[Joe Buddy]

I've had a pacemaker implant and I'm not sure about using a Mig welder now. I have been looking for an EMI shielding jacket to wear when I am welding but there doesn't seem to be one available. I weld mainly on sheet metal for classic cars and really need to continue. Any info on shielding?

[jwmacawful]

I've had a pacemaker implant and I'm not sure about using a Mig welder now. I have been looking for an EMI shielding jacket to wear when I am welding but there doesn't seem to be one available. I weld mainly on sheet metal for classic cars and really need to continue. Any info on shielding?

joe, please tell me you're kidding. talk to your doctor. go online and do some research. contact the pacemaker manufacturer and talk to them. get something in writing if you can. even if this is an urban myth like the contact lens scare this is way too important to maybe risk getting some bogus info.

[Joe Buddy]

I have checked and I have concluded that I am not willing to take a chance on damaging the pacemaker. I am trying to find shielding material cheaper than $1,000 a square meter. And no I am not kidding.

[Otto Nobedder]

Joe,

HF TIG is the hardest challenge for a pacemaker, for the EFI, but pacemakers have a lot of built-in protection.

If you want perfect protection, go to your nearest "renaissance fair" and buy a chain-mail jacket/vest from the "armourer", and rig up a way to clamp it to ground. Then, you're wearing a "Faraday cage" (google it), and are protected.

Steve S

[Joe Buddy]

I have been reading about the Faraday cage. There are silver plated fabrics that are used for this purpose but your idea is one I had not thought of. I have some experience with EMI shielding from Cape Canaveral and in Nuclear power. Way too expensive. I have used a wire mesh like you have described in High Voltage connections. I think I know where to get what you are talking about. Thank you for the reply. If I come up with a fix I will post it here.

[Otto Nobedder]

Cool. The average "Joe" doesn't know what a Faraday cage is.

Yes, please post back when you find a solution. There are others who have brought up the subject, so you're not the only one this concerns.

Steve S

[WerkSpace]

I have three sets of chain-mail butcher clothing.
These were originally used by cattle butchers.

I found them in a box at the metal recyclers in my area. (bought as scrap metal)
I paid $10 for the entire box of chain-mail. (for chest/legs and one arm protection)

So, check your local butcher supply outlets for this sort of gear.

Joe, If you want perfect protection, go to your nearest "renaissance fair" and buy a chain-mail jacket/vest from the "armourer", and rig up a way to clamp it to ground. Then, you're wearing a "Faraday cage" (google it), and are protected.Steve S

[noddybrian]

They also make stuff like that for divers working where there are sharks & I've seen similar worn in " specialist recreational clubs " & by "exotic " dancers ! ( but the mesh was a more open weave ! )

[Joe Buddy]

Some great ideas here. I am trying to set up a test with one of my neighbors to see how good the mesh shielding works. The butcher chain mail looks promising. I have 2 neighbors that work for Honeywell and know how to set up the test. Thanks for the input.

[noddybrian]

One other thought - in the UK overhead power lines running 330 KV are worked on live by electricians - they lift them up there with dedicated helicopters & they wear a "metalised " but very flexible material work suit that provides Faraday cage effect for them - could be worth searching what this suit is made from - all the testing & research for this I believe was done in Germany at a high voltage testing facility owned / operated by Bosch - maybe they could be contacted for advise or you probably have similar places in the states.

[Joe Buddy]

I talked to my neighbor that works at Honeywell and he works on equipment that requires EMI protective suits. He is going to see what is available that might work for my situation. I am an IBEW member but the guys that work the High voltage refer to us as "Narrow Backs" or "Low Voltage Men". That's OK. They wear size 48 shirts and size 3 hats. I know a few that can check on the Faraday Cage suit. Another great idea. Thanks

[Arno]

Perhaps also check out some hobbyist sites on building and operating big Tesla coils.

People like to build big ones and then use a similarly shielded suit and helmet to come close to the coil and have it discharge/spark/lightning along the suit to gound.

Eg: http://www.teslamad.com/faraday/faraday.html

Bye, Arno.

[Wobulate]

Joe Buddy,

Take a look at Mu-metal, it is a range of nickel-iron alloys that are notable for their high magnetic permeability, composed of approximately 77% nickel, 16% iron, 5% copper and 2% chromium or molybdenum.[1][2] The high permeability makes mu-metal useful for shielding against static or low-frequency magnetic fields. The name came from the Greek letter mu (μ) which represents permeability in physics and engineering formulae. A number of different proprietary formulations of the alloy are sold under trade names such as MuMETAL, Mumetall, and Mumetal2.

Mu-metal typically has relative permeability values of 80,000–100,000 compared to several thousand for ordinary steel. It is a "soft" magnetic material; it has low magnetic anisotropy and magnetostriction,[1] giving it a low coercivity so that it saturates at low magnetic fields. This gives it low hysteresis losses when used in AC magnetic circuits. Other high permeability nickel-iron alloys such as permalloy have similar magnetic properties; mu-metal's advantage is that it is more ductile and workable, allowing it to be easily formed into the thin sheets needed for magnetic shields.[1]

RF magnetic fields above about 100 kHz can be shielded by Faraday shields, ordinary conductive metal sheets or screens which are used to shield against electric fields.
[Reference: Wikipedia (free encyclopedia) "Mu-metal"]

I have personally used this metal to shield a high-resolution TV monitor from transformer magnetic fields, it worked very well.

Wobulate

[Joe Buddy]

Joe Buddy,

Take a look at Mu-metal, it is a range of nickel-iron alloys that are notable for their high magnetic permeability, composed of approximately 77% nickel, 16% iron, 5% copper and 2% chromium or molybdenum.[1][2] The high permeability makes mu-metal useful for shielding against static or low-frequency magnetic fields. The name came from the Greek letter mu (μ) which represents permeability in physics and engineering formulae. A number of different proprietary formulations of the alloy are sold under trade names such as MuMETAL, Mumetall, and Mumetal2.

Mu-metal typically has relative permeability values of 80,000–100,000 compared to several thousand for ordinary steel. It is a "soft" magnetic material; it has low magnetic anisotropy and magnetostriction,[1] giving it a low coercivity so that it saturates at low magnetic fields. This gives it low hysteresis losses when used in AC magnetic circuits. Other high permeability nickel-iron alloys such as permalloy have similar magnetic properties; mu-metal's advantage is that it is more ductile and workable, allowing it to be easily formed into the thin sheets needed for magnetic shields.[1]

RF magnetic fields above about 100 kHz can be shielded by Faraday shields, ordinary conductive metal sheets or screens which are used to shield against electric fields.
[Reference: Wikipedia (free encyclopedia) "Mu-metal"]

I have personally used this metal to shield a high-resolution TV monitor from transformer magnetic fields, it worked very well.

Wobulate

My neighbor has some that he will give me. For my application I'm hoping for something that is flexible and shielded. I should have something next week.

[michialt]

Joe;

If shop around at the Medieval Custom costume makers, try to find someone that will make you a "light weight" chain mail vest, but have it made from copper. But the most important thing is to make sure you keep a good ground attached to it.

By doing this you are creating a faraday cage. You want to use the best conductor you can which is why you use copper. But the most important is the grounding. The level of shielding you get is directly related to the quality of grounding you have,

I cannot speak directly about pace makers, and welding, my experience with this comes from working on electronic systems that were absolutely critical that they be protected and shielded from any form of electrical interference. Most of these systems had faraday cages built into them, or were housed inside buildings or rooms with faraday cages built into them.

[Joe Buddy]

Joe;

If shop around at the Medieval Custom costume makers, try to find someone that will make you a "light weight" chain mail vest, but have it made from copper. But the most important thing is to make sure you keep a good ground attached to it.

By doing this you are creating a faraday cage. You want to use the best conductor you can which is why you use copper. But the most important is the grounding. The level of shielding you get is directly related to the quality of grounding you have,

I cannot speak directly about pace makers, and welding, my experience with this comes from working on electronic systems that were absolutely critical that they be protected and shielded from any form of electrical interference. Most of these systems had faraday cages built into them, or were housed inside buildings or rooms with faraday cages built into them.

We have looked at that option and there could be problems with continuity due to oxidation between the links. Look at the link below. I thought I had found what I was looking for but there was no reply for the people that were needing the jacket. Look at the date also. Oh well.

http://www.pacemakerclub.com/public/jpa ... content.do

[michialt]

There are chemical dips for cleaning copper that would remove the corrosion for you. Just not too sure how well the copper would hold up to repeated cleaning like that. Especially with how small the links would need to be to keep it light enough to wear for any length of time.

I will be going back home for XMas to visit family. One of my friends is an electrical engineer that deals with electronics needing this level of shielding. I will talk to him to see what/if there is anything he would recommend.

[Cricket]

My 2 cents.

Keep in mind that you need to "shield" from EMR rather than from electric potential. So the conductance is much less important than magnetic properties. As far as HF welders(all inverters) emit a very wide spectrum of EMR(electro-Magnetic Radiation) you need a shielding material with very unique properties.
For 60Hz (transformer welder) regular iron(chainmail) would probably do. But you need some considerable crossection\thickness to it to be able to "absorb" enough magnetic flux.
Just conductive suite for the electritian - does not cut. You nee a MAGNETIC shielding, not electrical.

IMO... go for the transformer welder and a chainmail.

PS Wobulate actually answered very well but a little bit on a PhD side...

[noddybrian]

I'm not qualified to give scientific research here - but in laymans terms can we assume that if you don't wrap the leads around you & try to keep the torch away from the immediate area of the pacemaker the current involved will be relatively small - so the thickness of the mesh does not need to be huge in terms of current carrying ability - but as high frequency likes to flow around the outside of a conductor & favors lots of smaller conductors ( hence speaker wire is constructed from lots of very fine strands which are not really required for flexibility ) the ideal material would be a very fine weave ( much finer than chainmail ) of a relatively fine conductor - maybe I'm over simplifying things - but how about a very fine & thin woven material for light weight & flexibility & for extra safety a solid sheet copper shield over the pace maker itself - kinda like body armor with the steel / ceramic chest plate ? -

[Cricket]

Actually I shall not recommend ANYTHING to TS as I do not know pretty much anything about pacemakers internals or the level of EMR around the welder...

[WerkSpace]

For many years, NASA and other government agencies have been using carbon fiber for light weight EMI shielding. This has been true in many stealth aircraft and military projects. A quick search on the internet reveals a wealth of data supporting this idea. Carbon fiber is readily available at most hobby and plastics suppliers.

[Joe Buddy]

I'm not qualified to give scientific research here - but in laymans terms can we assume that if you don't wrap the leads around you & try to keep the torch away from the immediate area of the pacemaker the current involved will be relatively small - so the thickness of the mesh does not need to be huge in terms of current carrying ability - but as high frequency likes to flow around the outside of a conductor & favors lots of smaller conductors ( hence speaker wire is constructed from lots of very fine strands which are not really required for flexibility ) the ideal material would be a very fine weave ( much finer than chainmail ) of a relatively fine conductor - maybe I'm over simplifying things - but how about a very fine & thin woven material for light weight & flexibility & for extra safety a solid sheet copper shield over the pace maker itself - kinda like body armor with the steel / ceramic chest plate ? -

I mainly use a MIG welder. The problem is the electric arc at the work piece. The pace maker sees this as an erratic heartbeat I think. The arc would probably interfere with a radio if you held it near the piece being welded. I was told that a strong magnetic field is harmful also. This would include the alternator on a car while running. You would think that there would be a shielding jacket available at the local welding supply shop. I will get to talk to a pacemaker rep on the 12th of this month. I'll see what he has to say. The guys at Honeywell haven't come thru yet.