“Our Pilgrimage proves we are willing to give of ourselves for the greater good. What does it say about me if I turn my back on this?”
Tali'Zorah nar Rayya is a quarian and a member of Commander Shepard's squad. She is the daughter of Rael'Zorah, a member of the Admiralty Board. Though young, Tali is a mechanical genius.
Tali was an "out of left field" commission that I was hoping someone would hire me to build. I've always loved the look of that character, and it turned out to be an interesting and challenging task.
First, using the measurements supplied by the client, I had to produce a set of 3d blueprints to properly set the scale and fit of the helmet. Quarians wear these helmets for their entire lives to protect them against the germs and contaminants of the outside world. Coupled with their exaggeratedly svelte physiques, a sleek form-fitting helmet was crucial to capturing the overall tone and style of the character.
The 3d model was produced in 3dsMax with the help of my friend CGJeff (www.cgjeff.com), and the CAD work was all done in Rhino. I aligned the model over a custom head form from Poser6 to check the fit, tolerances, and overall shape of the form.
|Left - In-game model. Right - High poly remodel|
Once the digital model was properly scaled and positioned, I then developed basic tooling strategies for the shape using a powerful set of CAM software. Once the code is generated, it was then sent to a robotic CnC mill to be routed out of high density tooling foam. This was a 15lb density urethane foam that cut very nicely, and would be a great material for prototyping things by hand if you didn't have a robot to do it for you.
This is a sample of the foam used in this project, and the first prototype of the helmet. In this version the visor was to be removable, but this was later scrapped. The fit up between the face mask and the rest of the helmet looked much better when it was seamed up as a one-piece assembly.
After the parts came off the mill, I epoxy'ed them together using Loctite 5 min epoxy. Found at any large hardware store, this is a great adhesive agent for a wide variety of materials. Once assembled, the model got a generous coat of primer and spot putty to even out any rough spots.
This helmet ended up being version 5.0. In the first couple tries, the visor was left out of the master model and caused several issues with alignment when all the pieces came back together after molding. By cutting, molding, and casting everything as a single piece, you can be sure all the parts will line back up when all is said and done.
Based on this piece of fan art that the client really liked, Tali looks like she has a glass bubble piece on the mouth assembly. This part was made by taking a mold from a vacuum-formed 1" half dome, molded, then casting in a clear laminating resin. I don't currently have the ability to pressure cast parts, so I'm still fighting these frustrating little bubbles that occur when mixing.
After several arduous weeks of sanding and frustration with failed designs, I finally had a prop that was ready to be scrap molded. Normally I would polish the master copy to perfection before molding, but the tooling foam I used really limited the razor edge I could get on these parts. Once it was cast in a more durable material like SmoothCast300, I could go back and do a final wet sanding and clean up any soft spots that were still present.
Here are the scrap molds that I produced for a "clean up" copy of the Tali helmet. I've never used OOMOO silicone from Smooth-On before, so what better time than the present for a little experimentation. Now while this product may be just fine for pour molds, or parts with few undercuts and shallow draft angles, it's probably not the best silicone to use for a mold that will see a lot of castings. After pulling three of these helmets I could already see signs of tears and weak spots in the mold, but this was no problem as I only needed one fantastic pull to continue the project.
I was in IKEA a couple months back and found THE perfect icecube tray for casting registration keys. They are the dainty blue flowers that encircle the helmet.
A mold making trick I picked up recently was to create a "nest" for your part out of insulation foam, then build the mold wall like you normally would. This will save on clay, and keep your part from shifting while you brush on your silicone. As for the parting wall, I used a basic WED clay that can be found at any local pottery supply store.
For low viscosity silicones it's not a bad idea to put on at least two beauty coats before layering it up thick.
I had a pretty good idea OOMOO was going to be weaker than the other silicones I've used in the past, so I made sure to really get a good thick coat on both sides before applying the mother mold. OOMOO doesn't react to thixotropic agents, so Cab-o-Sil was used to thicken the material and keep it from running off the part and into a puddle of the floor.
Well, it looks as though I got a little ahead of myself and didn't take any pictures of the mother mold. For this gal I used a modified gypsum casting system called Forton-MG. It's basically just Hydrocal with an extra dry resin hardener and a acrylic latex liquid component. When reinforced with chopped strand fiberglass, the shells become nearly indestructible. Smashing up old jackets to fit in the dumpster becomes a workout in itself.
This was the first cast out of the scrap mold using tinted Smooth-Cast 300. The seams were fairly crisp, so finishing up with sanding, chopping out the visor, and painting was not going to be too much more work.
Once I was sure that I had a solid master copy from the scrap mold, I went about hacking up the CNC cut foam original to make a vacuum-form buck for the visor. Again, I apologize for the lack of photos, but here is what I came up with after molding and casting the visor portion in SC-300. By alternating colors when pouring layers, when you go back to sand the form you're more able to accurately judge the depth of the sanding. This helps to keep an even and uniform surface when working on something as delicate as a visor surface.
After forming a very thin sheet of styrene over the buck to seal it and even out any tiny flaws, I pulled several copies of the visor in .125" PETG. The results were very promising!
Back on the main part of the helmet, after preliminary sanding and dremeling out the visor area, I mocked up the helmet with a scrap vacuum-form pull and the "mouth puck" to see where we were. The original idea was to have a removable visor held to the helmet with neodymium magnets so that the client could pop it on and off for alternative photos. Turns out, with the way that this visor seats inside the helmet, being able to remove it while keeping a tight seam along the junction between the two was near impossible. We would have hand to go about hacking up a lot more of the helmet to add this functionality, and in the end we scrapped that feature and focused on preserving the aesthetic quality of the build.
To keep the seam between the visor and helmet flawless I first tacked the visor into place with superglue. Even though the buck that they were pulled from was molded off of the original milled piece, there were still issues with the fit. To remedy this, I filled any gaps with bondo and then sanded things down smoothly. This shot was a test of this method using a flawed vacuum pull.
The end was drawing near! At this point, most all of the parts had been assembled and hit with a layer or two of high build filling primer. This phase of fabrication can take as little as a day, or as long as a year depending on how OCD you get about every nook and cranny. The light smudging around the edge of the visor you see was the chemical etching the bondo did while seaming. Gradually polishing this down then torch smoothing the surface was a nightmare that could have been prevented by simply masking the visor with painters tape before installing it. When working with delicate optically clear materials, always be sure to protect the part from scratches and exposure to chemical contaminates. You'll definitely thank yourself later.
Now all that was left to do was install the back skull section, and paint! I found a phenomenal "brush steel wheel coating" enamel at Advance Auto Parts that really made the basecoat of this helmet pop. It has a little too much sparkly flake in it for my tastes, but once you start weathering and highlighting it dulls into a classy metallic sheen. I've never been great at painting, and would consider my detailing and weathering to be a bit heavy handed at best. Regardless, I am fairly pleased with how the final aesthetic turned out and certainly learned a lot about how I would improve upon the method for next time.
But enough talk, on to the final shots!
The back is held on with elastic banding at the pivot, and 2 sets of neodymium magnets below the ear.
After wearing this around for 5 minutes, it became very clear that a vent at the bottom was needed. This was a simple matter of zipping out a rectangular port, and super gluing in piece of mesh screen.
If you'd like to see more pictures from this build, check out my facebook page - www.facebook.com/jarmanprops, or head over to flickr - www.flickr.com/yodajammies
Thanks for reading!