Author Topic: Alternate to an antistatic mat?  (Read 11592 times)

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Offline DaleReid

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Alternate to an antistatic mat?
« on: September 12, 2013, 03:24:07 PM »
As an alternative to an antistatic mat, how about assembling the board on the surface of a cookie sheet? Non-stick isn't the kind with teflon coating, I'm thinking a regular old fashion aluminum one.

Or putting a sheet of tin (aluminum) foil down and assembling on that?

Is there a downside I don't see?

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Offline miraculon

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Re: Alternate to an antistatic mat?
« Reply #1 on: September 12, 2013, 05:12:44 PM »
Quote
Is there a downside I don't see?

Don't forget to remove the assembled PCB from the cookie sheet before you put power to it for a test. There might be a whole lot of shorting going on otherwise. #-o

Antistatic mats have >1M ohm typically, so you can get away with a power-up on them.

Quote
Or putting a sheet of tin (aluminum) foil down and assembling on that?

This is what I did. I put aluminum foil under one layer of newspaper on wooden table. I suppose that you could spray the paper with Static Guard. The leads poked through the paper enough to ground it while I was working on the boards. (see above comment though, I almost did that!)

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« Last Edit: September 12, 2013, 05:16:14 PM by miraculon »


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Offline wxtech

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Re: Alternate to an antistatic mat?
« Reply #2 on: September 12, 2013, 06:34:39 PM »
We used to make our own workshop antistatic mat.  Use a piece of indoor/outdoor carpet, not artificial turf, and spray it with clothes antistatic spray.  Or make your own spray using the liquid that was added to the clothes washer.  It's been too many years (mid 1980s) for me to remember the brand name sprays.
We used the tightly woven indoor/outdoor carpet because we inevitably dropped small parts into the carpet and we needed to be able to retrieve them.
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Offline Cutty Sark Sailor

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Re: Alternate to an antistatic mat?
« Reply #3 on: September 12, 2013, 07:22:12 PM »
a cloth towel and a mixture of laundry soap and water sprayed on it will also work well... don't saturate, just spray it... we'd do that in a pinch also.  They use to specify Tide... I think the original mat treatment was little more than Tide and water... the detergent sticks around, and absorbs moisture from the air...
 


Offline DaleReid

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Re: Alternate to an antistatic mat?
« Reply #4 on: September 12, 2013, 08:47:06 PM »
Thanks for the reassuring tips.

I'm not about to apply power  to this beauty unless it is sitting on a nice non-conductive surface, but thanks for the reminder/warning.  I can tell tales of people's meticulous work given an un-intentional smoke test by something just like that.

Or starting an engine having forgotten to fill the oil back up after pulling the plug and filter and getting distracted.

I'd forgotten the old trick about laundry detergent and a dense towel or cloth.  Neat ideas, all.

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Offline wxtech

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Re: Alternate to an antistatic mat?
« Reply #5 on: September 12, 2013, 09:15:32 PM »
It was a liquid fabric softner with anti-static properties.  Downside: fabric softner sprayed on a carpet makes it slicker than ice when the carpet is still damp.  Let it dry before you run across it.
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Offline DanS

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Re: Alternate to an antistatic mat?
« Reply #6 on: September 12, 2013, 09:49:33 PM »
Thanks for the reassuring tips.

I'm not about to apply power  to this beauty unless it is sitting on a nice non-conductive surface, but thanks for the reminder/warning.  I can tell tales of people's meticulous work given an un-intentional smoke test by something just like that.

Or starting an engine having forgotten to fill the oil back up after pulling the plug and filter and getting distracted.

I'd forgotten the old trick about laundry detergent and a dense towel or cloth.  Neat ideas, all.



Also, when working with static sensitive devices it's good for your body to stay grounded either with a wrist strap or keeping in contact with the grounded anti-static mat your work is on.

Offline dfroula

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Re: Alternate to an antistatic mat?
« Reply #7 on: September 13, 2013, 09:43:08 AM »
Regarding the wrist strap....Commercially-made wrist straps all have a 1 Megohm resistor or so in series with the ground lead. The resistor was usually hidden in the snap attachment on the strap itself. This is to prevent the worker from being continually connected with a low-resistance path to ground. I recall a technician at Motorola making a temporary ground strap with some solder braid, wire and electrical tape. He got a nasty shock when he brushed against a low current, high voltage power source in the circuit he was working on.

A low resistance ground connection attached to one's body while working on electrical equipment is definitely a bad idea!

Best,

Don
« Last Edit: September 13, 2013, 09:44:57 AM by dfroula »

Offline W3DRM

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Re: Alternate to an antistatic mat?
« Reply #8 on: September 13, 2013, 05:20:09 PM »
Also, when working with static sensitive devices it's good for your body to stay grounded either with a wrist strap or keeping in contact with the grounded anti-static mat your work is on.

This whole anti-static topic brings back memories of many years ago when I decided to add some additional memory to my computer. The instructions I received with the memory chips included dire warnings of chip destruction if I didn't follow the instructions exactly as stated. Those instructions included a cartoon of a guy sitting, "in the buff", squarely on a large array of aluminum foil that also included the memory chips and computer chassis sitting on it. Supposedly, this ensured that all components, including the person doing the installation, were all at the same potential thus eliminating the potential for a static problem. At that time I had access to both an anti-static mat and wrist-strap from my workplace but I never forgot the instructions and accompanying illustration. I wish I had kept them...
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