Electronics soldering mat?

[DWSmith]

Are these silicone mats worth it?

My wooden desk has a glass cover but it's very reflective.  What do you think about the mats on Amazon?  I saw one from Weller.  Any suggestions?

Seems like a smooth, flat mat would be more useful.  Is there such a thing?

[calzap]

On the bench, I use a slab of plywood covered with kraft paper.  When the paper gets too worn, it’s quickly replaced from a roll I keep on hand.  Kraft paper is surprisingly durable.  Can also write notes, do calcs and make drawings on it.                     Mike

[Psi]

They make your bench look good, and help prevent you setting fire to things or just burning them, which can happen with a wooden desk and hot air.
For hobby use ESD isn't really an issue.
Having a smooth surface is nice, rather than a wood surface full of dents that parts roll/fall into.

Depends if you have the money for one or not, for example I wouldn't buy a mat if you're having trouble finding cash for parts.
They're a nice to have. 

I'm not sure about glass,  it might shatter if you put thermal stress into it in a small spot.
Maybe a small work mat is worthwhile to cover the glass if it's cheap. But I wouldn't go overboard and cover your entire desk in blue ESD matting.

[SteveThackery]

Actually if it really is silicone, I would say the risk of static damage is too high.

I bought a silicone mat for repairing watches. It was a big mistake - the static build up was severe enough to make the parts actually jump around, and I could feel the hairs on the backs of my fingers moving.

So, I think there is a risk of damaging static-sensitive components. Having said that, are there actually any modern-day components that can be damaged in that way? Back in the day, the 4000-series CMOS chips were extremely vulnerable to ESD damage, but I think since then most (all?) chips have ESD protection. Does anyone know?

[Psi]

Actually if it really is silicone, I would say the risk of static damage is too high.

I bought a silicone mat for repairing watches. It was a big mistake - the static build up was severe enough to make the parts actually jump around, and I could feel the hairs on the backs of my fingers moving.

So, I think there is a risk of damaging static-sensitive components. Having said that, are there actually any modern-day components that can be damaged in that way? Back in the day, the 4000-series CMOS chips were extremely vulnerable to ESD damage, but I think since then most (all?) chips have ESD protection. Does anyone know?

You can still damage things, but yes, most things have enough protection that it's very unlikely.
It really depends on the part, some things are more sensitive than others and sometimes adding internal ESD protection negative effects the performance of the part so they leave it out

[Solder_Junkie]

When I worked in the electronics industry, ESD was taken very seriously. Hobbyists can do what they like in terms of static damage precautions, but I use an anti-static work mat and have used the same mat for years. It is about 3mm thick and earthed, I also use a wrist strap when working on any components that maybe static sensitive. The mats are quite heat resistant too, which is handy.

You will note that quite a few components from the main suppliers come in static safe packaging. So industry still has concerns over static damage. Mouser list a lot of anti-static mats and kits, some are very expensive but those by Chip Quik seem more reasonable, see Mouser item 910-CQ-ESDMAT-GRY1X2

SJ

[RoGeorge]

Are these silicone mats worth it?

It depends of the kind of work you are doing, and depends if you have a dedicated workbench vs. casual home furniture.

There are two main types, one is based on PVC and not heat resistant.  The other type is rubber based, which is heat resistant (you can roll a blob of melted solder on it with no damage) and also piercing resistant and (some) chemicals resistant.  Though, chemicals might left permanent color-stains, which will make the workbench look dirty even when it's clean.

At the home lab I have a dedicated workbench with an antistatic mat, but I didn't find the mat very useful.  The mat is more of a nuisance.  In fact I am using either a white sheet of paper on top of the mat (so I can just discard the paper once it gets dirty).  Otherwise, from time to time you would have to clean the mat, or even wash it, which either way is unpleasant and time consuming.

Another disadvantage is that small things, like tools and components, are harder to spot on a dark colored background like my mat (my mat is the rubber type, heat and pierce resistant, but dark green).  Same components on a white sheet of paper are so much easier to spot.

Yet another disadvantage for the antistatic mat is that it usually has a slightly conductive layer for antistatic grounding (which I never use anyway, in home environment and temperate climate you don't have sparks as in an office during winter).  That slightly conductive layer will capacitivly couple with any PCB you put directly on that mat, and may interfere with sensitive circuits, making you chasing ghosts and unexplained weird behaviors in boards that otherwise would work just fine.

I often find myself working on a slab/plank of wood of about half an inch thick (a "retired" food chopping plate from the kitchen).  But most of the time, just white paper on top of the antistatic and not grounded mat.  Either use the back of a large paper sheet from former wall calendars, or just a clean sheet of A4 paper.

[RoGeorge]

Forgot to say, when I've bought it, for about two weeks it smelled horrible. 

The whole lab and the whole house was smelling like burnt rubber.  Keeping the mat outside, in the sun for 3 days, or washing it with diluted vinegar and dish washing liquid helped a little, but didn't really fix the smell problem.  Eventually, after a couple of weeks of enduring with the mat laid on the workbench, the small totally vanished by itself.
https://www.eevblog.com/forum/reviews/anti-static-mat-smell/
https://www.eevblog.com/forum/chat/esd-mat-smell/

[SteveThackery]

At work the antistatic mats were yellow, and were remarkably durable, although you could burn one with a soldering iron if you did it deliberately. I don't know what the material was, but it definitely wasn't silicone. The yellow colour was to signify antistatic equipment: the mats, cords, wristbands and earthing plugs were all yellow. This was in BT, in the mid-1980s.

It's strange that a multimeter shows the mat as open circuit, although it couldn't really be so because of the need to slowly bleed away electrostatic charges.

I'm going to repeat what I said earlier: a silicone mat will build up some serious electrostatic charges. When small objects jump and fly around and you can feel the hair on the back of your hand bristling, then you know the static charge is far from trivial. I wouldn't put a circuit board anywhere near a silicone mat.

[tooki]

Are these silicone mats worth it?

My wooden desk has a glass cover but it's very reflective.  What do you think about the mats on Amazon?  I saw one from Weller.  Any suggestions?

Silicone I would avoid like the plague, due to static. No matter what the vendors say, most of them are NOT antistatic. On the contrary, most are very staticky, making them entirely unsuitable for electronics.

Seems like a smooth, flat mat would be more useful.  Is there such a thing?

Of course. Standard, classic antistatic (ESD) mats.

Here, Digikey has 200 of them for you to pick from: https://www.digikey.com/short/md7m1p3w

[tooki]

It's strange that a multimeter shows the mat as open circuit, although it couldn't really be so because of the need to slowly bleed away electrostatic charges.

Why is it strange? The resistance of the top layer of ESD mats is deliberately very high, so as to a) limit discharge current, and b) allow it to behave as an insulated surface for ordinary purposes. Typical resistance is on the order of tens of MΩ into the GΩ, with 100s of MΩ to single digit GΩ being the most common. Most multimeters are not capable of measuring such high resistances. The black lower layer has much lower resistance (tens or hundreds of kΩ). The idea is that the charge travels slowly through the top layer, but then reaches the "low"-resistance layer where it can reliably dissipate to ground.

[tooki]

Actually if it really is silicone, I would say the risk of static damage is too high.

I bought a silicone mat for repairing watches. It was a big mistake - the static build up was severe enough to make the parts actually jump around, and I could feel the hairs on the backs of my fingers moving.

So, I think there is a risk of damaging static-sensitive components. Having said that, are there actually any modern-day components that can be damaged in that way? Back in the day, the 4000-series CMOS chips were extremely vulnerable to ESD damage, but I think since then most (all?) chips have ESD protection. Does anyone know?

You can still damage things, but yes, most things have enough protection that it's very unlikely.
It really depends on the part, some things are more sensitive than others and sometimes adding internal ESD protection negative effects the performance of the part so they leave it out

Silicone mats can easily reach 20kV charge, FAR beyond what the ESD protection in most chips is rated for. I 100% agree with SteveThackery: I wouldn't let a silicone mat anywhere near any electronics, period. It's not worth it, given that alternatives are readily available.

[RoGeorge]

The rubber based mat I have has 2-3 visible layers, each of a different material and different thickness.  The conductive layer is underneath.  If I keep the probes at about 1cm apart underneath the mat, the DMM fluctuates somewhere around 4-8 megaohm or so, depending of how much pressure you put on the probes.  This bottom ans conductive layer resembles the aspect of a dense foam when looking closely, it is always black, has about 2-3mm thickness, and it is not very resilient.

Only the top layer is cut/pierce-proof.  This top layer can be in two colors from all that I've seen so far, blue or green.  It is the most rubbery and much thinner, only half a mm or so.  It can stretch a lot (it rather stretches than pierces), and it is a very good electrical insulator.  Though, being so thin, if you place a PCB on it, the PCB traces will form parasitic capacitances with the conductive layer underneath.  Casual circuits won't be affected, but high impedance or low signal circuits will most certainly malfunction.


Aside from the rubber based and the PVC based mats, there is a third type of mat that is made out of silicone, indeed.  Those are much smaller, thick of about 5-7mm, and usually not colored, white translucent.  They are only heat resistant, not pierce resistant like the rubber mats, and they are not antistatic.

Such a silicone mat is usually meant to be put underneath a board that will be reworked with hot air, because the silicone is very good heat insulator, so if you sit the board on such a silicone mat, you may rework/reflow larger boards that otherwise would have needed a preheater underneath the board.

https://duckduckgo.com/?t=ffab&q=translucent+silicone+mat&ia=images&iax=images

To complete the mat types bambuzlement, the so called "silicone soldering mats" that are colored, not translucent, and with some sort of electronic board in the picture and embossed compartments on its surface, those are often PVC mats with no resilience to heat.  Unless the max temperature is specified (has to be in the range of 400*C or so), they are most probably based on PVC, and they will melt instantly if you accidentally touch them with a hot soldering iron. 

[SteveThackery]

It's strange that a multimeter shows the mat as open circuit, although it couldn't really be so because of the need to slowly bleed away electrostatic charges.

Why is it strange? The resistance of the top layer of ESD mats is deliberately very high, so as to a) limit discharge current, and b) allow it to behave as an insulated surface for ordinary purposes. Typical resistance is on the order of tens of MΩ into the GΩ, with 100s of MΩ to single digit GΩ being the most common. Most multimeters are not capable of measuring such high resistances. The black lower layer has much lower resistance (tens or hundreds of kΩ). The idea is that the charge travels slowly through the top layer, but then reaches the "low"-resistance layer where it can reliably dissipate to ground.

Yes, of course you are right. I was just impressed when I found the resistance to be higher than my multimeter could measure, even with probes almost touching.

However, it has led to a false "rumour" that the top surface is actually a proper insulator and the mat works through some kind of capacitance wizardry. This is complete nonsense: the top surface is definitely conductive enough to bleed away electrostatic charges.

[Psi]

Silicone mats can easily reach 20kV charge, FAR beyond what the ESD protection in most chips is rated for.

True, but when did you last hear of a hobbyist blowing up a IC with a silicone static mat.
Even in small business repair shops you see silicon mats used because they have recessed compartments to hold screws and parts.

[SteveThackery]

True, but when did you last hear of a hobbyist blowing up a IC with a silicone static mat.
Even in small business repair shops you see silicon mats used because they have recessed compartments to hold screws and parts.

I don't know enough hobbyists to comment. However, I can basically guarantee that a 4000-series will die if placed on a charged silicone mat. (Yes, I know nobody uses them any more.)

We shouldn't refer to silicone mats as antistatic - they just aren't.

EDIT: One thing I found interesting is that static damage can make a 4000-series fail weeks or months after the damage is imparted. I had loads of those - the handling error was in the factory, but the machine would come into my workshop for repair after an apparently random period in the customer premises.

This was known about at the time and was called "premature ageing", although I never got to know in detail the exact failure mode. Full antistatic precautions were taken in my workshop, and after the initial repairs we never had any returns.

[themadhippy]

However, I can basically guarantee that a 4000-series will die if placed on a charged silicone mat. Yes, I know nobody uses them any more.

speak for yerself, i use em all the time

[SteveThackery]

However, I can basically guarantee that a 4000-series will die if placed on a charged silicone mat. Yes, I know nobody uses them any more.

speak for yerself, i use em all the time

Ah, that's interesting.

[floobydust]

I use a old commercial 3M (now Desco?) ESD mat, it must be 1/4" thick sandwich of three layers. It was expensive. Never use vinyl/PVC it's gonna melt.
Jim Williams appeared to just use his benchtop, I think melamine on MDF, at home as well. Bob Pease I could not see it, paper everywhere lol.

A very passionate EE who was a messy solderer, eventually he just bought an aluminum plate for his bench from Metal Supermarket and ended all the drama.

If you're going to worry about static charge on the mat, you also have to worry about surface charge on your clothes. A shirt can have a lot and they are all plastic, need to wear an ESD coat.
Sitting/getting up from a desk chair makes another shit ton of static. In Canada dry winters that can make many kV, just like Dave's video.
I have the habit of always discharging myself, touching ground before touching IC's and I have an LED indicator that shows current.

The 4000 series CMOS damage, I saw so much of that in the 80's, tech guys doing board swaps despite using anti-static bags.
An ESD hit would damage and punch through the gate- but the IC's kept working, for about 10 days... like clockwork.
It is apparently due to the ion migration happening with the (now leaky) gate current. So many callbacks until I taught them how to handle/install boards without zapping them.

[BillyO]

Seems to be a very negative feeling toward these mats.  I use them to prevent things form getting burned and have never had an issue with static.  Mind you, I do use them on top of an anti-static mat which is itself on a grounded (well, ground-able) metal sheet and my soldering iron tips are usually grounded  Maybe it's that my lab is not air conditioned and never gets extremely dry, or maybe I'm just damp enough myself to drain of static ( ).

Also, a non-conductive surface is not like a human in polyester socks walking on a nylon carpet.  The human can build up substantial static, considerably more (in terms of actual electron counts) than a non-conductive surface like a small mat, and because the human is conductive, they can potentially (no pun intended) release ALL of those electrons into a uncharged device, especially if it is grounded.  However, if such a device comes into contact with a non-conductive mat, only the few electrons immediately adjacent to the point of contact will be available to escape into the device.  The energy released is tiny when compared to the energy released by a statically charged human.

Anyway, I like them, have used them for decades and have yet to have a component "mysteriously" die on me including JFETs, MOSFETs and old 4000 series logic.

[RoGeorge]

A very passionate EE who was a messy solderer, eventually he just bought an aluminum plate for his bench from Metal Supermarket and ended all the drama.

Once I had a very expensive fancy mouse pad.  The mouse pad itself was siten in a large tray of billed aluminium.  It was horrible, too cold to the touch, plus you will eventually get black Al oxides on your ankle for rubbing your skin against aluminium.  It was also unconfortable to move around, hard to resit, and it was requiring a large flat surface, or else it was wobbling.  It was the worst mousepad ever.  Whoever thought to make a billed aluminium mouse pad tray, that was a horrible idea.  (Found it, this one:  https://www.newegg.com/func-1030-su-mba-bk/p/N82E16817114303 )

I think I still have it somewhere, kept it in the idea that I might use it as a radiator for power transistors.  An aluminium plate under your hands is the worst.  Never found any use for it.  Plus, it is said that, if aluminium enters into your body, it makes you stupid.  I only used that pad for less than a months, and look at me now.

Tell your friend to stop fooling around.  A metal plate is not a good antistatic material.  If he refuses, tell him the aluminium might had already got to his brains. 

[Sensorcat]

Interesting images for those who want to see how ESD actually does its damage:

https://desco.blog/2013/07/09/images-of-esd-damage-2/

[SteveThackery]

Mind you, I do use them on top of an anti-static mat which is itself on a grounded (well, ground-able) metal sheet.....

That shouldn't make a difference. The static charge that matters is the one on the top surface of the silicone mat. Grounding the bottom surface won't help.

[BillyO]

That shouldn't make a difference. The static charge that matters is the one on the top surface of the silicone mat. Grounding the bottom surface won't help.

Well, I agree.  But ... all that conductive stuff around the mat provides plenty of opportunity for bodily born static to be discharged.  However, did you read what else I wrote?  About how it's poor conductivity limits it ability to release energy?

I'll add to that the fact the silicone is not really the best material for developing static charges.  First, no one is going around and rubbing their soldering mat with plastics that are eager to give up or attract electrons.  Next, silicone itself is really not that eager to give up or attract electrons.  It will, but nothing like polyester or Nylon.  It's only real claim to fame is it's a very good insulator, which, as I already discussed, naturally limits it's ability to release much energy at all to any component that touches it.

I may not be a EE, but I am a physicist and a CET.  I will bet that you would have to try extraordinarily hard to get a silicone mat to harm a little MOSFET like a 2N7000, even by directly touching the gate to the mat and grounding the drain and source.

Anyway, you all do you.  If you hate silicone, you hate silicone, but that hate is unfounded.

I know it's only anecdotal, but as I said, I've been using them a long, long time without a single incident.

[SteveThackery]

Anyway, you all do you.  If you hate silicone, you hate silicone, but that hate is unfounded.

I cannot speak to the actual risk posed by a silicone mat to a modern electronic component - I don't know enough about ESD protection circuitry to judge how much static they will withstand.

What I do know, beyond any doubt, is that during the repair of a watch, an electrostatic charge accumulated on the mat, and this charge was strong enough to make the small parts jump around - literally. It was also strong enough to make the hairs on the back of my fingers bristle.

I don't hate silicone - don't be silly. I expected and wanted the mat to be a suitable surface for watch repairs and electronic work. When I saw how strong the electrostatic charge was, I realised I couldn't use it for watch repair; parts jumping around - potentially into oblivion - is disastrous.

As for electronics - I judged that such a strong static charge could put delicate components at risk. I didn't want to do that, so I decided to stop using the mat. I also decided to advise other people against using silicone mats for electronics work.

Even though I cannot provide proof that a silicone mat is harmful, I firmly stand by my position: 1/silicone will accumulate a surface static charge; 2/ that charge is too strong for watch repair work; 3/ based on my experience as an electronics technician, I judge that such a charge could be risky with electronic components.

It's not like there is no alternative; why take an entirely unnecessary risk?