Warhammer Mark Vb Godwyn Pattern Bolter Prop for Cosplay

Warhammer Bolter Project Introduction

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. I’ve since refined the design, building processes and materials I use.

Built primarily out of EVA foam with 3D printed and resin cast components, with the foam being sealed with Rossco FlexBond and the whole Bolter painted with acrylic paints.

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 3 layers of stiff high density EVA foam. 50mm forms the core and the 2 thinner outer layers form the mag well. 2 smaller plates go on top to form the upper (red painted) “shroud”. Having a bandsaw made cutting to shape easier than a knife.

I used a rotary tool to round off the front end where the foregrip will go. For the fore grip itself, I cut grooves 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 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.

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, some 3D printed parts were molded in silicone and cast in polyurethane resin.

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!

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. 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.

A Note About Rosco FlexBond

Rosco FlexBond handles just like PVA glue but it is super flexible. It can be wet sanded for a smooth glossy finish. It makes a good alternative to Plasti-Dip, especially if you are working in cold temperatures, a small space or inside your own home (Plast-Dip is toxic and needs ventilation and respirator). The downside is that it always stays tacky for me and the only way around that is enough layers of paint to cover it up, and/or a clear coat.

And then on to weathering.

Warhammer Bolter Build Complete

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

Warhammer Purity Seal

I have made some “wax” purity seals – 3D printed and then resin cast. I have made 2 sizes – 5am and 3cm.

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


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