Don Foreman wrote:
On Sun, 23 May 2010 20:01:02 -0500, "Snag"
wrote:

Wasn't it you that did all the research on the effects of welding and
magnetic field effects on a defib device ? A good friend of a good
friend has a defib , and is unsure about how safe it is to mig and
stick weld . I told him I'd seen some posts here and would try to
dig the info up . Poor SOB was out in his shop a month ago when
three (really !!) trees landed on it during a storm . I was over
there helping my friend (Bill the Machinist) clear the shop out so
it can be repaired , and his yard is a putterer's wet dream .

T'was I.

What I did was learn from the mfr of the ICD what their spec limits
were for magnetic fields and electric fields. They a

E field 50-60 Hz (AC) 1000V/m - 4000V/m
B field DC (static) 1 mT
B field 50-60 Hz (AC) 0.1 mT

I then did my own "site survey" by measuring the fields in the region
of my torso (before implant) while welding. I made the instrumention
I used to accomplish this except for a digital recording oscilloscope
I borrowed from a friend.

I can't say what might be safe for someone else because equipment and
welding practices may be very different. I did find that lead dress
was quite helpful in minimizing magnetic field strengths. I keep the
stinger cable as close as possible to the ground as much as possible
(even twist them) and I'm diligent about not having the stinger cable
form a loop near me.

I'm confident about stick and MIG, but I haven't tried TIG yet. The
electric fields approached the limits. They're easy to shield
against, I just haven't gotten around to making a shielding garment --
as perhaps a vest with Litz wire sewn into it. I actually think there
wouldn't be a problem because the HV in a TIG is also HF which
wouldn't penetrate very far into the body. In fact, that's exactly
why they use HF.

Thanks Don , I will forward this info to Larry .

--
Snag
"90 FLHTCU "Strider"
'39 WLDD "PopCycle"
BS 132/SENS/DOF