Luckily I had sequestered two giant John McCain for President corrugated plastic signs last year. Corrugated plastic is perfect for costume construction because it is very flat, light and strong. It would probably cost a fortune if I ever tried to buy it, but there is usually an ample supply poking out of vacant lots advertising Real Estate Investor Seeks Apprentice, or We buy Houses for CASH. I think it might even be lighter than cardboard.
|
I marked out the final shape with a sharpie and cut it with a utility knife. I wanted a box, so in some places I just cut halfway through and bent the sheet into corners. I used hot glue to cement the pieces together.
|
The hot glue wasn't holding well enough in all the corners, so I used zip-ties and duct tape to reinforce the assembly. |
The construction was pretty sloppy in places, but all of this will be covered in paper mache, so it didn't have to be attractive. At this stage it looks like a "last supper" costume or a banquet scene from Temple of Doom. Maybe I should just set up a trainset to go around my head. |
Besides building, I also kept an eye out for parts. I needed two clear domes, each 15" in diameter. They were probably going to end up being $40 each, but I had lots of time so I checked every other resource before I actually bought anything. |
I looked at bowls at Target and the 99 cent store, light fixtures at Home Depot, security camera housings on ebay, round skylight lenses at the round skylight store, and serving trays at the restaurant supply. |
I preferred plastic, but it quickly started looking like glass was going to be the cheapest way to go.
|
I had a backup plan. Recently while researching sculpting and mold-making techniques, I came across a pretty good tutorial on vacuum forming. Vacuum forming is used to suck hot plastic sheets down onto a shape, so that a thin clear plastic mold is created. I didn't want to have to build a whole vacuum chamber, and I definitely didn't want to sacrifice our home oven to experimentation (RIP clothes dryer), but I thought this method would at least be worth exploring. I made a visit to TAP plastics on Auburn Blvd. and found their thinnest acrylic sheet. Two 16" squares cost about $6 each and I was on my way to becoming master of my own domeing. "I'll be back on Monday after I ruin these", I quipped as I turned to exit. "Oh, here, practice on these", the guy at the counter offered, handing over three rectangles of scrap. Awesome! Maybe I could pull this off! My plan was to heat up the sheets with a heat gun and have them melt into a bowl shape. I grabbed a steel colandar and dropped the first sheet of plastic inside. I cranked up the heat gun and fired away. Nothing happened. |
I guess I've gotten used to PVC plastic melting in one minute. This took much longer, perhaps 5 minutes passed before the sheet started to droop into the bowl, folding like a won ton wrapper. This was obviously not going to work. The plastic was bending, but not really stretching. I needed it to stretch into the bowl and stay tight against the surface of the bowl in a nice clean curve.
|
On my next try, I took a page from the vacuum forming tutorial: I made a jig. |
I cut identical holes into two pieces of lumber and sandwiched a plastic sheet between them. I figured the only place the plastic could go was down, drooping into a nice smooth bubble.
|
I came back with the heat gun and it worked! I could make a little dome! Even under the gun for 10 minutes, or in the oven for 5, the plastic never got very pliant. |
I had to physically push down on the center of the plastic to get it stretched. |
When the plastic cooled I removed the wooden frame and pulled it out. It looked great! Maybe not as convex as I needed, but definitely a good step towards my ultimate goal. |
Next it was time to move up to full size 15" domes. I cut a larger jig, sandwiched a new sheet of plastic and squeezed it into the oven. Actually, I first tried a heat gun, but I couldn't heat the sheet fast enough to get it to soften up. The oven was the obvious next step. I laid out a sheet of aluminum foil in case my plastic melted all over the place. I cranked up the oven to 550F and turned on the broiler (in this case an overhead electric heat coil). |
Nothing happened. Well, actually, nothing happened until I looked away for a moment. The plastic drooped down to the rack! I threw open the door and pulled out my project. Bubbles! Damn. I missed the "hot enough to be pliable, cool enough to not bubble" heating window. I was going to have to be more vigilant. |
On the second attempt, I turned down the heat and stuck with the lower heating coil only, not broil. I set the heat at 400F, kept the door cracked open and a close eye on it. As soon as it started to droop, I yanked it out. I wanted a slightly more concave dome, so I gently pressed down with oven mitts. I know this sounds crazy, because I wanted a perfect smooth curve, but the hot plastic was elastic, bouncing back to smooth. |
Cool and out of the jig, it looked awesome! A perfectly smooth bubble. |
Spinning Tornado Costume |
Scott's AT-ST Costume |
Balloon Hut |
Feather Pinwheel |
QR Code Costume |
Paparazzi Costume #2 |
Solid Ice Beer Caddy |
Greg's Whiplash Costume |
Lloyd Dobler Boombox Costume |
Best Costumes on the Internet |
The Money you Could be Saving with Geico Costume |
Urban Gardening |
Kindling - wooden Kindle |
Box of See's Candy Costume |
Dwight Shrute Bobblehead Costume |
The Light Sharpener - satellite dish solar cooker |
The American Idol Judges Halloween Costume |
Sudoku Costume |
The Infinite Candelabra |
Baby June, hospital childbirth |
Hero's Engine |
Devo Hats |
Fandango Costume
Dr. Octopus Costume |
Jenga Costume |
Banana Skin Coat |
Fisherman |
Hypnodisk |
California costume |
paper mache satan |
spring shoes |
metallic wings |
fire without matches |
paper mache hummingbird |
paparazzi costume |
matchstick cats |
fish costume |
ketchup packet bear |
Africa costume |
push to cross sign |
paper mache globe |
paper mache alien |
pet coffin |
paper mache Elvis
How much is Inside? |
Pranks! |
Citizen |
Photographic Height Weight Chart |
Science Club |
Incredible Stuff |
Travel |
About
Home | Contact Rob
October 6, 2009.