Post by thread:[EE:] Poor Mans (or womans) static control

Boy! you can pay a lot of money for static control mats! What is a good cost effective way to control static at your workstation? I am sure a grounded steel plate would do the job, and also get me killed the first time I put my thumb across a live circuit. In the 1970's, we used to fix CB radios on top of a grounded steel plate covered by carpet. The carpet was a decent insulator, and the plate helped keep us out of trouble with the FCC. The carpet also kept the cases from scratching up. We always sent radios back shiny, clean, and without any additional scratches, much to the surprise of many truckers. The first time I ran onto this was the winter of 1992, I was wearing a sweater in a wood-heated house, which gets very dry. My PICs would work twice then short out. I ended up with a 12" square of anti-static foam from the local electronics supplier. Yes static is real, and I have had to argue this point with blankety-blank bosses who can't see it. It is time to buy another mat, or reasonable facsimile. What do you folks use? -- Lawrence Lile Electronic Solutions Project Solutions companies http://www.projsolco.com -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

At 09:47 AM 7/6/2004 -0500, spam_OUTllileTakeThisOuTSALTONUSA.COM wrote: >Boy! you can pay a lot of money for static control mats! What is a good >cost effective way to control static at your workstation? WOOD! I use unfinished wooden doors, sitting on wooden cabinets, on a wood floor. I can barely detect any charge on my static meter, even in winter. >I am sure a grounded steel plate would do the job, and also get me killed >the first time I put my thumb across a live circuit. In my first year electronics class, we worked on 5 tube radios, on metal tables, in a room that used to be a metal shop. Teaches you the "one hand" rule, pretty quick! >In the 1970's, we used to fix CB radios on top of a grounded steel plate >covered by carpet. The carpet was a decent insulator, and the plate >helped keep us out of trouble with the FCC. The carpet also kept the >cases from scratching up. We always sent radios back shiny, clean, and >without any additional scratches, much to the surprise of many truckers. A very good idea. I have a rubber mat (again, antistatic as it's somewhat conductive) that I bought at a gun show. No slip, no mark, and nowhere for small screws to hide. >The first time I ran onto this was the winter of 1992, I was wearing a >sweater in a wood-heated house, which gets very dry. My PICs would work >twice then short out. I ended up with a 12" square of anti-static foam >from the local electronics supplier. Yes static is real, and I have had >to argue this point with blankety-blank bosses who can't see it. It is >time to buy another mat, or reasonable facsimile. What do you folks use? Wear cotton a lot too. :) -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Lawrence, Yes, static is real. I won't bore you with details, but at a previous company I had the joyous opportunity to participate in finding root causes for field failures (>3 months) of the companys products. About 33% of the failures were due to bad chips - tracked down to static damage during the production process. This included both handling of parts and assembled boards. Most failures occur many months after the initial static discharge. You may want to google around - there are companies that sell a broad range of static control tech. At the very least, try suggestions #1,2 and 3 below. 1. Antistatic mat for workbench - $50 - $100 for 2'x4' sizes (digikey.com) 2. Wrist strap and cord (also from digikey) 3. Conductive storage containers for parts. This includes smaller boxes, and conductive bags (with antistatic sealing tape - not regular scotch tape!). Also, large parts bins that are antistatic with the frame of the unit grounded. 4. Lots more good stuff if your in a production environment, including heel straps, drag chains, floor prep chemicals and the like. 5. Dress requirements for people working in the area - cotton good, synthetics, wool and leather soled shoes bad. 6. The grounded steel plate is a bad idea. Zap!! - both you and any circuits being worked on. The carpet, although a questionable insulator is also a great static generator. Ken {Original Message removed}

Good conversation: I use "Cling-Free", a spray used by women to prevent nylon stockings from being affected by static electricity. Just spray it on the carpet. Lasts several hours. There is also a carpet cleaner compound that treats carpets for static, but I can't remember the name. --Bob David VanHorn wrote: {Quote hidden}> At 09:47 AM 7/6/2004 -0500, .....llileKILLspam@spam@SALTONUSA.COM wrote: > > >>Boy! you can pay a lot of money for static control mats! What is a good >>cost effective way to control static at your workstation? > > > WOOD! > I use unfinished wooden doors, sitting on wooden cabinets, on a wood floor. > I can barely detect any charge on my static meter, even in winter. > > >>I am sure a grounded steel plate would do the job, and also get me killed >>the first time I put my thumb across a live circuit. > > > In my first year electronics class, we worked on 5 tube radios, on metal tables, in a room that used to be a metal shop. Teaches you the "one hand" rule, pretty quick! > > >>In the 1970's, we used to fix CB radios on top of a grounded steel plate >>covered by carpet. The carpet was a decent insulator, and the plate >>helped keep us out of trouble with the FCC. The carpet also kept the >>cases from scratching up. We always sent radios back shiny, clean, and >>without any additional scratches, much to the surprise of many truckers. > > > A very good idea. I have a rubber mat (again, antistatic as it's somewhat conductive) that I bought at a gun show. No slip, no mark, and nowhere for small screws to hide. > > >>The first time I ran onto this was the winter of 1992, I was wearing a >>sweater in a wood-heated house, which gets very dry. My PICs would work >>twice then short out. I ended up with a 12" square of anti-static foam > >>from the local electronics supplier. Yes static is real, and I have had > >>to argue this point with blankety-blank bosses who can't see it. It is >>time to buy another mat, or reasonable facsimile. What do you folks use? > > > Wear cotton a lot too. :) > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > > -- Replier: Most attachments rejected -------------- Bob Axtell PIC Hardware & Firmware Dev http://beam.to/baxtell 1-520-219-2363 -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

At 08:35 AM 7/6/2004 -0700, Bob Axtell wrote: >Good conversation: > >I use "Cling-Free", a spray used by women to prevent nylon stockings >from being affected by static electricity. Just spray it on the carpet. >Lasts several hours. > >There is also a carpet cleaner compound that treats carpets for static, >but I can't remember the name. Funny story thereby hangs: I'm at a trade show, in Las Vegas, the VanDeGraff capital of the world. Our newest terminals are on display there, and we're doing our worst to them. I had a pair of plastic soled shoes that must have been the triboelectric opposite of whatever material the carpet was made from, because I could pull 0.5 - 1" sparks without much effort. So here I am, TRYING HARD to upset our terminal, in it's plastic enclosure, with plastic keyboard, doing a "Charlie Chaplin in the hurricane" impression, and getting absolutely nowhere. Meanwhile, across the aisle, is the Diebold guy with his stainless steel 2000# ATM machines, with stainless steel keypads, and a TON of sheilding internally. He's out there spraying the carpet with water every few minutes. I killed a few competitors terminals that day, (permanently) just by touching them. I wasn't even trying.. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

The last trade show I went to sported a half acre of non-static treated carpet on a cavernous trade show floor. Next to the appliances I was demonstrating, a guy was reeling shrink-wrap onto a pallet of stuff, making my hair stand on end, and the whole area was covered in polyethylene so the workmen putting up our booth would not spill things on it. You could FEEL the static, and get a free defribulator treatment by putting your chest against any grounded object. The Salton booth was literally the size of a football field (I paced it off) and in the middle of that was my appliance. The appliance had a stainless steel, grounded case. But if you touched it, the front panel display would go wild, and eventually it conked out. Metal cases are not all they are cracked up to be. -- Lawrence Lile David VanHorn <dvanhornKILLspamCEDAR.NET> Sent by: pic microcontroller discussion list <.....PICLISTKILLspam.....MITVMA.MIT.EDU> 07/06/2004 10:53 AM Please respond to pic microcontroller discussion list To: EraseMEPICLISTspam_OUTTakeThisOuTMITVMA.MIT.EDU cc: Subject: Re: [EE:] Poor Mans (or womans) static control At 08:35 AM 7/6/2004 -0700, Bob Axtell wrote: >Good conversation: > >I use "Cling-Free", a spray used by women to prevent nylon stockings >from being affected by static electricity. Just spray it on the carpet. >Lasts several hours. > >There is also a carpet cleaner compound that treats carpets for static, >but I can't remember the name. Funny story thereby hangs: I'm at a trade show, in Las Vegas, the VanDeGraff capital of the world. Our newest terminals are on display there, and we're doing our worst to them. I had a pair of plastic soled shoes that must have been the triboelectric opposite of whatever material the carpet was made from, because I could pull 0.5 - 1" sparks without much effort. So here I am, TRYING HARD to upset our terminal, in it's plastic enclosure, with plastic keyboard, doing a "Charlie Chaplin in the hurricane" impression, and getting absolutely nowhere. Meanwhile, across the aisle, is the Diebold guy with his stainless steel 2000# ATM machines, with stainless steel keypads, and a TON of sheilding internally. He's out there spraying the carpet with water every few minutes. I killed a few competitors terminals that day, (permanently) just by touching them. I wasn't even trying.. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

>6. The grounded steel plate is a bad idea. Zap!! - both you and any circuits being worked on. The carpet, although a questionable insulator is also a great static generator. No Sh**, Ken! Not only do you get high currents when you touch a PIC lead to it, but also when you touch your body to it when you are live. At the time, I used the steel plate because that is what the boss liked, but there is no way I would use a grounded steel plate today due to safety! For several years I have used a mat on a wooden bench without any apparent problems. The mat has a snap on it, but there is some grounded test equipment sitting onthe back corner of the mat, so I never bother grounding the snap. Cotton clothes, conductive foam, and care are the other techniques. But in setting up a new shop I am trying to think through all these things again. A wooden bench will probably be the thing to start with - durable, won't ground you, good for mounting things to. Many shops use plastic tables, and I don't like these. Techni-tool has a number of mats. Some are 2-layer type T2, some are 3-layer type Z, some are solid vinyl type B+, all costing between $35 and $50 for the smallest size. There is another mat costing $13.50 that is described as a "top" pad, 1/4" vinyl foam. Now it is logical that there is a type T-2, B+, and Z <sarcasm> however, I wonder why this one is so much cheaper? And what do all the types refer to? -- Lawrence Lile Electronic Solutions Project Solutions Companies http://www.projsolco.com Kenneth Lumia <klumiaspam_OUTADELPHIA.NET> Sent by: pic microcontroller discussion list <@spam@PICLISTKILLspamMITVMA.MIT.EDU> 07/06/2004 10:32 AM Please respond to pic microcontroller discussion list To: KILLspamPICLISTKILLspamMITVMA.MIT.EDU cc: Subject: Re: [EE:] Poor Mans (or womans) static control Lawrence, Yes, static is real. I won't bore you with details, but at a previous company I had the joyous opportunity to participate in finding root causes for field failures (>3 months) of the companys products. About 33% of the failures were due to bad chips - tracked down to static damage during the production process. This included both handling of parts and assembled boards. Most failures occur many months after the initial static discharge. You may want to google around - there are companies that sell a broad range of static control tech. At the very least, try suggestions #1,2 and 3 below. 1. Antistatic mat for workbench - $50 - $100 for 2'x4' sizes (digikey.com) 2. Wrist strap and cord (also from digikey) 3. Conductive storage containers for parts. This includes smaller boxes, and conductive bags (with antistatic sealing tape - not regular scotch tape!). Also, large parts bins that are antistatic with the frame of the unit grounded. 4. Lots more good stuff if your in a production environment, including heel straps, drag chains, floor prep chemicals and the like. 5. Dress requirements for people working in the area - cotton good, synthetics, wool and leather soled shoes bad. 6. The grounded steel plate is a bad idea. Zap!! - both you and any circuits being worked on. The carpet, although a questionable insulator is also a great static generator. Ken {Original Message removed}

digikey 16-1044-ND, $47. I've bought 3, one for me and two for two different clients I deliver circuit boards to, upon my insistence. ("if you don't buy this, I don't guarantee anything after it leaves the shop"). Couldn't believe how zappy this past winter was. J RemoveMEllileTakeThisOuTSALTONUSA.COM wrote: {Quote hidden}> Boy! you can pay a lot of money for static control mats! What is a good > cost effective way to control static at your workstation? > > I am sure a grounded steel plate would do the job, and also get me killed > the first time I put my thumb across a live circuit. > > In the 1970's, we used to fix CB radios on top of a grounded steel plate > covered by carpet. The carpet was a decent insulator, and the plate > helped keep us out of trouble with the FCC. The carpet also kept the > cases from scratching up. We always sent radios back shiny, clean, and > without any additional scratches, much to the surprise of many truckers. > > The first time I ran onto this was the winter of 1992, I was wearing a > sweater in a wood-heated house, which gets very dry. My PICs would work > twice then short out. I ended up with a 12" square of anti-static foam > from the local electronics supplier. Yes static is real, and I have had > to argue this point with blankety-blank bosses who can't see it. It is > time to buy another mat, or reasonable facsimile. What do you folks use? > > > -- Lawrence Lile > Electronic Solutions > Project Solutions companies > http://www.projsolco.com > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> >Boy! you can pay a lot of money for static control mats! What is a good > >cost effective way to control static at your workstation? Butyl rubber used for roofing is often conductive. Resistance level per square varies with the carbon impregnation AFAIK. Some types even have far more resistance on one side than other - which is ideal. This can be bought by the yard/meter from building suppliers but an excellent cheap source here is from firms which sell it for roofing and get it in in large bales. It comes wrapped in a cover sheet and the staff sell off the sheets for Christmas party fund. I haven't bought it for some years but it cost $NZ10 for about 2 m^2 which is an utter bargain for antistatic sheet. Do check with a multimeter - results vary BUT almost any degree of conductivity will be enough. Some is rather too conductive for safe use. Bare ccts run thereon may malfunction :-). Placing several sheets of photocopier paper under them will help :-) RM -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

even better than that, especially if you don't like the scent is a spray bottle full of water with just a little detergent in it. this works great on carpets and even plastic surfaces (i had a bench with a pvc top, lots of static-you could feel it move the hairs on your' arm! though i did use a little extra detergent with that. i sprayed it about 6 years ago and there still isn't any static on it). this is an old trick people used on analog meters with plastic faces so that they wouldn't build up static and affect the reading. and yes, wood is good, cotton is good. don't wear any synthetics, and apparently silk panties and nylons are really bad though i haven't tried it... i won't go near the insides of a computer or electronics with a synthetic shirt on, especially in winter. on the other hand cotton is good even on very, very dry days. as far as carpet, old carpet usually isn't a problem. new carpet is a huge problem, but most carpet 5-10 years old has enough misc. ground into it that it's not a problem. i live in wyoming where it's very, very dry and have had no problems even on old carpet (actually someone suggested replacing the carpet in my electronics/computer room, i said no way! new carpet is a zapper). i'm using a door as a bench now and even with the finish on it there's no problem. you can get really nice metal legs from grainger and make a large table cheaply (and buy a piece of angle iron to go between the back legs, it really stiffens it up nicely). of course you need a solid core door. because i have several monitors and computers on mine and it was bowing just a bit i epoxied a couple of pieces of "L" angle stock on the bottom to stiffen it, works very well and you can get that cheap at the scrap metal place, even cut to the length you need. i just used 4 lag screws on each piece to hold it down while the epoxy set. i also sanded off the coating where the angle iron was going. now it's rock steady and flat and i have no worries about overloading it. Bob Axtell wrote: {Quote hidden}> > Good conversation: > > I use "Cling-Free", a spray used by women to prevent nylon stockings > from being affected by static electricity. Just spray it on the carpet. > Lasts several hours. > > There is also a carpet cleaner compound that treats carpets for static, > but I can't remember the name. > > --Bob --------- -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.