Scratch Built GB1 Proton Pack (Image Heavy)


Well-Known Member
Hey Everybody!

I wanted to share the progress I've made on a scratch built proton pack I have been working on since the GB: Afterlife trailer dropped in January. I have wanted a proton pack my whole life but don't have the funds to just go out and buy one, and I have never been quite brave enough to attempt building one. When the trailer for Afterlife hit and it was like I was in a time warp and found myself a kid all over again. I had to have a pack to wear to the premier, so I researched all the ways I could go about making one, and stumbled across KCGhostbuster from GBFans foam speed build on YouTube. Inspired by how easy he made it look, I got started a day or two after the trailer dropped and my pack is finished now, sans electronics, and I hope to start the wand shortly.

If anyone else wants to build a pack, I highly recommend spending some time on GBFans as the depth and wealth of knowledge on that board is breathtaking.

I originally planned on buying one of the cheap Spirit proton packs and modding it, but after seeing how inaccurate it was I couldn't do it. The fact that the pack was reduced to 80% scale, and the wand 60%, pushed me off it entirely. One of the things I always remembered about the packs as a kid was their scale and how much the Ghostbusters struggled with wearing them. I wanted my pack to scale, and the only avenue that left was making it myself. Thus began my journey.

I decided I wanted to make a GB1 Proton Pack as I felt it had more personality than the GB2 pack. For one, the ribbon cable on the first film's pack is a more visually interesting cable, full of color and variation. I also loved how some of the minor details popped better, like the grey Gear Box knob in GB1 vs the black one in GB2.

Using a mix and matched set of blue prints I found on GBFans from Stefan Otto, Venkman 71 and the Palm Coast Busters, I got started using KCGhostbuster's recommended materials of EVA foam and foam core board, mixed with heaping doses of hot glue and contact cement. I started with the EDA Box and went from there building out the pack:


You can also see in the last image the MDF Motherboard I cut out for the pack to be mounted to. That board ended up being a failure, as did the second go round. Third try was the charm, but more on that later.
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The Gearbox is one area where I took, by accident, a bit of artistic license with the prop. This deviation from the actual prop wouldn't have happened if I had paid more attention to my source photos. Check. Your. REFERENCES.

Basically, I rounded the top when it should have dipped in, and my bottom fins come off the box, rather than basically being scored into it. Don't get me wrong, I like how it looks, but it's not screen accurate. The tube I used for the hose connection was an old pill bottle that I cut the end off as a 1" diameter piece of PVC didn't line up quite the way the plans said it would.

Shortly thereafter I finished the gun mount and used a plastic paperclip container that was the perfect dimensions to create the body of the HGA assembly in the upper right corner.

For anyone interested, the total cost of parts thus far was probably around $25 for the MDF board, a couple pieces of foam core, a pack of gym tiles for the EVA foam and the contact cement and hot glue.

At this point, I sealed the main body of the pack with Mod Podge and played around with adding a bottle end for the Gear Box hose to connect too. It didn't stay, but it's present in the photos.

The next part was a fun challenge, creating the bumper. I tried to scratch build as much of the pack as I could and the bumper was no exception. Using the Palm Coast plans I found on GBFans (meant, originally, for wood) I began cutting pieces out of foam core and EVA and putting them together like a puzzle.

It was ugly to start, but some styrene yard sale signs cleaned the edges up and created a piece that was lightweight, sturdy and curvy in all the right places:



I backtracked a bit from here and decided to go back and create the Booster Tube and Frame that went in the EDA I originally started with. I had two pieces of cardboard tube laying around that were amazingly the perfect scale. I used a piece of EVA foam to affix the smaller tube within the other and capped that same tube with more EVA. I then coated the outer tube in plastic wood filler to try and get rid fo the tube lines, followed by sanding, sanding, sanding.

I then sealed both of them generously with more Mod Podge:


By this point I went filler crazy and went back filling edges that I wanted to smooth using that same plastic wood filler. It bonded well with the foam, dried as easily sandable/paintable plastic, and was cheap. Win/Win.

I also worked on adding the Injector Tubes beneath the Power Cell in the EDA Box. These tubes were also free as they were extra legs to a set of plastic shelves in my garage that, again, happened to be the perfect size. I attached them by stealing a trick I learned from Norm Gagnon's budget plans by simply drilling a hole through both and using a dowel to secure them in place. Works perfectly.


Hoping to finish up the EDA Box, I began scratch building the PPD using a pill bottle that was roughly to scale. Scratch building can be stressful, but it does cut down cost...I filled the thing with more EVA foam and ran a dowel through it for the eventual tube to attach to, then capped it with a piece of styrene.

This next bit I take some pride in. I scratch belt the bellows that attaches to the bumper using...pirate coins. I have five boys, and they dress up in costume a lot. One of their favorite themes is pirate and we have coins EVERYWHERE. When measuring out how I was going to make the bellows, originally planning on using washers, I realized they would be so heavy they would break my foam bumper.

Trying to come up with a solution, I grabbed one of my son's coins on my desk and measured it, just looking for a point of reference on scale as I searched Nylon washers on Home Depot's website. In doing so, I realized the coin was the Exact SIZE. Thinking I'm lying? I printed the blueprints to scale. My pirate coin bellows? It's the exact same size, both width and height, and it weighs NOTHING. The bolt holding the coins and their foam spacers together weighs more than the entire bellows.

I sanded them down and had a rough bellows, ready to party:

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Going back and working on finishing parts, I bought the hex bolts needed for the HGA, as well as a metal washer to attach the label to. Everything was hitting in the right spot, though I ended up buying bigger bolts as I felt these pictured were too small compared to the reference images. I also worked on a solution for the tube my Gear Box hose would use to attach to the Cyclotron and found a $1 travel bottle from Target was the perfect size. I ended up cutting the end off and capping it with a piece of foamcore, which will show up later.

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The next challenge I tackled was the Booster Frame, the piece that goes over the Booster Tube I built earlier. It's an odd piece, originally made out of pencils and kitchen matts. Mine was made out of pencils, EVA foam, and a coffee cup. Turns out I had a coffee cup that had a piece of ribbed silicone for grip-sake that I hated. I took the silicone and cut it down to make the ridges along the frame, and built the rest out using EVA backed by styrene.

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The last big piece I was missing was the N-Filter, the round piece that sits at the bottom right of the pack, hanging off the Cyclotron under the Bumper. I found a coffee sugar canister that was the perfect size and, using a template I found online, drilled the off spaced holes found in GB1. I then reinforced the whole thing with EVA foam so it wouldn't collapse. I also built up the inner edges of the holes using that plastic wood filler again so that the material would seem thicker than it really was. I used the bottom half of the canister as the top had a pop lid. As such, I filled the bottom as well using the same filler to create a flat, smooth surface for the filter. I would go in later and simulate weld lines here with my glue gun.

I also filled the edges on the outside of the container, and coated the whole thing in Mod Podge, again.

On the prop there is an inner white layer and mesh screen that sits under these holes, which I easily recreated with a piece of styrene and a $1 strainer I cut into strips for use here.


I also went back and built the Ion Arm out of foam core and EVA. Sadly, I didn't think to take any photos of that part alone. I ended up bolting it to the EDA Box for stability, before doubly reinforcing it with hot glue.

I then laid everything out on the pack to see how I was doing and, voila, a very ugly proton pack lay before me:

While building I had steadily been buying the parts I couldn't scratch build (or didn't want to), like the Alice frame, the tubing for the pack, the various Legris elbows and other greeblies (which I ended up 3D printing) and the ribbon for the pack (Fincher Technologies is the best). When my ribbon arrived I drilled the hole for it to go through and realized how lazy it felt.

Sure, it's screen accurate to simply have a hole because in the film they never worried about people getting a close look into the pack. That said, I refused to believe that Egon would care so little about HOW the cable entered the body of the pack and, as such, took a bit of artistic license again to create a small tube and washer to serve as it's entry point. A small detail, but one I liked and felt improved upon the original, even if it's a detail only I will care about.

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I also built the ribbon cable clamp out of MDF and EVA foam, making sure I had both ends of the cable covered, so to speak:

By this point I had a pack pretty much ready to paint. I went back and added the faux weld lines in all the places visible on the pack using hot glue. I also had to go back and redo my motherboard as, once I had the body completed, I realized how badly I mis-cut the original. It took two tries, but I finally got a motherboard made out of MDF that gave the appropriate amount of spacing around the pack.

Here's a free tip, if you're making your own motherboard out of MDF or similar, build the pack FIRST, then make your motherboard. :p


Now, it was time to paint. I used Rustoleum 2X Flat Black for all the flats and then, for the textured parts of the pack, used Krylon Truck Bed Liner.


Masked for the bed liner vs. bed liner applied:


Not going to lie, I started to geek out around this time. I had a proton pack on my hands!
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After everything dried I drilled the hole for the wand's split loom cable to feed through so that I could actually attach it to the pack. Once again, the original prop simply had a hole there and, once again, I took issue with that and made a connector port for my split loom to attach to the bottom of my pack by:


I also began securing things together, such as using wall anchors in the Booster Tube so that the Booster Frame would have a solid point to connect to.


I also used my Dremel to cut down the acrylic sheets I bought to create my Power Cell and Cyclotron lenses, which looked great when installed.

The next, and probably biggest, remaining challenge was mounting the pack to the motherboard. I found a lot of great tutorials on GBFans and happened to have a piece of copper sheeting from an old project laying around unused. Rather than buy new material, I decided to be crazy and just use what I had on hand and made my own L brackets using the copper. Trying to maintain accuracy, I riveted the motherboard to the L frames, which was no fun at all, but created a fairly accurate board to mount to.


I also created spacers to go between the Alice frame (which I had to paint black vs the military green it came in) and the motherboard using my good ole' EVA foam. I drilled my pack, used some paint pens to mark the holes on the brackets, drilled my brackets and VOILA, the pack attached to the board pretty smoothly...more or less...

You will also notice I went in and attached my 3D printed bits and bobs, as well as my Ion Arm bars, created from wooden dowels.

Once I had the pack attached to the motherboard I went in and attached all my hoses and decals that I had printed on metallic vinyl sheets. I bent my cable to match the angles of the GB1 pack seen in the Omni magazine and various other source images as closely as I could. I generally did the same with all the hoses, doing my best to make sure they flowed around and under and over one another as they did on the original prop, which was a pain but worth it.

At this point I only needed to build my Clippard valve for the pack, which I had been avoiding due to scratch building fatigue, and weather it.


While scratch building my Clippard valve I also discovered that the original prop had a few details mine was missing: a metal prong coming off of one of the Dale resistors on the Ion Arm, and a weld bar between the Ion Arm and the Booster Tube to help secure both. I'm too anal to overlook those details, so I scratch built all three.

For the Clippard valve I found that a tube of acrylic paint was the same diameter as the valve and, seeing how I had a few dried out tubes sitting in my paint box, used them. Cutting them down to size, I cut the top off separately to reuse as the top of the valve, using my Dremel to cut the threading out. Borrowing from another build on GBFans, I used a travel bottle of mouth wash for the top and threading of the valve. I used EVA foam to connect all three and painted the body flat black, and the top and bottle cap silver, with the threading gold. It worked out perfectly and the labels fit it exactly. I also created the base of the valves out of EVA.


For the Dale resistor prong I used a coffee stir stick. I took one, heated it up slightly and squished the end with a pair of pliers. Once it cooled off, I drilled a hole and BAM, one prong, ready to paint.


Finally, for the welding bar on the Ion Bar, I used a Nerf dart. Yep, it's the perfect size/fit. I cut it down, capped it with Styrene and painted it. Once it was dry, I attached it with hot glue and created fake weld lines, also with the hot glue.


Last bit was the weathering, some of which you can see above that I started pre weld bar...
And here's where we are today. I still need to attach the Dixie cup bracket to the Gun Box for mounting the Neutrino Wand, but the pack itself is done.

My goal was to make it look like a pack that had been in semi regular use and had seen a lot of wear. I'm debating whether I took it too far, but for now I'm happy with it.






I'll post updates as I work on the wand, as well as the electronics for the pack. Since the film has been pushed back a year due to the Covid-19 pandemic I will have even more time to work on creating a full costume, hopefully complete with a ghost trap and a PKE meter.

If you've read this far, thanks, and I would love any feedback, good or bad. I want to make the best pack I can. Ideally, at some point in the future I'll be able to build a proper pack but considering I made this out of EVA and foam core with a dash of PVC and MDF, I'm pretty darn happy with it.

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