My son decided this year he’d like to go as General Grievous from Star Wars Episodes I,II & III. Â This seemed like an ambitious costume, but I was inspired by Boneboy’s General Grievous’ costume to give it a try. While not everyone wants to be the general for Halloween, I developed a few interesting construction techniques using PVC and foam-core that you might benefit from for other projects that use the materials. Although I’ve done electronic costumes before, this was my first ‘mechanical’ costume.
I had a few constraints that other costumes might not have. The first is that my son would probably have to wear some or all of the costume most of the day at school, the second is that he’d need to put on the remaining parts (and take them off) at school by himself, and the last is that it had to be reasonably lightweight.
Here’s another picture of finished costume. Everything was done ‘by eye’ from a few decent drawings I found on the web.
The underlying garment is a simple black overall from an inexpense costume. In a pinch, black pants and a black t-shirt could be used. The ‘mechanics’ in my costume are simple foam core construction, some with several parts. I had a version of this costume that looked even more mechanical made from all PVC, but it was unbelievably awkward to use and didn’t look as good.
Some of the multi-part foam core pieces, like the greaves on the arms and legs and the chestplate had a central black portion that was painted first. The foam-core was ‘weathered’ with a wash of diluted temperate paint and glued together with a hot-glue gun. I find that hot-glue guns make rather fragile joints and I don’t like using them for things that will move, but it was expeditious.
Since most of the parts have bilateral symmetry, I made paper patterns and the traced them onto the foam core before cutting.
Behind most of the foam-core assemblies was velcro. The remaining velcro half was carefully aligned on the black garment. The half on the garment was stapled in (although sewing would be better – I might still do that).
Attaching the assemblies with velcro worked well, but there were a few places (like the chest-plate and the greaves on the secondary arms) where I needed to attach foam-core to PVC, yet I still wanted it all removable and nudgeable. I puzzled over this a bit and came up with a way to cheaply make PVC snap connectors. Â Cut an inch or less of thin-wall schedule 40 tube, and then cut out 1/3 of the circle making a clip. You’ll need to turn the piece vertically in the PVC cutter to cut this section easily, otherwise it’s a bit of a struggle. Once you get this though, it takes only about 20-30 seconds to make a clip. If you cut out less than a 1/3 the clip is hard to get on the tube, and more a 1/3 and it doesn’t stay on well.
The Mask
I had originally hoped to vacuum mold the mask but with just a few days to go before Halloween, I decided to go with foam-core for the mask. I simulated the compound curves with tempera paint, and by constructing the mask in parts. The resulting mask was light and comfortable.
After contructing the mask, I did come up with an unexpected technique to curve the foam-core into simple curves. By aggressively rubbing it against the edge of a pole or desk, you can bend it into shallow curves. I’d used this technique for ages with regular paper even as a kid, but doing it with foam-core was novel to me. This greatly improved the look of the chest-plate and neck-wrap, and with enough time, I might have gone back and tried the mask with this way.
Rotating Secondary Arms in Backpack
The big enchilada was my goal to make the General’s secondary arms pop out the back. I saw this was possible from the other detail-light websites. I constructed a harness from PVC that fit onto my son’s shoulders like a scuba pack. Â Behind the back are two elasticated rotating arms that lever into position with a dowel to lock them in position. It took many tries to find a position for this rather uncomfortably placed dowel that my son could reach. Finding right tension on the bands to force the arms up quickly, yet not dangerously so was also tricky. I refined both of these before gluing the PVC in position. Be aware that these moving parts on unglued PVC will sometimes cause the contraption to fall apart!
Caution: these arms can move fast. It’s best to put your back near a way and look side to side before ‘triggering’ the arms.
Creating  Linear (Sliding) Joint From PVC
In developing the locking dowel, I used a dowel that fit through the whole of a quad PVC connector. I had to cut off two of the four sides to get a perfectly round hole through the connector that would accept the dowel. To prevent the dowel from slipping out, I use a small ring of thin-wall PVC schedule 40 around the tips of the dowel.
Contructing a Rotating Joint From PVC
I used a similar trick to construct a joint for the secondary arms to rotate around. Â In this case, I held the dowel in by drilling holes in the end and putting a long screw into the dowel. The cut-off quad PVC connector could rotate freely on the dowel.
Note that in order to make the arms to spring up, I had to extend the lever arm of the back side of the rotation dowel a few inches up and then attach the elastic to that. A subtle point in placing the rotating joints is that the arms cannot overlap entirely in their rotation, one of the arms is nearly an inch farther back than the other in order to separate their rotations arcs. I did this by putting a ’spacer’ tube of PVC in one of the rotating joints and making that dowel about an inch longer.
What’s Left
The cape completes the look and hides the backpack. It serves to prevent unwanted attempts to trigger the arm mechanism. Note that it will take some dexterity to keep the cape on and trigger the arms.
In the hours since this was shot, I added red felt ‘eyes’ to the mask and ‘claws’ to the moveable hands.
Materials
- 3 sheets foam-core
- Approximate 3×10′ tubes PVC
- 1 x 3′ dowel
- PVC cutter, glue
- A good knife that will work on foam core
- black tempera paint, brush
- Black jump-suit
- 2′+ of 1″ velcro
- Stapler
- Elastic for mask
If you enjoyed this article, check out my other other halloween projects:
General Grievous animated costume
Rocking Gravestone using K’Nex
Follow Creatrope on Twitter