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Modern super magnets replace the ancient torsion engine in a desktop catapult to get an awesome cubicle warfare machine!
Modern super magnets replace the ancient torsion engine in a desktop catapult to get an awesome cubicle warfare machine!
183 backers pledged $8,513 to help bring this project to life.

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    1. John Fehr 10-time creator on June 22, 2017

      While the original is no longer available, the mini is still available at promotex. (…) Thanks!

    2. Metorks on June 22, 2017

      The magnetapult was such a fun toy and made for an interesting conversation piece.

      Unfortunately, my magnetapult was recently broken by some visiting children while I was out of town. The remains were discarded, so I didn't even get a chance to attempt to repair it.

      Is there any hope for me purchasing a replacement?

    3. Rene Ochoa Dorado on April 4, 2013

      where can we get plastic replacement parts? i got four catapults and already had the launches break on two of them. the pressed cardboard fiber board is very fragile

    4. John Fehr 10-time creator on April 17, 2012

      Hi Craig!

      Since the magnets come stuck together, I can offer some guidance. (Had to do that for a couple hundred pairs. :P )

      What I do is put one of the metal discs on each magnet, and then put the magnets edge on against a wall. I then push one while using the disc on the other magnet to hold it in place. (You still have to push really really hard but the disc helps you stabalize a bit at least.) After that, keep them far apart! :)


    5. Craig Dunn
      on April 17, 2012

      So, after getting the steel discs finally removed from the magnets, the two N52's decided to reorient themselves end-to-end rather than edge-to-edge. I have now spent a good half hour trying not to smash my fingers and get these things to budge even a hair... no luck. I have tried using tools, but things tend to come flying towards each other and offer no mechanical advantage. I have tried finding thin cardboard or plastic to "slice" between the two magnets, but the attraction is too strong.

      At this point, I'm almost considering having to build this:
      just in order to separate these and build my catapult.

      Looking for more ideas before I spend a weekend building a device that will let me build a device that will take 10 minutes. :-)

      By the way, I made arrangements to work on the aluminum prototype John started. I will post here or advise John when I have something to show if I'm able to fix the prototype pieces (they need a lot of love because the thickness of the metal doesn't match the slotted cut dimensions). I should probably indicate that this will be a one-off effort and not something John (or I) will be offering... the expense is just not reasonable.

      Anyway, if anyone has more ideas on breaking these magnets apart before I go crazy and build an overkill device to do it, please share. Thanks!

    6. Charles Alvis on April 13, 2012

      Hi John, I got mine today and I am getting strange looks in the office. We you be sharing the drawings with us so we can make own modifications?

    7. Jeff Czapla-Myers on April 13, 2012

      Please keep us updated on the ABS triggers. My original trigger is getting a lot of use. :)

    8. Josh Orth on March 29, 2012

      I love my catapults, thanks so much!

    9. John Fehr 10-time creator on March 29, 2012

      Hi Tae!

      It seems that uneven stress on the legs doesn't manifest in a broken leg right away, but rather leaves a small imperfection that gets magnified when the arm strikes the stop plate. It may work ok for a few more throws and then suddenly you realize that only one side is supporting the arm. Further attempts will cause more damage until you're left with a throwing arm in a few pieces.

      Replacement arms are available through promotex. (email You can get either the standard ones or the somewhat sturdier extra-thick ones. The extra thick ones should last longer, at the expense of a bit of throwing distance. (The heavier the arm, the less distance the ammo can be thrown.) I would recommend buying extra ammo to save on combined shipping.

      Neither of these are standard items at, since the balls will be replaced by new ones shortly, and is not selling the magnetapults yet. It may take a week to ship, since I make these on an as-needed basis, and Bruce does the shipping.


    10. Missing avatar

      Tae Kim on March 29, 2012

      Hi Cadabra, any way to order replacement parts? my fling arm broke already! Had a blast with the office colleagues while it lasted though. (and believe me, we were careful about pressing down on both sides to 'load')

    11. John Fehr 10-time creator on March 25, 2012

      Jon: Yeah, there's still ammo left. Email with your address and he'll let you know the shipping and payment. (I believe its $5 for 10 balls plus shipping.)

    12. Wee Heavy Walter-Stern
      on March 20, 2012

      I found using a cardboard box helped seperate the magnet.

      Can we still get more ammo?

    13. Missing avatar

      Ben Freed on March 16, 2012

      Got my magnetapult, like it a lot. A couple tips I have. I struggled for a while trying to get the magnets and steel disks apart. I came up with my own solution to do it easily. Get some popsicle sticks and wedge one in between the magnets, with the steel disks still on. Then use another popsicle stick to pull off the small steel disk, by placing it so it's resting on the 2 magnets and then pulling over the surface of the magnets, sliding the disk off in the process. Then you can just wedge more popsicle sticks in between the magnets, I used 5 in between and I was easily able to pull them off of the large steel disk.

      On to firing:

      Of the 3 settings (no block, middle block, and bottom block) I found the middle block to be the best. The no block setting does not shoot very high and has a bit less distance than the middle. The middle block shoots higher and the farthest. The bottom block shoots the ball the highest, but has the least distance.

    14. Missing avatar

      Ben Freed on March 15, 2012

      Haha yeah, they never even got back to me...

    15. John Fehr 10-time creator on March 15, 2012

      Ben: Excellent! So much for priority service, eh?

    16. Missing avatar

      Ben Freed on March 15, 2012

      My tracking finally changed, looks like it will be here tomorrow!

    17. Missing avatar

      Ben Freed on March 12, 2012

      Didn't show up today, USPS said they didn't know where it was, they opened up a case for me and said someone will contact me within 24 hours with more information.


    18. Corey
      on March 12, 2012

      Got and assembled mine today... IT IS AWESOME!!!

      Very easy to build (follow the instructions, especially when you get to the point to check which direction to install the second magnet) . The balls included are perfect! I can shoot it across the room and have it bounce back to my desk, no problem. Thanks for an awesome project that delivered everything and more as promised!

    19. Missing avatar

      Ben Freed on March 11, 2012

      I'll give them a call if it doesn't come tomorrow. Thanks!

    20. John Fehr 10-time creator on March 11, 2012

      Ben: Weird. No update on the tracking since the 6th, eh? Did you try calling USPS with the tracking number you were sent? I know they scanned it wrong to start, but I've heard from a lot of other backers who've received theirs after that. If they give you the runaround, let me know ( and I'll give em heck and/or send you a new one if they've lost it.

    21. Missing avatar

      Ben Freed on March 10, 2012

      Aww, still no magnetapult :(

    22. Jim Levy on March 8, 2012

      Just built mine this evening.... and it's awesome! Those magnets are a bit scary, but building it is pretty intuitive. I might bring it to work tomorrow to try it out... Thanks!

    23. John Fehr 10-time creator on March 7, 2012

      Glad you got it working, Brian! A couple of things:
      1. I realized that I got overly strong magnets after I received them, but I'd already put 'N52 magnets' in the description, and I didn't want to appear to rip anyone off, so I kept them. Future versions may use N42, since the N42+metal discs are pretty close to N52 without metal discs. I found the easiest way to pull them apart is to first take the smaller disc off, and then slide one of the magnets off. They're attracted the weakest on edge, so the pull of the magnet on the metal should be stronger than the pull of the magnets together. Still tough to pull apart.
      2. Its not an extra piece! Heh... See the two slots on the top? That piece fits in those to add extra 'stops' for the magnetapult. (I think they're 20 degrees apart.) That way you can vary the trajectory.
      3. Good to know, I'll make them darker in the future.

      I tried making the arm the thinnest it could be while still being strong enough not to break. After an early model snapped, I thickened it considerably, and haven't had any snap since then.

      As to packaging the magnets in different bags... You noticed how hard it was to take them apart. Hopefully you didn't leave them within 6 inches of each other while assembling, because they're easily strong enough to pull towards each other. Many of the wooden parts are not very strong separately so putting the magnets on opposite ends of the box felt like it could end up with many broken parts. By putting the magnets edge to edge (the weakest attraction) and putting a disc on each side, I could limit the possibility of the two strong magnets causing damage during shipment.

      As for the ammo storage, I'm going to say that was planned! (It wasn't, but after building one, I too noticed it fit nicely.) Just be sure to keep your fingers firmly inside while launching!

    24. Brian Reddington on March 7, 2012

      Hey everyone! I got my magnetapult in today, and it's fully assembled. Let me give you some tips and whatnot

      1. HE IS NOT KIDDING WHEN HE SAYS THESE MAGNETS ARE STRONG. I spent 20+ minutes trying to separate the metal discs from the magnets. In the end, I had to ask someone else, because my fingers hurt too much from all the prying and sliding of magnets.

      2. When the assembly is finished you will end up with an extra piece. It's supposed to be that way. (but why, john?)

      3. It's kinda hard to see the white screws in the drawings on the directions. I used the video posted in the updates not too long ago. It helps.

      Now for John:

      - I know this is wood and stuff, but it still feels pretty flimsy. Every shot I'm afraid the whole thing is just going to come apart. It hasn't yet, but it just feels that way. I'm sure I'll come to trust the assembly more since a. you've done this before and b. i assembled it myself.

      -You really should have packaged the two magnets in two different bags.

      -Not sure if it was planned or not, but there's room under the magnets to store the ammo. They fit nice and snug.

    25. John Fehr 10-time creator on March 2, 2012

      Ryan: Excellent!

      Everyone: had someone play with it today, trying to cock it back by pushing on one side of the arm. Make sure you push down on both sides together, or you might have trouble setting the trigger...

    26. Ryan Moody on March 2, 2012

      Just test-fired mine. Works great!

    27. Øystein on February 6, 2012

      Finally a backer:)

      The tax limit in my country is in fact 35$, which is what I pledged. Could you mark the package with 20$, since this is what the product itself cost?


    28. John Fehr 10-time creator on January 29, 2012

      JR: Unfortunately, the chinese new year week put me a bit behind. I'm getting them to send me samples as soon as they're back, so hopefully I'll be able to update the project pics with the projectiles _before_ the end of the project. I really want to get custom printed ones as well, but if there's a delay for those, I'll give people the option of waiting the extra week, or getting plain ones right away.

    29. JR on January 29, 2012

      Have you found a suitable ball yet that you will order in bulk?

    30. Ken Davis on January 17, 2012

      upgrade to metal version. ++> 1 early backer spot now free.

    31. John Fehr 10-time creator on January 15, 2012

      I have been racking my brain trying to figure out some way to allow different sized projectiles, and I think I've figured it out. Hopefully an update coming on it today! :)

    32. JR on January 15, 2012

      Have you considered creating a "cup"-like attachment? That way smaller projectiles such as marbles or even M&Ms could be used. You may have already researched it but I was wondering if it had been considered.

    33. John Fehr 10-time creator on January 14, 2012

      It really depends on how far you want it to go. Just like a regular catapult, the less weight you put on, the farther it will go. Its meant for cubical warfare, so I didn't design it to launch stuff that would actually damage anything/anyone. (Other then knocking stuff over.)

    34. JR on January 14, 2012

      Is there some kind of recommended weight limit with these?