My son wanted to be a ghostbuster for Halloween, so here's a how to on making a Proton Pack. The costume at the store had an inflatable backpack, and that will not do at all.
Step 1: Gather Lots of Junk
Supplies needed: Back pack, glue gun, cardboard boxes (one that will fit over the backpack, the others for material), and lots of junk (bottles, tubing, wires, pipes, metal parts, and other stuff), cheap flat black spray paint.
Step 2: Main Pack Body
Start with the main cardboard box that the backpack fits in and cut holes for the straps. You will want to take the backpack out before you spray paint everything black. And you may take it out and put it back in a few times, so I left the flaps open and did not tape them shut.
Step 3: Glue on the Stuff
Get a good image of the Ghostbusters Proton Pack (Google images), and keep looking at the original and try to make the right shapes using boxes, plastic containers, bottles, cereal boxes, and hot glue. Which luckily looks like welding if you do it right. Improvise to make the complicated parts (fabricate stuff out of cardboard if you have to).
Step 4: Fabrication
To make the really hard or weird sized stuff, just look at the item's shape and carve it out of wood or cut it out of cardboard. Do not use Styrofoam (like I did) the spray paint will melt it a little! See the next step to see just how it melted. I made the this cylinder out of a large scrap dowel rod I had in the garage and the really large washer looking thing at the base of the larger tubing thingy I cut out of cardboard and stacked them up. Before you finish or even start this step, you will want to go to Google and search "Ghostbuster stickers" or "Ghostbuster decals". Look for a printable sheet of Warning labels and Hazard stickers. Print this off in color and in different sizes (mine used about 50%). This one came from Pintrest.
Step 5: Painting Time!
Once you have the Proton Pack the way you like, that is without the cool metal things and wires, and other stuff you don't want to be painted, it time to spray paint it black (I used the cheap $0.96 can from Wally-World). This used just a little more than one can so I had to go back and buy another. Here is a before and after, but check out what happened to the Styrofoam after the paint. The Styrofoam is clean and smooth before, but the spray paint made it really wrinkly.
Step 6: Add the Wiring and the Metal Stuff
After a coat or two and some touch ups (and you may have touch up after as well), it's time to add the embellishments. I added wires (every scrap wire and cut open phone wire I could find) The old style (not the clear type) phone lines have four colored wires in them. The main wire harness is a few cable cords, some stereo wires, and a 20 foot phone cord, just ran back and forth. This I split open to get the colored wires out. I hot glued them in place and cut the wires off inside the box, but I cut mine too short, and I should have tied them in a knot to make sure they would not be pulled back out. But you live and you learn, so learn from me.
Step 7: Gun Time
Again, go to Google and look up "Ghostbusters gun" and hit images to get a fairly good close up of what you are making. I started with a 2X4 cut it up and glued pieces together. Then I added a sprinkler handle hose from Goodwill, and some pipes and tubing. The sprinkler handle had the red on/off switch already. Then added some small metal item to make it look right, then added a green wire.
Step 8: Attach the Proton Pack to the Gun
Now it's tubing time! I luckily found two old C-pap masks being thrown away and gathered the tubing for this project. But they do sell all kinds of tubing at "Lo-Depot's" home improvement stores, if you can't find any tubing long enough for what you need here. I glued and re-glued and glued again, to no success, Finally I put in a couple of screws to hold the plastic end of the tubing to the plastic end of the water sprinkler to get them to stay connected. then I screwed the other end into the bottom of the Proton Pack where no one would see it inside the plastic bowl.
Step 9: Finish the Look
Next get a jumpsuit (or order as small as you can overalls in white, gray or green) and stich on some patches. I found a lady on Etsy that will custom make a patch with your name on it, and did that. Then I ordered the Ghostbuster logo patches, but they did not come in in time so I cut apart a can coozy with the right logos and used that. I think it turned out great!
So another thing I wish I did differently was to make a holder on the side of the pack so he could have both hands free, but I ran out of time.