4mm ETG

A place for general potato gun questions and discussions.
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tghhs
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Tue Feb 02, 2010 4:33 am

Ok thanks :)

msg to short
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Zeus
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Tue Feb 09, 2010 7:43 pm

chinnerz wrote:do you think this will aid in the destruction?
http://www.jaycar.com.au/productView.as ... BCATID=595
Supercap and ultracaps discharge in about five seconds. A well designed
cap bank will discharge in less than 500 microseconds. Just like what
Ragnarok said. It's good to see HV and spudguns together.
All hail the ETG.
245Tommy
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Fri Feb 12, 2010 5:52 pm

The chamber design I showed earlier only worked because the epoxy leaked past the mold and insulated more of the inside of the chamber than I thought. The new chamber uses a plastic tube as an insulator and it extends 5mm past the center electrode, on the first shot it put a lead slug threw 22gauge steel (at 370 joules) leaving the wooden tail in the hole. The plastic tube doesn't look that burned up so I should be able to get a few shots out of it.
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DYI
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Fri Feb 12, 2010 9:17 pm

Ah, I see you've stumbled across the capillary tube design much like I did back in June. Good job. :thumbright:

It would be interesting to see how much steel you can make it through when firing a steel dart. I'd guess you could manage 1/8" plate if your efficiency level is similar to mine.
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245Tommy
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Sun Feb 14, 2010 3:00 pm

After five shots the cartridge stretched and would barely fit in the breech but the plastic tube and electrode were still intact. I'm going to try shooting a dart into steel after I rewire the bank for 1000v.
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Zeus
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Mon Feb 15, 2010 2:29 am

When you say stretched, do you mean lengthwise, or around the girth of
the cartridge. I'm now taking far more interest in this topic as I now have
a 4700uF 450V capacitor.
245Tommy
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Mon Feb 15, 2010 4:32 am

Zeus wrote:When you say stretched, do you mean lengthwise, or around the girth of
the cartridge. I'm now taking far more interest in this topic as I now have
a 4700uF 450V capacitor.
The girth, it fit a lot tighter in the breech.
245Tommy
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Tue Feb 16, 2010 10:28 pm

I made a new cartridge with a capillary tube that extends 10mm past the center electrode and rewired the bank for 1000v 360J, I shot two 1/16" steel plates clamped together with some naildarts and the plate looked like wasn't even hit wtf?! Then I found a splattered piece of steel stuck in the ceiling, so I shot one plate but it still didn't go through, the hole on left was from the old gun with an extra propellant.
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rp181
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Tue Feb 16, 2010 10:43 pm

try a harder projectile/softer plate.
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