Warhammer Mark Vb Godwyn Pattern Bolter Prop for Cosplay

Warhammer Bolter Project Introduction

0.75 caliber Astartes Mark Vb Godwyn Pattern Bolter
Astartes Mark Vb Godwyn Pattern Bolter

Here is the chronicle of the 0.75 caliber Astartes Mark Vb Godwyn Pattern Bolter construction. Want one of your own? Contact me or check out my Etsy store. Also selling resin casts of purity seals.

As part of the The PropTarts of Punished Props Facebook Group, I decided to join their Secret Santa event. You get matched up with someone who wants a gift to be made for them. My recipient wanted a Bolter from Warhammer 40,000K.

Built primarily out of EVA foam with 3D printed (ABS+) grip, muzzle, laser site, Aquila emblem and some accents, and some foam clay. The 3D printed grip means your power armor can get a firm grasp without damage. It is affixed to the bolter with a short aluminium rod.

The foam is sealed with Rosco FlexBond and the whole bolter painted with acrylic paints. Since my airbrush does not like to spray clearcoats, only the magazine has had any form of clear coat.

The magazine is friction fit and should hold small items such as cash/keys/card, or snacks, or other small personal effects of choice.

Designing and Templating Astartes Mark Vb Godwyn Pattern Bolter

I actually used the nice 3D model produced by Jaiman Bhardwaj and turned the design into a template I printed on cardstock, since this was going to be largely a foam construction.

My 3D design skills are limited so I put the Bolter into Tinkercad to cut out the pieces I wanted to 3D print. I decided that 3D printing the muzzle, laser sight and other round parts for example would give a better result than foam or PVC pipe.

Since I was on a time limit and I wanted to reduce the amount of sanding, I removed the texture from the grip. I also did not reproduce the bolts that attach the top rail and sites to the bolter. I added some holes to mount the pieces with rod.

Since it is claimed a bolter is ambidextrous I put the port ejector and charging handle on both sides.

Warhammer Bolter Size

There’s always some debate on how big a weapon should be. Many people size it according to their hand. I decided NOT to make it full sized as I don’t know of a human big enough to effectively weild one.

A Warhammer forum discussed sizing and a popular method of sizing was for the weapon to have a 3″ barrel diameter, so that’s what I did. Based on this you should get a Bolter between 400mm and 700mm depending on what template you use. The one I made was 570mm.

Building the Astartes Mark Vb Godwyn Pattern Bolter

The main body is made out of several layers of EVA foam. The middle layers have some squares cut out for some slight weight and material saving.

Since I didn’t have a bandsaw (just a scroll saw with limited clearance) or forethought I cut all the pieces out before gluing them together. I clamped a length of wood to a table to allow me to align the longer edges. They were glued with contact cement.

I used a rotary tool to round off the front end where the foregrip will go. For the fore grip itself, I cut slots out of some foam then used a rotary tool to grind out a rounded end. This was then glued onto the main Bolter body and contoured with foam clay. The result wasn’t as neat as I was hoping but I was on a time limit and couldn’t dally.

The bottom edge of the “side plate” has a bevel so I used a bevel attachment on my rotary tool to grind a nice even bevel.

Since I don’t have a bandsaw with a fence I measured the middle line of my scroll saw table and clamped on some wood. I used a fine-tooth blade to then cut the top bevel of the Bolter.

Feeling the march of time the ejection ports are very simple – scored lines that I hit with the heat gun to open up.

3D Printing, Mold Making and Resin Casting

3D printing can be time consuming, but the final results satisfying. I knew I couldn’t make an accurate muzzle out of foam and the hand grip is going to get a lot of wear. The Aquila, foregrip frame and some other pieces were also 3D printed.

Since it can take hours to print, sand and smooth a part, and it was my end game to sell more of these on Etsy, some 3D printed parts were molded in silicone and cast in polyurethane resin.

The Warhammer 40K Aquila emblem mold and cast didn’t work out due to bubbles in the silicone and the thin nature of the emblem. As for the grip of the Warhammer Bolter. I initially created a 1 part mold for the handle, thinking I’d cast them 1 half at a time. Then I decided to turn it into a 2 part mold, hence the metal bolts and screws as registration marks. It is my plan to use a filler to reduce both weight and resin cost. A resin cast hand grip is around 4 times the weight of a 3D printed one.

Future plans will be to make a 2 or 3 part mold for the muzzle. For now that is just 3D printed each time.

After sealing the foam with (slightly watered down) FlexBond and allowing drying time, the 3D parts were attached; The 3D printed parts were sanded, and I used automotive filler primer to fill in more print lines and cracks. I had designed some small holes in all parts and used aluminium rod for the larger parts (and a stub of an 18 year old pencil for the muzzle!) and small metal rods for the other parts. While the grip had some 5 minute epoxy, the other parts simple had superglue to bond them.

Construction complete! Next step, on to painting!

Warhammer Purity Seal

This was something I didn’t get to finish. I got as far as making 2 complete wax seals but not the inscription. This was a combination and modification of 2 designs from Thingiverse, 3D printed and then molded in silicone and cast in resin. I made 2. It took some time to get the paint hue right and the paint I used would leave a strange surface tint that could be buffed off.

Painting The Astartes Mark Vb Godwyn Pattern Bolter

Both foam and 3D printed parts were painted gloss black before the colours were applied. The 3D printed parts and the main body of the bolter were painted in gunmetal while the Aquila emblem got a golden colour instead. The foregrip I added a little bit of black paint to the mix for a darker foregrip and to add some contrast.

I chose a bright red for the bolter which was fortunate since the black undercoat toned it down a fair bit.

I could never get my airbrush to properly spray clearcoats and with time against me I didn’t go out looking for a rattle can, and proceeded straight to weathering. This involved dabbing on some watered down blacks, browns and rust colours, then dabbing or wiping most of it off. The highlights I hit with some dry brushing.

Warhammer Bolter Build Complete

And it’s done! The recipient was extremely pleased with their gift.

Bolter Project Review

I now have a better idea on things I could improve the next time around. They include;

  • Gluing the main body together before cutting to shape/size. A bandsaw would help make this process easier
  • I messed up a part of the top rail but the glue set before I could fix it. “Battle damage”
  • The foregrip contours needed more time, which I didn’t have. I could either grind it out or fill it with foam clay again
  • Given enough interest, would like to mould and cast the 3D portions for speedier replication
  • More detailed magazine
  • More detailed charging handle, which could be 3D printed (and maybe molded and cast) as this seems a piece that might get damaged easy
  • Revisit the front sight, as this might also attract damage due to its position
  • Seal the prop with a clear coat
  • Potential future idea – mold and (roto) cast the entire prop?
  • Make a smaller purity seal, and complete the inscription

Want me to make you a Warhammer Bolter for your cosplay? Get in touch.


This web site is completely unofficial and in no way endorsed by Games Workshop Limited. Adeptus Astartes, Blood Angels, Bloodquest, Cadian, Catachan, the Chaos devices, Cityfight, the Chaos logo, Citadel, Citadel Device, Codex, Daemonhunters, Dark Angels, Dark Eldar, ‘Eavy Metal, Eldar, Eldar symbol devices, Eye of Terror, Fire Warrior, Forge World, Games Workshop, Games Workshop logo, Genestealer, Golden Demon, Gorkamorka, Great Unclean One, Inquisitor, the Inquisitor logo, the Inquisitor device, Inquisitor:Conspiracies, Keeper of Secrets, Khorne, Kroot, Lord of Change, Necron, Nurgle, Ork, Ork skull devices, Sisters of Battle, Slaanesh, Space Hulk, Space Marine, Space Marine chapters, Space Marine chapter logos, Tau, the Tau caste designations, Tyranid, Tyrannid, Tzeentch, Ultramarines, Warhammer, Warhammer 40k Device, White Dwarf, the White Dwarf logo, and all associated marks, names, races, race insignia, characters, vehicles, locations, units, illustrations and images from the Warhammer 40,000 universe are either ®, TM and/or © Copyright Games Workshop Ltd 2000-2011, variably registered in the UK and other countries around the world. Used without permission. No challenge to their status intended. All Rights Reserved to their respective owners.