[time-nuts] Conducting Bench Top Material

[Robert Darlington]

Hi Charles,

I'm in a similar boat where I've worked with static sensitive parts without
any problems without having so much as put on a wrist strap.  It's just
never been an issue, even with our RH sitting around 12% here in New
Mexico.  I've been shoulder deep in Cray and SGI supercomputers without
worrying about it.  Then the day came where I needed to do surgery on my
network analyzer.  I figured the $20 for the coating was cheap insurance.  I
don't have $37k sitting around to replace it should I fry it.   That was the
first time I ever put on a wrist strap too!

-Bob

On Mon, Jan 25, 2010 at 11:27 AM, Charles P. Steinmetz <
charles_steinmetz at lavabit.com> wrote:

> Bruce wrote:
>
>  Although over the years the non-conductive top has been an  asset in
>> avoiding short circuits, etc., I am concerned about static  discharges
>> when
>> handling modern semiconductors.  Would it make sense  to spray the
>> Masonite
>> with a weak copper sulphate or similar solution so as to  make the
>> masonite
>> slightly conductive, but not so conductive that 155 VAC  connections could
>> not
>> safely rest upon it?  Is there a better-suited  material that could be
>> used
>> to replace the Masonite?
>>
>
> I notice that many folks who have contributed on this thread use
> anti-static benchtops, but I have never found it necessary (and I try to
> keep the RH in my house under 45% -- it is generally 20% or less in the
> winter).  I've been fooling with static-sensitive parts for 35 years and
> haven't lost one to static yet.  With that perspective, my preferred
> benchtop is white Formica with a very, very slightly pebbled surface.  Very
> durable, including to molten solder, and small parts show up well.  I use
> rubberized "gunsmith" mats for preventing scratches to delicate workpieces
> (these happen to be anti-static, but that is not why I have them).
>
> Other bench thoughts:
>
> Bench depth is very important.  I sometimes work on equipment that is more
> than 24" deep, so I want at least 30" of clear space in front of any
> obstructions (power strips, Variac, test equipment, whatever).  In the past,
> I used a "flying bridge" over the rear 18" of a 48"-deep bench to elevate
> the test equipment, which worked very well.  Now I use 24" deep adjustable
> wire-rack shelving units behind a 30" benchtop (As others have pointed out,
> you can do the same with equipment racks -- I'm not a fan of rack-mounting
> test equipment unless the racks are anchored and everything is on slides,
> which I was not prepared to do).  I don't have enough shop real estate to
> have a permanent access aisle behind the test equipment, so the bench and
> racks have large (5") locking polyurethane wheels and can be pulled out
> relatively easily for reconfiguration.  This provides plenty of stability
> for electronic projects, but you wouldn't want to mount a big vise on the
> bench and try to bend 1" rebar.  For that, I have a separate metalworking
> shop.
>
> Bench height is also important.  I prefer a tall bench, suited to working
> standing or sitting on an ergonomic stool, so my bench top is 44" above the
> floor -- a bit below my standing elbow height.
>
> Finally, one can never have too many power outlets, or too much light, in a
> workshop.  Lighting should be arranged so that it doesn't cause specular
> reflections from the workpiece or the faces of test equipment.
>
> Best regards,
>
> Charles
>
>
>
>
>
>
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