Hey guys. My 5 year old has been pretty heavy into ghostbusters for about a year now. He has the game and both movies and it always shooting me with an imaginary proton stream. So logically he wants to be a ghostbuster for halloween, and i am told that the commercial blow up costumes are “not real” by my 5 year old.
So, i am building him a pack.
Let me state that obviously this is not going to be to scale or movie acurate, but i want to get it to the point where a real fan will see glaring mistakes, but the avarage person will think its amazing. So far i am using stefans planns as a bit of a guide, but not following all measurements to the tee. Right now im looking at the pack being about 1" shorter,narrower, and thinner than it should be to cut down its size and weight a bit. With my son only being 6 by the time halloween rolls around weight is a big issue. Right now i have been using foam insulation board to make most of the shapes, and then topping it with 1/8" plywood. The pieces seem to be both lightweight and strong. One thing i am concerned about is the spacer, which i planned to use the foam board for. 2 concers here.
I am not sure how i am going to make the sides nice and super flat/clean after cutting the foam.
Can i even paint this stuff?
If anyone here can offer some help with creating a nice looking lightweight spacer that would be great. As well ANY tips or help at all. I am not super handy so anything you can tell me will help…
Like what is that pink stuff i see many people using on their packs to fill in gaps? I am going to need to do this with much of my wood word i think.
Here is a picture of what i have done so far. No, its not perfect, but i think the shape resembles a proton pack at least. lol. I am removing the cake pan as i have bought a cyclotron from a member here. The blue box was going to be used for the gunmount and gearbox originaly, but i got a little more ■■■■ about the project and will be scratch building the gun mount box like i did with the gearbox.
regular spray paint will melt the foam core sides, so filling it with bondo, or even wood filler and sand it smooth- like I did is what you need to do. I’m sure another user will point you in the right direction for your other questions.
And don’t fret over accuracy, my pack is pretty inaccurate, but the average joe looks at and thinks it’s a movie pack.
I’ve never used bondo, but, like when it’s used on cars, it can be sanded smooth. I assume a block of wood and sandpaper would do it. Although I’d hand sand it. I don’t know how much aggressive sanding foamcore can handle.
You can also sand the pink foam smooth as well. Just grab a medium to fine grit sanding sponge, available at wal-mart, home depot, craft stores etc, and sand away.
If this if for a kid I would recommend using paper mache to prep the foam. Basically get a few copies of your local newspaper, tear pieces about the size of your hand, and use a mixture 1:1 mixture of elmers school glue and water. It will seal the foam and give you a good base for bondo if desired.
Has anyone ever tried wrapping the spacer with like some veneer? (sp?). I saw this stuff at home depot that looks like really thin wood and it comes wound around a tube, therefore it should be flexible enough to get around the top of the spacer.
that would work, or you could use styrene, which is used in for sale signs…which means no wood grain. Other wise, yes, you will need to fill the grain as it will show. bondo or wood filler/putty will work. Also, use **flat **black spray paint. Gloss will highlight every imperfection.
You can bend thin wood by soaking it in very hot water for a while, then bending it around the curved surface and clamping it in place.
Elmer’s glue should also work for sealing the foam for paint. Craft stores sell jars of it under the name “mod podge”. You won’t be able to sand that though, so you’d want to make sure the surface is smooth before you do that.
Usually people cut foam with a hot wire to get a smooth edge:
I must say I’m a bit worried that what ypu’re building is gonna be too heavy for a 6 year old. You’ve got a lot of wood on there, pvc, and you say you’ve ordered a cyclotron. Unless that cyclotron is vaccum formed plastic it’s probably heavy resin. I’d say you need a lot more foam on this pack.
Also, scaling the pack down by only 1" in each direction is going to leave you with a pack which is huge on the kid. I don’t know how tall your typical 6 year old is, but I’m gonna guess about half as tall as an adult, in whcih case the pack ought to be half as big.
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The cyclotron i ordered is aparently made from High Impact Polystyrene. The plywood you see there is actualy only 1/8" thick and very light. INside the gearbox and booster area is just foam. I am concerned about weight for sure though. How heavy exactly is the resin made stuff? I wasnt planning on getting alot of resin parts except for the gunbox, bumper and booster frame. (pretty much the stuff that i dont have the resources to build) Do you think these resin parts are too heavy? Also i still need a motherboard. I was thinking that thin plywood would be light enough, but has the tendancy to warp. Any suggestions here?
As the pack is in that picture it is weighing in at 2lbs. I put my sons backpack on and loaded it up with 9 pounds of ■■■■ and he was able to walk around find with it, but I am still aiming at comming in under 6 pounds.
As far as the size goes, I KNOW! LOL, its going to be huge on him. Its partly my fault. He said he didnt want a small one, he wanted a big one, and i simply didnt fight with him. At this point i wish i would have.
On the other hand he will get years of playing with the pack as he will not grow out of it.
You are going to run into a number of issues with this.
Measure the length of the pack layed out, and then measure him, from an inch above his shoulders down. Odds are, the bottom of the pack will be hitting his calves. He is barely going to be able to walk in it, let alone run or play in it.
Based off my builds of similar materials, you re looking at between 12 and 14 pounds for the pack. Put 2 5 pound bags of flour or sugar in a backpack, and put it on him… see how he manages with that. Keep in mind the pack will weigh two or three times more than that amount.
Packs are reasonably durable, treated properly, but any kid just isn’t going to be treating it like a prop.. he is going to want to play with it like a toy. We all repair our packs constantly, and we are careful with our gear. Expect a lot of repairs no matter how durable you build it.
Honestly, for a 5 year old, I’d just buy the new proton pack backpack that was released this week. Its practical, probably far more durable, and it won’t have to be repaired after every time he plays with it.
I have a lot of tips with our builds that are similar to yours in my thread here. read through it, and ask away if you have any questions.. and GOOD LUCK.
(I don’t mean to be a downer, but I think forewarned is forearmed)
Here is the news link from today with the order page for that pack I mentioned:
I built my entire pack from 1/8 thick basswood, which is lighter than plywood. In the end, it ended up weighing over 40 pounds. Of course, I had an aluminum motherboard, real clippard valves, brass fittings, washers for the ion knob, and a spacer made of MDF… but still, stuff that seems light can add up quick.
As for the weight of the resin stuff, I’d say it’ll weigh at least as much as it would if it were made out of wood or pvc of the same thickness. A resin bumper is gonna weigh a lot.
Also, I’m not sure how well that foam motherboard and spacer are gonna handle all the weight you’re putting on it. Have you considered how you’re gonna attach a heavy bumper to the foam spacer? I’m not so sure screws will hold well with it bumping around as he walks.
I see you mention a new motherboard though, so I guess the foam is just temporary. My first pack was a bunch of electrical boxes on a motherboard made of MDF. That’s kinda like 1/8" plywood. It held up well enough. You just gotta paint it cause the stuff is like cardboard and will disintigrate if you get it wet. Paint should protect it well enough though. Prime it first too, it will absorb paint like crazy.
But again, that’s gonna be too heavy for a kid. Even the electrical box pack was quite heavy.
I dunno what to tell ya as far as what you should do. I mean, if it was me, I’d be making the thing at least 3/4 scale and making it mostly out of foam. I don’t really think the kid needs a real bumper on there either… my first electrical box pack fooled adults, and I just had a strip of rubber for the bumper with a gray cylinder glued in the middle.
I would at least get rid of that PVC and replace that with a carboard or thin plastic mailing tube. That’ll get rid of a bunch of weight.
Good tips. Yeah, i showed my son the picture of that blow up pack and once again i got the "thats not a real one) response. I think my biggest mistake was when i told him i could get working lights into it. lol
I dont know. Kids only grow up once, and i usually never spoil my son, but he really likes GB and i want him to be able to go to school and really wow his little friends. haha (or get expelled for comming to school with an unlicensed nuclear accelerator!)
An accurate cyclotron/spacer made of MDF and a cake pan, fitted on an MDF motherboard, with electrical boxes, speaker housings, misc wires. The thrower is a star wars blaster with some vinyl tubing stuck in the end of it, and a tiny flashlight stuck in that. The n-filter is a pringles can.
And here’s a previous revision of it:
Where you can see I just colored a ribbon cable with marker and just taped a glue stick on it for the power cell.
I won $150 with the pack you see in the second pic. It’s held together with duct tape. Adults couldn’t tell it wasn’t the real thing. I’m sure you can ■■■■ some kids with something a little less accurate.
What are you planning to do for a lights btw? On my pack I stuck four blinking reflector lights in the cyclotron. They weren’t synched up, but they didn’t need to be.
Not bad AT ALL! What exactly is MDF? As far as lights, i came across these while checking out ebay one day. Has anyone tried lights from this maker before? They look pretty professionaly done, and i bet i could sell them if my son no longer uses his pack…or most likely use them in a movie accurate pack for myself.
MDF stands for Medium Density Fibreboard, its a type of wood where wood is mulched and then densely packed together. Its quite a strong wood, and doesn’t splinter or split as you’re cutting and it leaves very nice clean lines, but it is quite difficult to cut. If you’re gonna use MDF, I suggest using a power saw.
It’s usually a darker brown than what is pictured there and you can get it around 1/8" thick. You’ll find it at Home Depot, but not Lowes. It would be with their smaller size plywood, birch, etc. It comes in sheets like 6’ long by 4’ wide I think.
It’s very dense though. I’m not reccomending it as something to build you kid’s pack from. But it does make a good material for a motherboard. It’s super smooth, and cuts easily with no splintering. Creates a lot of nasty dust though. Will need to wear a respirator mask if you’re gonna cut a lot of it.
As for those pack lights, never seen those ones before. Never seen anyone use those large leds for the power cell or lots of little leds for the cyclotron either. Interesting take. For $78 though, you could almost get an Exoray pack light kit, and it would have the correct number of lights on the powercell, and could be interfaced with his thrower light kit and sound kit should you choose to get those eventually. Plus they’ll retain their value better than the jupiter ones:
Styrene plastic sheets are likely the easiest way to go. I get mine at http://www.ttplasticland.com/ locally. You can score and break then glue/weld quite quickly. With a steel straight-edge and cheap drywall circle cutter, you can mostly do all the required shapes. You might try posting on the NE Regional Forum to see if you can get some local help.
