DIY ESD mats

[Bloomfield]

I went to buy an ESD mat today and found they were a bit more expensive than anticipated. I'm missing some functions on my digital scope and I think it is probably a ribbon connector issue that shouldn't be much trouble to sort out. I'd like to take the proper precautions against static though before I open it up. Can anyone suggest a cheap and easy solution for an ESD mat? It doesn't need to be durable as it's just to get through this one job. I do have a proper wrist strap to use with it.

Thanks,
Andy

[glebert]

Is this a benchtop mat or a floor mat you are talking about? Are you concerned about ESD from your body or from a component being set down onto a surface and picking up a charge that way? If you are just concerned about ESD from your body I think a wrist strap should be sufficient. FYI, I worked in aerospace and semiconductors for 20 years and really the only time we worried about ESD was flight hardware for satellites. But, scopes are pretty sensitive devices so I think a strap is not a bad idea.

[nevetslab]

I had a 24" x 18" ESD mat for a while, but somewhere along the way it got left behind. All I have left are a pair a bit larger than a standard computer keyboard. But, I've been saving all those Antistatic bags parts come in from Mouser, Digi-Key and other distributors, and when I'm concerned about it, I'll make use of those, slit open to double the size, and, I always have my Anti-Static wrist strap handy to plug into a known power ground.

[Bloomfield]

It would be for a bench mat. I do have some of those bags; I suppose I could flatten those out and use them. In that case should I clip the wristband to the bags as well as the safety ground circuit?

[Enzo]

Yep, the idea is to make your body part of the same ground as the board sees. Those large semi-clear black bags or the pink ones.

If you are not planning to power up, a sheet of aluminum foil will work for temporary.

[mozz]

A wrist strap is used to drain any charges your body may accumulate. There is usually a 1 meg resistor in there. A esd mat would be connected directly to ground.

[Bloomfield]

Thanks guys, I'll try using those bags.

[tedmich]

the bags (supposedly) have a limited lifespan, thus no one sells clear pink mats. Material is either static dissipative OR conductive and grounded (see Wiki entry below)
and the units are "Ohms per Square" not sq inch or sq. meter etc. (see why CF is a terrible choice for circuit boards...)

Dissipative releases charges gradually, while conductive needs to conduct quickly to earth/ground. Plastic is a KILLER DIELECTRIC thus it makes terrible triboelectric static, the pink additives help this dissipate, until they don't and the plastic that remains zaps things.

[Mick Bailey]

ESD floor tiles are pretty cheap and could be used on the bench - from around $15, though I don't know how this compares to what price you've been given for a specific bench mat. They can be had with a standard press-stud on one corner and are usually 500mmx500mm.