[meteorite-list] edm wire cut meteorite

[MexicoDoug 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.