I'm duly impressed. I went back through the archives, made up this set
of excerpts from Don's postings. Makes a very interesting read.
Did I say I was really impressed?
Excerpts from Don: (Make sure you look at the dates AND times!)
Does an implanted cardiac defibrillator preclude use of MIG and TIG,
particularly TIG with HF?
My limited web research indicates not but I'd like to see more data.
Here's what I've found thus far:
1/13/09 12:40 AM
Summary: not lookin' promising.
I've had contact with some good people: a senior fellow engineer at
a major ICD mfr, a former employee (engineer) of a major ICD mfr and
friend of many years, my wife's niece who is a former cardiac nurse
of 30+ years experience, and helpful others.
There are reported cases of weldors returning to work with ICD's but
the reports are sketchy on details. One report mentions a minimum
distance of 24" between weldor and cables, work and torch. That ain't
how I weld: my face is right in there with 2 diopter lenses in my
The experience of having a defib misfire has been variously described
as being hit by lightning and being kicked in the chest by a mule. I'd
rather skip that experience. Welding is fun, being kicked in the
chest by a mule very probably isn't.
I can't seem to get data on acceptable field strengths (E-field and H
or B field) that won't cause an ICD to malfunction. I opined that
this is probably because the goddamned lawyers make this data highly
proprietary. That was confirmed by the engineer (and friend) formerly
employed by a major mfr. Goddamned lawyers.
So I'm about SOL here, not being up for a mule kick in chest while
experimenting, candyass that I am.
Helluvit is that I have no friends who can do TIG and MIG, though Karl
Townsend's son "the kid" may be a savior. Neither of my sons are at
all interested. One daughter is, and she's done some nice work with
MIG but she lives in Brooklyn NY so she's not exactly local.
Mar, bless her hawrt, has volunteered that she might do a Vo-Tech
course in TIG and MIG. She'd be a natural, that based on her
precision quilting and prowess with handgun, both hand-eyes
coordination activites. TBD how that goes, but whatta teammate for
even considering it, eh? Hey, she severely aced ground school for
pilot licence for previous hub in the bad old days. Highest score
they'd ever seen if I recall correctly. What a fool he was for doing
her wrong, what good luck for me and eventually us. Goin' on 30 years
now and it just keeps getting better.
Most folks are quite happily "weld free" in their dotages, right?
Still, it's a bit of a lump to be prohibited from practicing a skill
and activity I've enjoyed developing over decades and frequently find
useful in my shop. Oh shit oh dear, poor me.
I intend to wallow in this for a while, fuck you if you can't take a
joke. I'm not happy about this, but it's no secret that gettin' old
ain't for sissies.
1/13/09 11:20 PM
Lots of new data today. Tons. I actually did get some real EMI
specifications, thanks to the good folks at Boston Scientific. The
key spec is probably 60Hz B field at 1 gauss (0.1 millitesla).
Finally, something I can get some traction with. I need to make some
measurements, but I think 1 gauss might not be a problem if I dress
the cables well and keep the current below 200 amps which would not be
an issue at all. I could probably keep it below 125 amps without
giving up much. Gotta build a little gauss sensor. I'll do that
tomorrow. I have linear Hall sensors and instrumentation opamps in the
goodie box, no prob. I can TIG a shielded box together for it since I
can still TIG. Fitch is loaning me his scope meter (battery powered,
digital, with memory) for logging data while I weld mask-down. That'll
arrive tomorrow by UPS blue label. I can piss and moan with sleeves
I'm learning that part of the problem here is an attitude problem, and
I don't mean mine. I either need to get the electrofizz doc's
attitude shifted or find a different one pronto.
I'd forgotten that one of my gentleman shooting buds used to work at
Guidant, now Boston Scientific. Sent him an email last night. He
shook his old-colleague bush a bit and lordy did the fruit fall! One
particularly encouraging note was from a Senior Engineering Fellow who
happened to be skiing in Taos but answered other Senior Engineering
Fellow's call anyway. For those unfamiliar with engineering orgs or
academia, few engineers attain the status/rank/title of Fellow. It's a
bit like General in the military, except that I think most Fellows are
paid better than Generals.
His first comment was particularly encouraging:
1) Don't worry about this affecting your hobby lifestyle. There are
many things that can be done to limit the risk of unintended shocks.
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