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Registered Member #3302
Joined: Sun Oct 10 2010, 02:21PM
Location: Finland
Posts: 42
Yes sure, you can post pictures and other stuff about your build here, I am interested in seeing your build.
About the wider distance increasing the performance probably is because the arc length increases so the resistance also increases, meaning higher percentage of the used energy is used in the chamber. I dont know how thick cables you used and what was your capacitor's ESR but in my build I used pretty thick cable and my caps had pretty low ESR compared to most electrolytics so in my case it might not have affected the performance as much because the chambers resistance was very high compared to other resistances in the circuit even if the distance between electrodes was pretty small, so pretty much all the energy was used in the chamber regardless of the distance.
Registered Member #8558
Joined: Thu Dec 06 2012, 11:38PM
Location: usa
Posts: 57
This is a really awesome project. It inspired me to build my own etg. It is based mostly on your basic design. I designed the gun in inventor and had one of my friends machine the parts. It is really cool and works about the same as yours. I plan on adding a lot more capacitors. One of the things that i noticed is that the splatter from the gun appears to be aluminum oxide. It takes a lot of energy to convert aluminum oxide to aluminum so some of that energy should be recoverable in the etg. I am planning on buying some fine aluminum powder as is used for thermite and coating the foil with a paste of that and water to see if that increase performance.
But anyways awesome project thanks for the inspiration.
Registered Member #4603
Joined: Wed Apr 25 2012, 07:33PM
Location: Austria
Posts: 159
Hi! I tried 400V - huge difference!!! The power increases by factor three or four.
Setup: massive contactor as switsch, transformer for up to 520V (variac used), 3x 6000µF @ 450V parallel. There is a magnet under the nylon screw wich holds the stell BB in Place
Penetration:
The projectile went through 2x 16mm medium-density fiberboard, a jack wolfskin catalogue (360 pages), it stoped in another catalogue right before my bullet stop (3mm steel plate) at page 150 xD
Registered Member #3302
Joined: Sun Oct 10 2010, 02:21PM
Location: Finland
Posts: 42
Very nice increase in power :D If there is a chance you could take a short video of it firing it would be also interesting to see. Do you have access to a chrony or can you measure the projectile speed with some other way with reasonable accuracy?
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1.4kJ electrothermal gun
