Materials Monday: Assembling Final Boss Grade Mirai Frame

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I've been waiting for the Cortex Mirai dolls to come out for years.  That isn't an exaggeration--literally, years. 

The reason is, I really like hard-bodied dolls with non-strung articulation.  Vinyl is nice and light, but it's like a stain sucking sponge, and you're always a little worried you're going to stick a pin through it when using it to fit for sewing.  Resin is nice and strong, but heavy and a paint in the butt to pose, even if you've sueded and wired the body.  You can make it easier to pose, but it will never really be able to compare to a friction jointed doll.

I have a Hujoo ABS 1/4 doll which has just fantastic articulation, the problem is the sculpting isn't... great.  Therefore, when a hard-skinned version of the beautifully sculpted AND beautifully posing Smart Dolls was announced, I thought I would finally be getting my ideal!

Now the Cortex dolls come in 3 grades: Pre-assembled, Ninja (you put the shell together but the frame is assembled) and Final Boss Grade (you put together everything).  Final Boss Grade seemed perfect for me because a) I like to see how things work and b) I like to make my own adjustments.  I've been tweaking doll skeletons since my very first Pullip doll arrived brand new & broken in 2004.  I'm good at it.

So let me get this out of the way: Assembling the frame was not easy

The shell?  Yeah, that was cake (coming next week in part 2!).  The main problem with the frame was that the only official instructions were Danny Choo's official video guide, which assumed that you'd be doing it in the store as part of the Frame Challenge, in which case you'd be sitting at a table with a skeleton you could refer to with what kind of screw goes where labeled on the frame.

For me, I had to stop, rewind, play, freeze, rewind, to see which way each bit went, and then count up how many #8, #14, etc screws were used, compare it to how many I had, and figure out which screw was which # and therefore went where that way.  Why not just experiment?  Stick a slightly too big or too long screw in the wrong place, it's a hell of a lot of work to fix.  Screw, unscrew, rescrew any plastic hole, it will get gradually looser every time.  I know this from experience, so I was careful to get everything right on the first try.

That's why I came up with this:

Save it, print it, whatever.  You get 3 screw sizes, which I just call Small, Medium, and Large (or short, medium and long.  whatever).  They go where the chart says S, M, L.

Another problem is that you shouldn't assemble the frame exactly as in the video and then put on the shell bits.  You specifically SHOULD NOT ASSEMBLE THE SCREW ON FEET PARTS. 

This comes back to the reason I didn't just screw things together to see if it was the right screw for the hole. 

When you screw them together, then take them apart, insert them into the foot bits, and screw them together again, you can't get the feet together quite as tightly because the screw will not go in as deeply as it did the first time as it's now also going through the shell.  Then when you need to remove the feet, the peg pops out of the foot more often than the shaft comes out of the leg.  Not a big deal if you're not taking the feet off a lot, but kind of an issue if you have tight shoes that might not want to give up the foot, or want to swap out flat feet for high heel feet.

So anyway, don't do it.  Just don't assemble the feet until you do the frame part. 

Here's the list of tools I used to assemble the frame.  Most of them are tools Danny listed as you'll need, too. I didn't include a Q-tip in my pic, but I also used those for grease-smearin'.  I use a flat head screwdriver to tighten screws as it's less likely to strip the head.

My additions are parallel gripping pliers (for gripping hex nuts like a wrench, the jaws open with a | | shape vs most pliers which have jaws that open with a \/ shape).  I needed these to snap the ball joints together.  I thought maybe it was because of my small, girly hands--except I can crack open walnuts bare-handed (an excellent party trick for making creeps disappear, btw) so when it comes to hand strength, I'm pretty good. 

My other adjustment is to drill holes into one side of the tubes where arm, wrist, and ankle shafts go into the body.  For this you need the smallest drill bit you can get, and whatever tool you have handy to drill with it.  Mine is a 1/16" or 1/32" or something ridiculously tiny, smaller than the wire of a paper clip.  You don't NEED to go that small, but smaller is better. 

Let's cover the holes and why I did them first, since that's what I think I'm going to get the most push back over:

Why pressure release holes?  Because even with grease, pushing, removing, re-applying grease, pushing a teeny bit further, removing, re-applying grease, I couldn't get some of my shafts into my tubes.  Like I said before, I've worked with a lot of plastic frames, and I only pushed with as much force as I could before I could feel the plastic starting to give.  That's bad, nobody wants snapped plastic bits. 

These dolls were designed to have really good torque, which I love, and I didn't want to lose that which I would if I did the obvious solution of sanding down the shafts a little bit.  Torque also wasn't the whole of the problem: whenever I removed a shaft to re-grease it, I heard "sssssssssssssssssssssh-POP!" which made me realize that the issue I was having with removing the pegs had at least a little to do with a vacuum, so the difficulty I had with inserting them probably had a lot to do with resistance from compressed air.  The solution: a valve.  A valve wouldn't affect torque at all.  So I drilled a teeny hole, tried again, and the shaft went right in, nice and snug without having to apply 'might-snap-plastic' force.

To measure for where you need your pressure release holes, hold the shaft of your peg alongside the tube you're supposed to insert it into.  Mark a dot with a pencil about .5cm or 1/4" CLOSER than the end.  The ankle/wrist tubes are solid plastic, so it doesn't matter where you put them in as it's not going to cause a weak spot.  The upper arm is split, so I decided to put it in between the seams for the most structural integrity. 

Drill the hole.  You're only going to drill until you hit the hollow core, not all the way through.  Done.  Easy-peasy.


The Ball Joints:

Ok, so this part there is no pictures because it took both hands to do so no hands for picture taking.  Also, the modification I made was so slight I don't think a camera would show it because I couldn't see it with the naked eye.

The shoulder, wrist, and ankle joints are in 3 parts.  The base, which is a round end with a little bit in the middle sticking up that you slide the ring part over, and the cap, which looks like the base except the part in the middle is even tinier and should, in theory, snap all three pieces together nice and snug.

The trick is you have to push the cap on perfectly straight.  While you have a joint that you are holding together in one hand that you've greased, so your fingers get greasy because you can't snap it together straight very easily, and the more you try the more grease gets everywhere and the harder it becomes. 

In Danny's video he suggests you use the provided sanding sponge to wrap around the joint.  The sanding sponge in the kit wasn't big enough, and wrapping the joint in my T-shirt rag didn't provide enough grip. 

My solution was the wrenchy-pliers.  I held the base in one hand, lined up the cap over the greased donut bit in the center, wrapped it up in my rag (to protect the plastic from getting tool-mark indents), and used my thumb and forefinger (of my holding hand) to keep the edges parrallel and then applied pressure with the tool.  This worked on almost all of the joints.

But not all of the joints.  One of the shoulders just Would. Not. Go. I even ended up bending the little peg in the cap almost to the point of breaking.  Something was clearly wrong with that joint.  I disassembled it, examined it, and saw no obvious issues.  No flashing that hadn't been removed, etc.  It was just impossibly tight. 

So I opened the hole (in the base, that the donut/ring joint was pushed onto) very slightly by running my razor around the inside.  Not even enough that I was getting curls of plastic coming out, it was just a veeeery slight scrape, test, scrape again, test, until the peg went in.

When the peg DID finally snap in, the fit was tight.  If I had to do this again, I think I would try scraping the other ball joints slightly in the same way to make it easier to insert by hand so I wouldn't need the wrench, as scraping out the hole did not remotely loosen up the torque--if anything the ball joints are too tight, I had to open and slather on extra grease just so that they'd move.  I don't know if it's a temperature difference where I am to the conditions the doll was designed for, but these joints were just too tight by default to be put together in the way they are in the video. 


The Exception:

There's one last bit that I had an issue with that I wanted to talk about for any prospective frame-assemblers.  That's the cap on the bottom of the upper arm that holds the 2 edges of the upper arm together.  Adding this made the elbow shaft that inserts into the upper arm impossible to fit.  I couldn't get the end of the shaft into the opening, not even a millimeter.  I added the drill hole just in case that would fix it, but that didn't do a bit to help. 

I'd already assembled the shoulder joints which I'd had to modify with a razor, so I knew some of these pieces just wouldn't fit together without some assistance so I scraped out the inside of the arm after the cap had been added on both sides until I could get my greased shaft in.


Apart from these bits, the rest of the skeleton frame assembled the same way as it did in Danny's instructional video, which you should watch.


Total assembly time for my first frame (including all fixes and video watching/rewinding, counting up screws, fetching dremel & wrench) 1 hour 20 minutes.   I did not make the 1 hour challenge.  Oh well :P