What We’ve Been Up To

You might be able to guess by this conversation between my friend Jason and myself:

Jason: Doh! Had a catastrophic magazine failure.
Sebastian: What happened?
Jason: Body came apart and rounds went flying everywhere.
Sebastian: At the glue seams?
Jason: Yeah. But it wasn’t the glue. The plastic failed.
Sebastian: Ack
Sebastian: I wonder if painting some epoxy on the outside and letting it cure would strengthen the magazine body.
Jason: Maybe. I’m going to try making the walls a little thicker.
Jason: The failure was due to a mistake in the scad file. Its not a design problem.
Sebastian: Good to hear

In case you didn’t figure it out, we’re attempting to design a “high capacity” or “extended” magazine that can be printed on a 1200 dollar 3D printer. Whether we succeed or fail, I will report on the effort. Jason is doing most of the work, since he’s the one who owns the printer. My contribution to the project was designing the follower. Obviously we can’t print a spring with a printer that extrudes ABS plastic, so we won’t be making that ourselves. What are they going to do? Outlaw springs? A spring would not be remarkably hard to make, but just to save the frustration we’re going to use a spring from a broken magazine for the same gun.

Turns out this is a lot harder than would have been anticipated. I had to make changes to the follower last night, and Jason has had to make several modifications to the magazine body. There’s also been modifications necessary on the printer. My feeling is this would be fairly easy to make work on an expensive commercial device, and that the limits of home 3D printing are being pushed to the limits on this project.

It is our intention to definitively show that banning magazines is a fool’s errand in a world where people have easy access to this kind of technology. Once we have a working design, anyone with the Makerbot printer, some glue, and a spring, could download our magazine design, print it, and have it work. I will publish the design here, because I want it to spread far and wide. I’d like to see Paul Helmke try to argue we need to ban CAD drawings too, or restrict 3D printing technology. You can’t put the genie back in the bottle. We’re going to do our best to prove that.

Stay tuned to this blog for further updates on our progress. I might invite Jason back to post on some of the stuff he’s worked on, since the last time readers here heard from him was in 2007 when his Calico M950 blew up in his face (both he and the gun are fine now). I have created a new category for this topic.

24 thoughts on “What We’ve Been Up To”

  1. Since the idea is to get a functional magazine, not a pretty one … have you considered a little redneck silver gilding? (duct tape).

  2. I don’t see the point of your experiment since all someone has to do is put up a “This is a high-capacity magazine-free zone” to thwart it.

  3. Awesome! This sounds like an neat project. There are a ton of things that could be neat to make.

  4. High cap magazine for what? AR? Might be able to get it to work. Do you know what the yield strength of the plastic is? Might want to make some basic test bars to find that out. Once you know that you can calculate the wall thicknesses you need to take the load.

    The other strengthening method you could try is embedding drywall tape in your mag body. It would be a like a poorman’s fiberglass composite. Dunno if you could use additional curing methods to improve the strength of the final part after it exits the printer.

  5. As noted above, if that doesn’t work print the body -thinner- and do the build up with layers of epoxy and fibertape. Like old Glock mags it might swell a bit fully loaded but the magwell would provide support at least for the part that -has- to be narrow.

    It would still demonstrate that existing tech makes bans ludicrous.

    If they could make cannon barrels by binding -wood- with iron and brass, a home-made mag which is only constraining spring pressure is easily imaginable if the machine can make the tube to spec dimensions.

  6. Hell, even without plastic-printing, it’s not like it’s hard to make most magazines just out of bent sheet metal.

    It’d take some fiddling to get the feed lips right, naturally, and you’d probably end up hand-carving a master follower and then casting (plastic in plaster, say) more, but…

    You don’t even need a $1200 printer to make a magazine good enough to prove that serious criminals will never be stopped by a magazine ban.

    Seriously, a reasonably talented junior high student could make one in shop class.

    I could make one in my garage, with maybe $50 in tools. ($180 if you want a nice shear/brake to make things cleaner and faster).

  7. This much is true, but the purpose of doing this with a 3D printer is that it takes very little to no skill in order to make one. We’re doing all the hard work. To do metalworking or injection molding is within the reach of a hobbyist, but it requires some talent with tools and mechanical things. This will require setting some parameters in the printer software, and hitting print. The machine does the rest.

  8. “I’d like to see Paul Helmke try to argue we need to ban CAD drawings too, or restrict 3D printing technology. You can’t put the genie back in the bottle.”

    Yea, and the same goes for lathes and milling machines…

  9. From a purely materials engineering perspective, it sounds like insufficient plasticizers in the polymer mix.

    That may or may not be fixable depending on the printer.

  10. Oh… if it is plasticizer mix issue, and you can’t correct it in printer; you may be able to correct it by printing the mag in two halves, and suspending a nylon, glass, or metal matrix in the printing area (on an armature with lead wires for example). Then you just epoxy the two halves together.

    Alternately, you could epoxy a layer of the same material over the inside and outside surfaces. It wouldn’t be as strong, but depending on the printer it might be easier.

    Neither are particularly difficult, and both should produce the desired result.

  11. This isn’t a sophisticated unit. It’s an extruded thermoplastic, which isn’t honestly that strong. That’s part of the difficulty we’re having.

  12. What direction are you running the ABS extruder? Are you building up the layers parallel to the baseplate from the bottom to the top or are you running them along the length of the mag body? The latter will probably be stronger because the weaker bonding lines will be along the barrel of the mag instead of along the length where all the spring load is.

  13. Sebastian: True, true.

    Though they’ll still need to glue, finish, and assemble. It’s gotta be a easier than cutting and bending.

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