[TheForge] was cutting 1/4 copper now welders

[Kevin D]

what a great looking book/cd!  thanks, Kevin

 -----Original Message-----
 From: theforge-bounces at mailman.qth.net
 [mailto:theforge-bounces at mailman.qth.net]On Behalf Of Steve Smith
 Sent: Thursday, April 14, 2005 7:40 PM
 To: Sponsored by ABANA
 Subject: Re: [TheForge] was cutting 1/4 copper now welders


 Kevin, Grover, whoever else has plenty of time:

 Scientific American magazine used to run a column "The Amateur
 Scientist", which was an amazing experimentalist's column. You name it,
 they did it, mostly from scratch. Lasers, rockets (no manufactured
 engines...), telescopes starting with a porthole, plasma torches, atom
 smashers, ruling engines for making diffraction gratings. Wonderful
 stuff that strongly influenced me growing up.

 Did I say plasma torches? Yep. In the early 60's they had a column on
 such. As I recall, the torch was water cooled and was bench mounted
 pointing up. It "vaporized most metals instantly, including tungsten.
 Ceramics took a little while...". I think it would be really tough to
 adapt to a cutting torch (and it would probably have a huge kerf).

 If you want to dig into "The Amateur Scientist", all of it from the
 1920's thru the end of the century, it is available on CDROM:
 http://www.amazon.com/exec/obidos/ASIN/0970347626/qid=1113521388/sr
 =2-1/ref=pd_bbs_b_2_1/002-2539502-2820810
 Watch out if the URL gets wrapped, you may have to cut and paste a
 second time. Really fine stuff if you're into building and experimenting
 with just about anything.

 Steve

 Grover Richardson wrote:

 > Actually, my interest is work related.  We are doing some work with
 > arcs/plasma.  The gas is conductive and will provide a longer
 arc distance
 > than just air.  According to the manual, it will strike an arc easily, so
 > that would make sense with the higher Voltage startup.  As I
 remember, the
 > startup arc is ac.  So, essentially (it appears) an arc may be struck at
 > most any reasonable distance, and then the operator would move
 the electrode
 > into the proper working distance.
 >
 > Me, I'm an old stick person, and never messed with a tig/mig
 before.  Except
 > for repairing a few.
 >
 > The welder we are using, TIG, has a arc starting circuit which
 generates a
 > very nice spark plug type arc (bounces around and very thin), which
 > initializes the main arc.  I guess I need to look closely at the open
 > circuit Voltages.  I need to take the welder apart anyway, to
 get inside and
 > take some measurements.  Will make the startup measurements also.
 >
 > I had warned my student about Voltages being dangerous, but now
 the warning
 > will be increased!!
 >
 > Thanks.
 >
 > -----Original Message-----
 > From: theforge-bounces at mailman.qth.net
 > [mailto:theforge-bounces at mailman.qth.net] On Behalf Of Steve Smith
 > Sent: Wednesday, April 13, 2005 9:47 PM
 > To: Sponsored by ABANA
 > Subject: Re: [TheForge] cutting 1/4 copper
 >
 >
 > On top of that you need a higher open circuit voltage to strike the arc.
 > 300V comes to mind, but I don't know where from.
 >
 > Steve
 >
 > Grover Richardson wrote:
 >
 >>Hmmm.  140 VDC, 40 Amps.  That's enough to fry a monkey.  I didn't
 >>know it was anywhere near that high.
 >>
 >>-----Original Message-----
 >>From: theforge-bounces at mailman.qth.net
 >>[mailto:theforge-bounces at mailman.qth.net] On Behalf Of Kevin D
 >>Sent: Wednesday, April 13, 2005 12:11 PM
 >>To: Sponsored by ABANA
 >>Subject: RE: [TheForge] cutting 1/4 copper
 >>
 >>
 >>Grover,
 >>
 >>Just looked this up on; http://store.cyberweld.com/milspec625.html
 >>for a MILLER SPECTRUM 625 PLASMA CUTTER
 >>
 >>
 >>Quick Specs: Spectrum 625
 >>Rated Cutting Capacity Rated: 1/2 in (13 mm)
 >>Quality: 5/8 in (16 mm)
 >>Sever: 7/8 in (22 mm)
 >>Rated Output 40 A at 140 VDC, 50% duty cycle at 40? C / 104? F Plasma
 >>Gas Flow/Pressure 6 CFM at 75 PSI or 170L/min at 517 kPa Weight Net:
 >>57 lb (26
 >>kg)
 >>Ship: 60 lb (27 kg)
 >>
 >>Kevin
 >>
 >>
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