[HELP] Attaching prop pipe to backpack

[Fuzzytux]

Hi everyone. Long time lurker, first time poster. Hoping someone might have a brilliant epiphany for an issue I'm having.

Working on a cosplay of Joel from the game The Last of Us, and I'm stuck (no pun intended) on how to secure the pipe to the side of the backpack. The pipe is PVC and weighs about 1lb, and the backpack is canvas.

In-game, the pipe just sort of floats with no obvious attachment point (reference below), and my preference is for my cosplay to match that as closely as possible.

My "brilliant" plan was to glue two strong neodymium magnets inside the backpack (the red circles in the photo), one inside the main compartment and one inside the small side pocket. I'd then glue two more to the pipe (covered with tape), and voila! Unfortunately, this isn't working. The pipe flops around and falls off pretty easily (and these are REALLY strong magnets). I think this is due to a combination of the thickness of the canvas (since magnetic attractive force drops off exponentially with distance), the lack of friction between the canvas and the pipe, and with the non-rigid structure of the backpack (so the pipe shifts a lot as I move). Plus, this isn't even in a busy convention environment where I'm liable to get bumped into frequently.

I've considered a few options:

1) Glue the pipe to the backpack - should keep it secure, but then it's not removable for photos, etc - not ideal
2) Attach a second strap near the bottom and use the two side straps to secure it - may or may not keep it secure, but then I'm adding a second strap that doesn't exist in-game, sacrificing accuracy
3) Add more duct tape to the outside of the backpack and glue the magnets under that - would reduce the gap between the magnets and might help keep it secure, but then I'm adding tape that doesn't exist in-game
4) Figure out a way to add rigidity to the backpack's structure so the fabric doesn't move as much - might reduce the amount of movement as I walk enough to keep it secure

Thoughts? Suggestions? Anything obvious that I'm missing? Any thoughts would be greatly appreciated. Thanks!

 

[ScoobiJohn]

you can get some really powerful magnets and they should be able to hold it even with cm or two of separation - but its still likely to be floppy so i would try to add rigidity on the inside of the backpack - you could shape it slightly to so the pipe sort of fits into a grove so it doesnt flop around and break the magnets hold - shouldnt affect the look from the outside - you could also go silly and get a magnet with 30kg of hold or something

quick test - and was a little uncomfortable even with them that far apart

 

[Fuzzytux]

you can get some really powerful magnets and they should be able to hold it even with cm or two of separation - but its still likely to be floppy so i would try to add rigidity on the inside of the backpack - you could shape it slightly to so the pipe sort of fits into a grove so it doesnt flop around and break the magnets hold - shouldnt affect the look from the outside

So you're suggesting adding some sort of channel on the inside that the pipe would fit into from the outside? That's an intriguing idea I hadn't considered. So a sort of half-cylinder or something out of styrofoam and glue in place?

you could also go silly and get a magnet with 30kg of hold or something

I'm using a 1" x 1/8" disc magnet set into a metal cup. The metal cup redirects the magnetic field towards the front, which simultaneously strengthens and shortens the field. It's supposed to have a hold of roughly 55kg (the cup magnifies the force by ~4X), but it still breaks pretty easily. I think the canvas thickness is really affecting the hold strength, even though it doesn't seem like it should.

 

[ScoobiJohn]

yeah exactly - or a section of pipe slightly larger diameter than the outside one - as for the magnets - dont know about those cup things - i'd just go with straight magnets they have plenty of hold and if those cups are reducing the distance in exchange for power its not worth the trade - the pipe isn't heavy but because it might move as you walk better to have it so can keep hold and drag it back where it needs to be - i dont know what those magnets of mine are rated for but i know they are dangerously strong - the inevitable getting a finger caught between them happened - cant resist playing with magnets

 

[Riceball]

Another option would be velcro. Black for the pipe and on the pack paint it to match the pack so it will blend in when the pipe isn't there. You'll have to take the pack off to reattach the pipe but it won't require a whole lot of work to add the velcro,

 

[Fuzzytux]

yeah exactly - or a section of pipe slightly larger diameter than the outside one - as for the magnets - dont know about those cup things - i'd just go with straight magnets they have plenty of hold and if those cups are reducing the distance in exchange for power its not worth the trade - the pipe isn't heavy but because it might move as you walk better to have it so can keep hold and drag it back where it needs to be - i dont know what those magnets of mine are rated for but i know they are dangerously strong - the inevitable getting a finger caught between them happened - cant resist playing with magnets

Oh my. That's one heck of a magnet. I can't go with anything that large, because the weight of it will hang down from the canvas of the backpack. But you're right about the cup. I just tried a magnet against a small steel backing plate and it's much stronger. I did a test by hot-gluing another magnet to the pipe and the glue-to-pipe connection failed before the magnet-to-magnet connection did. I'll try using epoxy to attach the magnet to the pipe and doing a final test.

 

[ScoobiJohn]

if the connection is that strong maybe should go for a weaker magnet - dont want to be fighting it every time you want to get it off

 

[division 6]

So what is the purpose of the pipe?
Is it ever removed?

Of it doesn't do anything I would bolt it to the pack with a strip of something inside the pack to keep it stiff.

 

[Fuzzytux]

So what is the purpose of the pipe?
Is it ever removed?

Of it doesn't do anything I would bolt it to the pack with a strip of something inside the pack to keep it stiff.

It's a prop that's meant to be removable (since it's a weapon). It would stay attached most of the time, but I may end up removing it periodically for photos. Agree that bolting it would be the easiest, but I'd prefer having the option to remove.

 

[Fuzzytux]

Got it. I ended up cutting two small notches into the pipe so the magnets wouldn't stick out quite as far, used JB-Weld to attach them and then taped over.

The trick was to attach the each magnet inside the backpack to a steel nail plate, and then glue that whole piece to in the interior. That drastically increased the holding power without reducing holding distance. I've tested walking around and shaking and everything seems to be holding pretty steady, so I think I'm good.

Thanks all! Really appreciate all the advice. Sometimes it just helps to bounce ideas off of people.