Dr. Horrible Lab Coat and Freeze Ray

Dr. Horrible, our favorite musical madman, looks (and sings) great.  You, too, may look great, but it will take some work.  I'll describe how to make your very own freeze ray with a flashbulb to blind your arch-anti-villains with, and as a bonus you'll get a head start on making a knee-length, side-buttoning, mad-surgeon-style lab coat!

Materials:

• An assortment of tubing from the plumbing section of your favorite hardware store.
• Cans of spray paint in your favorite mad-sciency colors.  I used matte black and metallic silver.
• Some boxes.  I used a pair of cardboard boxes I had lying around.  If you want to make a more durable freeze ray I'd suggest trying to find a plastic or metal box.
• A cheap disposable camera
• A few lengths of wire, some hot glue, and duct tape.

Tools:

• Soldering iron
• Wire strippers / cutters
• Knife / scissors
• Saw (anything capable of cutting through the pipe you bought).

Decide what you want your freeze ray to look like.  There aren't many good shots of Dr. Horrible's freeze ray in the film, so I let my imagination go where it would.

• My process, using cardboard boxes and tape for my housing, was to cut into the cardboard with (what else?) a box cutter, being sure to keep as much built-in structural integrity as possible.
• Once you have several box segments, attach them in your chosen configuration with duct tape.
• Arrange and cut, if necessary, the plumbing segments and cut holes in your box to place them into.  Be careful not to cut the holes too big or you'll have to do it all over again because they won't hold the pipes.
• Put the entire assembly together to make sure you like the effect before committing to it.
• Take care that you put your tape down as smoothly as possible and cover any strange edges and textures; we're going to paint this, but a bit of spray paint won't hide much by way of blemishes.
• You'll want to be able to get to the inside of the box, so leave a door of some kind.  I had the large side simply taped down along one edge and loose along the others.

The most exciting part of this project was building the flash for the freeze ray.  Please be careful when doing this; the primary flash capacitor in the disposable camera I used was nearly the size of my thumb.  Before working on any part of the circuit, discharge the cap by shorting it with a screwdriver (that has a plastic or rubber handle, please!).  Once you've shorted it it should be safe to handle, but capacitors can be evil little buggers and build up charge over time...prevent this by taking a bit of wire and wrapping it around the leads to create a semi-permanent short.

The camera was impressively simple and rather interesting to someone who knows a bit about photography.  The only part we need for this project, though, is the flash unit.  By far the most complicated thing in the camera is the circuitry that charges the flash. How Stuff Works has a wonderful description of how this works, so take a few minutes to make this a learning exercise and figure out what's actually happening here.

There are four pieces of particular interest on this board: two switches, an LED, and the flash itself.  One switch is the trigger...it closes the circuit to discharge the large capacitor into the final step-up transformer, ionizing the gas inside the flash tube and letting current tear through it, creating the actual flash.  The other switch closes the first circuit that connects the batter to the primary transformer, stepping up the 1.5 volts from your standard AA battery into 200 volts stored in the capacitor (the second transformer turns that into somewhere between 1000 and 4000 volts to ionize the flash tube).  The LED lights up when the flash is fully charged and ready to fire.

These four components will need to be carefully desoldered from the board and wires soldered in their place.  We're not modifying the circuit, just moving things  around.  I had to desolder the flash capacitor to get at the flash tube, so once again be careful with it.

You'll need to decide where you want the switches and the LED.  The flash should go in the end of your freeze ray's barrel.  I put the charging switch on the primary handle, the trigger switch underneath the housing just in front of my front grip, and the LED on a back corner of the box so I could see when I was properly armed.

It turned out that I needed to glue my charging switch into my handle before I fully assembled the handle, so I put wires on both the switch itself and on the contacts on the flash unit.  That way I just had to twist them together to finish the assembly.

To prepare the handle for the charging switch, drill a hole in one of the elbow pieces (the one that will be on top, if it matters in your design) and use a file or dremel to smooth it down.  Fit your switch in there so it seats nicely and is easily accessible.  To keep mine in place I used hot glue.

Now you just need to paint the boxes and pipes to give it a nice finished look.  Go somewhere with good ventilation (preferably outside or, if you live somewhere like the Pacific Northwest where it never stops raining, in an open shed) and set up a cover your work surface so you don't get paint all over it.

I had two colors, black and silver, so I had to be careful not to mix them.  First set up the housing and paint that.  If you're using spray paint like I did, go easy and take several coats.  I had to learn the hard way once that spray paint will clump and drip something awful if you try to get a complete coverage on the first coat.  Just take your time; it dries fast and the end result will be much better.

While the box was drying off to one side I used the scrap cardboard left over from cutting the boxes as stands for the plumbing.  If you're using a metallic spray paint be careful: it tends to be a bit thicker than the normal spray paint and takes longer to dry fully, especially if you put down thick coats.

When you put everything together you'll probably have some pieces that need touching up.  Place painter's tape over everything that you don't want to get painted before you spray.

Now you have everything ready to put together.

Be careful of the pipes...I just put them in by cutting my holes slightly small and using friction to hold them in place.  Cardboard is not particularly sturdy, so this didn't work too well.  Try using lock nuts or some other way to hold the tubes onto the housing (yes, I see you in the corner with the sheet-metal housing and welder.  We're all very proud of you, I'm sure; now did you bring enough to share with everyone).

Before your flash will actually charge you have to remember to remove the safety bridge you installed across the terminals of the flash capacitor.

You're painted, assembled, and ready for mayhem.  Once you've collected the rest of your costume there'll be no stopping you.

If you've done some poking around on the internet (or you're a huge fan of Joss Whedon's other work) you may have noticed that Dr. Horrible's lab coat and Death Ray are BOTH reused props from one episode of Firefly -- The lab coat is one of the doctors' uniforms and the Death Ray is the weird force-gun that Jayne gets hold of in "Ariel."

Fairly thorough looking on the internet didn't find anything satisfying for sale, so if we want a lab coat with some of the key details of Dr. Horrible's (the side-buttons, the unusual collar and proper length) we'll have to make it ourselves.

I'm not much of a tailor myself, but my girlfriend found a pattern to use as a starting point and modified it for me.  She chose McCalls pattern number 2233, Uniform Essentials.  It has the right style of collar, and it was easy to extend down to knee-length.  The front panel was also easy enough to extend around to the right side.

See the attached pictures for more notes.