If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #963
Joined: Tue Aug 21 2007, 08:50PM
Location: USAF Academy
Posts: 3
I guess I should start at the beginning. A few years ago I built a coil gun out of a disposable camera that I had asked the 1 hour photo people for at Wall-mart, I guess that is the gold standard for beginners... especially if you are only in middle school. After that I built another single stage gun that used several capacitors wired in parallel. This one worked much better and I could move larger projectiles, but using a Fast food straw as a barrel kind of limits what you can do. I have done some serious research into this and I have decided that I would like to make a portable version that is much more powerful. I still plan on sticking with a single stage, but I would like to use a 16V cordless electric drill battery to charge the caps. My barrel is a glass Pyrex lab tube. I figured that would be the best material I could get. The problems I have run into are:
1-identifying some capacitors that are not enormously bulky and can deliver some serious stopping power. 2- A good way to charge the caps. (This is my least researched area.) I do know how hot the camera board gets on charging and I know it wouldn't handle it. I just need something to handle more power that is easy to make or find. 3- And finally, I really can't find an easy way to make decent coils. They always end up looking like my fishing real (instead of perfect like all the ones I see on the internet in pictures.)
All the custom parts for my bull-pup design will not be a problem to make, I have very limited access to a 3d shaper if I need it, but I still need to gather all the necessary electronic components.
Banned Registered Member #110
Joined: Fri Feb 10 2006, 12:23AM
Location: Banned City
Posts: 85
Drinking straw is not that much of a limit. You have to pass 100m/s and 20 joules for it to be a problem. I used a few rolled paper barrels, a straw would be an upgrade and I plan on using a straw but never can find a matching diameter. Why a straw? - as thin a wall as can be. The barrels job is not to support the coil. Get that out your head now before you get corrupted.
Also go to a better source or dare to the source cause here is not the place anyhow.
Registered Member #32
Joined: Sat Feb 04 2006, 08:58AM
Location: Australia
Posts: 549
Single disposable camera CG was my intro to coilgunning, too.
Try going to a shop that sells junk or salvage and see if you can find an external flash unit. They come with much larger caps and chargers that have actual grunt. I've found many that have been thrown out for having cracked cases, etc, going quite cheaply.
For making decent coils, it's essential to have a setup where the coilform rotates rather having the wire wrap around the coilform. Even better if you can hook up the coil to a low-speed motor system of some sort to make a lathe.
As Rapidust said, the barrel is really to guide the projectile. It must be as thin as you can get for high efficiency so do not try to use it for structural support. Drinking straws aren't that bad, actually, for small projectiles.
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
something practical
