Re: "Metal muffin baking tins are good" -- was " K3 ESD"

[Gary Hvizdak]

In reference to the subject of proper ESD protocol, Fred (K6DGW) just posted
"Metal muffin baking tins are good".  Please note that this is INCORRECT.

If a metal muffin baking tin (or any conductor for that matter) were brought
into direct contact with an ESD sensitive device, and the two were not
already at the same potential, then the rapid momentary current flow (i.e.
discharge) could easily zap the ESD sensitive device.

ESD mats have a specific surface resistivity to ensure that any potential
difference -- between the mat and devices placed on it -- is gradually
dissipated over a period of several seconds, as opposed to (I'd guess)
somewhere on the order of a few micro seconds for a metal muffin tin.

Thus the instantaneous current surge (when coming into contact with the
muffin tin) would be on the order of a million times greater.

73,
Gary  KI4GGX
K3 #2724

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[AC7AC]

CONTENTS DELETED

The author has deleted this message.

[David Gilbert]

That's no guarantee of anything.  It doesn't address the issue of
instantaneous static dissipation from the component to the muffin tin
itself (which has capacity to its surroundings and acts as it's own
charge sink).  Reread Gary's comment about surface conductivity.

Dave   AB7E



On 12/18/2010 5:10 PM, Ron D'Eau Claire wrote:

> To avoid damage just follow the same protocol as you would when installing
> the part in a circuit board.
>
> Ideally the tin would be grounded through a 1 meg resistor.
>
> Ron AC7AC
>
> -----Original Message-----
> In reference to the subject of proper ESD protocol, Fred (K6DGW) just posted
> "Metal muffin baking tins are good".  Please note that this is INCORRECT.
>
> If a metal muffin baking tin (or any conductor for that matter) were brought
> into direct contact with an ESD sensitive device, and the two were not
> already at the same potential, then the rapid momentary current flow (i.e.
> discharge) could easily zap the ESD sensitive device.
>
> ESD mats have a specific surface resistivity to ensure that any potential
> difference -- between the mat and devices placed on it -- is gradually
> dissipated over a period of several seconds, as opposed to (I'd guess)
> somewhere on the order of a few micro seconds for a metal muffin tin.
>
> Thus the instantaneous current surge (when coming into contact with the
> muffin tin) would be on the order of a million times greater.
>
> 73,
> Gary  KI4GGX
> K3 #2724
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[AC7AC]

CONTENTS DELETED

The author has deleted this message.

[k6dgw]

On 12/18/2010 3:50 PM, Gary Hvizdak wrote:
> In reference to the subject of proper ESD protocol, Fred (K6DGW) just posted
> "Metal muffin baking tins are good".  Please note that this is INCORRECT.

As usual, Gary is correct in that ESD mats are not great conductors, but
good enough, so that charges drain more slowly.  Metal muffin tins don't
fall into that category.  My saving on this is that they were part of my
equipotential plane [which included me], and knowing what Gary pointed
out in advance, I kept everything on that plane all the time.  I should
have made that clear, and an ESD mat/wrist strap is always the best way
to go.  I just didn't want to buy one :-(

I should also have mentioned that many metal muffin tins have a Teflon
coating.  Teflon is an insulator [actually a pretty good one], and will
also generate and hold static charges.  If your wife's muffins come out
of a Teflon-coated pan, don't use it.  Andrea bakes our muffins in a
couple of very old pans that are not coated, she uses little paper
cupcake liners to keep them from sticking.

Whatever you choose to do, just keep everything, including you [through
the big resistor] and the ESD bags/foam at the same potential.  I
recommend remaining clothed, however unshod does help if you're on carpet.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2011 Cal QSO Party 1-2 Oct 2011
- www.cqp.org
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[David Gilbert]

I thought we were talking about putting parts INTO the tin.  If you
gradually equalize the potential of the parts with respect to the muffin
tin before putting them into it, yeah ... that will work OK.  But then
the resistor to ground from the tin is a don't care .. it doesn't
accomplish anything as far as ESD goes.

Using the same protocol as stuffing a PC board is good advice, but the
only thing a resistor to ground accomplishes is to provide a reasonably
common reference point if you're moving stuff (components, tools,
yourself) around from place to place.  Once everything is in the same
spot it doesn't have much meaning.

Dave   AB7E



On 12/18/2010 5:43 PM, Ron D'Eau Claire wrote:

> Not if the tin is grounded.
>
> If not grounded, the capacity charge is taken care of by touching the tin
> before touching it with the part, just like when installing a part in a pc
> board.
>
> As I said, use the same protocol as if installing a part in a pc board.
>
> Ron AC7AC
>
> -----Original Message-----
> That's no guarantee of anything.  It doesn't address the issue of
> instantaneous static dissipation from the component to the muffin tin
> itself (which has capacity to its surroundings and acts as it's own
> charge sink).  Reread Gary's comment about surface conductivity.
>
> Dave   AB7E
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[John-483]

They are best when filled with fresh muffins!

John
k7up
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[gm3sek]

David Gilbert wrote:
>
>That's no guarantee of anything.  It doesn't address the issue of
>instantaneous static dissipation from the component to the muffin tin
>itself (which has capacity to its surroundings and acts as it's own
>charge sink).

Muffin tins are no problem if they are treated in exactly the same way
as that other large lump of metal - the K3.

Ideally, place both the K3 and any metal containers on the anti-static
mat to equalize potentials with the rest of the setup (including your
own body) and to provide a slow, gentle discharge path.

As an absolute minimum, bond everything together (including yourself)
using jumper wires with 1Mohm series resistors. Do this FIRST and you'll
be in good shape for ESD protection in any situation (up to and
including a flying magic carpet made of nylon :-)

As others have said, "green wire grounding" is a separate issue. You
should do that as well, but that is strictly for your own safety - it is
NOT part of your ESD precautions. Don't think about "grounding" until
you have FIRST bonded everything together through series resistors.



--

73 from Ian GM3SEK
http://www.ifwtech.co.uk/g3sek
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[George & Jan]

Even better = chocolate cup-cakes

George
AI4VZ

   *   *   *   *   *
They are best when filled with fresh muffins!


______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html