I built this costume for my girl (dressed as Ripley) to wear at our Halloween party. I used a 1/12 model kit to get dimensions and used a ton of reference photos I found on the web. Between the fact that she's 5-1 and that I wanted her to get under our 8' ceilings I scaled the loader down to about 80% actual size - with a few adjustments here and there. Everything was built completely from scratch except the beacon light on top and the 4-point racing harness. Total time spent building: about 180 hours over the course of 10 weeks.
I am missing photos for a few steps (like the wiring) but the comments I received on my Slideshow convinced me this should still be a full instructable.
To see a clip of the loader in action:
UPDATE: G4's Attack of the Show gave a nice little shout out to the costume and the instructable! (jump to 1:20)
Step 1: The Foot
A 1x6 piece was attached on top of the foot and the lower foot is shaped with 1/2" foam insulation and 1/8" Lauan . The lauan paneling is light, and pretty cheap, and it adds a lot of rigidity to the foam. All the foam was cut with a hot wire tool I got from a craft store and then sanded smooth.
Step 2: The Lower Leg
The lower leg was formed from lauan panels with foam attached for extra detail. The clamps are holding the foam pieces on the back of the leg. You can also see the gaps in the foot have been filled with caulk.
Then the lower leg was primed and spray painted. Foam disks were cut, shaped, and painted to be used for all the joints. They are not highly detailed, but they look convincing when it was all done.
Step 3: The Upper Leg
Step 4: Adding Lower Leg Details
Sintra sheet was used for the leg guard/grill and for two disks (painted silver) to separate the upper and lower leg to allow the knee to move easily.
The leg padding is pipe insulation cut in half. The foot tread is a chunk cut from an auto rubber floor mat.
Step 5: Finishing the Leg
Padding was added to upper leg, again from pipe insulation cut in half. A black piece of fabric runs between the back of the upper and lower leg.
Step 6: Adding Cylinders to the Leg
The upper tube is a piece of PVC covered with foil duct tape. The lower tube is a thick cardboard tube, covered with contact paper (for smoothness), then painted. The end mounts were formed from Sintra and glued on.
The same components would be used later for the arm cylinders.
Step 7: One more time!
I actually made paper templates of all the large foam and lauan pieces before making the first leg. Using these templates for each leg ensured they'd come out identical. Later, I did the same thing by making templates for the arms and grabbers.
Step 8: The Operator Cage
Later a strip of electroluminescent tape would circle part of the cage to light the operator's face (you can see this best in the youtube video).
Step 9: The Body
Lauan was added for the sides of the main body, but only a sheet of foam in the back. This means I wouldn't be attaching the very large arm cylinders in the back as a weight savings measure.
Some 1x3 lumber goes around the top of the body to add the support needed for the arms. Small blocks are also used to support the mounts were the head section will pivot.
Step 10: The Head
Step 11: Attaching the Harness, Beacon
The amber beacon light was also mounted on top. The light originally used a high-intensity halogen 12V bulb, but wanting to use a small, light battery, I replaced the bulb with two yellow LEDs and ran those and the motor off a 9 volt battery.
I shortened the "beaver tail" feature in the back where all the hoses are supposed to attach. This made it easier to set down and easier to navigated a crowded party. From the back angle you can see how the head section mounts to the main body. There is a piece of threaded rod running across with an aluminum tube covering it.
With the harness attached, it was finally time for "Ripley" to take an early test drive!
Step 12: The Arms
Also at this point the grabber/hands are coming along nicely toward the right of the first photo.
The arms were completed, primed, and then painted. The upper arm is below and the lower arm on top of the second photo.
Toward the right of the third photo you see a wrist joint on the lower arm. This is just a rigid, faked joint so that the grabber wouldn't flop around too much. A portion of a plastic bottle was use for the round cylinder sides of the wrist.
Step 13: Shoulder Joints
Step 14: The Grabber
The second photo shows the finished thing. The grabbers swivel 360 degrees and pinch together.To pinch, they slide along two aluminum tubes, so they can be positioned open, closed, or anywhere in between. Unfortunately I didn't have time to perfect the mechanics to power that (mostly I started running out of time), so I left the motors out and left them to be positioned by hand.
Step 15: Wiring and Final Assembly
The second photo shows how the cage lifts so the operator can get in.