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.

Magic Rose

 

 Turns out I never shared instructions for my rose. After being pressured by a whopping one request, I've decided to share this abomination of red cards with the 3 of you who actually look at my blog. I actually posted this tutorial on a site that shall remain nameless, where it was equally unused and found absolutely useless. Here's aiming for 1 out of 2!

(Open the images in a new window for full view)

 

If you attempt this, please share your results. I'd like to see how they turn out and what you chose as your "most hated abundant red card".

Horse Bridle and Wear Tests

I've spent the past two weeks letting people examine the horse in person. So far, it's holding up well. No visible signs of damage to the hull, and minimal wear. Only issue so far is a sheared wire attachment support in the neck which was quickly repaired. Survived some handling by some children. Only problems presented so far is the potential for solar radiation discoloring the hide. I'll need a phase-out plan for the horse when it reaches that stage. Until then, I've taken precaution to limit the amount of sunlight exposure on the horse.

One of the current ideas is to add horse armor, or at the minimum, a saddle and stirrups. However, I did end up needing to make a bridle for the horse. After examination of how a bridle was constructed, I had a small problem: my horse has no mouth to put the mouthpiece in. X-acto knife to the rescue!

 First, some reinforcement parts were added to the mouth, which also helped define the mouth region. Afterwards, I added a slot along the mouth line, about 1mm thick, to allow for a paper clip to slide through. The cut surfaces were coated with loc-tite glue to help control material wear and to seal the edges to the effects of water. Of course, this does render my original horse head template semi obsolete as it does not account for a mouth slot.

The bridle was built with the following (use at your own risk):

You'll need some paper clips or wire, and some needle nose pliers to form the mouthpiece. It'll also require an array of belt buckles, last covered in a previous post. 

Strap width is whatever you find handy. I ended up with 4-5mm thick ribbon to use. The original plan was to use fake leather from salvaged wallets, but the length was too short. I ended up using the same method from Aelia's armor straps and laminating two strips of brown ribbon together using fabric glue. Fabric glue holds fairly well compared to hot glue, and there's low potential of delamination due to high temperature. The result is a low cost and fairly stiff set of straps, adjustable for all your equestrian needs. Some sewing was required to hold the straps in the right directions. I wasn't going to trust glue to do the whole job.

For the low price of $2 for brown ribbon and $4 for glue, it's not a bad result. Especially considering it's adjustable and doesn't look horribly off, and I know very little about the actual construction. Looks acceptable to the untrained eye and that's all that matters for me.

Now with some reins, we can properly ride the horse! The horse has always been meant for Aelia to use. She's gotten few presents the past two years, and now she gets the biggest of them all, despite never having a horse in Valkyrie Profile. I always liked the idea of a mounted lancer, especially after playing Mount and Blade: Warband. Now I can terrorize the countryside and impale at leisure.

This Weekend's Project: 1:6 Scale Violin

This weekend's side project is severely lacking in the explosives department.

Tried my hand at #2 in Stringed Instruments Series, a Violin. The guitar was a fast project, and quite fun to do. This project however, was anything but quick, and mildly annoying to develop.

A quick search for violins yielded a blurry resized image of professional violin plans. The image was about the size I needed, and mildly blurry that I could still read it. After some resizing and quick drafting of some plans, I formed the basis of my violin body, in the same way I built the guitar.

This looks nice and simple, with tape holding the frame to the template, but the image lies! Taping a 5mm wide strip of Magic card and trying to get those pointed parts right was painful. Took a lot of time to get the laminations to stay in place while the rest of the frame dried.
 

Making the two faces was interesting as well. A violin has a contoured front and back, whereas the guitar I could slap on a solid face and call it a day. I took the contour map, made a model of it, then used it to form the pattern for my violin. Both sides differed in curvature, so I got to do this twice. Went through a good amount of cards trying to get the shape right.

After forming the sheet for the face, it was a good time to start cutting out the F-holes. Cutting them after being fully assembled would prevent me from cleaning up the other side of the holes. Unfortunately, the size of a violin prevents me from strategically placing the card back in interesting ways on the sides. What you see now will be obscured by clutter and will look less interesting.

 

Building the neck was much more difficult than the guitar. Here's a side view of how the inside was constructed. A hollow curve for the scroll, and lots of cobbled together laminations for the neck support. Peg holes were made using a 1/16" bit on a hand drill, same as with the guitar.

The main issue was trying to get the scroll shape, while keeping the side profile as a single card.I chose the more elegant route than the quick and dirty route of rolling up paper or shaving down the face to achieve the effect. It's a barely noticeable effect, especially at a distance, but I like knowing that it's there.

Stringing the violin was the same as the guitar. Stick white sewing thread into holes, stretch, wrap around pegs, repeat multiple times. I toyed with the idea of making the pegs capable of tightening the strings, then decided that was the stupidest idea ever. I jammed some knots into the pegbox and retained them with paper clips, then called it a night.

I have never played the violin. I can only guess that the chin rest is there to prevent your facial acne from creating a circular spot on the violin from contacting it for hours. Decided to try to make it removable for the sake of being able to. Worked out fine by using a bent paper clip anchored to a 4-card stack. The chin rest gets held in place as well by the spike I rammed into the tailpiece to hold it in place. I figured since there's some metal thing holding it in a real violin, I can jam one in mine to prevent mine from flying off after a slight nudge.

The bow used a large paper clip to provide support. I had underestimated the size of a violin bow. I always thought they'd be shorter than the violin. Seems like some are longer than the violin themselves. I opted for a 4/4 size violin and bow, so it's quite monstrous. The bow just uses paper to thicken the paper clip, and to provide an attachment point for the two bits that hold the string. Gluing them directly to a metal paper clip would have been ineffective and utterly silly. I ended up painting it with gloss black enamel and spraying it with a coat of clear gloss coat. Will that hold up against rough use? No idea!

I ended up using about six cards worth of material for this project, but ate up about 4 cards in development. Most of the parts were leftovers from the horse. This project helped deal with the pile of small scrap cards sitting on my desk, which is always nice as large projects yield a lot of semi-usable scrap.

More Horse Progress

There's slow progress for the horse. Just haven't had much of an incentive to get it going farther than it currently is.

In order to determine how the neck sections will be concealed, I started developing the frame for the horse's body and skin. Since it's going to be hollow, I've experimented with a more lightweight means of making the skin than the old method of piling on 110lb cardstock tubes until the shape gets fleshed out. The method involves making use of the tube framework that holds the body together, and adding depth gauges all along key points, then connecting them together with two thickness strips of 110lb cardstock. The resulting model looks like a wireframe outline of the desired shape, and presumably uses less material. It's a lot more fragile, but that's where the depth gauges come in to support the skin. The MtG skin should be thick enough to support itself once curved and glued.

Building the body requires the legs to be somewhat fleshed out as well. Tubes have been glued over the screws to provide access points. They're all outside the horse this time instead of the cosmetically better looking underside/inner side of the horse. I'll probably be tightening them often, so it's probably for the best. The screw assemblies compose of a countersink bolt, spring washer, two washers and a nut. The nut is held in place inside the center of the tubes by strips 2.5 Magic cards thick, 2mm wide, forming a hexagonal housing to prevent nut rotation. These will be later plugged with a 110lb cardstock core so the nut doesn't travel axially, fully restricting the degrees of freedom. If this wasn't added, tightening the bolts would be tedious and difficult since there's nothing to hold the nuts in place.

Since I've opted for the neck to bend downwards, I need to conceal the gaps that result. Rather than make a giant rotating joint that resembles a LEGO horse, I chose to go a more difficult route.

With the neck region and movement limits defined, I could figure out how much gap I needed to cover. At full upright, the neck has a large exposed gap at the bottom and a small gap at the top. The system has a static upper region, and a dynamic lower region.

At mid position, the edge of the upper triangular shaped cover piece lines up with the edge of the neck opening. The lower cover sinks inwards into the chest cavity, assisted by a set of hinges.

The neck further bends downwards 22 degrees to allow the head to reach the ground to do grazing poses. This does cause another gap in the upper region of the neck, which needs to be addressed. The lower cover dips downwards and inwards to provide clearance for the neck assembly. The purpose for this mechanism is to allow for a curved and molded shape to fill in the gap. Due to the nature of how I designed the neck base to bend in two sections with hard stops to prevent overtravel, a static section was not feasible. I needed something that would move to allow for clearance of the second neck joint that connected the accordion structure to the body.

The neck assembly, removed for detail, shows the general layout. A notched portion inside the lower cover prevents the cover from falling out the gap when the neck is fully upright. It acts as a hard stop around one of the structural tubes inside the body.

 

Here, the two hinges required to create the movement needed for the lower cover are visible. The hinge base also serves to strengthen the neck base against buckling. Also visible are the wire assemblies that hold the neck sections in place and limit rotation. The yellow wire section has less stiffness than the middle and lower portions. The assembly was too stiff with all three supports being made of stranded wire.

 So right now, the horse has a semi-finalized neck and the rough outline for the body. Remaining tasks involve stiffening the rear legs and fleshing out the rest of the body. I'll also need to adjust the center of mass, as it's currently front heavy due to all the neck structures.