PING Don Foreman

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 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.

How about a fencing scoring lame' (Metalized vest for foil/jacket for saber) and ground it? Wear it under your leathers.

Just a thought

Thanks Don , I will forward this info to Larry .

Excellent lead!

Fencing scoring lame is quite expensive, but investigating that lead me to

Thanks!

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

Karl

Wow! What a fascinating web site! I had no idea such material was possible.

Thanks, Paul

These guys even have ready-made EMI garments! Scroll down to the tee shirt at

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.

From the same link...rather fascinating when thought upon....

Gunner

Hmm ... Perhaps EMI resistant yarmulkes for those who spend a lot of time on cell phones and are worried about brain cancer form the RFI?

Enjoy, DoN.

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. ---------------------------------------------------

That was last millenium's model. The new ones are underground, and aimed straight up.

Could increase the risk of lead poisoning though :-(

Mark Rand RTFM

That's how they reduce the risk of brain cancer! :