[meteorite-list] edm wire cut meteorite

From: MexicoDoug_at_aol.com <MexicoDoug_at_meteoritecentral.com>
Date: Thu Dec 22 14:18:26 2005
Message-ID: <1f3.18bca363.30dc55f9_at_aol.com>

Nice fodder. How much $ & how figured?
 

skyrox writes:
for those curious, here's some interesting fodder:
i just got done PARALELL slicing my huge social circle , ga slice. as i did
not need that much of it and wanted to sell some to defray cost, i also
wished to retain a COMPLETE slice for my collection. so i took the big slice over
to http://www.atlantaedm.com and they said that they could do it. we thought
about using a magnet to hold the unusually- shaped piece, but we decided to
balk on that as we were afraid that the powerful neodymium magnet would mess
up the computer in the $250,000 charmilles edm machine or that the voltage
through the wire would demagnetize the permanent magnet and the piece would
drop, etc. we opted for a vise instead. we clamped it on one end and the wire was
to start in at the clamp, turn 90 degrees and continue through the slice and
out the end. $200 and 6 hours later the job was done- a perfect, lengthwise
bisection on the slice accurately paralell to the finished surface to
15/1,000th of an inch. i wound up with 3 pieces and with loss of only 15/1,000th, it
 was so not an issue. what we learned about cutting iron skyrox on edm:
plan on ALOT of wire breaks- the magnetite/ rust rind is NOT nearly as
conductive as the rich metal interior and it BREAKS the wire as there is no
abrasive action (it is all eletric spark vaporizition- like millions of tiny
lightning hits along the wire surface to the meteorite surface). to do it right,
you first need to grind the rim down to the silver metal to avoid breaks. with
that done you can pretty much walk away from it and come back when it is
done. this process also takes place UNDERWATER- rusters need not apply. TROILITE
is also a wire breaker as it too, has a different electrical conductivity.
the FINISH is a very smooth, unusually FROSTED, colored surface with rainbow
tones from the burning (similar to color/ tecture of heat-tempered file handle,
etc.). this is easily buffed off w/ 600# sandpaper, and does not affect the
etch pattern. the ACCURACY is beyond what any abrasive saw could even hope to
deliver. the COST is very high and the TIME is very slow. that should answer
most q's about this unusual method of cutting irons. i will take PIX of all
piece b4 etch for those intersted.
 
Received on Thu 22 Dec 2005 02:18:17 PM PST