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  • josephaguilarsanch

Grenadier Helmet

Jorge's Helmet was my most ambitious project and came to define my 3D assembly style of prop making. Since then I have gained lots of experience and wanted to come back and update the files to include plenty of the features that you all have been asking for privately

My inspiration for this project was motivated by the fact that I am no expert prop maker and I wanted to model my helmets in such a way that makes printing/painting/assembling them more accessible to people with less experience/fewer resources.

Additionally, I wanted a model that could accommodate common 3D printers, so that the model is accessible to everyone.

Coming back to the project, I wanted to keep all those same things in mind but rectify some of the things that gave me an issue when printing the helmet as well as bring some much needed functionality to the helmet itself.

With that being said, lets take a look at everything I did to ensure everyone can own their own piece of Reach history.


Major Features

Unique, Easy-To-Assemble Design.

This helmet was designed to fit together like a 3D puzzle. This model was originally comprised of 40+ pieces, but now accomodates over 80! (Parts that can be mirrored are included as singular models w/ instructions to reduce file size). All of the large major pieces are designed to snugly fit together utilizing aligment pegs that allow for the helmet to be securely assembled/dissembled without the need for screws/glue. Some of the smaller accent pieces require glue to place in their slots, but outside of that, this helmet is printable in such a way that a vast majority of the pieces do not require glue to assemble, this ensures that there are no ugly seams to hide/sand away.

Below you can see two pictures, both show how the helmet slides together one piece into another. The first picture show how all the "central" pieces slide together from the front.

The second photo shows that all the "side" pieces slide in from the sides and lock all the rest of the "central" pieces in place.

The optimal order to assemble the helmet can be found in the video at the beginning of this post.

Helmet Customization

This model features the most customization of any of my helmets. The model features 4 separate attachments that can added and removed at will. All attachments as well as their attachment features in the main helmet can be mirrored to be attachable to either side of the helmet.

Additionally, there has been a massive functionality update that includes ventilation systems, lighting systems, and speaker systems.


The helmet comes with a stock version of the overhead visor and one that accommodates the UA attachment. There are additional versions that accommodate overhead fans for cooling/venting, but I will talk about that in a later section.

The overhead visor is able to swapped out on the fly as it slides in from the side and is locked into place by two, printable, hex-key compatible screws.


The HUL attachment comes in an easy-to-print 2 part assembly. The front plate and back body are printed separately and attached via 4 small alignment pegs. This allows for printing both pieces without supports.


While the HUL[3] attachment is not available for the Grenadier helmet in-game, I thought that there was no need to limit this model (plus I had recently modeled it for my Commando Helmet which you should absolutely check out). The attachment features a multi-part, sleeved design that locks together using insert-able antennas in the back.


The CNM attachment also features a multi-part, glueless design that only requires a small drop of glue to attach side button.

Functionality Update

I've never included space specifically dedicated to internal electronics and would supply them on a case by case basis when requested. That all changed this past week when I decided that with all the many features I have added to the Grenadier for private requests, it was time to release an updated version of the helmet.

Removable Chip Insert

It was brought to my attention that the Reach version of the helmet does not feature the AI chip insertion feature like the Halo 5 version does. I included two seperate versions of the large main cap and the top of the neck to allow others to make a choice as to what version of the helmet they want.

Ventilation System

The newest feature, and the one I am most excited about, is the added ventilation system. The side plates and cheek plates now feature a square slot to fit hobby duct fans. This slot is connect via duct to the front of the helmet, where there are several options for small printable vent covers. The slot is a 52 mm square, so it should be able to fit 50mmx50mmx15mm duct fans with ease.

Here are some pics of the two printable vent covers.

Additionally ventilation was added to the top of the helmet and is only usable with the UA attachment. The slot is a 42mm square and should plenty of room to attach a 40mm hobby fan.

Forward Lighting Accommodation

Directly underneath the side duct ventilation is a separate channel and casing to accommodate various lighting fixtures of your choosing

Integrated Sound System

Each ear piece comes with a circular hole to easily insert 40mm hobby speakers. The hole is 42mm wide and features a large bottom square feature to allow for wires to easily pass through.

Visor Insert Features

The inside of the helmet features Guides to hold the visor in place. While the visor can sit on these alone I would recommend a low strength glue or tape to help fasten hit while still allowing you to remove the visor.

Sizing Ring

Model includes a sizing ring to help you scale the helmet to fit over your head. Sizing ring is equal to the size of the throat of the helmet so make it so you can fit your whole head through without slicing your ears off. In my case, I was able to print the whole helmet at 93% scale, which saved plenty of time and made for a better fitting helmet.

Multiple Visor options.

This model includes a full kit to help you make a mold capable of casting a resin visor. A resin visor in and of itself will have some reflective properties while more importantly allow you to make the visor see-through and a color of your choice. It also allows for more complex geometries than vacuum forming and makes for a sturdier visor. I went with a simpler mold shell design without an alignment baseplate for this design. The visor and mold shell sheathe together, so just ensure that the visor plug is not touching any of the walls before pouring in the molding agent. As usual, I recommend glueing the two pieces to a flat piece of cardboard. The mold shell is designed to be able to flip over and stand flat when pouring in Resin to ensure the top does not leak or pour resin.

Visor Resin Volume: 192 mL

Visor Rubber Mold Volume: 621 mL

You can find a more detailed explanation of the resin casting process in my "Builds" section.

This visor also comes with something I've never added before, a visor buck.

This will allow people who prefer a vacuum formed visor to do so.

Smooth Ergonomic Interior

This helmet has a large smooth internal cavity that makes for a very comfortable feel. Adding padding takes it to the next level.



*This build was done before the major functionality update and does not feature those improvements*

I am no master prop maker, but I could not anticipate how well this helmet came out!

The multi part design made sanding and painting each individual part much easier and allowed me to get a glossy smooth finish all the way up to each edge on the helmet. If the helmet was one solid piece, all the nooks and crannies would've been a real pain to try and smooth and would probably have lead to visible layer lines on all those inner edges.

When painting this model, I was able to get such a glossy finish by using a new technique of alternating between primer and bondo.

- First, apply a layer of sand-able filler primer to you initial 3d print.

- Next, sand away as much of that layer as you can with one quick pass of sand-paper, electric sander, dremel, etc. You should still have some spots where you still see the primer in the deeper layers, more uneven areas. I usually use 80 grit for this. This is not meant to get the object super smooth, mostly just to show you where bondo will be necessary

- Next, apply bondo to the spots where you still see the gray primer. I usually wet sand this away with 600 grit. This works well with the bondo shown below. If you get the bondo that is not premixed and comes with the hardening agent, you may need to use higher grits to get through it in a timely fashion. Again, don't spend too much time on this layer either, just make sure you sand enough away so that all the previously grey/primered areas are now red and smoother than they were before.

- Next add another layer of primer, wet-sand this with 600 grit till your model is now smooth. You should be able to see light reflect of the primer at this stage. I recommend 600 grit because it tends to hit the sweet spot of smoothing the paint, but also sanding the paint away quickly if its still not perfectly smooth. This will make quick work of swirl lines from the previous grits.

- At this point your piece should be mostly shiny-grey. You may see some small problem areas at this point, so repeat the previous two steps in these small spots as necessary.

- Lastly, you apply your paint! For this project I chose glossy enamel paint. The enamel paint tends to be hardier and stick to the props better. They are also more resistant to damage. Additionally if you need to sand it, it sands slower and can act the same as the primer from previous steps.

The piece that require the most repetitions of these two steps were the main helmet, especially because that raised feature on the top was not originally connected and I had to glue it in place and get rid of the seams. I have since changed the model to have these two pieces come connected. Additionally I printed the main cap upside down so the entire top of the helmet had horrible quality due to the supports and me getting them off. But as you can see in a lot of the pictures, despite this piece being the roughest by far, I was able to get it to a mirror-like finish.

The visor making can be viewed below.

1: I glued the visor to an old pizza box.

2: I then placed the mold shell over top the visor plug and used spray adhesive to keep it in place. I would not recommend this because it turns out it was not a tight seal and I had some silicon leakage. I would recommend hot glueing it to ensure you have no leakable areas. I used spray adhesive because I was impatient.

3: Next I removed the visor from the mold and placed the mold back in its shell. If you cant remove the mold without destroying the shell, you can always just print another, this is why I make the shell so thin, to save on materials. For my next project I will be experimenting on two piece shells, held together with small bolts.

4: Next determine how much resin you need, I list the amount earlier in this post, however, if you decide to scale the helmet, you'll need to do a bit of math. Mix as instructed with whatever dye you want.

5: I have a small vacuum chamber, so you can see I putt out the bubbles with that

6: I pour the resin into the mold, and since I included a little extra just in case too much gets stuck to the cup/mixing stick, I pour the excess into some small gem molds I made the other day.

Below you can see that the visor initially comes out pretty cloudy. After I sanded/polished it you can see that it starts to become see-through.

For this process I usually go 600>1000>1500>2000>3000 grit sandpaper on the visor. Lastly, and most importantly I finish with a microfiber cloth and Flitz polish.

Also note, that the resin visor is somewhat malleable, so when putting it in your helmet you can squish it so that it fits through the throat if it stretch out during the polishing process. In my experience It takes a lot of force to deform it so it is still pretty sturdy and does not effect the polish.

After all that I was all done! You can see the video of me putting the whole thing together below.

Note, that it must be put together in the order shown, back to front, then the side pieces lock the whole helmet together.


What Next?

If you are looking to create you own models like this one feel free to checkout all of my tutorials on 3D modeling and prop making techniques.

If you are looking to purchase the model so that you can print your own you can find it in the store.

Lastly, make sure to check back in every once in a while to see what I've been working on

Thank you for your time


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