Sierra One Starfleet uniform from Star Trek Online

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New Member
Hi everyone - I'm new to fan costumes / cosplay, especially for Star Trek, so I'd like to seek some advice.

I've been thinking about getting a costume made to wear at conventions / parties in the future - however, the design I'm interested in is from the Star Trek Online MMO soft-canon rather than from the TV series/feature films:


Away with the questions:

- What is the Trek fan community attitude towards soft-canon costumes, in general?

- I know that CosplaySky makes and sells a version of the design shown, but based on the photos and user reviews, I find the quality to be extremely lacking (especially in the cuts, sewing and material selection, which looks amateurish compared with canon costumes). What are people's thoughts?

- I also considered signing up for the 1701st Starfleet Uniform Club forums, but activity there seems to be sparse and mainly focused on canon uniforms (not to mention then garish color scheme of the website)

- Because STO's storyline is set in the early 25th Century, depicting a re-militarization of Starfleet, the uniforms have become more rugged-looking. I'm trying to figure out what types of fabric to use (Cordura? Ripstop? Ballistic Nylon), but I want to balance this ruggedness with the desire to make the costume feel like a logical evolution from canon uniforms.

I can provide more reference images / conceptual artwork on request.

Comments and critiques would be appreciated.

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Well-Known Member
Hi Sumghai!

Sounds like a fun project!

I have worn non-canon stuff before, and if they can recognize what you're tryining to do, the community seems to be pretty tolerant.

The 1701st is mostly focused on canon outfits, but they do have a thread just for 'conceptual' uniforms, and people do post there. They are a good resource.

I am not a fan of any of the cosplay sky stuff I've seen (in photos) I suggest the hardcore DIY method!

Good luck, I look forward to seeing what you come up with!
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New Member
Yeah, I'm strongly tempted to lean towards DIY myself, although I have no experience in sewing/clothes making.

Looking at Cryptic Studios' official wallpaper chronicling Starfleet uniforms through the ages, I've noted that the actual 2409 Sierra uniform in-game consists of the jacket in the box art and baggy trousers tucked into knee-high boots:


While I found the ruggedness of the Sierra jacket to be attractive, I didn't like the trousers and boost so much, since they envoke more "gung-ho Starfleet Marine" than "Starfleet officers as astute diplomats first and reluctant soldiers second". Conversely, I liked the straight-legged (and split-bottomed?) trousers seen throughout DS9 / VOY, as they were utilitarian whilst looking fairly professional.

Interestingly, the Star Trek: Countdown tie-in comic for the 2009 Star Trek film features a simplified version of Sierra with the aforementioned straight-legged trousers:


In light of this, I did some conceptual art showing my final, desired combination of the STO Sierra jacket with the Countdown trousers (far left):
(Cropped from something I previously posted on deviantArt)

Does that look okay to you guys?


New Member
To start off, I'll be looking at the combadges and rank pips. These will be made via metal cold casting, and secured to the costume with rare-earth magnets to avoid damaging the fabric with pin holes.

In Star Trek Online, the Sierra uniform devices have a brass/gold-like appearance. Rank pips are rendered as beveled parallelograms, while the badges have the iconic Starfleet delta shape inset into a slightly-raised border and the departmental symbol engraved in the center:


Of course, those familiar with the game may be wondering "But sumghai, there's a badge that's included with the limited Collector's Edition of the game. Why don't you just use that?". That's because, being limited edition badges, they're not in the marketplace anymore - besides, I also want to make variants for the different Starfleet departments.

So I knocked these together in SolidWorks:

From left to right, we have:
  • Plain - Worn by civilian consultants or (according to in-game lore) Starfleet Intelligence
  • Tactical - Worn by those in the Command, Tactical or Security departments (STO uses red uniforms for security guards instead of gold)
  • Engineering - Worn by those in the Engineering or Operations departments
  • Science - Worn by those in the Science or Medical departments

The limited edition badges are 2.25" high, but I'll be going for dimensions of 2.50 x 1.67 x 0.23" instead. I also will need to cut some cavities at the back to glue magnets in, which I'll discuss in a future post.

Next up were the rank pips, and apart from their parallelogram shape, actually follows the half-pip/full-pip precedence set in The Next Generation. The pips are 0.625" high, 0.42" at the top/bottom edges, and 2.5mm thick. The parallelogram is slanted at 60 degrees:

While I was working on these, some people over on /r/sto admonished me for not also doing pips for the new Odyssey uniform standard, and so I obliged. Unlike the Sierra pips, the Odyssey ones are silver vertical bars worn on the right collar similar to the TNG pips, 0.625" high, 0.3125" wide and 2.5mm thick. The backing piece is also curved rather than flat:

Next Steps
- Design the backing strip for the combadges themselves
- Determine what size/shape magnets to use and in what arrangement
- Determine what metal powder-to-resin ratio would produce the desired lustre and sheen in brass (Sierra) and aluminium (Odyssey)


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New Member
Despite the lack of interest / feedback so far, I suppose I'll keep on posting these updates.

As mentioned previously, I will be using magnets to secure the badges and pips to uniforms, rather than safety pins or velcro squares like in the actual TV series. One of my goals is to devise a way for a combadge to be removed and reaffixed onto a person's chest without requiring awkward fiddling and double-checking in the mirror.

Steve Maxwell from K&J Magnetics pointed out to me that a pair of neodymium disc magnets of the same dimensions and grade will (very reliably) attract center to center, practically eliminating positional misalignments. I thus reasoned that two pairs (four total) would additionally eliminate rotational misalignment as well.

So here's a CAD rendering of the backing strip for the combadges, with pockets cut out where disc magnets will go:

The nominal magnet sizes I will thus be using in this project are:

- 1/2" dia x 1/16 thick discs for combadges
- 1/4" dia x 1/16 thick discs for the 2409 parallelogram pips
- 1/2" x 3/16" x 1/16" blocks for the 2413 rectangular pips

Now, as for the question of what ratio of metal powder to resin to use, to get an actual metal-like effect:
- I asked a few esteemed RFPers with prior experience in cold cast metal props, but never heard back from them
- Smooth-On suggested 1 metal : 1 resin part A : 1 resin part B
- Other crafting websites / suppliers suggested 2 metal : 1 resin part A : 1 resin part B instead

Given that my parts are small and have tight areas, I would ideally want the resulting mixture to be as low viscosity as possible, but I figured I'd take a leap of faith and go for 2:1:1, since the actual item volumes are each less than 5 cm3. If I was making larger items, say a plaque, I'd probably have used the 2:1:1 as the surface gel coat, and backfilled it with plain resin instead.

Next Steps
- Getting the positive master mold made
- Getting the casting supplies

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New Member
So here's a quick rundown of the process I will be using to cast the badges and pips:

  1. Master molds are made via CNC Milling or 3D Printing
  2. Negative "daughter" molds are cast from the masters with flexible RTV silicone rubber
  3. The final items are cast from the silicone "daughters" with a mix of polyurethane resin and metal powder, then trimmed to remove sprues and excess flashing

The "daughter" molds can be reused several times before wearing out, at which point replacements can be re-cast from the master.

For my first attempt at making master molds, I turned to 3D printing via an online 3D printing service platform, which put me in touch with a local printer.

Unfortunately, despite the promises of the printer, the prints turned out quite poorly - any of the pins for the sprue lines snapped due to poor packaging, and the coarse texture of the prints completely obliterated the desired surface details of the items (such as the shallow chamfer on the pips). The printer was also meatheaded enough to put the wrong recipient name on the parcel, and then blame me for "changing my requirements" when I pointed out the quality issues.

In the end, the online 3D printing service ruled in my favor and gave me a full refund, so the exercise wasn't a complete loss. That being said, I will never be using that printing service again, and certainly not with that printer.

P.S. - The print on the top right was treated with acetone vapor polishing, which due to the meathead's inepitude, did not mitigate any of the issues.

Next Steps
- Getting the master molds made via an alternative method


New Member
So it's been a looong time since I last visited this project! After relocating because of a career change, I finally made some real progress.

I managed to get my hands on a Nomad 883 Pro Desktop CNC mill by Carbide 3D. This meant I could now machine higher-quality master molds myself, instead of engaging the services of a machine shop, who generally aren't interested in small one-off projects anyway.

Here, I'm roughing one of the combadge masters out of Renshape, a medium density polyurethane tooling board more commonly used to make fibreglass mold plugs. I invested in a small collection of various solid carbide endmills, including some micro endmills with extra long reach to get all the fine details and deep features.


The completed master molds, coated with acrylic clear gloss paint to seal the pores in the Renshape.


Closeup of the Command combadge master mold.


Closeup of the 2409 Pips master mold. Note the smooth chamfers and radii in the pips, as well as the crisp recesses in the half-pips.


The daughter molds were made from Smooth-On Mold Star 30 RTV silicone rubber, which has a mix ratio of 1:1 A:B by volume.


Silicone mold casting in progress.

Mold Star 30 generally does not need degassing, but I would pour the mixed silicone into the mold as a very thin stream to break up any air bubbles. I also periodically sloshed the silicone around to coat the mold surface evenly.


The cured silicone rubber daughter molds. The white spots on a few of the molds was a goof-up on my part - towards the end of a tub, I didn't mix/scrape the bottom properly. That said, they seemed to have cured properly anyway.


For my first resin casting trial, I chose to start off with the combadge backing piece.

I sprayed some Mann Ease Release 200 release agent, brushed it gently over the entire mold surface to ensure an even coat, then left it for five minutes before hitting the mold again with a second mist coat.


For resin casting, I'm using Smooth-On's Smooth-Cast 325, tinted with a couple of drops of So-Strong Black tint. Smooth-Cast 325 has a very short pot life (2~3 minutes), so one has to mix and pour very quickly.


A syringe helps make depositing mixed resin easier.


To improve the final strength of the casting, it needs to be post-cured around 150°F / 65°C for a few hours. As I do not have a proper lab drying oven (and I'm not keen on using my kitchen oven, either), I cobbled together a ghetto hotbox out of a simple wooden enclosure with an old incandescent light bulb.


My first resin part!

A few minor dimples and a slight orange peel finish, but since this backing piece will be hidden inside a costume, this isn't a major issue.


Casting the 2409 and 2410 pip backing pieces.

The 2410 pip backing is a two-part mold, so I held the mold halves together with some scrap acrylic and rubber bands. In hindsight, I should probably have covered the one-part 2409 pip backing mold with a weighted polypropylene sheet to ensure a crisp flat rear surface.


Demolded combadge and pip backings, with sprues and flashing not yet removed.


For the 2409 Combadges, I'm using Smooth-On's 325 mesh brass powder. The mesh size is quite important because the powder needs to dispense properly in the resin, and fine powders would give better finishes once polished.

To further improve the surface finish, I dusted the mold with brass powder, tipping out the excess for reuse.


Working with metal powders is no laughing matter - they are classified as eye and respiratory irritants, so invest in a good pair of safety goggles and respirators with the proper dust filters.

Also, make sure to change your filter cartridges regularly as per local ordinances - in New Zealand, it is six months from when cartridge is first removed from its packaging (according to WorkSafe regulations).


In this test, I'm using a 1:1:1 volume ratio of Smooth-Cast 325 Part A : Part B : Brass Powder. I'm also adding a little So-Strong Brown tint, as some folks on here claimed this would give better definition to my castings.

The trick here is to mix the metal powder with the Part B first, and allow air bubbles to come out first before adding the Part A - once the cold cast resin is fully mixed, you only have a short time before it starts to gel and become difficult to work with.


This is where I dun goofed.

Originally, I estimated the volume of resin and powder required based on the volume calculations of the mold cavity in SolidWorks, plus a little bit of tolerance for material left behind in the mixing container. While injecting the mold, however, I thought I didn't mix enough cold cast resin, and so in my panic, I declared this as a short "shot", and didn't weigh the mold down. Around ten minutes later, the resin already in the mold started to expand a little, filling up the rest of the mold.


Demolding my first (trial) cold cast.

The dull mustard-like appearance is expected, as the resin has seeped into the dusted brass powdered mold surface, which we can polish later.


Back of the trial cold cast, showing how the mold halves were pushed apart by the expanding resin.


I gently buffed the casting with some 0000 grade steel wool, followed by a rag soaked in Brasso metal polish. The metal lustre of the dusted brass powder came out, but the brown tint made the casting a shade too dark, giving it a somewhat aged brass appearance.


With this knowledge, my second attempt was far more successful, and closer to the desired appearance of the final product.

Left: Second attempt with untinted cold cast resin
Right: First attempt with So-Strong Brown-tinted cold cast resin


Going forward, I won't need to tint my cold cast resin pieces for this project.

I've cast a few more items since then, and I'll post photos of them here once they're ready.
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New Member
I had pretty much all of the badges and pips cast and polished shortly after my previous post, but it wasn't until the last couple of weeks that the weather in Auckland finally stopped being so humid, that I was able to finally finish painting the half-pips.

So here's the complete set of Brass 2409 and Aluminium 2410 badges and pips:



The finish is more satin than the glossy mirror of licensed TNG/DS9/VOY combadge reproductions, but I feel it fits better with the utilitarian look of the Star Trek Online uniforms. The recess inside the half-pip (bottom right) was sanded lightly, primed and coated with black satin automotive paint. Once dried, I then rubbed a little Brasso to clean it up.


To glue the magnets to the badges and pips, I used some two-party epoxy adhesive. I quickly scribbled a cheat sheet to remind myself which orientation the magnets go for each badge and pip, so that they would remain compatible with any replacements I make in the future.

Also, I found that laying the magnets on a ruler makes it easier to knoll (arrange) them while keeping them separate.


Neodymium magnets typically come with a nickel coating for protection, so to make sure that the epoxy firmly sticks to the magnet itself, I scratched up the glue side with a file.


The magnets glued into the castings.

For those wondering why the bar magnets are smaller than the cavities I cut in the 2410 pips and backing, this is because I designed the badges and pips based on Imperial magnet sizes to make it easier for Americans to find replacement magnets, but only metric sizes were available in New Zealand - NZ Customs has now banned the import of buckyballs and buckycubes desk toys, and have heavily restricted all neodymium magnets to "industrial applications" only.

Also, the small circles on the back of the combadge where the resin had foamed up were the aforementioned sprue marks that have been sanded down. If I make more of these in the future, I'll probably pick a less humid day to cast them (and invest in a pressure pot).


Captain on the Bridge!


I didn't have a proper turtleneck shirt for the 2410 uniform, so I had to improvise with a couple of clothespegs ;)

Now that the badges are done, I'd better get back to the next piece of my costume - a Stapleton Nemesis phaser.
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