This is a semi step-by-step guide of how my girlfriend Jess and I built our Ghostbusters proton packs for Halloween 2008! We ended up spending just under a month and just over $200 on each pack. Not including random tools here and there that we needed.

No expensive lightboards or sound packs here. This is 100% homemade and on the cheap.

Here is a couple stills of the final pack.

Step 1: Costumes

The costumes themselves were simple as hell and only took a night to do.

Flight suits off of Amazon.com
Paratrooper Belts off of Amazon.com
Boots off of Amazon.com

Then a couple custom patches off of Ebay to read 'Hogan' and 'Morrison' and of course the No Ghost symbols and we were pretty much good to go!

Just a few details needed adding like the gloves, circuit board (which were junked old sound cards) and some random tubing which can be found easily at Home Depot.

But in making a Ghostbusters costume remember...90% of the work in the pack.

Step 2: Cutting the Motherboard

To start off we cut the 'motherboard' out of masonite board we found at Home Depot. This is the same stuff you'll find clip boards made out of. Just a much bigger sheet of it. We then downloaded the blueprints we needed from [ GBFans.com]GBFans.com and cut away using a Dremel. This made a HUGE mess by the way, so do yourself a favor and either cut it outside or in a space that's easily cleanable like a bathroom.

Step 3: Sculpting the Parts

Once again we started out by looking at stills and downloading the blueprints we needed from [ GBFans.com]GBFans.com. But the site was also great to find out how most people went about constructing their own packs. We found that most people seemed to cut their parts out of wood and/or vacuum form them. We on the other hand didn't want an all wood pack because of the weight, and vacuum forming was just going to be too complicated and expensive.

So we cut our parts out of insolation foam. This stuff is very dense and very pink. And perfect in terms of weight and ease of use. Jess and I had both used this stuff while at art school (SCAD) and with a little work you can get some great results.

But we also went one step further to really get things smooth and the corners sharp by coating each piece with spackle and then sanding it down. This really is the key to getting a foam pack look like machined parts. It even leaves a very nice and subtle texture that really feels like steel machined parts.

Then by adding a couple pieces of PVC you start to really get down the shapes needed for an authentic Proton Pack.

Again Home Depot was the store of choice.

(These are obviously just a couple of the parts we made, and don't include the battery pack etc.)

Step 4: Dollar Store Heaven

Another great place to find parts is the Dollar Store. That's where we found a perfect plastic Tortilla Bowl and a few colored document folders that we used for gels in the battery pack and Cyclotron.

Step 5: Bumper

This was made by simply bending a piece metal window siding we found at Home Depot.

Step 6: Getting Ready for Paint.

We used Gorilla glue to join all the parts to the motherboard. And now we're pretty much all assembled and it's time to get the packs ready for paint! And a BIG part of getting them ready is by putting a heavy coating of Gesso over the entire pack. Why you ask? Well foam has an odd reaction when exposed to the chemicals found in most spray paint.

It melts.

So to prevent that we gave it a protective coating for Gesso.

There are some water based spray paints out there made by Krylon, but we had a hell of a time finding Matte Black. This stuff tends to spray on kind of runny anyways, so this is the preferred method we found.

(Other random parts on the packs include a Radio Shack project box for the mounting of the Wand, and craft wood ribbing glued onto the appropriate parts)

Step 7: Back in Black

Now that the packs are all painted we then started to attach the ion arm and the black ribbed tubing (electrical department Home Depot).

Step 8: Light 'em Up!

Now here's the really fun part. Making the LED circuits.

This should be treated as a separate project as it did take quite a bit of work, and should only be taken on by someone who has soldering experience.

The battery pack is a simple chaser circuit, and the Cyclotron is just 4 blinking LED's daisy chained together each with a slighly higher capacity capacitor.

To make life easier I went ahead and just purchased ready made kits at [ AllElectronics.com]AllElectronics.com. Just dig through their LED and Kit sections and you'll find tons of fun stuff to play with.

We then put them into the pack and were ready to move onto most expensive part of the pack...

Step 9: The Gunbox and Wand

To start out I sculpted it out of clay based on the dimensions of the blueprints. I then made a silicon mold and casted it out of resin.

I ended up needing around 7 lbs of silicon to make the mold which ran me $125 for 10lbs. That was the big expense since I had to order it online. The resin you can find at pretty much any craft store and was only $25-$30.

Then with a little sanding this puppy was ready to go.

The grips were handles found in the gardening department at Home Depot, which we then spray painted matte black and wrapped in standard electrical tape.

All the little parts on the gun were made out of sculpy. And the same approach was taken on the pack as well.

Step 10: Alice Packs

We ended up attaching our motherboards to the ALICE packs using simple zip ties that we pre-drilled holes for. Then just added a couple pieces of Pipe foam for added comfort.

Step 11: Wiring It All Together and Finishing Up.

All of our electronics made their home inside the Gunbox. And each circuit had it's one closed power source of a standard 9v battery. This was done to keep things simple and extend battery life from 3 hours to almost 9.

This took a few hours to wire up each one and resulted in a rats nest of wires inside, but it got the job done. Electrical tape and hot glue is your friend during this step to prevent any shorts.

I added in a LED Bargraph that lights up and also a tri-color LED in the gun tip, which was made out of a turkey baster found at the Dollar Store.

Step 12: Demo Video

And that was pretty much it! All the stickers were found once again on GBFans. Here's a demo video of it all working!

Step 13: Random Stills

Anyways, I hope this instructable helped you out. And good luck in building your own pack! It was a much bigger undertaking then either Jess or I thought it would be. But it was so much fun to do together, and we're both so happy with the final result.

Plus it finally fulfilled my childhood dream of owning my very own Proton Pack!

To end here are just some random stills of the other parts of the packs not mentioned in this instructable. Oh and also my cat because she's awesome.