This Weekend's Project: Cleanup

 Never officially finished the Demoman and posted any of the results on this blog. Been overdue for two years. Wasn't entirely happy with how it came out, but I had a chance to redo some of the problems I really didn't like about the first attempt. It's a good opportunity to share what I've learned during the process.

 

First, I didn't like how I did the head. Plain generic expression. I carved a slight grin to his face. Can't say it's my best work, but it helps a lot. Not bothering to completely redo the head this time. It wasn't as bad as the first Medic's head. That was horrible. This was one of the later sculpts that wasn't entirely made of suck.

 When I started out, I was still using some lackluster materials to accomplish the job. Notably belts made of black construction paper fastened together with a wire hook that was neither strong or pleasant to look at. Had a chance to correct that by making some fake leather belts. Picked up an imitation leather wallet and stripped it apart for materials. They're just long enough to make a belt, with some extra length to it. In this case, they were enough to go from the Y shape fork in the back to the front belt. It being vinyl, it was easier to assemble than regular cloth. I had the lovely option of either sewing the belt straps together, or just using hot glue to get them into place. Either method provided a satisfactory result. If you're trying to avoid seamwork, a thin application of hot glue will work. Just don't expect stellar results in extreme heat. Or leave him out in the sun.

 

  The grenades on his vest were made of Sculpey. Bad idea. They were heavy, and not to mention, didn't glue well to anything. I had made sleeves around the thick middle section, and glued those to the straps. Now with better tech, I made the grenades out of 110lb cardstock rolls that are much lighter and more willing to be hot glued into place. I did experiment with fabric glue, but that wasn't strong enough to hold that into place. It may have been if I had let the fabric glue cure for more than an hour. I wasn't taking any chances.

The smiley face was originally paper taped to his crotch. I guess that's how it's supposed to be. It doesn't provide a good result though in 1:6 scale as the tape degrades. For a permanent solution, I glued the paper drawing to a small piece of white cloth, left 2-3mm of cloth over the top, and sewed it to the pants. Fabric glue in this case worked wonders. Don't even bother trying using regular glue with fabric.

The pants themselves, I altered so they weren't as loose at the waist. Not sure what I was thinking at the time, but they were obscenely baggy. As a result, he had loose rapper pants that constantly needed pulling up. Unfortunately, unlike rappers, he didn't have underwear. That was a dead giveaway that his body wasn't actually black either... I added velcro to his fly and narrowed the waist to allow for less mishaps involving pants. Because a drunken man and pants never tend to be good friends.

I learned long ago that you cannot paint directly on rubber. Well, you can, but it doesn't stick. It rubs off easily and does nothing useful for something that will receive heavy play. However, I did learn that if you put kneadatite over rubber, you can cheat and make it paintable. It does add a ridiculous amount of thickness to the medium, which in the case of a flexible rubber hand, any thickness is ridiculous. The hands were immobile and not even worth trying to use to hold anything. Method #2 to the rescue! With the power of enamel paint, you can paint rubber, just not well. If you cover it with a layer of Loc-tite or super glue of any sort, it'll form a nice solid layer that's thin but still somewhat ok. I haven't fully tested the durability of it, but it's an improvement. You may ask "why not just buy a body of the correct skin color?" I'll reply with "This body cost $5 and the correct one costs $30." That body also requires a totally different head. I'm not making another head. Inverse Michael Jackson it is!
 

Now that the Demoman's officially done, I'm liking him a little better than how it was originally. I didn't make many photos with him in it due to his hands being a liability in holding props. And that he looked mediocre. Now, I can close the project also officially get rid of it for extra shelf space. It's finally in a state that I'd consider "presentable" and safe for someone to handle.

This Week's Project: Weight Loss Program for Miniguns

Chalk up another item on the list of "things I'd prefer not to ever redo but ended up doing anyways".

I had an opportunity to try out building something with the new revised minigun schematics I posted a while back. Seems that there's some errors that needed to be corrected with those schematics, in terms of a few dimensions being wrong. As posted, they either require longer support arms on the handle mount bracket (sheet 2), or a shorter profile on the outer barrel support (sheet 1). A modification of 2mm more on the handles or 2mm less on the outer barrel support (actually that needs to be dimensioned in general) will fix the problems. Oh well. None of you actually are using my plans anyways, so you're not affected.

Since this build used the newer schematics and improved building methods, I have officially designated this model as the "production" model. I've taken the opportunity to try out different build methods to lighten up the minigun as much as possible. Also, I've forgotten how I built it in the first place, so I had to.

The main differences in the production model and the prototype involve the larger, more liberal use of Magic cards. The whole handle bracket for the prototype was purely 110lb cardstock, whereas I've taken the opportunity to experiment with hollowed assemblies for the lower bracket. The ammo chute, power control module and bottom pipe mount were built the same way with Magic cards. The piping itself was done properly, at the elbow. I achieved a cleaner bend by notching sections of tube evenly to form a gentler curve than the atrocious abrupt elbow on the prototype model.

The drum is the biggest change. I made the drum as thin as possible knowing that a wall thickness of 1mm is sufficient for the mildly cosmetic nature of the shape, and that I was going to reinforce the middle and ends with a three card layer circle plug. There's now a taper from the aluminum section to the start of the black region, a task not feasible back then in the era of manual sanding. Having a Dremel allows for greater opportunities! The end caps on the prototype may have been constructed from a back of a art sketch pad due to the supreme rigidity. That material is also significantly heavier than Magic cards.

The minigun barrel spindle assembly was built with purely 110lb cardstock this time. I think I may have used a plastic tube in the prototype to reduce friction. That may also have been a big factor in the weight reduction.

 The rest of the build was the same as the last. Except I had no idea how I pulled off making the rear handle bracket without a Dremel. Or in general. I ended up shearing off a section in the middle and needed to reinforce it with a paper clip rod. I'll call that "planned strategic structural enhancement".

I noticed a long way though that I undersized the minigun barrels from 6.35mm to 5mm. I don't really care and I don't think anyone else does either. It looks OK as is. Makes painting the barrel assembly easier.

Here's the completed production model Sasha, Serial Number 0002 (assigned one, as though I'll be making more, but you never know). The Mini MS stand I bought a while back finally found a good purpose. Just the right height to display this monstrosity.

The build took around a week (with copious breaks in between part fabrication), and definitely was made easier with pre-existing plans. However, I had some quality issues with the large drum that resulted in a warped outer surface. That entire drum needed to be scrapped and redone, costing a day's worth of work. It's not particularly an annoying project to do, but it's not pleasant either. I did achieve a noticeable weight reduction, but not enough to allow the minigun to be properly wielded by the Heavy.


As for the fate of Prototype S/N 0001, it shall remain in possession of The Vortex as no smart person would want the flawed model (and I actually like the older one better for some reason). S/N 0002 shall be used as barter for rare and exotic trade goods.

This Fortnight's Project: Sticky Launcher

Decided to try compressing the firing mechanism used on the Rocket Launcher into a smaller space. As it stood, it used one mechanical pencil spring and one retractable pen spring. The goal was to simplify it down to a single spring for actuation and firing.

Mechanics
In reducing the size, I chose to use the smaller mechanical pencil spring (12mm uncompressed, 4mm compressed) as the propulsion method. Preliminary tests with the smaller spring yielded satisfactory results in terms of projectile range and speed.

The firing rod was also size reduced, with a diametrical drop from the Rocket Launcher's 3.175mm bamboo stick to a 3mm diameter Gundam part runner. The firing stroke was limited unlike the Rocket Launcher's massive 70mm displacement to a more modest 16mm. Previous experiments in firing mechanisms showed that additional stroke length did not appreciably contribute to projectile performance.

Actuation
This design uses a paper clip bent in a box shape to act as a flat spring. There are two "arms" that connect to an obstructing rod to block the head of the firing rod, with the remaining side fixed to the barrel. Actuation is provided by a 3m MtG laminated arch that depresses the paper clip arms, lowering the obstruction and allowing the firing rod to complete the stroke forwards. A very primitive mechanism, but it offered reliability.

The initial design used a fairly long flat spring, with arms 20mm long. It worked just as well after a reduction to 13mm in length. For this design, a shorter mechanism is ideal. A shorter spring provides a longer stroke and requires more effort to depress, giving the user more of a sensation of pushing a button.

Diagrams
Perhaps the most pointless part of the post, since none of you are ever going to try to build this. Posting it here as reference regardless. Only core mechanism parts are diagrammed. The model's fairly simple that you can half-ass the rest and still have it look decent.

Prototype Testing Results
The initial prototype cycled through several rounds successfully, but there was some sign of wear where the firing rod head contacted the latch spring. There was also a significant reliability problem with the initial design, where pushing the firing rod back with any ordinance met with some interference with the latch spring. To solve this problem, another step was added to the firing rod, so the latch secured a section in the middle of the firing rod head than at the front. Stroke travel was not affected.

Ammunition

 

For the sticky bomb, I used a clear Gundam runner and stuck the ball of spikey death on top. From estimates, a sticky has spikes that are 1/5 of the diameter in height. I wasn't concerned with accuracy of the sticky, but more of "will it fit in this stupid launcher". A 7mm ball with 2mm spikes barely worked, as my inner barrel diameter was 11mm. Had to trim them down a little to fit better. Also, for ease of loading, I opted not to put a spike on the front of the projectile. 

Prototype Demonstration (With test fire)

I really need to learn how to make videos that don't suck so bad.

Notes
In another case of "crappy TF2 modeling", it should be noted that the game model when viewed in first person vastly differs from the model viewed in third person, unequipped. The dimensions for the side plates on the ammunition drum changes. The part that I presume is an ammunition ejection port also flops sides. I suggest that one or the other be chosen for making a replica, and not both. I used the 3rd person, unequipped viewmodel for this project.

In terms of production costs, this model can be assembled for around 6 Magic: the Gathering cards and some generous amounts of cardstock. Not that you'd need one since no one else has a 12" Demoman, and this model's pretty bland, visually.

Assembling a Sentry Gun

Doing some more clean up with documentation. The TF2 Sentry Gun paper model is very under documented. Magically jumps from a base stand to a level 3 within four days.

I've recently uploaded revised schematics to replace the very ineffective ones posted about two years ago. However, there's no documentation of how the parts were assembled. Time to fill in those gaps.

Building a Sentry base
The base needs to be stiff. 110lb cardstock without special treatment methods will be ineffective in supporting the loads this model will encounter. Recommend using 110lb cardstock only for tubing and using thick laminates of Magic: the Gathering to assemble every part on the base.

Magic cards offer good strength for little material. Treat them like sheet metal when building the front legs. Use thicknesses of 8 cards to create 2.5mm thick sections. The curved side frame posts were built in that manner. A thickness of 4 cards was used for minor sections like the upper parts of the front legs.

 110lb cardstock is weak when used as a plane sheet, but when rolled up with or without support of a 3.175mm wooden rod, it's sturdy. The main post and rod running through it were done with both methods: using a wooden inner rod and without.

 These rear legs are very troublesome. You're going to have minimal adhesive holding these parts together. Recommend making biscuits and joints to connect the sections. Super glue is recommended for these parts.

 Tubes, Tubes, Tubes

 A lot of the sentry will be large sections of material. The trick is to lighten up the material as best as possible. The ammo drum was built almost like a papercraft model, with lots of empty space inside. Making the drum solid would contribute excess weight to an already unstable model. Here, there's the inner drum (left), outer support drum (middle), and the outer shell (right), which is composed of a tapered cylinder. The outer shell fits alongside the outer support drum to stiffen one side, while providing the tapered shape on the other side. Magic cards were used for the flat backside, offering good planar stiffness with minimal warping.

 I built the ammo drum support arm in sections. Don't do that. Build this section as stiff as possible, and out of as few pieces as possible. This part is very problematic as it supports a lot of load and will be subject to constant bending for the rest of the life of the sentry. Don't even try using 110lb cardstock without some inner support material. Stiffer the better.

The minigun assemblies are designed to spin, but also designed for weight reduction. The arch shaped supports are fleshed out using tubes on the curved ends, and troughs made of Magic cards. Tubes offer stiffness with shape, and the cards offer stiffness with flat surfaces. The only time something needs to be completely solid is for shapes 3-4mm thick or less.

For the barrels, they span a length of 40mm, but you can support them on the edges with 12-16mm of material. This lightens up the parts significantly.

For this build, I considered using pre-existing plastic tubes to minimize friction when rotating. Not a big issue in the long run since it won't see much rotation. The tubes offered strength and volume for little effort. The barrels themselves need rework, but I've drafted new plans for a stronger set in the newer plan revisions.

 There's a bit of sag from the barrel weight, since rolled up 110lb cardstock is still heavy. There's little room for a counterweight, but adding more mass to the supports only loads the center mounting plate more. The goal is to minimize overall weight as well as keeping it balanced. The first objective helps with the second.

 The Turret

The rocket turret is another part that requires lightening. The image above demonstrates how it was built: four tubes running along the length, with tabs on the sides to allow for a cover to be placed around it. Build this like sheet metal and not like a milled object. 

These support arm parts for the turret were built light and stiff. They may appear thick, but they're mostly hollow inside.  

The amount of "large mass supported by a thin strut" situations on this model are numerous. Luckily, this is the least severe of the situations. The white support base is made of several layers of 110lb cardstock, but can be done with Magic cards. The trick is to use the thickness of the material to your advantage for small details.

Wiring the Sentry

This wire assembly can be tough. You'll need to find wire with a sleeve diameter of 3mm, or make your own by rolling printer paper around some thin wires. Printer paper is soft and bends easier than 110lb cardstock when rolled. Goal is to keep the rolled thickness to a minimum. Thicker the walls, harder to bend. 

Attaching the wires to the plate can be done by leaving bare wire on the ends and threading it through a sheet. Just glue another sheet to sandwich the wire ends in, and they should remain in place.

I've documented the ammo belts here, and with the rest of the new diagrams, that should cover all the miscellaneous aspects of building the sentry gun.

Now.. Just need to properly present the completed model this time around.

Revised TF2 Sentry Gun Schematics

Reworked all the original 1:6 scale Team Fortress 2 Sentry Gun schematics I had posted previously, so that people could actually use them. I was innundated by a single comment requesting the originals be refined. Should be fully documented to the extent that you could theoretically CAD and CNC your own parts. But would you trust the accuracy of a guy hand drawing part diagrams with a ruler, protractor and a circle template guide? Probably not!

There's 8 sheets to work with, 7 of which contain dimensioned drawings for all the individual components. They're designed to take advantage of common sizes when working with paper, so you'll see a lot of 3.175mm and 6.35mm diameter holes and tubes, corresponding to a 1/8" and 1/4" hole punch. Easier than cutting a 6mm circle by hand. Best built using 110lb cardstock and Magic: the Gathering cards.

Sheet 1: Deals with the center support post.

 Sheet 2: Front legs and rear supports

 Sheet 3: Mounting plate for miniguns and ammo drum

 Sheet 4: Ammo Drum

 Sheet 5: Rocket Turret assembly

Sheet 6: Miniguns

Sheet 7: Rear legs

Sheet 8: Miscellaneous Assemblies

Next time: tips on weight reduction and building techniques using these diagrams!

This Weekend's Project: Reworking the TF2 Rocket Launcher

This weekend's project comes from the pile of "looked ok 2 years ago, but looks like crap compared to newer stuff" programs. The Soldier's rocket launcher has been a simple and primitive build. The paint has been very lackluster. However, there was little improvement possible for the build, leaving just a new paint job and maybe a few extra polygons.

Here's the 2008 prototype model (top), compared with the 2010 production model (bottom). Major changes include the less-half-assed construction, increased weight due to a liberal use of Magic: the Gathering cards for a stiffer build, thinner inner barrel diameter, and the addition of a firing mechanism.

Yes, this model fires out projectiles.

The Mechanism
Let's go build ourselves a working paper rocket launcher, shall we? First, let's explain a few things. This mechanism is a simple, using a total of two moving parts: a trigger and a launcher rod. There's two springs, easily obtained from mechanical pencils.

 

 The mechanism works by the use of this odd shaped metal wand and a wooden 3.175 diameter dowel with a 6mm diameter head. The barrel diameter is 6.35mm, giving the rod enough clearance to move around freely.

 The rod fits in a slot that runs through the diameter of the barrel.

 The part that dips low at the top between the "ears" obstructs the head of the launcher rod from moving. Pushing the metal wand upwards into the slot in the barrel allows the dip to slide into the barrel wall, leaving the barrel clear. It's a simple mechanism that is reliable and fairly easy to build. The downside is that it requires a large diameter barrel to make good use of it.

The Build
You'll need the following schematics for the major components:

You'll need the following tools:

• This excel spreadsheet from this explanatory post explaining how to make cylinders out of paper 
• 110lb cardstock (don't even bother using printer paper)tack of Magic: the Gathering cards (or structural equivalent, Yu-Gi-Oh! cards need not apply.)
• X-Acto knife and a cutting surface, and regular scissors
• ruler
• Sandpaper (coarse grit at a minimum)
• Elmer's glue (any strength, but not a Glue Stick), and Super Glue of any type
• Paper clips (smaller the diameter, the easier)
• One 1/8" (3.175mm) diameter wooden stick
• Guide to building with Magic: the Gathering cards (optional)
• Pliers (Jewelry Beadmaking pliers HIGHLY recommended, regular needle nose pliers mandatory)
• Badass paper clip bending skills

The level of involvement of Magic card use for this project is minimal and borderline optional. There's only one part that requires cards, and it's pretty easy. The biggest challenge will be your ability to bend a paper clip to this following component:

 This is the key to a successful construction. The closer you are to the dimensions, the better the result. The two legs of the wand have a little protrusion for holding the end of the spring between the head and the middle of the wand. Without that small protrusion, the wand will slide out of the handle, and the spring won't have anything to push against. Your success will depend on whether you can replicate that out of a paper clip. Hope you bought that 100 pack. Don't even try it by hand.

About building the wand: Use a beadmaker's jewelry pliers with thin rounded tips to initiate small bends. After the bends get close to a "U" shape, compress the entire "U" together with needle nose pliers. You'll have two chances to get it right. You can usually undo the bend once before the metal is too fatigued and snaps apart with a second attempt.

About the spring: start from the wand's open end and take the termination end of the spring coil and thread it around the two legs. Spin the spring around until it eventually screws into the region. You should be able to compress the spring while it sits in between the wand head and the protrusions in the middle without any obstructions.

Building the components
 

 The center object is the trigger housing. The housing preferably should be made of Magic cards. The side wall is 2 cards thick, and the thin walls are 3 cards thick. A plastinated wall made of 110lb cardstock and enough super glue permeating through it may be acceptable, but is very messy. The center of the trigger housing has two walls protruding inside the trigger pathway. This is there to keep the trigger from falling out too far. May be critical if your spring is too stiff or too long for the wand. This, and the bottom of the trigger will be the only parts that Magic cards are helpful for, but can be done without.

 Now if you've built all the pieces, you should now have the following items:

 These are the major components needed. Anything not mentioned in the drawings is stylistic and not structure critical. Depending on your spring length, you may need to either trim it down or change the dimensions by pushing back the rear end stop into the conical part.

The sight works better if you use Magic cards. I did it with 110lb cardstock 2 years ago and it was acceptable.

 The rear part of the launcher is made of three conical sections. You can put them together by making cones or carving down a cylinder. Not structurally important, as long as it stays together.

The build is mostly tubes and squares. A simple project by normal means. I recommend doing some test fires before gluing both halves together. Always good to verify the mechanism works reliably now than have to redo a section later because of a failure. The mechanism isn't the best, but it's effective. You will need to push the trigger in as you load the rocket launcher so the head can clear the obstruction. I haven't tested out other means of assisting the load mechanism, but there's some room for improvement.

After you've assembled the rocket launcher, you'll want some rockets. I recommend making generic projectiles 5mm in diameter and fairly long so you can push the launcher rod in with it. They go fairly far using mechanical pencil springs, despite my reservations.

Happy blasting! (Now with video!)

TF2 Minigun Documentation

Doing a bit of housecleaning on this mess of a blog. Realized that I've never posted the drawings used to build the Heavy's minigun.  The drawings were used as a backdrop for the finished model. It's like I suddenly had a minigun built, without any construction progress documented at all. Not too useful if I for some reason need to rebuild one. Luckily, I've re-drawn 95% of the parts properly, so that even you have a chance in hell of reproducing the minigun!

 There's four sheets of diagrams total to document each part. This model can be built entirely out of 110lb cardstock and 1/8" diameter bamboo sticks, with little or no Magic: the Gathering requirement for strength. You'll need a good understanding of how to read an engineering drawing, otherwise parts may get confusing. All dimensions are in millimeters.

Assembling them all together is left up to you using a general idea of where the parts go. Shouldn't be too hard. I haven't split up the parts into basic components, so how you go about it is up to you. There's a lot of weight for the model, so you'll have to get creative in saving weight. It won't be a good beginner's model, but handy if you need to draw most of the gun using CAD, and wanting the result to be in scale. 



EDIT: Thanks to wargrounds for pointing out some errors in the schematic that make the assembly ambiguous. The updated schematic is here and the old one taken down.

This sheet details the spinning barrel assembly.  Details how the inner and outer assembly are made, along with the end cap to allow the inner assembly to stay in place while allowing for rotation.

 Miscellaneous decorative elements and the supports for the carrying handle.

 Main handle assembly and small view of how the barrel is assembled using the featured rod.

All these parts deal with the  ammo drum and the six barrels. The center item with the multiple specified lengths of tube to make deals with the individual sections of the barrel. These fit over the 115mm long rod, and are spaced out with the four disks and the muzzle.

 It looks huge, but it is 1:6 scale despite what I thought it was. This will help you figure out where everything goes.

I'm in the process of cleaning up some old drawings to save folder space. Nothing like having a folder stuffed full of schematics for 1:6 scale junk no one wants to build.