Halo 4 Spartan helmet build, completed, seeking advice.

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madmanmick

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Hi all,

I recently decided to build a Halo 4 Spartan helmet for cosplay purposes. I decided to do this project using 3D printing, as I picked one up in January and needed a good project to do. I used Big_Red_Frog's 3D model available on Thingiverse (http://www.thingiverse.com/thing:158120) as a base for this project... turns out that doing it via 3d Printing is a very slow and finnicky process, but I ended up with a result that I thought was pretty good.

Seeing as I have already finished the helmet some months ago, I thought I would post here about my journey and experience in 3D printing and then molding/casting in resin. Maybe some other people who are looking to go down this road will gain some insights from what I have been through!

When I first commenced this build, I had ABS plastic loaded into the printer, so I decided to stick with it... that was a mistake. I had so many troubles with warping and shrinkage, temperature banding and such. Many of the pieces that came out at the end had heaps of defects that required many hours of repair to get the final helmet looking good. I'll start with some pictures of the printing process:

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Some observations about this process:

1) Don't use ABS for large or long prints. It was extremely hard to get the plastic not to shrink, lift off the plate, warp, band with temperature changes. I'm using a Flashforge Dreamer, and I know there is a design flaw with how it measures temperature, which can cause banding and defects on long ABS prints.
2) Gluing the parts together is easiest done with ABS paste, which is basically abs filament or offcuts dissolved in acetone. Works great, sticks fast and dries hard.
3) Aligning all of the parts together was a huge issue, because many of the parts had deformed along the joints during the print. This took ages to fix, using a combination of ABS glue and Bondo/Rondo to fill cracks and joints.
4) Some of these pieces take 10 hours to print. This is despite using 200 micron resolution and only 15% infill. All up I reckon there was around 70-80 hours just to print the parts.
5) I probably put another 40 hours into joining, filling, sanding and refining the printed helmet. The lesson here is to make sure your prints come out as close to perfect as possible... also, print at 100 micron. 200 micron leaves ugly looking contours on the print which are awful to fill and sand out.


If I had to do this again, here's what I would do instead:

1) Print in PLA plastic. Since the helmet is being molded and casted, it doesn't matter how durable the plastic is long term. It also has very few issues with banding, warping and NO SHRINKAGE!
2) Cram as many pieces onto your build plate as possible, to minimise the time spent printing.
3) Get your filament from a reputable source. I once had a jam in the filament, because it had been wound too tightly on the spool. Luckily I was home and heard the printer straining... basically the filament had locked to itself on the spool and wouldn't release. I had to cut it off, and unwind around 20-30 metres of filament, then re-wrap it... but after that I had no lock-ups.
4) Get your printer settings right with some medium sized test prints before going straight to the parts.
5) If you see a piece warping on the plate early on, cancel it, fix your settings and print it again. Throw away the part with warp.

Here's what the helmet looked like once I had finished the printing and joining, and after sanding and filling. Note that I was silly enough not to print the chin piece that came with the M10 bolt holes, so I manually cut them myself, re-filled, and mounted M10 bolts. This sucked, because the chin piece is essentially hollow, and cutting through it makes it awfully unstable, and you have to fill a huge volume very slowly with bondo to get the holes clean.
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After this, there was a HUGE amount more of filling and sanding. I used a combination of bondo/rondo/spray primer/spray primer and filler to get the helmet smooth. Also, the 3D print was missing many of the small details on the helmet, which I had to sculpt in DAS clay or use plasti card and the glue to the helmet.
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I think I've hit an image limit, so I'm going to to post the rest of this in separate entries.
 
Continuing on with photos...

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The front detail above the chin, below the visor, was sculpted in DAS, based on screenshots I could find of the singleplayer Spartan helmet. If you are wondering, P-RAD was an old nickname from school, so I stuck it on the visor as a maker's mark.

Lessons learned:

1) Don't 3D print a helmet as a base for casting... it sucks! Only do it if you intend to wear the final print. But make sure your print is bloody awesome in quality.
2) Sanding and filling a 3D printed helmet is so time wasting... see comment 1. I've had experience with this before when sanding and filling a Pepakura helmet to get a decent finish.
3) I'm sculpting the next helmet from clay... none of this drama!

Following on from this, when I was finally as happy as I could be with the surface finish, I started on creating the rubber mold.
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I've already tried to make a silicone mold once before, on a pepakura stormtrooper helmet. I failed miserably, but learned so much, I was determined not to fail with the Spartan helmet.

Important observations when doing this process:

1) Have enough silicone ready to go, I had a 5kg bucket to use, I think I ended up using half. If you run out, and can't buy more within 48 hours, you risk the new silicone not bonding to your existing silicone.
2) This is best done in HOT and DRY environments. At the time, it was cool and wet... for a week. It took me around 7 days of continuous work to make this mold. I'm not certain why, but I believe that because the humidity was so high, and the weather was cool, each layer of silicone I painted on took anywhere from 10-15 hours to set to a tacky finish, which is when you are meant to put on the next coat.
3) The mold needs to be THICK. I'm talking 1/2 of an inch. If it's not thick enough, it won't be stable by itself, and will just collapse if you try to sit it in the mother mold. MAKE IT THICK!
4) Registration marks are everything. I used an ice cube tray to make pure silicone keys, which I then glued to the surface with more silicone. When you place these, make sure you place them in such a way that your mother mold can be pulled cleanly away from the silicone mold without catching.
5) Place your cut seam in a location that's easy to fix with sanding and filing once you make the resin. If it goes through tricky details and valleys, it will be really hard to fix afterwards.
6) When you cut the seam, use a really sharp pen knife, and only do one cut. If you take the knife in and out of the silicone, and make multiple cuts, you will end up with a messy seam on the inside, and the surfaces won't mate together perfectly.
7) Make sure you create a nice and clean ledge at the aperture to the helmet (the neck hole). You want to have a clean and neat ledge here, because when you cast it in resin, it is easy to know where to pour the resin up to, and it will be much easier to cut it away and clean it up once the resin has cured.

Next post is on to making the mother mold.
 
Making the mother mold well is incredibly important. I previously failed to make a good mother mold on my pepakura storm trooper, because the plaster was too thin and fragile. Also, I didn't use good registration keys on the silicone, so the mold wouldn't sit firmly in the mold, which made it useless.

I had previously told myself I wouldn't do another mother mold in plaster, because it's so messy and time consuming to do right. I considered doing this one in fibreglass, or using the plasti-paste type equivalents, however I decided not to use either, because of 1) toxicity (fibre glass), 2) Not being familiar with the methods, 3) Cost. Plasti-paste is very expensive in Australia, like Silicone. (My 5kg bucket of RTV-2 silicone cost around $240 AUD).

Henceforth I decided to take what I had learned and make the mother in plaster. This mold was a combination of Hydrocal (which I ran out of) and then pottery plaster from Boral.
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Due to the shape of the helmet and placement of the registration keys, I had to make the mother mold in 6 separate pieces. All of these pieces had to lock together cleanly to support the silicone mold inside.

Observations for making a plaster mother mold:
1) It must be thick. Aim for 2cm in thickness, and make sure you use one to two layers of scrim netting inside each piece. Without scrim, the plaster parts will shatter very easily.
2) Do some test pieces with your plaster first, to make sure that it's not expired or defective. Make sure you get your ratios right of plaster to water - always add plaster to water, never the other way around.
3) Make the flanges where your pieces meet very thick, and tall. That way it's easy for them to lock in together nicely. Also, it pays off well to put registration bumps into the flanges, so that they have spots where they lock together easily. To do this, when you start laying on your first plaster parts, use a plasticine wall as your boundary for the part, and press in some neat and deep circular marks. These will come out as concave marks on this piece. When you pour the adjacent part, the plaster will fill these concave marks, and create convex circles. This means both surfaces will join cleanly afterwards.
4) Use lots of vaseline on your plaster flanges. If you don't grease them up good, when you pour the next plaster parts, they will bind together, and you will need to smash them apart with a hammer.
5) Run the scrim up the flanges of your parts, this gives them much needed strength.
6) It's also a good idea to use small wood blocks or other keys to place on the join line of flanges when you are pouring the plaster. This leaves a rectangular negative cavity in the join between two pieces, where you can stick in a flat head screw driver to help prize them apart when you have finished pouring resin.
7) Use a respirator. Plaster dust contains silicates.
8) Have several decent sized buckets around for mixing plaster, that way you can alternate between them so you don't lose time.
9) Don't mix too much plaster at once, it can set too quickly which will mean you are wasting plaster.
10) When building your flanges, it's good to wait until the plaster has set until it feels quite thick and resilient. Then you can spack it onto the flanges and it will easily hold it's shape, instead of just flowing away. This is really important for the flanges as they stick out from your mold a fair way.
11) One thing I didn't do was create ledges on the flanges for clamps or bolt holes. This may work better than what I had to end up doing, which was to align all the pieces as best I could, then belt them together tightly.
12) Your final plaster mother mold will be HEAVY, mine would have weighed around 10 or so kg's. The heavier it is, the harder it will be to do slush-casting.

Next post is on to the resin pouring.
 
I had hoped that the resin pouring process would be the easiest part of the process, but lo and behold, it came with it's own set of new issues to face. I used TC-808 slush casting resin for this pour.

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Problems that occured during this cast:

1) When pouring each layer of resin into the helmet and slushing it around, there were a number of times where the resin became thick like cottage cheese upon contact with the previous layer of resin. This made it very hard to slush it around evenly, and it created thick and bubbly spots in the cast. I had mixed and stirred the resin in separate cups at the correct ratio, I believe the problem may have been that I did not wait long enough between pours for the existing layers of resin to cool off.
2) I had decided to wash out the silicone mold, because there was plaster dust sticking to the inside. I let it dry for a while, but it was still damp on the inside when I commenced pouring in resin. The resin containers said that the resin was not affected by the presence of water, so I didn't think this to be a problem. I'm pretty sure that the dampness inside the mold is what caused me surface issues when I finished the pour.
3) When I was pouring the resin in, the silicone mold must have shifted inside the mother mold at some point early on. This probably happened because you have to swing and tilt the whole helmet around to spread the resin around evenly. Because of this shift, I was left with two problems - the first being that the cut seam that ran along the side of the helmet wasn't aligned, and I ended up with two different levels on the outside of the helmet on either side of the cut seem, which required much repair. The second issue is that when the mold shifted, it caused the back part of the helmet to deform. The end result is that the back right section of the helmet is physically deformed and out of symmetry. This required significant bond and repair to fix. BE CAREFUL WHEN POURING! Make sure that your silicon mold is very tightly fit into your mother mold, and that it can't move around.
4) When I pulled out the resin helmet after finishing (I used 2kg of resin all up for the helmet), the surface had pulled any remaining dirt/paint/grit off the inside of the rubber mold. This required sanding and more repair...
5)There were several sections of the helmet on the exterior where the resin had poured and left large air cavities under the surface. I had to cut away almost all of these areas down to a point where the resin had no more air pockets. These then needed to be re-filled and sanded...
6) Several areas of the resin on the outside were still sticky when it had been left to dry. I don't know why this happened, but I think it must have been that the mold was damp in these places, which prevented it from curing properly.
7) Cutting out the visor hole and cleaning up the neck seem was an ordeal. I used a compass saw, a dremel and files to get this right, it took AGES. I spoke with a guy who does this stuff a fair bit later on, and he suggested that I should use a hair dryer or heat gun to heat up the resin where I want to cut and clean, then use a sharp pen knife to carve through the resin. Apparently this is quite easy to do and the resin is quite easy to cut away when it is warm.
9) It might be a good idea to inset your visor mounting screws or nuts into the helmet when you are pouring the resin, so they are fully integrated into the helmet. Trying to fit these in later was quite difficulty, and even bondo didn't seem to 100% bind to the existing resin, which made the joints weak.

Next post will be on clean up, painting and detailing.
 
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I painted this helmet pretty quickly in the scheme of things, it was very hard not to be impatient and get this finished. Here's how I did mine:

1) First thing to do is spray primer the helmet in flat grey, did around 2 coats.
2) Spray the whole helmet in flat black, did 2 coats.
3) Taped off the areas of the helmet that were to remain black at the end.
4) Sprayed the entire helmet 2-3 times with a silver spray.
5) I then did coats of red. Stupidly I used gloss instead of stain.
6) When the red went on, I used a razor blade to scrape away the red from the edges, to reveal the silver underneath. This helps produce a weathered/battered effect on the surface. I made a mistake however, by not letting the silver dry fully first before moving to red. As such, the red sort of dissolved the silver underneath in spots, and when I scraped the edges, all I got was the black undercoat.
7) I drybrushed the edges and seams with silver paint for more wear effect.

Finally, on to the visor and foam liner.
 
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Observations about the process:

1) To create the visor, I bought two cheap motorcycle visors from E-bay. I ruined the first visor by cutting it with too small of an overlap around the visor aperture, so I had to throw it away. The second visor was cut much large, so I wouldn't have a problem with fit. Unfortunately it's plain black, so I wasn't big on the overall look of the visor.
2) Bending a motorcycle visor to fit inside is pretty easy, but it leaves a substantial gap between the outside surface of the visor, and the helmet itself. This looks crap from the outside. I used a black sponge like foam to fill in the cavity between the visor and the helmet, which looks pretty good.
3) Mounting the visor to the helmet was really hard. I tried glue (didn't bind to the resin), I tried screws and nuts (didn't bind to the resin) set in with bondo, I tried velcro (inside of the helmet is very uneven, the velcro didn't stick well). I ended up buying special screws and nuts to mount it, though they were quite large. The nut has four spikes, and a hollow threaded post hole for the screw to set into. The purpose of these particular nuts is to be hammered into a wooden surface, then the screw can be fastened in from the other side of the panel. The spikes on the nut bind it firmly into the wood. I mounted these to the resin helmet by embedding them in bondo. this worked fairly well, though I'm still not convinced they will not break away from the resin under the stress of the visor (one already did, which I had to repair).
4) Using the motorocycle visor method takes up lots of valuable internal space of the helmet, which then significantly affects the head size that will fit inside, and the comfort of the wearer.


To pad out the inside of the helmet, I used soft yellow foam around 1 inch thick that I bought from Clarke Rubber. This was glued in with hot melt glue, which worked really well. The helmet ended up fitting me perfectly, but unfortunately it doesn't fit anyone with a bigger head than mine! Here's why:

1) The original 3D print model from Big_red_frog was too small in size. It would be really useful for people to publish dimensions of the overall helmet so you can get an impression of size, but no one ever seems to do this... I really needed to scale it up around 10% to compensate for the issues that arose, then it would have fit almost anyone.
2) The resin was too thick in places, which cramps internal space. Also, the neck hole wasn't cut wide enough... though this would be easier to do with the heat gun and knife method. Many people with wide heads can't get their head in past the neck hole.
3) The visor mounting system takes up too much space at the front. People with big noses won't fit well, because it rubs up against the visor.
4) The foam was too thick at 1 inch. Perfect for me, not great for others.

I want to post one last entry, with recommendations about how I would do this differently going forward.
 
Here's how I would do a helmet differently next time:

1) No more 3D printing. I would sculpt it in clay or some other subtractive material, this is easier to work with and requires less repair to get it clean.
2) Pour the resin into a silicone mold that is completely dry and clean. I would also wait around 10 minutes between pouring layers of resin, to avoid the cottage cheese effect and creating air bubbles from escaping heat.
3) I will use a heat gun and knife to cut the visor and neck holes more cleanly.
4) I will find a way to vacuum form the visor, so as to get a perfect fit. This will result in a larger internal space, also being easier to mount to the helmet, and will look much better.
5) Find another system to tightly sit the helmet on someone's head. I have seen posts about integrating strap systems and such, so this might be the way to go.

I'm already working on my next project now, which is a Stormtrooper helmet from Episode 7 of Star Wars. I'm currently almost at the end of the sculpting phase, about to move on to the molding phase. If you want to check it out, go here:
http://www.therpf.com/showthread.php?t=242262&p=3690504#post3690504

If anyone has advice for me about my experience, what I could do better, things I should avoid (etc. etc.) please feel free to post!
 
Hello.
I use a FF dreamer with ABS and have not had nearly as many problems as you have had .
A few questions ..
what are your settings at . how do you prep your bed?
what slicer ect ? I wish had a easy way to share config files .

I used it on ABS for 2 of the big red frog prints and only had a few minor issues . most are due to Human error with the infill %
I run solid on all my non prop prints.

For me I raft every thing . use the left extruder for ABS untill last week when clogged the nozzle .
Hairspray bed prep.

what version of firmware and FF desktop app do you use . there site is a tad cryptic at times to get the latest versions.. they had a firmware update on the 16th that fixed a few bugs on the machine ( if your printer's used with a dedicated PC or mac that is not on the interwebz You might have missed it )

for joints . pick up a printing pen. its a easy way to use up extra material and its great at gap filling . they are 80 bucks .

Peter ...
 
Hi Peter,

So I was printing between 220 - 230 degrees celsius, bed generally at 100 - 110 degrees. I use blue painters tape over an aluminium bed, sometimes I used general stick glue to assist with sticking. I usually printed at 15% infill, with 3 external perimeters. I used Simplify3D to slice the models, as I find it has awesome levels of control, and generates GCODE files quite quickly. All items were printed on rafts.

Now i always hairspray the painters tape, but I'm printing in PLA which I find much simpler to control.

I do have the original prototype 3Doodler from Kickstarter, but I found that if I extrude ABS plastic from the pen onto the ABS printout, it wouldn't bind properly. Anything I tried to stick together would delaminate with very little force. I understand that the FF Dreamer has a problem printing for long periods of time with ABS, because the Y carriage is made of thermoplastic, which has actually melted and deformed during long print sessions for other people - particularly if both nozzles are running.

So you print all your parts at 100% infill? That must take 20+ hours per component!
 
AHhhh...I use the stock flashprint program. v3.
when I had my first printer the PBsimple It used rep host . I did miss the tweakability of it but in the end the stock FF software was Good enough.
I run 6 perms and 10%-15% for prop and non Armor .. Armor is 100% but as its walls are 2-5mm per area its not a big deal..
105 bed. 235 nozzle . I run the local FRYS SHAXON stuff and its done good . One set of clogs in 8 months is not shabby.


For the pen . use a butane lighter micro torch and premelt the edges a few sec ahead of the pen..Bonds like a dream . If you ooze too much then use some flushcut side cutters to take snip while its hot.
 
Thanks for the tricks, the butane lighter torch sounds like a good way to get the bond going. When you say 6 perms, do you mean 6 perimeter layers? Do you print at 100 or 200 micron for helmets?

Also, what have you found to be the best trick for leveling out a printed surface to get rid of the layer bands? I've tried using spray primer/filler, but this doesn't seem to fill just the hollows, it also builds on the peaks.
 
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