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Registered Member #3637
Joined: Fri Jan 21 2011, 11:07PM
Location: Buffalo, NY
Posts: 1068
I know people use PVC pipe quite a bit, but what are some other options of using? From what I understand the more conductive the worse the performance of the coilgun will be.
And, what do you typically make projectiles out of? I see all of these coilguns with nice smooth "bullet" like projectiles...Do you machine them by hand?
Registered Member #1525
Joined: Mon Jun 09 2008, 12:16AM
Location: America
Posts: 294
Inducktion wrote ...
I know people use PVC pipe quite a bit, but what are some other options of using? From what I understand the more conductive the worse the performance of the coilgun will be.
And, what do you typically make projectiles out of? I see all of these coilguns with nice smooth "bullet" like projectiles...Do you machine them by hand?
Thanks!
Use some kind of plastic. I've had great success with ABS, and my current project uses Teflon (lowest available friction coeff). The thinner the barrel wall and the closer the barrel inner diameter is to the projectile diameter the better. This minimizes the air gap, which hurts efficiency.
Metal barrels can attain lower wall thickness, but you will need to cut slots beneath each coil to minimize eddy currents.
For projectiles, the easiest thing to do is go to the hardware store and buy a nail with whatever thickness you desire. Then with a hack saw and metal file, you can cut it to the desired length and polish/sharpen.
Registered Member #3888
Joined: Sun May 15 2011, 09:50PM
Location: Erie, PA
Posts: 649
I've been using rewound solenoids for the coil form, barrel, and external iron, with the plungers used as the projectiles.
wouldn't buy them from there, but it has plenty of images to show what i mean. I bought a dozen large solenoids from bgmicro or goldmine-elec (can't remember which) for like 2 bucks each. They're sold out now however. If you require more barrel outside the coil section then you can use whatever material you want.
Registered Member #1451
Joined: Wed Apr 23 2008, 03:48AM
Location: Boulder, Co
Posts: 661
I'm a big fan of slotted brass. You can get brass tubes at hardware stores and they have a very low coefficient of friction with steel. Very thin walls and look good. As long as they are slotted under the coil, no problems with eddy currents!
Registered Member #1526
Joined: Mon Jun 09 2008, 12:56AM
Location: UK
Posts: 216
I can`t think of a good reason to have a barrel at all. After all, firearms use a barrel to apply force over a longer distance and to impart spin to the projectile while coilguns don`t use theirs for either of those things.
Registered Member #1526
Joined: Mon Jun 09 2008, 12:56AM
Location: UK
Posts: 216
The same way you normally make one but...without a barrel! Make something to hold the projectile in just the right place before the coil, it`ll still be sucked through.
Registered Member #3792
Joined: Sun Mar 27 2011, 06:07PM
Location:
Posts: 136
The barrel - less design has been implemented by Another Coilgun in some of the coilgund and they were successful. So, i imagine that a coilgun without barrel will not have differences from a barreled one.
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what to use as a barrel?
