ciladog Posted January 4, 2011 Share Posted January 4, 2011 I’ve got a problem with static electricity building up in me and discharging back to my sandblast cabinet with constant shocks in very dry weather. The cabinet is grounded to earth in two places. The discharge is happening through my arm where it enters the gloves and feels like I’m part of an electrical circuit. It’s very annoying. I’m guessing that the charge is somehow related to the sand hitting the rubber gloves and charging me. As my arm leaves the rubber glove, there is a metal plastic collar that retains the gloves and that is where I am getting shocked. The spark jumps from my arm to the screw that holds the collar in place. Anyone have a similar problem and does anyone have a solution? Link to comment Share on other sites More sharing options...
ianinsa Posted January 4, 2011 Share Posted January 4, 2011 Hi there, It would seem as if the fixings through the ring are being insulated by the rubber 'glove' from the cabinet itself! To test this either check using a circut tester for continuity from the ring to the cabinet itself or if you don't have one simply tape a piece of aluminium foil across the edge of the ring on one side and to the cabinet onthe other thereby earthing the ring and see if this solves the problem. If this 'solves the problem then remove one fixing and refix ensuring a good earth. Good luck! Ian B) Link to comment Share on other sites More sharing options...
ciladog Posted January 4, 2011 Author Share Posted January 4, 2011 Good guess ianinsa but not the problem. I went into the shop to check, and I saw the ring was plastic. I fired the cabinet up and turned off the lights and the spark jumps from my arm to the screw that holds that collar in place. I wear rubber soled shoes (I'm not grounded) and I am being charged like a Van de Graaff generator. When the charge is large enough, it discharges and that is like every second. Link to comment Share on other sites More sharing options...
ianinsa Posted January 4, 2011 Share Posted January 4, 2011 Well, what can I say, on old cars they used to have an earth chain or strap to counter static that built up on vynil seats etc. maybe you should tie a light chain to your belt dangling to touch the floor to bring you down to earth. Are you wearing a nylon anorac? Sorry I don't really mean to take the xxxx! But what can I say! lol Ian Link to comment Share on other sites More sharing options...
edge9001 Posted January 4, 2011 Share Posted January 4, 2011 where are you? grounding of static is an issue in areas with sandy soil or very dry areas. if you have the cabinet grounded to the earth directly pour some water around the grounding stakes. Baqck in my miitary days we would ensure our radios and antennas were grounded in iraq by saturatingt the grounding stakes. the sandy soils didnt do much to discharge the static. Link to comment Share on other sites More sharing options...
Fosterob Posted January 4, 2011 Share Posted January 4, 2011 You need a little ground strap on your wrist attached to the cabinet. Like is used for circuit board work. Had the same problem on a glassbead cabinet and the wrist strap solved it. Rob Link to comment Share on other sites More sharing options...
ciladog Posted January 4, 2011 Author Share Posted January 4, 2011 What would you make a ground strap from? Link to comment Share on other sites More sharing options...
ironsmith Posted January 4, 2011 Share Posted January 4, 2011 you can buy a grounding strap at any radio shack or computer repair shop, and all it consists of is a wire with a comfortable velcro strap attached to you and the wire continuing to an alligator clip to attach to what you want to be grounded to... seems like a good way to fix the problem. I imagine you could make one with some stranded insulated copper wire?? here is an example of one ... Link to comment Share on other sites More sharing options...
monstermetal Posted January 4, 2011 Share Posted January 4, 2011 I have had the same issues. I have found if you keeP the item your blasting in contact with the metal floor of the cabinet I don't get shocked Link to comment Share on other sites More sharing options...
Fosterob Posted January 5, 2011 Share Posted January 5, 2011 If you want to try it out then get a wire with an alligator clip on each end, clip one end to the cabinet and the other end to something metal attached to your skin-metal watch band... The little band ironsmith shows has a snap to disconnect the wire from the wrist band. Rob Link to comment Share on other sites More sharing options...
Eric Farrar Posted January 20, 2011 Share Posted January 20, 2011 Here is a really simple fix that I've found works great. Take some 12#-8# copper strand wire, insulated - about 4-6 feet or even less if you really can't find some. Even as thin as 14# can work, but I prefer a bit more protection. If your blasting cabinet is grounded, just strip about an inch of the insulation from one end of the wire, and wrap around a loosened bolt that is clean - just to be safe, I used a self-drilling sheet metal screw in a pilot hole on a cabinet leg. Secure the wire on its way to the gloves. One glove will do, but for extra safety, you can run a second wire for the other glove. Strip off about 3" of insulation from this end of the wire and feed it into say, the thumb of your rubber gloves. You will be static safe as long as your thumb contacts that wire. If your cabinet isn't grounded, attach another wire to the same self-drilling sheet metal screw but this one goes to ground somewhere. Some ways to accomplish this: grounding rod rammed down at least 8' - must moisten the ground daily if in a desert type climate.... Structural steel of your shop may be grounded.... Tie into the electrical ground from a power cable (this is just about the last choice for finding 'ground').... The static is a result of air flow and particulates being blown around... Ground can be the air compressor chassis or the generator chassis..... Basically what ESD Injury Prevention comes down to is common Ground. If you are electrically grounded to any type of Grounding Network, you will be safe. All equipment should share ground - that keeps an electrically neutral relationship between all equipment components and operators. Hope this was usefull and not just a guy with a brain injury rambling.... If I rambled, forgive me - I have a brain injury from being blown up WAY too many times. Link to comment Share on other sites More sharing options...
OddDuck Posted January 20, 2011 Share Posted January 20, 2011 The nice thing about the ESD straps is that they are (check the manufacturing specs)fairly high resistance, and made of thin stranded wire for safety. If you are wearing one, and happen to touch a live circuit for whatever reason, the strap won't pass enough current to be dangerous and will burn out way before you get hurt. Using plain electrical wire won't protect you in this circumstance. ESD straps are also pretty darn cheap last time I checked. Link to comment Share on other sites More sharing options...
ciladog Posted January 20, 2011 Author Share Posted January 20, 2011 I like that solution. Thanks much. Link to comment Share on other sites More sharing options...
MattBower Posted January 20, 2011 Share Posted January 20, 2011 Not rambling at all, Eric. That was a very informative post. Thanks. Semper Fi. (Or hoo-ah, as you Army types say. ) Link to comment Share on other sites More sharing options...
Eric Farrar Posted January 21, 2011 Share Posted January 21, 2011 Just thought I'd clarify one thing.... The cheap DIY method I described earlier is only an ESD (electro-static discharge) prevention measure; NOT a way to think you are safe when working on electrical systems. The grounding straps shown by Ironsmith and discussed by OddDuck are just the beginning of ESP (electric shock prevention) PPI. ESD generally deals with minute amounts of current but can be at high voltages. ESP deals with high currents - no matter the voltage. 1/2 an Amp can kill if it goes through you the (right?) way - even at low voltages! Just remember the 10% rule - gotta be 10% smarter than what you're working on or it will be the one working you! ..... More ramblings from the guy with certified mental defects...... Link to comment Share on other sites More sharing options...
Scott Hightower Posted February 5, 2011 Share Posted February 5, 2011 Add a ground strap from the nozzle to the cabinet. Scott Fab ManagerWelders360.com Link to comment Share on other sites More sharing options...
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