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banned on 5/26/2009 Registered Member #1877
Joined: Mon Dec 22 2008, 02:03AM
Location:
Posts: 147
I just got 5 KJ of capacitors, 400v x 3900 uF nichicon. me and a friend are building a rail gun with them, we have everything planned out, except we don't know what we will use for the rails, aluminum will probably melt every time, copper is a bit to soft, so we thought we would use bronze, although it is still mainly copper, it is harder and stronger. what do you guys think? also, advice for where to get a hockey puk SCR and clamp? (and maybe a price)? thanks,
Registered Member #1062
Joined: Tue Oct 16 2007, 02:01AM
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Posts: 1529
A SCR capable of 5kJ in a railgun will be expensive. Copper is soft compared with other metals, but it is still hard. It will not affect it. Why would it matter if it is soft?
banned on 5/26/2009 Registered Member #1877
Joined: Mon Dec 22 2008, 02:03AM
Location:
Posts: 147
i was thinking corrosion. and i have heard horror stories of people paying lots of money and having the copper absolutely ripped to shreds. i just want it to last. and the thing with bronze is that it contains mostly copper anyways, so it will be nearly just as conductive. just with an added hardness to it. and abou the SCR's, do you have a price range? or a place i can get a quote? thanks
Registered Member #1062
Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529
In my 5.6kJ railgun, there was hardly any damage on the rails. Bronze will probably hurt the performance due to its resistance. Now solid silver rails would be nice =)
SCR's capable of repeated shots will probably be past 200$.
Registered Member #90
Joined: Thu Feb 09 2006, 02:44PM
Location: Seattle, Washington
Posts: 301
Try Class II or even Class III copper. You can get copper that's been annealed and alloyed to different hardness levels.
According to Pierce Metals online metal supply company:
Class I (C11000) is commercially pure copper and is most commonly used for welding fixtures, anodes, bus bar in electrical power installations, ground straps, commutators, etc. It is easily bent, soldered, drilled, riveted and formed to fit almost any design specification.
Class II (C18200) combines high electrical conductivity with high strength. Typical uses include welding electrodes, current carrying arms and shafts, circuit breaker parts, and all parts requiring higher strength than commercially pure copper yet requiring high electrical conductivity.
Class III (C17510) has high thermal conductivity combined with good hardness, wear resistance and high temperature strength. Machines better than C110 alloy.
I used Class II and was a surprised how hard it was to cut with a hacksaw.
Cheers, Barry Attaching the electrodes of knowledge to the nipples of ignorance
banned on 5/26/2009 Registered Member #1877
Joined: Mon Dec 22 2008, 02:03AM
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Posts: 147
Its been a while, but i recently found 2 huge bars of zinc in a scrap bin at my dads workplace. they are about 1 inch by 1 inch and about 20 inches long. how well would solid zinc do for rails? they also have lugs at the end, i think they were used for sacrificial anodes of some kind. Nick,
Registered Member #289
Joined: Mon Mar 06 2006, 10:45AM
Location: Conroe, TX
Posts: 154
Bronze has about three times the resistance of copper. Copper is historically the best choice for rails. As far as erosion goes; design your gun right and it wouldn't be a very big issue. To be more accurate though, I believe you are referring to arc ablation of the copper, not erosion. Technically, the best material for spark gaps and the like is molybdenum due to it's excellent ablation resistance. It's not practical for rails though as it is not nearly as conductive as copper. Just design you injector right and keep your tolerances tight and you should be fine.
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Rail material for railgun?
