easy source of static dissipating work mat?
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easy source of static dissipating work mat?
 
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My new K3 is on it's way. I have anti-static material that my
motherboard came in but that's not enough to work on & be static free. Where can I easily & quickly get an anti-static mat and grounded wrist strap? Thanks1 Gary KA1J _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: easy source of static dissipating work mat?
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Radio Shack.
Dick, K6KR -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Gary Smith Sent: Thursday, December 11, 2008 9:01 PM To: [hidden email] Subject: [Elecraft] easy source of static dissipating work mat? My new K3 is on it's way. I have anti-static material that my motherboard came in but that's not enough to work on & be static free. Where can I easily & quickly get an anti-static mat and grounded wrist strap? Thanks1 Gary KA1J _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: easy source of static dissipating work mat?
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Beware that the Radio Shack 276-2370 portable ESD mat does not properly
bleed off static charges. Appended below is a message I sent on this subject back in February. Al N1AL On Thu, 2008-12-11 at 21:04, Dick Dievendorff wrote: > Radio Shack. > > Dick, K6KR > > > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Gary Smith > Sent: Thursday, December 11, 2008 9:01 PM > To: [hidden email] > Subject: [Elecraft] easy source of static dissipating work mat? > > My new K3 is on it's way. I have anti-static material that my > motherboard came in but that's not enough to work on & be static > free. > > Where can I easily & quickly get an anti-static mat and grounded > wrist strap? > > Thanks1 > > Gary > KA1J ================================================================= -----Forwarded Message----- > From: Alan Bloom <[hidden email]> > To: [hidden email] > Subject: [Elecraft] Radio Shack ESD mat doesn't meet spec > Date: Wed, 27 Feb 2008 09:51:25 -0800 > > Well, I've convinced myself that the Radio Shack portable ESD mat, P/N > 276-2370 doesn't work properly. > > The "ESD Association" http://www.esda.org has promulgated an > industry-standard test for ESD mats, ESD S4.1. It is the standard > specified by most commercial mats. I decided not to spring for the $70 > to buy a copy of the standard, but other information I found on the web > describes the test in general terms. It uses two circular electrodes, > each weighted with 5 pounds, spaced 10 inches apart on the mat. The > "Point to Point Resistance" is specified to be: > > At 40-60% RH: 10^6 - 10^7 ohms > At 20-40% RH: 10^7 - 10^8 ohms > At 10-20% RH: 10^8 - 10^9 ohms > > I don't know what the RH here in Santa Rosa was yesterday when I did the > test, but I don't think it was very low since it has been raining > recently and the ground is still damp. For sure the resistance > shouldn't be below 10^9 ohms (1 gigohm) and probably more like 10^8 or > 10^7 (100 or 10 megohms). > > I measured 2.5 x 10^10 ohms (25 gigohms), which puts the Radio Shack mat > way out of spec. > > Test procedure: > > I didn't find a specification on the electrode size, but in the photo of > a popular tester they look to be maybe 3 or 4 inches in diameter. For > my test, the electrodes were two saucepans, each about 7 inches in > diameter and weighted with 5 pounds. They were spaced 10 inches apart > on the mat (3 inches edge-to-edge). I connected a 0.1 uF film capacitor > between the two pans and charged it to 15V with a power supply. > > I set my ancient Simpson analog volt-ohm meter to 60 uA full scale. If > I touch the leads across the capacitor immediately after charging, the > needle momentarily jumps to about 6 uA (1/10 full scale) as the > capacitor discharges through the meter. If I wait half an hour (1800 > seconds) for the capacitor to partially discharge through the mat > resistance, the needle jumps to about 3 uA. > > An R-C network discharges to 3/6 of original voltage in about 0.7 time > constant. So the time constant must be 1800/0.7 = 2571 seconds. That > implies the mat resistance is 2571 sec / 0.1 uF ~= 2.5 x 10^10 ohms. > > Al N1AL > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: easy source of static dissipating work mat?
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> > I didn't find a specification on the electrode size, but in the photo of > > a popular tester they look to be maybe 3 or 4 inches in diameter. For > > my test, the electrodes were two saucepans, each about 7 inches in > > diameter and weighted with 5 pounds When measuring the resistance of a two-dimensional conductor (like a mat), the resistance can be measured with point contacts, such as ordinary test meter probes. One of the interesting properties of two-dimensional conductors is that the measured resistance is independent of the spacing between the probes. In other words, one will get the same measurement on an ohmmeter if the probes are one centimeter apart as if they are one meter apart, provided the mat is larger than the probe spacing. This result may seem counter-intuitive, but it makes sense if you think about the lines of electic current that flow between the probes. Widely spaced probes have more area for the current to flow into, thus compensating for the fact that the probes are far apart. Thus the resistance is an intrinsic property of the conductor and not of the geometry of the measuring setup. Interesting, no? 73, Jim W8ZR _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: easy source of static dissipating work mat?
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Dr. James C. Garland wrote:
> One of the interesting properties of two-dimensional > conductors is that the measured resistance is independent of the spacing > between the probes. In other words, one will get the same measurement on an > ohmmeter if the probes are one centimeter apart as if they are one meter > apart, provided the mat is larger than the probe spacing. > > This result may seem counter-intuitive, but it makes sense if you think > about the lines of electic current that flow between the probes. Can't resist: http://xkcd.com/356/ Jon LA4RT _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: easy source of static dissipating work mat?
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In reply to this post by Gary Smith
Thanks for the suggestion of Radio Shack. I really hadn't thought of
them. They and Lafayette Electronics used to be such a great source of so many components, walls of stuff but much less so today. As reviewing the assembly PDF in advance shows, I will be best advised to have one during assembly. Thanks! Gary KA1J _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: easy source of static dissipating work mat?
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In reply to this post by Gary Smith
Gary, The K3 kit has two sub assemblies that come in large conducting plastic bags. I used these bags for an antistatic mat. I put these bags down on the work bench overlapping to provide a good conducting surface. If you want you can cut open two sides of each bag and fold open the bag to double the covered surface. Don |
Re: easy source of static dissipating work mat?
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At 07:59 AM 12/12/2008, Don Nelson wrote:
>The K3 kit has two sub assemblies that come in large conducting plastic >bags. I used these bags for an antistatic mat. I put these bags down on the >work bench overlapping to provide a good conducting surface. If you want you >can cut open two sides of each bag and fold open the bag to double the >covered surface. > >Don I don't understand how that material is supposed to function, but I tested a piece of it (may have been from some other source) and found that it was not conductive, at least as far as my DVM could measure. I concluded that I could not trust it to drain off any static charge from a workpiece - wrong? Jerry W4UK _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: easy source of static dissipating work mat?
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A ESD bag and a mat are 2 different animals, a ESD bag (silver)
creates a faraday shield around the object protecting it from esd (think tinfoil) an esd mat is a relatively high Z conductor designed to bleed off charge as to avoid arcing (think rub feet on carpet and touch doornob.) there are also pink 'esd' bags that are not shelded but are simply made of a plastic which will not generate static electricity. A ESD bag is not a suitable replacement for a mat. Matt KD8DAO http://blog.MattIsKichigai.com On Fri, Dec 12, 2008 at 10:29 AM, Jerry Flanders <[hidden email]> wrote: > At 07:59 AM 12/12/2008, Don Nelson wrote: > >> The K3 kit has two sub assemblies that come in large conducting plastic >> bags. I used these bags for an antistatic mat. I put these bags down on >> the >> work bench overlapping to provide a good conducting surface. If you want >> you >> can cut open two sides of each bag and fold open the bag to double the >> covered surface. >> >> Don > > I don't understand how that material is supposed to function, but I tested a > piece of it (may have been from some other source) and found that it was not > conductive, at least as far as my DVM could measure. I concluded that I > could not trust it to drain off any static charge from a workpiece - wrong? > > Jerry W4UK > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Jerry Flanders
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Ron D'Eau Claire wrote:
> Even so, I have the long habit of touching the ground terminal directly > whenever I'm sitting down at the bench and donning my wrist strap. That way > I'm discharged before I ever put the wrist strap on. And, truth to tell, if > I'm doing something simple and quick such as reinserting a board in the > radio, touching the ground before picking up the board is all I do. I may have mentioned this before, but I like the idea so much I'll repeat it: I have a metal yardstick (a meter stick too, since it's calibrated in inches and cm) attached to the top of my workbench at the front. It is connected to the common ground via a 1 meg resistor. When I sit down my arms always rest on this, even if I forget to put on the wrist strap. I also have an aluminum muffin tin connected through its own resistor to put small parts in. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: easy source of static dissipating work mat?
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In reply to this post by Jim Garland
On Thu, 2008-12-11 at 21:45, Dr. James C. Garland wrote:
> > > I didn't find a specification on the electrode size, but in the photo of > > > a popular tester they look to be maybe 3 or 4 inches in diameter. For > > > my test, the electrodes were two saucepans, each about 7 inches in > > > diameter and weighted with 5 pounds > > When measuring the resistance of a two-dimensional conductor (like a mat), > the resistance can be measured with point contacts, such as ordinary test > meter probes. One of the interesting properties of two-dimensional > conductors is that the measured resistance is independent of the spacing > between the probes. In other words, one will get the same measurement on an > ohmmeter if the probes are one centimeter apart as if they are one meter > apart, provided the mat is larger than the probe spacing. > > This result may seem counter-intuitive, but it makes sense if you think > about the lines of electic current that flow between the probes. Widely > spaced probes have more area for the current to flow into, thus compensating > for the fact that the probes are far apart. Thus the resistance is an > intrinsic property of the conductor and not of the geometry of the measuring > setup. Interesting, no? > > 73, > > Jim W8ZR Yup, the resistance of a two-dimensional surface is dimensionless, typically measured in "ohms per square". If you have a square of the material with electrodes along two opposite edges, the measured resistance is independent of the square size. For example if you double the size then both the length and width double, cancelling each other out. Al N1AL _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: easy source of static dissipating work mat?
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In reply to this post by Jon Kåre Hellan
:=)
On Thu, 2008-12-11 at 23:29, Jon KÃ¥re Hellan wrote: > Dr. James C. Garland wrote: > > One of the interesting properties of two-dimensional > > conductors is that the measured resistance is independent of the spacing > > between the probes. In other words, one will get the same measurement on an > > ohmmeter if the probes are one centimeter apart as if they are one meter > > apart, provided the mat is larger than the probe spacing. > > > > This result may seem counter-intuitive, but it makes sense if you think > > about the lines of electic current that flow between the probes. > > Can't resist: > http://xkcd.com/356/ > > Jon LA4RT > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: easy source of static dissipating work mat?
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In reply to this post by Gary Smith
_______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: easy source of static dissipating work mat?
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In reply to this post by Gary Smith
On Fri, Dec 12, 2008 at 12:00 AM, Gary Smith <[hidden email]> wrote:
> My new K3 is on it's way. I have anti-static material that my > motherboard came in but that's not enough to work on & be static > free. I purchased mine from Jameco for less than $25 combined. generic Anti-Static mat <http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=10584&> they have a couple different sizes available at reasonable prices. generic Anti-Static Wrist Strap <http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=34552&> -Michael, VE3TIX _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: easy source of static dissipating work mat?
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In reply to this post by Vic K2VCO
Thanks for the ideas! I have a long metal ruler, but even better yet, a
thinner strip of copper that I can glue to the edge of my desk for discharging through a resistor. 73, Bill K9YEQ K2 #35; KX1 #35; K3 #1744; mini mods -----Original Message----- Re: [Elecraft] easy source of static dissipating work mat? Ron D'Eau Claire wrote: > Even so, I have the long habit of touching the ground terminal directly > whenever I'm sitting down at the bench and donning my wrist strap. That way > I'm discharged before I ever put the wrist strap on. And, truth to tell, if > I'm doing something simple and quick such as reinserting a board in the > radio, touching the ground before picking up the board is all I do. I may have mentioned this before, but I like the idea so much I'll repeat it: I have a metal yardstick (a meter stick too, since it's calibrated in inches and cm) attached to the top of my workbench at the front. It is connected to the common ground via a 1 meg resistor. When I sit down my arms always rest on this, even if I forget to put on the wrist strap. I also have an aluminum muffin tin connected through its own resistor to put small parts in. -- 73, Vic, K2VCO Fresno CA _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Gary Smith
> A ESD bag and a mat are 2 different animals.....
Right on that.
I haven't done this, but here's some info:
I *think* there was a "Hints and Kinks" article in QST
quite awhile ago where a guy made a "mat" using
some Masonite (tempered hardboard, etc) and a
quantity of India Ink. He said (as I recall) that the
India Ink has a lot of carbon in it. When applied to
the hardboard, it drains off any static (provided it's
grounded of course).
Just to throw more meat into the ring.....
While building the K3, the instructions never tell
you to power up any "bare" circuit boards that are just laying on
any mat or bench. For temporary use what would be
wrong with, say taking some aluminum foil, and gluing
it to "whatever" and grounding the aluminum
via a megohm resistor?
For a wrist strap, in the past I've used a metal watch band
with an insulated wire attached and grounded via another
1 meg resistor.
Wrist straps (a kit of parts and the strap) might still be available
at "BG Micro" on the web. It's OK for temporary use.
If a person does a lot of PCB work, one should invest in
something more substantial. Mouser has a very nice metal wrist
strap
and coil cord set for ~$20. For a mat, there was a company at
Dayton
selling used ones that looked really nice, going for $25 or so.
I think they're on the web...Google. Also, there's the auction
sites.
73,
Charlie, N0TT
_______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Nothing at all. I've build KD1JV's ATS-2, ATS-3 (both are SMD), one K2, three K3s and numerous other projects using a $2 foil oven liner grounded thru a 1M resistor and a wrist band clipped to the foil. I lay some black ESD foam (supplied with something I've now forgotten about) on the liner if I'm concerned about scratching anything. 73, Bill |
Re: easy source of static dissipating work mat?
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In reply to this post by Matt Palmer-4
Matt Palmer wrote:
> A ESD bag and a mat are 2 different animals, a ESD bag (silver) > creates a faraday shield around the object protecting it from esd There are two types of ESD bag, and I think that Elecraft use the pink ones, which are very high resistance and do not generate a charge with friction. I believe the silvered ones do work like mats. Also, when measuring resistance, you need to make a line contact, not a point contact. Two ideal point contacts will result in an infinite resistance. I'm fairly sure that two circular contacts, produced with the same probe and pressure will not produce a constant resistance, but will actually scale with separation in the expected way. > (think tinfoil) an esd mat is a relatively high Z conductor designed > to bleed off charge as to avoid arcing (think rub feet on carpet and > touch doornob.) there are also pink 'esd' bags that are not shelded > but are simply made of a plastic which will not generate static > electricity. A ESD bag is not a suitable replacement for a mat. -- David Woolley "The Elecraft list is a forum for the discussion of topics related to Elecraft products and more general topics related ham radio" List Guidelines <http://www.elecraft.com/elecraft_list_guidelines.htm> _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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