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Registered Member #1062
Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529
I recently started expirimenting with ETG's. My first one was a plastic tube, a little less than 1/2". This worked great, and made a nice loud bang and a 2 foot long "flame". I got tired of the crappy construction, and made a new one out of 3/4" PVC (sch40). For some reason this seem ALOT weaker, and can hardly push the Al foil ball out of the <1ft barrel. Why is this?.
Im using a capacitor bank charged to 330v, 4 3900uf 400v caps in parrellel, and a voltage doubler with the same cap (acts as a charger and a 800v, 1450ug capacitor). After firing, there is still about 60v charge.
Registered Member #567
Joined: Tue Mar 06 2007, 10:55AM
Location: Singapore
Posts: 147
You mean electrothermal gun, right?
I would hazard a guess that you're using more water in your bigger ETG. More water= more energy required to vaporize all of it, but you're using the same cap bank, so maybe that's the problem?
Registered Member #1062
Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529
Water? i am not using water, just some aluminum foil hard shorting the capacitor bank. Here are some still frames of the vid i took. The first one is with a "plug" on 1 end, and the other 2 are with both ends open.
Registered Member #567
Joined: Tue Mar 06 2007, 10:55AM
Location: Singapore
Posts: 147
Perhaps I've misunderstood? When you said ETG, I thought of an electrothermal gun- A cap bank is applied to a small amount of water, which is vaporized into steam to drive the load.
Or are you actually exploding the foil itself to drive the load?
Pretty pictures, by the way, if a bit blurry. But nice sparks.
But either way, my point still stands, with a bigger diameter, there's more stuff to vaporize, making it harder. Try using something like a ping-pong ball wrapped with foil? Though I'm afraid the ball may melt.
Registered Member #1062
Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529
its not even a flat short, when its finished, half the charge remains, and ive had thicker wires explode than this one. I think its fine to short lytics if its not high cycling rates, any input on this?
ETG can be water, but metal dust is used too (thats what larda did) I just dont have metal dust on me. There are two versions: plasma and vaporazation.
I have tried it with water, but its too powerfull until i make a proper setup.
The pics are blurry because its a frame from a video, 30fps =/
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ETG - why so bad?
