Helvetica 'Foofers' Bold (foofers) wrote in rarsuit,
Helvetica 'Foofers' Bold

Dragon Tail Tutorial

One of the most common questions I get while performing as Scabrous the dragon is, “How did you get the tail to move?” A lot of folks expect servos and technical stuff, but it’s all just gravity.

This is still incomplete, but I wanted to get the ball rolling. There are parts shown of two different tails in progress, and a few steps are lacking photographs. My camera also just crapped out again, so I filled in some gaps with poor-quality cell phone snapshots. I’ll come back to this and fill in the blanks as time permits. In the interim, most of the information is here, if a bit sloppy. Please let me know of any errors or glaring omissions, and I’ll refine this.

You can see the tail in action in this video of Scabrous at the 2008 Maker Faire in San Mateo, California:

The tail design was inspired by these toy snakes I’d seen in Chinatown. Unlike the usual plastic-jointed ones, here a strip of leather down the middle provides the flexing motion. The otherwise-rigid structure of the snake is such that it can only bend on one axis (horizontally) - it doesn’t bend vertically nor does it twist. It doesn’t sag or go flaccid…it can only wag:


So there’s a spine of sorts inside Scab’s tail. It’s made from a strong and lightweight plastic material called Sintra or foamed PVC; this is both lighter and much less prone to cracking under stress than other sheet plastics like acrylic. I used the 1/8" thick sheets. Comes in many colors, though of course nobody’s going to see it inside the tail. A good sign fabrication shop will sell this stuff. Found mine at Tap Plastics, or there’s also a local independent plastics & sign fab shop near me called Tri-City Plastics. Usually I’ll buy scratch-and-dents or smaller pieces out of their scrap bins to save a few bucks.

A note regarding PVC: while essentially harmless and inert in solid sheets and in the finished product here, care should be taken to avoid breathing or ingesting the dust that results from cutting and sanding this material. Goggles and a respirator (or at the very least, a good-fitting dust mask) are highly recommended. Work outside or in a garage, thoroughly vacuum your workspace after cutting, and wash the dust from your hands and arms (if you really go to town and get the dust all over yourself, have a shower and change of clothes afterward).

The flexible parts of the tail are made from 2-inch nylon webbing…the heavy-duty sort of stuff used for mountaineering backpacks and belts and the like. I usually get this at REI, but a well-equipped hardware store or fabric store may have something suitable. Be sure to get the 2" width though, the narrower stuff won’t do. (To do: add photo of webbing here.)


There are a few different ways to cut the foamed PVC. Score-and-snap, if you have a plastic scoring tool…but I much prefer the control of a scroll saw. (To do: add photo of scroll saw here.) A small hand saw will also do, if you're patient. Or a bandsaw, if you’re impatient.

After cutting, the edges of the PVC (Sintra) should be sanded smooth of all burrs, etc. Fairly coarse (like 180 grit) sandpaper works for this. I try to avoid power tools for this step because of the PVC dust. The hot tip here is to use wet-or-dry sandpaper, and work under a trickle of running water. This avoids the problem of dust and also keeps the sandpaper from clogging up. (To do: add photo of wet-or-dry sandpaper here.)

Most of the PVC will remain flat, but there are a few spots where some curves may be desirable. The best tool for this is a heat gun (a hair dryer will not get hot enough). If you come up with a design that requires tight, 90-degree bends, you’ll need something that can deliver a fine jet of hot air…a butane-powered soldering iron with a hot blower attachment works, or a reflow soldering station. If you don’t have any of these tools, the plastic can also be softened in very hot boiling water. Again, because of chemical concerns, I’d suggest getting a nasty old pot at Goodwill for this, and of course you’ll want some beefy gloves (or at least some oven mitts) to avoid getting burned.

Electric drill. (To do: add photo of drill here.)

Lighter. (To do: add photo of lighter here.)

Finally, a rivet tool is used to join the various parts together. Avoid the temptation to use small nuts and bolts, because these will come apart! A basic rivet tool can be had for about $20, and if you’re prone to making crafty stuff you’ll be finding all kinds of uses for it down the road anyway.

I can’t claim credit for the insights into Sintra, heat-bending or riveted construction…much of this was learned from the legendary Legend the Gryphon!

Here’s a couple of test pieces I made using heat-bent Sintra, 2" nylon webbing, and rivets. I was experimenting with some two-axis flexy ideas here…these are not like what’s inside Scab’s tail! But you can see the various bend types and how things are attached with rivets:


There’s a strong temptation to fasten a tail firmly to a belt around one’s waist. That works fine for most fuzzy creatures, but for an anthro-lizard with a stout tail, it looks all wrong…the tail will sit too high, and will form an unlikely and uncomfortable-looking angle from the wearer’s spine to the tail’s spine. Scab’s tail actually hangs pretty low off the butt, in order to look a bit more like a continuation of the wearer’s own body, and not something just bolted onto the side:

The shape of the tail was sketched in Adobe Illustrator. Once the size and basic outline of the tail was determined, I added several perpendicular cuts down its length to provide the flex points. This is not the actual pattern, just a sketch of the idea:

The pieces were then separated and rearranged as necessary to fit on two 8.5x11 pages that I could print. Note that because we’re going to be making a PVC sandwich, two copies of each part are needed. An easy way to do this is to weakly glue two layers of PVC sheet together using rubber cement, then rubber cement the pattern sheet on top of this, then cut along the lines. The rubber cement lets it all peel apart easily later. If you plan to be making a lot of tails, you can stack up as many sheets as needed, whatever will fit through your saw (again, just remember to double up so there’s two copies of every part).

There’s one additional piece not shown on the pattern, because it was just eyeballed and cut by hand: there is a “butt plate” that sits perpendicular to the tail where it connects to the body, so the tail spine doesn’t end up in your butt crack. You’ll thank me later. This is one of the parts that gets heat-bent, in order to match the curve of one’s rump.

Lengths of nylon webbing are then cut to fit the gaps where these pieces join. Note that the webbing runs in strips perpendicular to the length of the tail. It does not run from base to tip! Each hinge gets a length of webbing, and we’re flexing it width-wise to get the tail movement. You can see this on the blue test piece previously shown. After cutting the webbing, use a lighter to clean up the frayed edge and keep the material from unweaving.

You might notice two different belt arrangements in the photos below. First tail I made (and the one I’m still currently using) used 1" webbing for the belt, and a length of Delrin rod to provide some structure between the belt and tail itself. After a few hours, this gets really painful! It’s too prone to “digging in.” The second version (the red tail) uses a much wider belt to distribute the weight more comfortably. And to reiterate the initial design point: the body support structure you see there (again, red tail) does not fasten tight around the waist…rather, the two rounded ends will be drilled and riveted to a wide belt. The belt is worn firmly around one’s waist, but the tail itself is allowed to hang down lower on the butt for a more natural shape. (To do: add pictures for this.)


“And then a miracle occurs.” But seriously, I don’t have any photos of the assembly process right now. (To do: add some build progress photos!) What happens is that the pieces of webbing are sandwiched between pairs of PVC sheet. Holes are drilled for the rivets (usually a 1/8" bit or so) through both the plastic and the webbing. Rivets are fed through these holes, a backing washer is installed, and the rivets are fastened into place. It can help immensely to lightly join everything first with a bit of Barge cement or hot glue so that parts won't shift around. Here’s a picture of a completed tail spine, if that helps:

That may look like an excessive number of rivets, but trust me, it’s not. People cannot resist the temptation to pull your tail. They will pull it, and pull it hard. Especially drunk people at Renaissance faires. Always have a handler. Armor helps, too.

Here you can get an impression of how flexy it is, and a bit of that sandwich construction is visible here:

Some of those tight, right-angle bends (needing the butane torch or reflow solder gun) are used between the first segment of the tail and the butt plate. Again, because of the tail-pulling factor, a strong mechanical connection is required, so rivets are used here; don’t use PVC glue.

So that’s the spine. The “meat” of the tail is made from polyurethane upholstery foam. I don’t recall the exact type used (they usually just have these meaningless inventory codes with no correlation to the material’s properties). What I did is go to Bob’s Foam Factory and ask for a 4 inch thick slab of “the softest of the polyurethane foams that you have.” Latex foam is even more flexy, but it costs a fortune and has a much more limited lifespan. Stick with polyurethane.

Foam can be cut with an electric turkey knife, a disposable snap-blade knife, scissors that you want to kill, or sometimes even pinching off little bits with your fingers. Standard costume-making stuff, so I hope you won’t be put off if I gloss over that; it’s already covered in a lot of detail elsewhere.

Here’s a tail that’s had just its coarse shape cut:

Because this is going to be covered with a spandex “skin” rather than fur, it was necessary that the foam surface be especially smooth…spandex leaves nothing to the imagination! A Surform shaver helped smooth out all the little peaks and valleys. This makes an incredible mess and is best done outdoors!

Something I did that really helped with the sway of Scab’s tail is to scoop out little gaps on the inside of the tail, right along the joints. This keeps the tail from being too springy and rigid…yet the outside skin is still smooth and contiguous, and you don’t see bumps in the material. In addition, a couple of very short but hefty bolts were added (one midway, one near the tip) to add a little weight and help create a pendulous motion. Some folks swear there’s animatronics involved, but it’s simply a bit of weight and a little swing of the hips.

The foam was then attached to the spine using Super 77 spray…but rubber cement or even hot glue would work just fine.


With all the mechanical stuff out of the way, it’s time to do the more traditional costumey sewing and detailing work.

The skin of the tail is 4-way stretch wet-look spandex. It’s simply two pieces, basically a sock, sewn inside-out and then inverted as it’s pulled over the tail form. Nothing fancy.

Sexay beast!

The scale dots are real easy; same technique as I used on the hands. It’s simply t-shirt puff paint. Rather than going for realism and attempting to add every last scale on the character, I was judiciously applying “the fifteen foot rule” and aiming for just a reasonable texture representation.

Puff paint normally takes a full day to dry. I was doing this in the late summer, and found if I put this all-black tail out in the hot sun to dry, it only took an hour or so.

The color stripes were then added using airbrushed fabric paint. If you don’t have an airbrush, don’t fret. I’ve since found that stippling the fabric paint on with a sponge is a lot easier and looks just as good at any reasonable distance.


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