This Quarter's Project: 1:1 scale M136 AT-4

This spring's project was an M136 AT-4. This piece accompanies Morning Rescue as a set. The goal was to have a rocket launcher that can store items inside, possibly one's lunch during the convention it would be used at. As a result, this program was called a Rocket Luncher, or Morning Breakfast. The launcher was designed for easy transport in mind and ease of assembly: the launcher was a commissioned piece that needed to be mailed out in a relatively nondescript box. I therefore designed the tube to be assembled from three shippable sections that fit in a fairly short box.

Morning Breakfast started off life as a three inch diameter $7 mailing tube from Office Depot. The tube was sized, then cut down to three sections for easy mailing. The center solid bands are simple connections between the sections.  The required diameter was at least 92mm per my estimates, which required me to expand the outer diameter from 78mm. A liberal arrangement of triangular supports made of Magic cards were placed all around the circumference, supporting a four thickness shell of 110lb cardstock which would serve as the actual outer shell. The shells were made in segments where I could attempt to hide the seams with attachment straps.

The project was designed to replicate as many of the features of the AT-4 in storage and ready to fire conditions. The goal was to add folding sights, cocking lever, safety and firing switches. The main issue was the lack of decent reference material, as I have no actual model to copy the dimensions from and the photos out there are questionable at best for scaling.

The folding sights were difficult to approximate dimensions for. I did manage to find an expired auction listing intact spare sights that I could easily copy the dimensions for. The center aperature on the rear sights are 2mm and 7mm per the manual I found circulated, which allowed me to determine the remainder of the dimensions. These were liberally constructed with Magic cards and some stiffened tubes with super glue and 110lb cardstock.

The sights fold neatly between the storage compartment's rails, which would eventually be protected by a slip cover. The rails were stiffened by bamboo sticks, so they would not shear apart during use. The front sight is approximately the same as this assembly, but with smaller pins for retaining the sights.

The housing for the firing lever was the most difficult to replicate. My approximations are sufficient, but could be done better if I had access to a real copy. The parts were freehanded, then transferred to a template which I could then shape and minimize seams.

The shutters for the sights were simplified to reduce the amount of work required; the curves were approximated with straight edges that I smoothed (not really) out. The rail was stiffened with a trimmed bamboo stick approximately 2mm wide. The shutter was made of an upper and lower half, both stiffened with a healthy heap of Magic cards. Both were sandwiched together afterwards.

After both shutters were built, the details were done with laminated 110lb cardstock. The letters were crudely drawn and cut, so the (useless) instructions on the covers would stick out after a coat of paint. One sloppy test coat later, and the results were mediocre.

The shoulder rest was another element that was difficult to approximate dimensions for, until I realized that the lines match with specific portions of the octagonal muzzle cover and ends. That made copying it easy. It started off as a hollow 110lb cardstock shell, reinforced with two layers of Magic cards, then an array of 110lb cardstock tubes so it would not collapse when subjected to any force. The strap was made using a cheap wire picture frame I found at a Wal-Mart, and secured with a nylon webbing with a Size 24 snap fastener.

After a vigorous painting, I secured the elements in place with straps, approximately how they'd be on a real AT-4. Whether I did that remotely close to the real model is anyone's guess.

The rear exhaust port still has the end cap from the mailing tube in place for storage. I didn't bother painting that black to mask it.  The safety pin was made from a paper clip. All the bolts on the end section are actual bolts, adding a bit of weight to the overall model, but were easier to buy than build approximations for.

The springs for the red safety lever and the folding sights were taken from some hair clips bought at a dollar store, and bent to fit. As a result, the safety lever can be held down, and the flip up sights actually flip up.

Pulling the sight covers back (and ignoring the instructions to "Press" ), the sights pop up.

 The cocking lever slides somewhat freely, and the firing switch is spring loaded to allow for maniacal button pressing.

The overall costs for developing and building the AT-4 were fairly low, but annoying. The plans are not refined, and therefore will not be shared unless there's enough demand for it (which from this blog, means they'll never be released). I don't plan to label the launcher, as this needs to be shipped out fairly soon and I'd need to design all the graphics for the instructions with my mediocre graphics processing skills.

Completing Morning Rescue

Well, that was a terrible 7 months. Here's the latest update:

Mission Accomplished. 

So, I've clearly failed in item #2 of my original plans. No shutters for me. I decided to give up on making the impossible possible, and cut my losses.

The two sand reservoirs required a clear domed structure which I did not have any means of fabricating. A trip to a Michaels yielded this peculiar item (also purchasable off Amazon, apparently, if you want one). Looks like a portable epilepsy inducer. I bought it and destroyed the item, saving some children from a cruel fate, and netted some components in the process. Turns out the covering splits in half and is the perfect size for the reservoirs. Now, to build a structure to hold the domes in place on the shield.

Build two of these and we're set.

I sealed the open sides with a piece of plastic card sleeve, to form what looks like a terrible Diablo health icon at 70% HP. I may have put more sand than I'd like.

In order to make the little channels of sand that "flow" from the sand reservoirs, I decided to try molding them. Easiest way was to cut a template in cardboard, overlay one sheet from a toploader sleeve, and melt it into shape with the tip of a hot glue gun.

That yielded some weird shapes that were damn near impossible to seal with sand.  But they sure fit well.
 

I did manage to fill the parts with sand, and seal them up by sandwiching a ton of sand and hot gluing the space between the part and another sheet with copious amounts of glue. Then I tacked them onto the reservoir housings. They added a negligible amount of height but I could have compensated earlier by trimming down the housing heights.

The end goal is a very subtle, raised bubble that does absolutely nothing. You can probably just paint this red if you were lazy, and no one would really notice or care.

On the subject of painting... time to completely ruin my work by a lackluster paint job, a signature of every project I do. I used Krylon's satin finish nickel to do the outer components, and smeared a glob of horrendous red/silver mix all over the center for a metallic lavender. I made sure to use a pipe cleaner to spread some silver unevenly all over the center housing and outer rings for that extra "1st grade look", because nothing says winner like a grinning child who shat himself. 

 

 And thus Morning Rescue was completed. The project ultimately consumed more cards in development than the actual piece took to build. Probably took under 25 MtG cards for the final construction, and about 50+ for the abomination that never came to light. The plans I used are rough, but probably not good enough for an aspiring cosplayer to make use of. I don't think anyone's dedicated enough to machine their own gears out of cards anyways.

This Month's Progress: MORNING RESCUE

Three weeks have passed. What have I built and learned about Homura's Time Shield? I learned that no amount of Morning Rescue can make this go smoother. Here's my current project goals and the resulting mess that ensued:
 

1. Build the most detailed Homura's Time Shield from Puella Magi Madoka Magica out of freakin' Magic: the Gathering cards. Since no one else builds with MtG cards, I'm already a winner. Hooray for shallow goals.
2. Make the gold shutter covers for the sides open. Not "removable" where you pop them off and lose them during a convention. They must open and retract into the shield.
3. Add loose sand. No cheating with painting the sand containers red. The sand containers must be spheres and cannot be cheap jello cups or colored gems.

With the project goals defined, time to shoot myself in the head with an AT4. Let's take a look at what I've uncovered during the course of making this.

Planning and Research

There's two principles of building this shield: Aesthetically or Accurately. Aesthetically being that with exception of the center gearbox, the shield's features are symmetrical. Accurately being the result of my research into the actual shield itself: as close to the anime concept/production art as possible. Interestingly, you cannot have both.

This particular screencap highlights asymmetry in the sand flow device. The green boxes highlight non-uniformity in the teardrop shapes. The red boxes show where the dimensions differ where the teardrops connect to the center. One can reasonably argue that this is due to the animator's decision to not bother making it perfectly symmetric since that would involve more work. Let's assume that this is a once-of error.

The line art/concept art for the shield. However, I've mirrored the half and shown it in green. Original is red. There's numerous dimensional differences. These differences also match what was in the screencap. I was led to believe that this was perhaps the result of sloppy source material resulting in sloppy details in animation.

I was about to do a "corrected" version of the shield, where everything is symmetrical. Other examples of the time shield did this, since it's easier to do and looks less odd. However, the final piece of evidence that led me to proceed with the asymmetrical design was the production notes sleeve. Brief glance, the cutout is symmetrical. Upon closer examination, there are subtle signs that the differences were intentional. It's a lot easier to replicate something that's symmetrical especially with computers. It takes more effort to make something not.

Construction

Compasses are useless. The compass lead is blunt and imprecise. It's easier to draw a circle by making two holes on a strip of paper (equaling the radius), pinning one end to the center, putting a pencil on the other hole, then looping around. It's also reliable since you don't need to adjust the compass each time for repeated passes. So much for buying a compass.

Building gears teeth-by-teeth by gluing each tooth equally spaced around a cylinder is tedious. Given the alternative of cutting each tooth around a circle, gluing teeth one-by-one is easier. Screw building gears ever again. At least they're decorative and don't need to bear loads.

My plans focused on making the shield shutters open using gears.  Worst idea ever. I do not want to cut gear teeth by hand with a knife. Archimedes did it, but I sure as hell don't want to. Did I abandon the effort to make the shutters open? Nope! After some math, I determined the dimensions to get a four bar linkage going that would open both shutter halves with a small 30 degree turn.

The plan is to have the two large rectangles attach to the shutters, then have them open up by rotating the center ring and bar. If it doesn't work, I can always just scrap it, build a static shield, and cry in a corner. My development tests have shown the concept can work; it's just a matter of not screwing it up.

Currently, here's where I'm at. The outer ridges were difficult to judge the height of, since the line art and screencaps don't give much depth about any features. I'll consider releasing plans if someone really wants them.

More progress whenever it comes. Let's hope I succeed. 50 sheep tokens are resting on this.

Miscellaneous part upgrades

I've finished up a set of long needed upgrades to address a joint problem: lack of a locking mechanism to retain the pin swivel joints in place. Long overdue, but I now have the tools and tech to pull it off. The main priorities were to upgrade the arms with this new tech, then the legs.

The mechanism is fairly simple, but annoying to build by hand in multiples. The principle is to use a locking ring clamp around a groove in a pin. The ring must have an opening to behave like a spring, so it widens as the pin passes through, but contracts after the groove reaches the position. The ring should then hold the pin in place but also allow for rotation. Much easier to do with plastic parts than Magic cards and paper clips.

The main components required are a cylindrical pin, a spherical shape at the top of the pin, a sleeve and a metal ring. The sleeve is comprised of two halves: the lower half that covers the pin, and the upper half that houses the sphere. Between the two halves, the metal locking ring rests, and will lock into the groove created by joining the sphere and pin. For the pins, I used the trusty cube to create 6.35mm diameter pins. The spheres were built using a tapered 90mm long strip of 110lb cardstock rolled around a 3.175mm (1/16") diameter bamboo stick.

In order to create uniform diameter sleeves, I had to build some tooling. Rolling up some paper around a bamboo stick, I now have roughly uniform rods to roll Magic cards around. These were built using a simple excel spreadsheet to calculate diameters in terms of paper lengths and thicknesses. I had some old ones from a few years back, but re-made some new ones to help do fit checks. Probably would be easier to use drill bits since metal doesn't deform as easily as paper, but that's how we roll.

I used Magic cards rolled around the 6.35mm (1/4") diameter rod to form a sleeve with the thickness of two cards. That thickness is the minimum I found needed to allow the rings to bend outwards and also remain stiff. A strip about 45mm long is enough for the inner housing. I used another 45mm long strip to connect the two halves with the ring in between to hold the assembly together.

 For the rings, I straightened out a paper clip and rolled it around a 5.7mm diameter rod with the help of beadmaker's pliers. There's a bit of fine tuning afterwards with the finished pins to get them to lock snugly.

The new locking mechanism allows me to do another upgrade: fixing the ankles. Right now, the ankles are just a hinge joint. I opted to upgrade the feet to provide two swivel joints and a hinge joint to allow for better poseability and stability. However, the foot requires a more delicate structure due to the small envelope. Therefore, I needed to downsize the scale of the locking pin mechanism.

In order to build more delicate portions, I had to downscale the pin joint from a 6.35mm (1/4") diameter pin to a 4.2mm diameter pin. The rings also had to get scaled down. The hinge joint pictured above ends up being 8mm wide and will support a 4.2mm dia lower pin and a 6.35mm dia upper pin.

 The hinge goes into two different sleeves to form an ankle joint for a foot. The smaller 4.2mm dia pin goes into a 4.2mm dia ID x 6.35mm dia OD sleeve with its own locking ring. The ID of the ring ended up being 4.1mm. The larger 6.35mm dia pin goes into the shin.

Here's the component breakdown of the leg. The pins were left unsanded, to allow the glossy coating of the card to help reduce friction. The sanded tubes are unsanded in the inside.

Adding depth to the pins so they aren't just sticks. Was easier to super glue blocks of card to the sides, then carving them until they were round. 

Fleshing out the calves with liberal use of 110lb cardstock. 

To finish the foot, I traced out a footprint, and marked the regions to trim off on the sole. The black Sharpied out regions get cut off to form a rounded block that I can then carve with a hobby knife. Perhaps the most difficult part of the job, as the foot needed to be smooth and not look like total ass.

After long hours of not doing anything productive, I whittled down the foot to shape to something remotely considered acceptable to a blind man. More liberal use of 110lb cardstock fleshed out the shape of the legs. After this, it was ready for a coat of "pale sickly girl" paint tone.

The new foot and ankle fixes some problems with articulation, allowing for better balance and stability. I can now reduce my reliance on obitsu stands, at least for barefoot poses.

I'm quite happy with the stiffness and strength of the new joints. I do have to upgrade two more dolls with this mechanism, assuming nothing goes bad with Hotaru's new ankles over time unexpectedly.

Finishing A Horse

Nearly three months after initiating building the first components for the horse, and nearly five months after deciding to build this, I've reached the end. Last time on the Vortex'o'suck, I had finished the entirety of the horse's neck, with means to conceal the largest gaps resulting from neck articulation. All the pre-planning and well-documented work ended there. Now it's time to throw that all away and free-hand everything. Why? Because I have no plan from here on out!

With the neck mechanism built, I can figure out the envelope for the chest cavity to conceal the sections. This involved cutting away the chest cavity and replacing the scaffolding with some nice solid walls. Most of the thin strips of cardstock will remain to keep the structure, but thin areas like the chest were removed entirely. They have served their purpose.

Using an old technique of "build a pinata", by gluing strips of paper until a hollow shell is formed, I completed the chest cavity that houses the neck assembly and hides the gaps. This technique will be used for the rest of the horse from here on out, and was the single cause for the delay in completing the horse, since it's an unexact method and tedious to do. 

 The upper assembly required a new cover. I peeled the previously built scaffolding away and formed a new cover. I opted for a double layer of card to ensure structural stiffness and to conceal join seams on the other side by hiding them between two layers.

 Here is the new cover, with the old scaffolding in place over it. The fore legs have been fleshed out with 110lb cardstock internally, and a single layer of magic card over it.

Building all the leg cover plates was annoying. I could wrap the entire body around with a layer of card like I did with the camel, but there were some sections that it wasn't feasible with due to the hinges. So, I decided to go with sets of mirrored cover plates to reduce the number of unique parts and to allow for somewhat easy assembly.
   

Once the wireframe support was constructed, more pinata building was in order. The opening on the side of the rear leg was added to account for the supports holding the rear legs in place. The rear leg assembly itself was a balance of form and function, as I could either go for a structural column between the legs, or remove it entirely and let the legs complete the shape themselves.

Some trimming later, and I built a dividing column for the rear legs. Some pillars were added to maintain strength, even though there should be zero interaction in the direction of the plates during normal operation. Figured it's a better option to do this now than deal with depressions in the card face later.

 With the rear structure completed and the front skin done, it was time to make the rest of the body. First off, I ended up breaking my personal rule of not using lands for construction. You can see the outer shell made of some swamps. They came in some free intro packs and I was actually dwindling on chaff cards. Not like anyone's going to care if I use some Tenth Edition swamps. People already assume I'm using lands anyways. I need to save the most horrible of cards for other projects. The skin was reinforced in some areas with two or three layers of card. Damage was a concern, and repair would be difficult. I am keeping the templates for all the free-handed sections in the event I need to redo sections, but I'm hoping I won't need to. 

 After assembling the last remaining parts of the horse, I added a tail (which I had never made provisions for in the first place) by putting two twisted strands of black electrical wire flanked by some black wig hair. I probably need more hair. The wire's there so I can attempt to put the tail in dynamic poses, which so far doesn't work.

 Adding all the skin and remaining sections used up a total of 69 cards. With the previous sum of 246 cards, I'm slightly over the original budget with 315 cards. Still not bad. Is it worth building a 1:6 scale horse out of cards? Totally not. I'd recommend buying an artist's reference model if you want it as a reference, and I'd recommend buying a professional made one for $99-300 that isn't made of flammables and cellulose. Although neither of those lets you have silly poses with 1:6 scale figures.

If you're interested in the plans for the horse, drop a comment or send a message. Otherwise, I won't bother posting them. They need some clean up anyways.