Coil Gun question *FINISHED PICS*

[joannaardway]

As this topic is still fairly high up the page, and I wanted to show off my new gauss pistol, I reckoned this was the place to do it.

I prefer the term "gauss pistol" to "coil gun" - it sounds cooler.

Nice and cool, and quite practical - not totally finished, but working.

Link

It's made from old camera flashes and an old broken watergun, and cost me nothing but a few inches of solder and electrical tape - not bad.

There are 6 capacitors rammed into the various spaces quite well. 4 in the handle, 2 in the back, with room for maybe 2 more if I want to add them. Total capictance - about 720 uf.
The back section also stores a modified camera circuit to charge the whole thing.

I still need to attach a few extra bits - a proper battery holder for starters, and I'd like to fit in a relay for a bit more power, and to avoid getting shocked again.

Other than that all the bits are on board the casing. The switch is less than ideal, but it does the job - just about anyway.

The actual coil is made from about 30 metres of fine wire, for around 650 turns in 7 layers.

It'll punch a small bit of metal rod about 10 metres, or through a few layers of paper on a good day. It's good fun though.

[Pyro Ninja]

sounds very cool

[joannaardway]

I forgot to mention it, but it has a small, but noticable recoil (1/8"-1/4") - which is quite amusing.

I might make it semi-auto with a gravity fed magazine when I find more time and an appropriately sized solenoid.

Painting is also on the books for when I deem it finished.

[Hotwired]

Ah good old black electrical tape

I suspect my coilgun has an undersized coil

If you're getting it through multiple sheets of paper then mine, with 1160uf (the 580 I said before was just one of 2 cap banks...) should be able to do a bit more

Btw, have you checked out how hot the coil gets after firing?

I'm pretty certain my 2m wire coil reaches over 80*C just after firing.

Not sure if I can bring myself to wind a larger coil by hand. 2m takes forever. Maybe I can enlist a toy motor to help

[Recruit]

Use a drill insert the barrel into the drill chuck lightly so you dont crush it
and make sure you have like cardboard disks with a place that is about
the sives you want the coil to be.

[joannaardway]

Ah good old black electrical tape

I suspect my coilgun has an undersized coil

If you're getting it through multiple sheets of paper then mine, with 1160uf (the 580 I said before was just one of 2 cap banks...) should be able to do a bit more

More than possible - As I said, that's 30 metres of wire on about 720 uf. I'm planning to make it more efficent with a relay which might add a little power. A coil a bit longer than you mention might help. You might be losing power by maintaining the field too long.

Btw, have you checked out how hot the coil gets after firing?

I'm pretty certain my 2m wire coil reaches over 80*C just after firing.

No idea of temperature. Its kept inside a bit of cheapo DWV style pipe so it can't easily be got to. It's safe from damage though. I think the current is into 3 or 4 figures though - with no sign of melted plastic yet.

But, on a similar note, I get very impressive sparks from the trigger switch when I close it, which probably wastes a huge chunk of energy (thus, I need a relay)

Not sure if I can bring myself to wind a larger coil by hand. 2m takes forever. Maybe I can enlist a toy motor to help

That 30 metre coil took about 40 minutes of patient and accurate winding and taping each layer in place. The coil has 7 layers, and is about 5 cm long.

A toy motor would wind it quite fast, but not as neatly as I have.