Hi all. This is my instructable on how to make a smoking snake, originally intended as a Halloween decoration. Before reading or attempting to make this, please be clear that dry ice can hurt if used or handled inappropriately, and I take no responsibility for any harm this may cause to you or others. That said, both myself and my younger brother (six) found this to be rather fun.

I welcome any comments or criticisms, but please try not to be too harsh.

Step 1: Equipment/Materials

This may seem like a large amount of stuff, but you can probably find most it them lying around.

Materials:

Card/Cardboard
Newspaper
Masking Tape
PVA Glue (or similar)
Paper Towel (to clean up
Led lights
Electrical Wire
330 ohm Resistor (optional)
Flexi-Tubing
Insulation Tape
Plastic Tub (Can substitute for glass jar)
2x aa Battery Case
Latched Switch
Paint
Terminal Block
Barbeque Skewers
Dry Ice

Equipment:

Pen/Pencil
Computer (for research)
Craft Knife
Glue spreader (piece of card works fine)
Paintbrush(es)
Wire Stripper/Cutter

I have not included photos of everything, because there really is no need to. If there is an item you are unsure about, please leave a comment, and I will upload a photo.

Step 2: Research

Like all good projects, I began this one with some research. This was very brief, and consisted only of an images search to find a picture of the snake to model my design on. I decided that a cobra looked rather evil, so would do nicely. You can base your design on any snake you like, depending on what you are trying to achieve. As I said before, mine was for a Halloween decoration so did not need to be all that realistic.

Step 3: Mark Out and Cut

I chose to use corrugated card because it is what I had to hand, but I know from previous models that cereal box card works just as well, if not better. Having chosen your card, you must mark out your design. This can be done in separate parts, e.g. body, head, neck, and fangs. Now cut out the design using the craft knife. This will vary in difficulty with the complexity of the design.

Step 4: Stick Together

Now that your design is cut out, you will begin to see it take shape. If you cut out the parts separately, you will need to assemble them with the masking tape. Any amendments to the shape are best done now, as it will be difficult to do further on.

Step 5: Bulk Out

With the basic shape now ready, you will need to make the body look like a body, rather than a bunch of floppy card. This is done by attaching newspaper with masking tape. Screw up the newspaper into long strips, balls, and whatever other shape looks appropriate. Attach this to the snake outline, to give a decent size. You will have to use some judgement in this step, and go by eye to see how much padding looks reasonable in relation to the overall size.

If you want to make the snake stand up, then barbeque skewers can be taped to the card.

Step 6: Special Effects

This step outlines how to connect the electronics and smoke tube. I will assume you already have a working knowledge of electronics. If not, you can either leave out this step, or learn from one of the many electronics instructables out there. This entire step can be left out if you do not want to include the smoke system and electronic lights in your snake.

Electronics:

Connect the positive legs of the LED lights together with electrical wire. I soldered mine, but this is not essential so long as there is a good connection.
Connect the negative legs of the LED lights together, just like the positive ones
Cover any exposed wiring with insulation tape, but leave a small area on each of the positive and negative wires.
Position the LED's on the snake, and secure with masking tape.
Attach a wire to the exposed positive section, and run it down the underside of the snake to where you will position the battery pack.
Attach the 330 ohm resistor to the end of this wire.
Attach the end of the resistor to the switch.
Attach the switch to the positive terminal battery pack.
Attach a wire to the negative terminal of the battery pack, and run it along the underside of the snake, and attach it to the negative wire from the LEDs.

Smoke system:

Make a hole in the lid of your container or glass jar, roughly the size of your pipe.
Force the pipe in the hole, and secure with insulation tape. Blue tac can be added as a seal.
Run the pipe along the underside of the snake, and position inside the mouth. It is a good idea to reduce the size of the pipe, to create a nozzle. This simply involves forcing a pen tube into the end of the pipe, before pushing it into position.
Secure the pipe with masking tape.

Step 7: Paper Mache

This step creates a hard outer body for the snake. This will also hide everything underneath, so any imperfections can be covered up. Additionally, this will prepare the model for painting.

Begin by tearing newspaper into small strips. One by one, generously coat the pieces in glue. Then, taughtly place the strips over the snake. Repeat this process until the entire snake is covered in a layer of paper mache. Take care not to obstruct the LED lights or the dry ice nozzle. Leave the glue to dry, then do the same again. Keep building up the layers until you have a hard outer shell on the model. This can be anywhere between 2 and 8 layers. Once thed glue on the final layer has dried, you are ready for the next step.

Step 8: Paint

This step is simply painting the snake. You will have to come up with your own pattern, but don't be too exact. My model looks nothing like the pattern on the snake I based my design on, but no one would know that when they look at it. A simple black background with a bright criss cross or lines is simple to apply, and gives a great visual effect.

There is no need to use conventional methods of applying the paint. On mine, I did not once touch a paint brush. I used cotton balls and cotton buds, to great effect. Feel free to be creative, after all - it’s your project.

More than one coat of paint will be required, but don't rush, as this will lead to smudged edges and a very disappointed creator. Give the paint plenty of time to dry to achieve a nice looking snake.

Step 9: Use

To use your snake, combine dry ice and hot water in the tub or jar. This will feed "smoke" up the tube, and out of the mouth. Add batteries to the battery case, and turn the switch on to light up the LED's.

A good place to put the snake is inside a basket, with some canvas covering the batteries and dry ice tub. I put mine outside the front door to scare passers by, as I used this for Halloween, however you could put it anywhere you liked.

Step 10: Additions

I used a margarine tub for the dry ice chamber, and found it didn't have a good enough seal to work properly, and as such I recommend using a glass jar.
This instructable is only a guide, and will require some creative thinking, however feel free to leave a comment if you have any thoughts, questions, criticisms, improvements etc.
I will be entering this instructable into the MakerBot Challenge, so please don't forget to vote!