Fallout 4 Nuka-Cola guy - Sintra build, pic heavy

[nathancarter]

Hi,
This is my first big thread here and my most elaborate Sintra build yet. I'll try to keep a current progress shot in this post. Acknowledgements and props to other Sintra builders such as Johnny & Junkers Cosplay.

My goals: to make the bubble helmet easily removable from the harness, yet securely latched into place when it's on; and to have adequate ventilation inside the bubble so it's breathable and doesn't fog up.

The vast majority of the build is freehand. I'm making temporary templates from paper and cardboard, transferring those templates to Sintra, then heat-forming and gluing. Lots and lots of trial and error. I'm also using some vacuum parts for the tank and hoses; I'm not good enough to build the shape of that tank yet.

The bubble globe is an acrylic lighting globe from Amazon. I got the 16" globe; there's also 14" which might look a little sleeker and slimmer but would be very claustrophobic inside.

Disclaimers: This won't be perfectly screen-accurate for four reasons - first, I'm doing a genderswap; second, the inspiration artwork is sparse (I've only found four images) and the details are different on each; third, I've got to make it wearable and breathable; fourth, I'm just not that good yet. My proportions and detailing is somewhat off but I hope it'll still look good and be recognizable.

References:

Current state as of 8/31, right before loading it up for Dragoncon. No full-body pictures yet.
Shoulder harness is 100% complete, paint is glossy, decals are applied, foam padding and velvet lining are in place.
Bubble section is 99%, I need to repaint a couple of sections (won't happen till after Dragoncon) and file down a screw head tonight. Fan works, bubble is not stuffy or uncomfortable, and my battery-pack door and latch are magical.
Red backpack/tank is con-ready but only about 90% "complete" - I tried to make an acrylic top dome and failed, then my Dremel died, so I just made a flat top lid and decorated it with some scraps and lights. Looks pretty cool but is very far from canon. The whole thing needs a repaint anyway.
Zapper was commissioned, zapper holster needs velvet lining taped inside (tonight) and another coat of paint (after con). Flask was a vendor room purchase, flask holster needs another coat of paint (after con).
Outfit is constructed, my undergarments are appropriate for tight pants (heh), my boots are terrible for walking Dragoncon. Need to starch the jacket collar.

First step was to work on the base harness piece. This took a couple of tries. My first attempt was going to be a little more accurate to the reference, but the straps go right under the armpits and I'm sure I wouldn't be able to wear that for long. Also, the buckles look different in each reference, so I decided to make them just snap on instead of straps that buckle on.

Initial draft out of cardboard looks terrible and fits poorly. Straps are right in my armpits, no thanks. I made a second draft and it was only marginally better.

After the second bad draft, I realized that the cylindrical part of the bubble support was much more of a constraint than the support harness, so I drafted that next. I made a ring by using two different sized pot lids as templates, then rolled cardboard into a smooth tube that fit inside the ring, and trimmed it to fit my shoulders and chest. It's at this point that I remember that my collarbones aren't symmetrical, and the whole thing is never going to be perfectly symmetrical on my body.

Third draft of the harness, this time using the cylinder support as a guide instead of just freehand. Works a lot better. The bubble helmet fits nicely after widening the opening so my head fits through. Also added the back guard panel, which is a surprisingly complex shape - it's not just a simple cylinder, it's a conical section.

Disassembled and transferred the cardboard template to paper. By tracing only half the cardboard, and folding the paper in half before cutting, I can ensure nicely symmetrical templates. That wave-like shape is the cylinder segment, flattened out.

Transferring the paper templates to the Sintra. Tape it down so it doesn't slip and slide around while you're drawing.

I found out that if you heat Sintra enough that it starts to get very soft, it will distort a little bit, lengthening in the X direction and shortening in the Y direction. For slight heating and gentle forming, this isn't a big deal, but if you're doing a lot of sculpting of precise parts, it is significant.

The lesson from this is that if you're cutting parts that will be very heavily shaped, make sure your template is drawn with a centerline parallel to one of the original edges of the material. Otherwise, the distortion will cause your part to skew oddly and diagonally.

Initial batch of pieces cut. The harness body and the rectangular outer cylinder are cut from 1/4" material, the other parts are from 1/8" material. The rings were VERY hard to cut, as I don't have the appropriate tools or workspace.

Next post: Initial shaping and assembly

 

[nathancarter]

Initial heat-shaping. I temporarily stacked the rings with foam blocks and tape, to make a buck (I guess that's the word) around which I could form my cylinders.

Since my rings aren't perfectly symmetrical (bah), at this point I started to mark my parts with a sharpie, clearly defining a centerline and the front edge.

Shaping the inner support cylinder. Getting the ends to butt nicely together for a Sintra cylinder is hard; taping them down helps a lot. I intentionally made the center cylinder piece about 1/4" too long, so I could first make it overlap, then trim the overlapping ends for a pretty clean butt join.

Shaping the outer cylinder. I believe the saying goes, "Measure twice, cut once." I did not do this. That outer cylinder is supposed to go all the way around, and butt together with a bit of overlap. long, heavy sigh.

Well, this just means that I'll have two butt joints instead of one. I could have just cut out a second piece that was long enough, but I already wasted a big chunk of material when I was cutting that piece and my guide slipped off, giving me a wavy edge. This part is going to be 100% hidden anyway.

Hard part of the build #1: The latching mechanism.

There's an outer cylinder, and an inner cylinder, with the rings in between. One of the rings will be permanently mounted to the inner cylinder and one will be on the outer cylinder. The two pieces have to securely lock together, yet be easily removable.

Brainstorming on how to make the latches. I had to sleep on this for a couple of nights, then eventually I found inspiration in the removable lighting modifiers on one of my photographic lights. I don't know what to call this type of twist-and-lock latch, but here it is - I'll let the photos hopefully speak for the design.

Taped the latch pieces together so they're as identical as I can get, then finishing the shaping with a Dremel and heavy-grit sandpaper. Use breathing and eye protection, sanding Sintra makes gross powdery dust.

Latch engaged:

Latch disengaged:

All taped together. The latches work.

bottom view:

Next up: Gluing the pieces together, and fine-tuning the shape

 

[nathancarter]

Fine-tuning the shape and gluing.

For the most part, I'm using dual-melt hot glue in a high-temp glue gun. That usually works pretty well: The temperature of the glue is above the thermoforming temperature of the Sintra, so it makes a pretty sturdy bond; it has enough volume to fill in medium-sized gaps where my shaping and engineering isn't perfect; and, if I need to retry, I can gently heat the dual-melt glue with the heat gun enough to soften it and release it. The downside is that it's kinda messy, and on a big project you'll invariably burn yourself, and I just found out on this project that the sandable filler-primer does not like very thin "smears" of hotglue (pics to follow).

Cyanoacrylate is supposed to be pretty good too; I may use this when I need to bond Sintra to something else (probably not on this project though). Some people say E6000 is good, I haven't used it on Sintra either. High-temp glue sticks in a high-temp glue gun will make a pretty permanent and tough bond.


I don't have many fun pictures of fine-tuning the shape. I used a utility knife and heavy-grit sandpaper to refine and smooth the joining surfaces as much as I could. It took a long time, even though everything fit nicely with the tape.

The "walls" of the latching ring are made of four flat "sticks" of 1/4" Sintra, butt-joined to the latch hooks. For a strong butt join, I use a combination of staple-gun staples (on the non-visible side) and hot glue.

The fitment of the latching ring into the inner diameter of the main outer cylinder is sad, really sad. I'll fill it in later so it doesn't look quite as sloppy. For structural purposes I cut twelve triangular buttresses and glued them into place.

I'm reclaiming a globe that we had previously used for my wife's Barbarella costume. The opening was already widened and there were mounting holes already drilled. For cutting, use a Dremel - the speed will melt its way through the acrylic instead of cutting, reducing the likelihood of cracking. A hard cutting tool like a jigsaw is too aggressive and violent.

Making the mounting brackets for the bubble. A flat piece of Sintra approximately 1"x2", bent in half to about a 30-degree angle, then gently heated and pinched and pushed and shaped to fit against the inner wall of the main cylinder and the outer wall of the bubble. Lots and lots of heat-forming and test-fitting going on here.

Remember in post #1 where I said that the Sintra will slightly distort when heated enough that it's very soft? This is where I learned that. I had cut these brackets out of scraps, three from one piece of scrap and the fourth from a different piece of scrap. One of these guys was not like the other, so I had to make a fifth one and discard the oddball.

They're ugly but functional, and they're going to be hidden.

Glued these into place, drilled holes to match the existing mounting holes in the bubble, and bolted it on with machine screws, washers, and nice-looking cap (acorn) nuts.

It works. It fits. It's alive.
Click to play video, sorry that it's Photobucket.

 

[nathancarter]

Okay, now that the main structure is in place and the latch is working (WHEW!!) it's time to add the fan and detailing.

I had considered computer case fans, but ultimately decided on the high-volume battery-powered fan used for inflatable mascot suits. Runs for a long time on cheap AAs (I have a zillion rechargeables) instead of 9V, and moves a lot of air. Downside, it's very noisy. I can't really hear much inside there anyway.

My original intent was to put the (relatively heavy) battery pack inside the backpack/tank, and the blower on the helmet. With a magnetic electrical connector, the fan would automatically be powered on when the top half is latched into place. Well, my fabrication and electrical skills aren't quite there yet. Maybe on another build.

Before building the fan and vent hose, I need to built the large flat shield piece that goes on the back of the bubble. I had done my first test-fit out of cardboard but it wasn't quite right. I transferred half that template to paper, then back to another big piece of cardboard. Pretty happy with this second test-fit, with the exception of needing a little more to fill in the bottom edge. Back to another sheet of paper, then onto the Sintra.

This first pic, you can see my patch in the outer cylinder where I did not measure twice, cut once.

Shaping went pretty easily on this piece, a gentle heat over the entire piece, then a quick bend to fit it onto the main cylinder and globe, taped it into place, then a little more heat to "set" the shape.

Now I'm starting to figure out where the fan will go. [Pictures in my photobucket are out of order, grumble]

Gonna cut a hole right there to accept the dome on the back of the blower housing.

For the vent hose. The source material shows a corrugated vent hose and an elbow at the front. I don't have a clean corrugated vent hose handy, plus I'm concerned that the corrugation might slow down airflow. Laminar flow, turbulent flow ... it's been twenty years since my fluid dynamics class.

Vent hose is a 75-cents squirtgun from Walmart, a lightweight thin-walled plastic tube. Actually, it's two of those because I messed up the first one.

Cut off the working parts with a hacksaw or dremel cut-off wheel (utility knife didn't work on this hard plastic). Test fit to the fan output. This will do nicely.

When bending or heat-forming tubing or pipes, fill them with dense-packed sand, sugar, or cat litter - UNUSED cat litter - to keep them from kinking. Also, when making the curve, don't simply apply a bending force, as this will make the inner diameter of the curve crinkle up. Instead, think of it as pulling and stretching the outside of the curve. This will give you a smooth curved surface on the inner curve and outer curve.

If you're done heat-forming and have drained out the sand, but then you decide that you need to make just a little tiny fine-tuning adjustment, you better fill the whole thing back up with sand again. If you try to heat it up and curve it "just a little bit more" while it's empty, you will mess it up and have to drive back to Wal-Mart at 10:30pm to get another tube.

OK, so we have the outer vent tube but it still needs to point into the bubble. In the original reference images, the vent tube leads to an elbow that's at about 3-o'clock on the outer shield.

Problem #1, that's where my latch hook and bubble mounting points are. Poor planning on my part, I'm going to have to put the vent tube pass-through pretty far back on the outer shield.

Problem #2, the inner wall of the bubble is not at all parallel to the outer wall of the outer shield piece.

I could add an elbow piece on the outside and a second short segment of tube to the gap between the shield and the tube. That's a little closer to the original reference images, but I'm concerned that a hard right turn will slow down the airflow, plus trying to shape and fit that second piece of tube would be really hard.

So, I cut an access hole through the shield - and through the latching ring! - and heat-formed the vent tube into a relatively sharp angled elbow. It's ugly - real ugly - but it'll be hidden. In retrospect, this is probably not any better for airflow than having a separate elbow connector. Oh well.

For my own reference, I traced the shape of the outer shield onto my high-tech cardboard work surface, then shaped the tube to fit along that reference line.

After dumping out the cat litter and washing the tube, here's my fitment.

Pretty satisfied with that, so I use a bunch of hot-glue to permanently mount the fan.

Time to build a housing for the battery pack that flows nicely with the fan. This is a kinda difficult bit of design and engineering for me, to make a curved housing that fits on top of another curved housing. The paper in my previous pic is my first draft.

Here's a cardboard draft, this is the second or third revision. It's starting to fit like I want it to.

Transferred my pattern to paper then 1/8" Sintra, cut it and heat-shaped it. I formed it around a butter jar that's about the same diameter as the blower housing.

Fine-tuned the fitment, cut and shaped the ends to fit reasonably well against the blower housing. Ugly, but I'll patch these up later.
Added buttresses for structure, and built a door with an old hinge and cabinet-door magnet from my junk stash.

Some decorative brackets to hold the hose in place, and hide the gonna-be-ugly seam between the blower housing and vent hose.

Video of door fitment and battery pack. The battery pack is a very tight fit. I didn't properly account for the space of the magnet and the extra length needed by the power cable.

Next up: Patching a bunch of seams with Apoxie Sculpt, sanding and sanding and sanding.

 

[B Wo]

Cool! Looks like this will be a fun build to follow. Fun idea.

 

[Dspongberg]

Very cool build, I'm hoping that Nuka-World is a good DLC.

 

[Rnc88]

This is coming along very well. you really have nailed the symmetry, which is very difficult in a scratch build, BRAVO! I don't know if it'll help, but I have the lithograph, and Her position is slightly different from the others. from what I see, no more is visible, but if you need I can supply a picture. good luck!

 

[nathancarter]

Lots of progress since my last post, will try to get some more pictures up but might have to wait till after Dragoncon.

Let me just say, I'm in love with the gloss black Rustoleum Industrial Enamel over the sandable filler primer. Even a single very light coat is gorgeous.

And I'm annoyed as hell at the red Rustoleum 2-in-1 paint+primer stuff. The color is great, application is extremely finicky. I'm pretty good at rattle-can painting, but I'm going to have to re-do all the red parts after Dragoncon, after this stuff has cured enough that I can sand it off. 2 days of curing was not enough for sanding and second-coating, even though the can says 48 hours.

 

[nathancarter]

OK, picking back up after a successful DragonCon.

Did a ton of seam patching with Apoxie Sculpt. This stuff plays very nice with the Sintra; it sands and takes paint very similarly. For a seam that's "pretty good", I'll mix up the Apoxie, roll out a little thin snake (1/16" to 1/8" in diameter, lay it onto the seam, mash it down real good, then use a wet finger to smooth it out and blend the transition from the Apoxie to the Sintra. If I'm lucky, I can get it in one step and minimal sanding is needed. If the original seam was pretty bad, it might take two steps: First step to build up and fill in, let it cure overnight, then the second application of Apoxie to smooth and blend.

The Apoxie is somewhat heavier than the Sintra, and much more expensive, so if I have a very large gap, I'll jam a scrap or a shaving of Sintra down in there to take up as much volume as I can, then use the Apoxie to fill and patch and blend.

Laying down a thin snake of Apoxie along a seam:

Then pinching off the excess, mashing it into place, and smoothing/blending with a wet finger:

The joint between the orange plastic fan body and the Sintra battery pack housing was pretty rough, so it took a fair amount of material to fill it in, build it up, and shape it; later it took a moderate amount of sanding to knock it back down and smooth out the transition. It's not perfectly one piece now but it's pretty good.

Same thing on the lower half and shoulder harness.

As mentioned before, my work on cutting out the rings was pretty shoddy, and the joint between this ring and the latch pieces was really bad. So, I built it up with more Apoxie, with the intent to sand it down later.

Let all the Apoxie cure, then sand where needed. Do a good job with application and smoothing with wet fingers, and sanding will be minimal.
After sanding, this is actually looking pretty good, I'm OK with how it's turning out.

Moment of truth: the first coat of primer reveals all my imperfections. I used Rustoleum 2-in-1 Sandable+Filler primer. This is a high-build primer that will fill in and cover many small imperfections (or small details) and can be easily sanded to a nice slick finish.

Next up: Continuing to add details and refine surfaces

 

[nathancarter]

Something unexpected: The filler primer did NOT like any little smears of hotglue, where I had wiped off the excess. On visible blobs of hotglue it was just fine, but on the little smears that were invisible before paint, it looked pretty rough, it peeled and cracked.

This is in a place where I had tried to take a little shortcut, the underside of the latching ring would rarely be seen anyway. Well, I sanded down the cracking primer, and patched and smoothed this seam too. No shortcuts for me, I guess.

Next, going back to the upper part of the helmet. This is on the inside where the latching ring fits poorly with the main cylinder. This is going to be very rarely seen, but it was just so bad, I had to fill it in. On the right is the little "snake" of Apoxie, on the left is where I've mashed it down into the seam.

Something I've been procrastinating on, is the hole where the vent tube curves and enters the helmet. The hole is way too big and the elbow in the tube is ugly. Thought about filling it with hotglue and Apoxie sculpt, but I want to be able to disassemble the thing without destroying it, if I ever need to repaint it or make an update.

I sketched out a couple of possible designs, wasn't really happy with either one of them; the bottom one would be easier to make but not flow with the rest of the design; the top one would work with the design but be very difficult to make out of Sintra due to the compound curve shape.

Then my wife suggested mimicking the shape that I built for the battery pack housing, I slap my own forehead and say "why didn't I think of that?" So here we go.

Sketched it out a couple times in cardboard and paper to get the shape and fitment right and refined. Tape the paper into place, make notes on the paper as to what needs to be adjusted.

On the right is my original template for the battery pack housing, on the left is my first draft for the vent elbow cover.

Some up with a final layout , transfer it to Sintra, gently heat-form it to shape.

Glue it into place, add some little triangular buttresses similar to the ones on the battery pack housing.
Cut and shape a top cover that's similar to the battery door, but I ultimately decided that I like the look of this piece without the top cover, so it's not part of the final design.

Not shown: using Apoxie Sculpt to patch the seams on this front vent-tube housing. Same method as above, but I'm getting better at it - the blending work on that is one of my favorite parts of the whole build.

Hardware for my battery door. The pink tube is from my junk bin, it's the inner LED-diffuser sleeve from a broken toy lightsaber (the plastic saber blades were used to make Lady Loki horns, but that's another thread).

I was originally going to have the pink tube curve up and over, to plug into the little "tunnel" at the top - so it slots into place when the door is closed, and pops free when the battery door is open. Didn't have the skill to make that happen. The first try with the white was really bad, so I scrapped it. The second try with the pink was also really bad, but salvageable if I clipped off that extra curved bit. So, the upper "tunnel" just sits empty now, I might make a little radio antenna that goes into it or something.

Everything's coming together. Moment of truth #2: gray primer over the whole thing. (the pink and red tubes were not in place for the painting, of course)

Look at this. I'm SUPER HAPPY with this part.

It fits. It sits. Starting to look good, and although my con deadline is rapidly approaching, I'm feeling very confident about this build.

Next up: working on the tank and hoses.