After 3 years of planning, I finally built a 13' T-Rex costume. It is based on an aluminum backpack with an aluminum neck linkage setup for full neck and head motion. It incorporates cable control for mouth chomp. The entire body is L200 closed cell foam with a layer of open cell foam to form the textured skin. All skin detail was done with modified Dremel tools and soldering irons. It weights roughly 50-60lbs I'd estimate.
Step 1: Source Material
I researched a lot of online videos, Chinese manufacturers and photos. Lots of screen shots of the neck linkages in particular which was very difficult to nail.
Step 2: Aluminum Substructure
One of the most critical components of this build was simply the rack upon which the costume was built. It made it so easy to roll out into the driveway, lock the wheels, spray a gallon of paint, and then roll it back into the garage to dry. You can't tackle this without one.
I took collapsible hinges from Amazon and attached them to the aluminum backpack. I ran heavy gauge L-bar aluminum forward and connected it with a scrap of steel tubing. This formed the main mounting structure.
Next the neck was fabricated using Rod Ends, aluminum round rod, and other metal stock. If you're trying to build this, the best thing you can do is decypher the photos for the rough geometry. These were the key parts that made so much motion possible on multiple axis.
I then mounted a backup camera system since I knew there was no other way I would be able to see. THIS WAS THE BEST PURCHASE OF THE ENTIRE BUILD!!!! Able to navigate pretty easily even in a night club with zero external view holes.
I powered mine via a portable laptop charger that has a 12 volt output.
You can also add cooling fans which are powered off the same battery pack
Step 3: Pattern Making
I drew a simple silhouette of the shape I wanted. You will trace the profile onto L200 (cross linked polyethylene foam) foam twice. Add marks down each edge so that you can align the two pieces (pulling tension to achieve curves). Combining two pieces will result in forming the body from the spine down about 2/3rds down the side. You will then cut a wide strip that forms the belly. This is repeated for the tail section. The process of foam fabrication is complex and I recommend following Evil Ted on YouTube and buying a membership to Stan Winston School. All the techniques used have taken me 6 years to master and hours of videos.
Step 4: Foam Fabrication (project, Trace, Cut, Glue)
Then came the main portion of the project.
Step 5: Adding Texture
Lots of texture added with a mix of soldering irons with various tips, dremel sanding wheels which have the grit extended past the tip to cut perfect circles into the surface, and lots of razor blade trimming.
Step 6: Zipper Closure
I glued in a zipper on both the chest and tail to allow me to get it off the rack and put it on easier. Available on amazon
Step 7: Paint
I painted with a glue based sealer (Rosco Flexbond) to stop the open cell foam from functioning as a sponge. If you do not do this step you'll spray gallons of paint, it will stay porous, and it will never dry. GIVE IT TIME TO DRY CLEAR. Then I shot multiple light layers of various shades of Sherwin Williams acrylic. I highly recommend this specific brand since they use a very high acrylic content so you seem to get more flex and less cracking.
Step 8: Hands and Tongue
I took dish washing gloves, cut the sides of the fingers and applied superglue to combine the digits. L200 was sanded into nails and glued using Barge contact cement. Finally liquid latex was tinted with the same acrylic paint used for the body and applied in thin coats.