3D Print an Articulated Warhammer 40k Power Fist




Introduction: 3D Print an Articulated Warhammer 40k Power Fist

Last year, I made a Crimson Fist Space Marine Costume. Everyone really seemed to like it, you can find the instructable I made outlining the costume's creation here: Gary Sterley's 40k Space Marine

While the feedback on the costume has been awesome, the most popular feature, by far, is the articulated Power Fist prop. A lot of effort went into that piece. It gets a great deal of attention and generates many questions. I have been asked numerous times to do a stand-alone instructable on it's creation, and inner workings, so here it is!

The following is a detailed step by step of the creation process behind my articulated Warhammer 40k Power Fist. WITH VIDEO! I made a video diary documenting my progress on this piece. I will post a link to a video in each section.

Step 1: A Plan of Attack

Inspiration struck me after seeing a super talented fella by the name of Henrik Pilerud, make his own Power Fist. You can find his facebook page HERE. Henrik is a huge inspiration for me and my build, and a swell guy in general. Keep up the good work fella.

Henrick made his powerfist out of foam. It looks great, but after some thought, I decided to take things in another direction. Foam is a great medium, but things like wall thickness, and a lack of real structural stability make it difficult to creating mechanical parts with it. I simply could not fathom a way to create a working foam finger that would be durable, and stay as close to the game model as I had envisioned. My wife had recently bought me a Solidoodle2 3D-printer for Christmas, and I was actively looking for projects make with my new toy. I fixed it in my mind that the working parts would be made from 3D printed plastic and got to sketching. this took a few days of deep thinking and planning, but in general, below is a list of what I was hoping to accomplish.

My goals:
-stay as close to the game models as possible
-make all fingers articulate, realistically.
-all pieces must fit together without the use of visible hardware (see goal 1)

Step 2: Become a 3D Designer (kinda)

Now that I had an the kinks worked out (at least it made sense in my head) I needed to transform my 2D scribblings into a 3D model that my printer could both understand, and produce. My experience with my printer thus far had taught me that those two concepts are not mutually exclusive in the world of 3D printing.

I have NO BACKGROUND in 3D modeling. So, I had some learning to do. Up until this point, my 3D prints were all things downloaded from thingiverse. Now, I needed to build a 3D model from scratch, one with multiple moving parts, no less.

For this process I used Google Sketchup. There are MANY modeling softwares out there, but this program is free, and relatively simple to learn. Two very important factors. My background in graphic design might have helped me to some degree, but the modeling process was a SLOW one, filled with mistakes and revisions to my original plan. But after numerous version numbers and countless hours, I had what I thought was a solid design.

My design consisted of 3 segments per finger. Each segment would snap inside of the previous segment and terminate at the fingertip. No hardware needed. Along the spine of each finger would be a taught elastic band that would hold the finger straight. This band would be held in place by rings built into the interior of each finger. Along the belly of the finger would be a pull-string that would be tied to my digits. By pulling these strings the Power Fist's fingers would curl over, and fold in on themselves thanks to some clever design work. It is also worth noting that all the fingers are identical. I simply scaled each one to created the different sizes of each finger. Work smarter, not harder, eh?

I exported my STL files and fired up the printer.

Step 3: 3D Print, Scrap It, Start Again.

Satisfied with my design and confident all the joints would fit together and move freely. I began printing.

After a while...a long while... I had one finger printed. It was complete enough that I could begin testing. The tests were mostly successful, but I did run into trouble. As it turns out, weight became a big issue. My test rig taught me that the elastic bands just weren't enough to support the weight of the fingers.

This was a big setback. The flaw was in my 3D model so I had to go back into design mode and gut my design. Again, this was a LONG process. I spent more time modeling this thing than I did in any other one step in my costumes creation, by far. Did I mention I am not a 3D Modeler?

To correct the issue, I did two things. First, I broke each finger segment into 4 separate panels that could be printed flat, and assembled after printing. Second, I stole some inspiration from nature and modeled each panel after insect wings. Each panel is printed flat, and has a thin outer skin. The skin is roughly 3-4 layers thick. Then I added support ribs throughout the panel to give it strength. Notches and registration marks were added to make certain the panels align as intended during assembly. and all the necessary guides for the cables were also printed integral in each panel.

Next step: 3D print....Again.


Step 4: 3D Print... Again.

Lessons learned, improvements made, I set out to 3D print yet again.

This time around, things went better during testing. The weight reduction was very successful. I was able to save around 40% in the weight department and I do not believe I sacrificed much at all in durability.

Satisfied with testing I did on a single finger, I set my printer loose on the remaining pieces. My printer is NOT fast. I believe the whole thing took my machine around 48 hours of print time. I was still working on the rest of the Space Marine costume though, so I had plenty to keep me busy while I waited.

After a few days, All my pieces were printed and I could assemble my Power Fist.




Since I am printing in ABS plastic, I used acetone to bond all the panels together. This created a chemical weld, way better than glue in my book. But for god's sake....use a respirator kids, those vapors are nasty.

One by one, all my segments were printer. I was able to run both my elastic bands and pull strings through the interior of the digits, and then snap all the fingers together. During this time I made improvements the the forearm mount. This was made from 1/4" ABS plastic sheets. That I heated and bent around my arm. Foam padding was added, as well and velcro straps to snug it down onto my arm. It was finally a wearable prop!

Now it was time to add the foam body, embellish, and paint!


Step 6: Body Work

The Power Fist was functional, and I was able to strap it to myself, but I still needed to create it's body.

For this I used to same foam the rest of my Power Armor was made from. With the help of some pictures taken by my man Henrik, I made a pattern and scaled it to size. Once It was hot glued into shape, I did a test fit with the upper torso of my suit.

Well please with myself (LOL) I began adding the pal panels and decoration to the body of the Power Fist. The decorations consist of a halloween skull, Wings cut from foam, some grimdark latin lettering and a few rivets (also made of foam).

NOW I had something looking very much like a Warhammer 40K Power Fist and it was time to throw some paint at it.


Step 7: Paint Work

Body work complete, it's time for paint. Since I am a Crimson Fist, the power fist needs to be...you guessed it... crimson! Of course it's not as simple as just painting it red. First disassemble, then it's paint time.

All of my foam seams were smoother over with latex caulk. This hides the seams. Foam cannot be painted with aerosol spray paint. The surface of the foam will melt if you do this. To prevent this melting from happening, you must first seal the foam. You can use something as simple as Elmer's glue as a sealant. I used Plasti-dip, a rubber spray, on all of my foam surfaces. this will protect the foam from the chemicals in the spray paint.

After a few coats of Plasti-dip, the foma is ready for a base color. For this I used a dark red krylon fusion. the finger are also painted this color, only they do not need the Plasti-dip. After my base dries, I apply a bright red highlight to the edges and high-wear surfaces to give them some pop. Once that is dry, it's time for detail painting.

The wings and skull get airbrushed in a slew of shades. Browns for the wings, and whites/grays for the skull. Layer, layer, layer until you get some good depth. All the text and rivets were hand painted with some gold acrylic model paint. After that, while you still have the airbrush handy, add some dark shadows ad grime to corners, crack, crevices and any weathering you added. For a final touch, drybrush silver into the scratches and edges of the piece to make it look like its seen some heavy use.

Voila! Time to smash some skulls!


Step 8: Smite Your Enemies!

Now you can enjoy the fruits of your labor! You should have a fully articulated Power Fist to crunch people's melons with, or fist bump as you see fit.

While this was only one piece in a larger project, it was by far the most complicated, and time consuming thing I have built to date. That said, it was a great learning experience and I'm super happy with how it turned out. I'm still no expert in 3D, but I am working on it, and building on my experience. I'll definitely be printing more projects in the future. Never stop learning ;P

Thanks for reading!!!


RPF build thread (power fist starts on page 11): Space Marine Build
My Facebook: Gary Sterley Studios
My YouTube: Gary Sterley on YouTube
My Etsy Store (Power Fist STL Files are Available): Store

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    36 Discussions

    Awesome build and I was hoping that you would post this part too. Thank you for you effort and documentation on this.

    Lightning claws next?

    2 replies

    this is very epic and i agree with naustghoul, 10/10 for design,paint, and construction! i don't have a 3D printer, however and i have no clue how to do the articulated power fist with out one. how would i do it without one???

    ooh it makes me want to purge heresy in the name of the god emperor

    Do you have a PDF file for the foam wrist/body

    I dont suppose youd be willing to share the STL files for it, to save a guy some time would you?

    I was wondering if I could do this with cardboard would that be suitable for the project?

    WOW this Is Sick Amazing!!! Awesome Build

    this is owsem I am going to try this.

    this is so cool, amazing work there and idea!

    This is incredible. Thanks for sharing your process. It came out great

    This is absolutely epic. Nice job on everything. I think that, given the popularity and availability of 3D printers, everyone should be learning at least a little 3D modeling. It needs to become a standard class in high-school. I sure wish I was taught while growing up.

    3 replies

    They were just introducing electric typewriters when I was in high school. I am now trying to understand why some printers have a hot plate and some don't. I will have to learn more before I buy.

    I know the feeling! My class was the first class in our school to get to learn typing on electric word processors. I'm very thankful we at least learned that, as I use it every day of my life.

    The plastic tends to cool from the outside in. If the temperature difference is too great during cooling, the part starts to warp. A heated build platform helps even out the temperature of the part, and should help warping, and perhaps adhesion to the build platform.

    Mileage may vary though. In my experience, 3D printers have something of a personality. What works best on one, may not be best practice on another.

    This is really awesome! I hope you win dude!

    Freaking sweet. I followed your build over on the RPF (followed your Sith Stalker which is awesome as well and I'm currently working on that helmet) and the whole thing blows my mind. Definitely voted. Congratulations on the feature and good luck in the contest.