1st Build Trying something new (#time-poor-builder-dad)

[graza]

My son wants to be a Spartan for Halloween. I've really left this far too late to get started, but here goes. Last year I 3D printed the Mandalorian armour on my Ender 3. This Spartan build looks way more intimidating...

But I've got a kind of CNC machine, home built, that can cut out foam core. It was built to cut out scratch-built RC aircraft using plans from FliteTest. Foam core isn't flexible like EVA, but CNC cutting is going to save me lots of time I hope.

YT video of my machine cutting out a stencil:

 

[Kahn 319]

My son wants to be a Spartan for Halloween. I've really left this far too late to get started, but here goes. Last year I 3D printed the Mandalorian armour on my Ender 3. This Spartan build looks way more intimidating...

But I've got a kind of CNC machine, home built, that can cut out foam core. It was built to cut out scratch-built RC aircraft using plans from FliteTest. Foam core isn't flexible like EVA, but CNC cutting is going to save me lots of time I hope.

YT video of my machine cutting out a stencil:

that's a really cool machine, this is not really on topic with your build thread but would it be possible to set it up to cut out eva foam? or is there something about the consistency of eva that would make it unable to do so? asking for myself, i always struggled with getting good cuts when using foam.

 

[graza]

would it be possible to set it up to cut out eva foam?

It's using a reciprocating needle (really just a bit of wire, attached to a brushless DC motor) to pierce the foam core. I doubt it would pierce EVA foam as it's way more dense. A drag knife might do it, but I guess the tool paths would have to be generated by CAM software like Fusion 360? Not sure though and I don't have the experience to do so.

 

[Wraith0912]

The CNC machine is an interesting little bit of hardware, but given that you're not sure if it can pierce other types of foam, I'd say 3D printing is your best bet here. I'm wondering, which Spartan does your son want to be? Does he want to be Chief or his own custom Spartan? Does he have a favorite armor set that he wants to wear? If so, you can take a look at the 3D model index and see what's available (likely more stuff out on other sites, but they will likely be paid; these files are all free). Also, since you're crunching for Halloween, I wouldn't worry too much about post-processing the pieces; sizing and printing are the important things here. Looking forward to further updates on your project!

 

[graza]

which Spartan does your son want to be?

He's quite enamored with Sergeant Jerome, but I was just starting with The Armory and the Halo Infinite MJOLNIR Mark VII 1.1 unfolded Pepakura files. The 3D model index is new to me so I'll have a look at some of that. Thanks!

The already unfolded, simplified, and laid out on a page of the files I've downloaded is a big head start for me. The general process for the CNC is something like this:

1. Measure my son and size a PDO model,
2. Print from Pepakura to PDF
3. Import the PDF into an SVG using Inkscape
4. Select and "Combine" the different SVG paths (Control-K)
5. Select and "Join" the coincident nodes along the path.
6. Duplicate, mirror and place groups/paths that need to be cut out twice.
7. Save-As a Gcode file for the CNC machine using an Inkscape extension.
8. Send it to the CNC using Universal Gcode Sender.

As advised in the tutorials I'm starting lower down, below sight lines, with shin guard. I made a mistake yesterday in step 3 and opened the PDF directly in Inkscape rather than importing it into a new document. It didn't work out when I output the Gcode because of some weirdness in the PDF's coordinate system that the Inkscape extension didn't account for. So I'm repeating steps 4, 5, and 6 today unfortunately. Results of that for the shin guard attached.

For the helmet and some of the smaller more detailed parts, I'll 3D print them.

 

[Wraith0912]

He's quite enamored with Sergeant Jerome, but I was just starting with The Armory and the Halo Infinite MJOLNIR Mark VII 1.1 unfolded Pepakura files. The 3D model index is new to me so I'll have a look at some of that. Thanks!

Jerome's a good choice! He does wear Mark IV armor instead of Mark VII though. I don't know if you'd want to reconsider switching fully over to that set or if you'd want to make a sort of "what-if" set of Jerome in Mark VII, but either way is up to you. For Mark IV, both a 3D printable version and the Pepakura files it was sourced from can be found here. There's also another version of the Mark IV helmet found here, and if you want to shake things up a bit, Jerome has also used a more Master Chief-styled Mark VI helmet whose files can be found here. I can't really weigh in much on the Pepakura front since I've never gone that route, unfortunately, but I hope you're able to find these links useful.

 

[graza]

I don't know if you'd want to reconsider switching fully over to that set or if you'd want to make a sort of "what-if" set of Jerome in Mark VII, but either way is up to you. For Mark IV, both a 3D printable version and the Pepakura files it was sourced from can be found here.

Thanks Wraith0912. Those are very nice Mark IV Pepakura files and it gives us something to talk and think about - good father-son time. They're quite nicely unfolded too, an could potentially be cut out and glued by turning off the flaps.

The main thing I am told by my son is that Jerome has the red stripe painted on his armour. I'm not sure if that's a matter of rank or something specific to Jerome's back story. I'm new to all this. It's my son who has chosen this character.

 

[Wraith0912]

The main thing I am told by my son is that Jerome has the red stripe painted on his armour. I'm not sure if that's a matter of rank or something specific to Jerome's back story. I'm new to all this. It's my son who has chosen this character.

No worries! Jerome's stripe is purely a cosmetic thing. While he is the leader of Red Team (Halo Wars 2 has him also be promoted to a Commander), it's mainly a way of distinguishing him from the other Spartans in his team. He also has an emblem of a traditional-style Spartan helmet on his right shoulder, while his teammates have their own separate emblems in the same place. Halo Wars 2 also has his Spartan number, 092, written on his upper left chest piece. Halo Wars 1 doesn't have this, so it's up to you whether you want to include that or not.

One important detail to note is that the direction of his stripe is different from Halo Wars 1 to Halo Wars 2. In HW1, it starts from the top middle of his chest then goes diagonally down to the right. In HW2, it goes from the top right of the chest diagonally down to the middle. I've never noticed this detail until now, but again it's up to you which version you'd like to do.

Note: the first image is a piece of concept art, hence why he has the shoulder emblem but not the stripe. The second image is Halo Wars 1, the third is Halo Wars 2.

 

[graza]

Having had a good look at the Mark IV versus the Mark VII files, I think I'm going to have a much easier time with the Mark IV! The chest plate in particular is much simpler.

As a test, I've rearranged things for the foam board cutting CNC machine. Once sized for my son, the pieces for the front half of the chest plate fit on a single A2 sheet. I'm still dialling in the CNC cutting depths etc. It failed halfway through, but a test cut on a piece of scrap look like they'll come together reasonably well (with enough hot glue and tape):

Assembly is going to need bevel cuts of the adjoining pieces but this stuff is easy to cut. Curves can be formed in different ways, wet the paper on one side or remove it altogether. The taped seams won't be invisible but let's say it's a "feature of the armourer's technique".

This technique may not work in the end, but as I said, I'm short of time and it's fun to try something new.

I have also found some STL files on Thingiverse including the helmet, so I've started working on sizing/splitting/printing that. Meshmixer is a great tool for splitting up something like a helmet that won't fit on my Ender 3. The first print failed resulting in a bunch of "spaghetti", but the next attempt looks good so far.

 

[ForwardUntoDusk]

Having had a good look at the Mark IV versus the Mark VII files, I think I'm going to have a much easier time with the Mark IV! The chest plate in particular is much simpler.

As a test, I've rearranged things for the foam board cutting CNC machine. Once sized for my son, the pieces for the front half of the chest plate fit on a single A2 sheet. I'm still dialling in the CNC cutting depths etc. It failed halfway through, but a test cut on a piece of scrap look like they'll come together reasonably well (with enough hot glue and tape):


Assembly is going to need bevel cuts of the adjoining pieces but this stuff is easy to cut. Curves can be formed in different ways, wet the paper on one side or remove it altogether. The taped seams won't be invisible but let's say it's a "feature of the armourer's technique".

This technique may not work in the end, but as I said, I'm short of time and it's fun to try something new.

I have also found some STL files on Thingiverse including the helmet, so I've started working on sizing/splitting/printing that. Meshmixer is a great tool for splitting up something like a helmet that won't fit on my Ender 3. The first print failed resulting in a bunch of "spaghetti", but the next attempt looks good so far.

Looks good! That CNC machine for the foam looks like its working out great.

How many walls are you printing with on your 3D printer? Seems like the infill is showing though quite a bit... Or is that just because of the lighting?

 

[graza]

How many walls are you printing with on your 3D printer? Seems like the infill is showing though quite a bit... Or is that just because of the lighting?

Thanks! I'm running with a layer height of 0.28, extrusion width of 0.4, two walls. I think it's just the lighting, but in any case it'll be taken care of by the filling, sanding, priming and painting needed to cover up the layer lines.... Oh the sanding!

 

[graza]

Making some (slow) progress with this... The helmet chin guard will have to be attached with magnets or something because I didn't allow enough space for my son's head to fit through the bottom. His head will fit inside though, I got that much right! I have been researching the latest in 3D print smoothing techniques and will have a go at painting on glazing putty + acetone/thinners.

The chest plate has been started using foamboard. The pectoral plates were first and don't look the best - I should have started with something less up-front. Time permitting I may do them again. I'm fairly pleased with the back of it so far. I have some very soft EVA foam from one of last year's Halloween costumes that I plan to use to attach the front and back of the chest plate.

The accuracy of the CNC machine is helping, but there's still lots of 45 degree angle-cuts to make to fit the parts together. The FliteTest plans have some interesting techniques that could be applied. Some rabbet cuts might be better in certain circumstances, but probably really only applies to 90 degree joins.

 

[Wraith0912]

It's coming along great so far! That back plate especially looks really clean. Don't worry too much about parts like the pectorals not being at the spot you'd want them to; the idea of "perfect being the enemy of good" goes double for crunch builds like this. Looking forward to see where you go next after the chest is done!