[Elecraft] Anti Static Mats

[Alan Bloom]

On 04/06/2014 01:10 PM, Sam Morgan wrote:
> Due to the recent subject of Anti Static mats, I did a little googling
> and thought I'd share my findings.
...
> maybe Alan or someone more knowledgeable than I can let us know if the
> Sierra is really up to the standards we need met?

 From my 2010 posting
http://www.mail-archive.com/elecraft%40mailman.qth.net/msg94407.html

    "So my recommendation is to buy a mat such as the Desco model that
    has a data sheet that specifies that it meets ANSI/ESD S4.1 or
    ANSI/ESD S20.20."

I recommend against using a mat that has no specifications other than 
asserting it is an "anti-static mat."  I found that the two I bought and 
tested both had too high a resistance to do any good.

=======================

On 04/06/2014 02:20 PM, Lynn W. Taylor, WB6UUT wrote:
 > One thing worth noting: 1000x lower resistance isn't necessarily
 > better,

Right, you don't want the mat to be too low a resistance either.  Do not 
substitute a metal sheet for an anti-static mat.  That just makes it 
even more likely you will zap something.

=======================

On 04/06/2014 01:43 PM, Larry Lopez wrote:
 > They made me take an ESD course at work and well I have a few
 > comments I feel forced to make.

Larry had a number of good points, for example:

 > When you have a discharge you might have failures months or years
 > later.  It may be damaged and it may work fine.
 >
 > For a while.

Exactly right.  ESD is insidious.  People think that if you didn't feel 
a "zap" when you touch something that there was no electro-static 
discharge.  But a discharge that you can't feel can still be enough to 
damage a sensitive part.

=======================

On 04/06/2014 12:10 PM, Fred Townsend wrote:
...
 > As a consultant I have done ESD audits of factories. If they know
 > the audit is coming all the wrist straps are in place. Surprise
 > audits are another thing. I find the straps and footwear to be
 > rarely used. How can they get away with that? The answer is they
 > have good work habits that avoid ESD problems rather than bleeding
 > off static build up.

I think in many cases they actually are not getting away with it as well 
as they think.  Part failures happen for a reason.  If the reason can't 
be found it could well have been ESD.

Some factories do in fact strictly enforce static-safe procedures. 
HP/Agilent "got religion" on this many years ago, at least here in 
Sonoma County CA.

 > Here are a few everyday hints the pros use.
 > 1.	Wear cotton!
... [etc. etc.]

All those suggestions can help, but they are not foolproof.  It requires 
constant vigilance to make sure you don't make a mistake.  Rather than 
go to all that trouble, why not just use the anti-static mat and wrist 
strap and be done with it?  If the wrist strap is too awkward, an ankle 
strap is a good alternative.

Alan N1AL