ESD-ifying plastic containers with conductive paint - Page 1
Forum section: electronics / general

author: Aleksolder
author_rank: Contributor
timestamp: August 17, 2014, 03:27:29 am
content: This sounds to me like it would work. Can anyone see why this would not eliminate ESD in the containers?Zinc and aluminum paints conduct, though with much less resistance than ESD-safe plastic (I can't find ESD paint here in Hong Kong, nor get it sent here).I propose to paint the interiors and exteriors of my plastic storage containers, park them in a stack on a piece of ESD mat that is tied to the same earth as my workbench mat. I would only handle them while I'm tied down as well.Although the containers will almost certainly continue to 'try' to generate static as I slide them around, it will immediately dissipate through the conductive paint to the mat, which I suspect is the same principle as in the conductive ESD-safe plastic containers.In addition, I'm going to start inserting sensitive items into conducive foam before putting them into the plastic containers. Perhaps that would obviate the paint, if I stay tied when grabbing the foam.I'm pretty sure I've correctly understood Dave's pink bag discussions.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 17, 2014, 05:38:22 am
content: Metal paint would be a rather heavy-handed (and messy, and not very durable) way to do it; fortunately, you don't need much conductivity at all. What's good enough? Supposedly, average everyday dish detergent!I don't know how well it'll stay smeared onto a plastic surface, or if it will be absorbed and require re-treatment, or what. Or what the lasting effects are, in contact with electronics.It sounds like you're extremely paranoid about a very simple thing. If I had to store very sensitive electronics in that type of container, I would store boards individually wrapped with metallized mylar or other antistatic bags, and call it done. That's good enough for shipping them in cardboard boxes, after all.Proper handling is far more effective than having approved ESD equipment around. When picking up a board, touch a known ground point (screw terminals, connector shields, etc.). Avoid sensitive (data or otherwise) connectors, or touching components directly. If nothing else, carry the board by the edges to avoid touching anything at all. When placing the board on a conductive surface, or installing in equipment, touch that surface first. If you're sitting in a chair, beware that shifting your weight can induce static; ground yourself whenever you move.I've never had a failure I can attribute to static charge, following these procedures. Touching things carefully and avoiding static is as natural to me as, say, avoiding germs is to a germophobe. In both cases, there's a specific set of gestures you should follow, and those you should avoid.Assuming you already follow this sort of procedure, the only thing ESD mats grant you is the ability to handleextremelysensitive electronics, like naked micron-scale CMOS gates (maybe a concern around GHz RF work, but other than IC fabs, not much?). Reason being, even with a ground to discharge to, the transients (induced ground differential, induced electrostatic) may be enough to cause problems, and the extremely high resistance of ESD material discharges those potentials gradually, avoiding those transients.Tim

author: Aleksolder
author_rank: Contributor
timestamp: August 18, 2014, 12:04:09 pm
content: Thanks for your thoughts, all very reasonable, and perhaps I am going too far. They are loose parts, BTW, and I was thinking of the paint as a way to avoid putting them into safe envelopes, which take up a fair bit of space in the little storage compartments.I'm going to Shenzen for a few days tomorrow, and will nevertheless keep my eye open for ESD paint, though not go out of my way for it.The picture is of a recent shipment of OLEDs that I received. Onto the foam you see, he placed a sheet of clear, stiff plastic. Onto that, he laid out the OLEDs so beautifully, and then put another sheet of clear plastic, over which he applied abundant scotch tape. 18 of 20 DOA, the remaing two died the following day.

author: SirNick
author_rank: Frequent Contributor
timestamp: August 19, 2014, 07:11:04 pm
content: Quote from: Aleksolder on August 18, 2014, 12:04:09 pmQuote from: T3sl4co1l on August 17, 2014, 05:38:22 amNow that's what I call "a clean room"!

author: grantbob
author_rank: Unknown
timestamp: August 19, 2014, 11:45:49 pm
content: Bil Heard showed some stuff on the this episode of Dinosaur Den:http://youtu.be/VlRe4nxgKjM?t=29mthat he used to spray some of his bins called Licron Crystalhttps://www.techspray.com/d-5-licron-crystal.aspx.Seemed to work for Bil.-grantbob

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 20, 2014, 07:58:27 am
content: Putting a low-resistance coating will make things potentially a lot worse. You are creating a capacitor which can store a charge ready to discharge to a component pin.People tend to forget what the "D" in ESD stands for. However much charge is floating around, it will only do damage if there's a low impedance discharge path. e.g. you touch a pin on a part on a PCB, where the rest of the PCB provides enough capacitance to ground to provide a low impedance path for the discharge impulseThere is no problem with loose parts in plastic boxes. Adding conductive foil or paint will create a hazard that wasn't there to start with.

author: coppice
author_rank: Super Contributor
timestamp: August 20, 2014, 08:18:03 am
content: Quote from: mikeselectricstuff on August 20, 2014, 07:58:27 amSometimes the D seems to mean discharge, and sometime it means dissipative/dissipation. An ESD gun clearly uses D for discharge. An ESD mat clearly uses D for dissipative. In other cases its rather vague.

author: george graves
author_rank: Super Contributor
timestamp: August 20, 2014, 08:48:17 am
content: Would anyone argue that storing components stuffed into EDS black foam, and that store in a cheap plastic container is 99% as good as bare chips in ESD container?Also - I have no clue if this works, but I'll rub my containers down with an clothes-dryer anti-static sheet. Just as a precaution. Not that it matters to much. 89% humidity where I live next to the water in Seattle WA.

author: Aleksolder
author_rank: Contributor
timestamp: August 20, 2014, 12:47:23 pm
content: Quote from: mikeselectricstuff on August 20, 2014, 07:58:27 amLike so much on this subject, procedures are key. You can probably do anything you like, provided you have a procedure to match.I like the suggestion of sticking parts into conductive foam, then into any container at all. If the container is insulative, you must be aware of the difference in potential when you pick up the part (I would say touch the conductive foam first, while tied to your mat). If the container is conductive, same goes, but if it's conductive and sitting on your mat, then there won't be a potential difference to begin with.