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 .
What I did was learn from the mfr of the ICD what their spec limits were for magnetic fields and electric fields. They are:
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.
There's a nice little business opportunity. Make up a few dozen RF welding aprons complete with a certified study of how well it works and start marketing them. Just do eBay, Craig's list and a couple newsgroups for your advertising
These guys even have ready-made EMI garments! Scroll down to the tee shirt at
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The primary concern with stick and MIG welding is magnetic field, which this would not be effective against. It will provide good protection against the HF E-fields of TIG using spark-start.
Shielding against low-frequency (50-60Hz) and DC magnetic fields is not practical short of a fairly heavy mu-metal breastplate. Mu metal is very expensive, and if shaped or worked it must then be hydrogen-annealed to restore its magnetic properties. The best way to deal with magnetic fields is to minimize the fields in the first place. With care, welding currents of up to 200 amps are possible.
I would say that spot welding is not possible for a person with an ICD. I wouldn't get within 20 feet of a spot welder.
This vendor does offer balaclava shields. Catalog #A219, $59.95. They are most effective in brain cancer risk reduction if used while jabbering into the cellphone at an airport in a tongue other than English or Spanish.
On Mon, 24 May 2010 11:00:50 -0500, "Karl Townsend" wrote the following:
I'll bet certification and business insurance for that one would be quick, cheap, and easy, huh?
But it's a good idea. OTOH, lames go for "only" $129-159 on Amazon.
--------------------------------------------------- I drive way too fast to worry about my cholesterol. ---------------------------------------------------
On Mon, 24 May 2010 09:10:04 -0700 (PDT), " snipped-for-privacy@coinet.com" wrote the following:
Now we can make _comfortable_ tinfoil hats that aliens waves can't penetrate!
--------------------------------------------------- I drive way too fast to worry about my cholesterol. ---------------------------------------------------
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