Hi In a previous video, I showed how you could make your product effectively transparent to a thermal imaging camera even when you have the lid on. And you can do that using cling wrap because cling wrap is both visually transparent obviously, as well as thermally transparent. That's why you can still see me through uh, on this thermal imaging camera through this cling wrap. and that's really useful to be able to see the performance inside your product, the airflow, the thermodynamics, and your components heating up, and things like that with the lid on with the cling wrap.

and that's really useful. But it seems kind of obvious that cling wrap is both visually and thermally transparent because we always think in terms of visual, but that's not always the case. There are materials where you can see through them visually like this, but they're opaque to a thermal imaging camera like this and I'll show you those in a minute and vice versa. There are materials that are transparent thermally to this thermal imaging camera, but you can't see through them visually and I'll demonstrate that.

Now prepare to have your mind blowing look at this. Just a regular plastic shopping bag from RS Components I've been buying some components visually opaque. You can't see through this if I put this bag on my head, which is probably an improvement. You won't be able to see me on my camcorder here visually, but watch the thermal imaging camera Cy Look at that.

you can see right through. You can see my head straight through this bag because it is thermally transparent, but visually opaque. Beauty And then at the opposite end of the scale, you got this glass. Obviously visually transparent as you know.

but watch the Thermal Imaging Camera Tada It completely blacks me out. There's a few uh Reflections on there thermal Reflections of My overhead light and you can see those visually as well on my camera. but the thermal energy cannot get through this glass regardless of how thin it is. It just doesn't work.

The material is not designed to pass thermal energy and that is why this. Flur E8 Thermal Imaging Camera here doesn't use a Glass Lens like my camcorder here does because it wouldn't let through the thermal energy it had just block it. So it actually uses a Geranium lens. Really expensive geranium lens lens that is very transparent in that thermal IR range that this camera is designed to operate at.

So how does all this magic happen? Well, you probably need a physicist to explain it properly and I'm just. well, a humble electronics engineer, but it all has to do with bang. Gap Energy levels. Certain materials have different band Gap energy levels in them and different types of light be they visual light or thermal uh light which is lower in frequency either be absorbed or let through depending on the band Gap energy level in the material.

That's why you can visually see through this, but thermally can't and you visually can't see through this, but thermally you can. And the cling R just happens to be really, really good at passing both, but some other type of energy it may not let through at all. So there you go. All has to do with physics.

Love physics. Beauty In my previous video, a lot of people mentioned the cling wrap I used could generate ESD and that could damage electronics. Well, yes, it's possible. And yes, cling wrap of course does generate ESD.

By the way, if you haven't seen the previous video, I'll link it in down below. So I thought I would just, uh, measure that and see what the values we actually get. And if it's really going to be a major issue, this is just Koh's brand. Cling Wrap I Have no idea what type of uh cling wrap it is.

There are many, uh, different types. Apparently some of the older ones work on electrostatic, uh, buildup and charge. The newer ones have chemicals added to make them sticky and all sorts of stuff, so not entirely sure what this one's made of. Anyway, generic CO's brand could have been.

uh, you know it's just rebadged. anyway. I've got my Surface DC Voltmeter here and this will tell me the Uh charge in kilovolts at 1 in. So I've got to try and keep the cling wrap at 1 in away from the sensor.

it's going to be near enough. We're just looking at ballark readings here, so I'll I'll reset it and here we go. I'll take the cling rack off. Um, off the roll.

I've got to step around my camera here. It's really quite annoying. Um, and yeah, we expect some buildup. Of course we expect be very surprised if this doesn't generate any charge buildup.

here. we go. Yeah, we saw it Peak at 2,000 there, Something like that. Okay, so it does certainly build up a charge.

and if we lay it back down on the ESD mat here and well, yeah, it's gone back down. let's reset. Let's reset it again. And if you bring it back up, yeah, it does build build up, that charge back up again.

So there you go. So yes, it could be an issue if you're uh, going to get these near your boards. I mean obviously, you wouldn't recommend wrapping your boards in it, but for putting it as a case over a product? Eh, not a huge deal now. of course, those sort of levels you can generate more yourself.

So um, you know, with your clothing and other stuff walking across the carpet and other traditional methods of building up. um, static. So really, yes, cling wrap could potentially be dangerous ESD wise. but then so are you if you're not Es if you're not taking proper ESD precautions and everything else.

so you know. really. Let's also test what happens if we roll it back onto this roll and then unroll it again. Does it build up the same charge? Tada No, it doesn't look at that.

So if you want to minimize the charge on your cling wrap, just wrap it back up and then re deploy it like that and it's not a huge deal at all. It's It's not nearly the same as when you take the brand new stuff off the roll and let's have a look if I do the brand new stuff again. Here we go. Yeah, there we go.

So that brand new stuff certainly builds up a charge. So is it a problem if we put it over a product as a lid? So let's take this PC as an example. and let's unfur our cling wrap and bring it in like oh, this. sorry, yeah, it's G I got to make sure it doesn't touch.

There we go. I Mean you know we only talking a couple of hundred volts there. It's not a huge amount, it's not a Hu Oh, there we go. 500 at that point.

but it hasn't. Not there we go. That could just be not the movement of the thing. But anyway, it's not a it's not as big a deal as you might think once it's on a grounded product like that.

And if I do that again by rolling out the cling wrap from, it's already rolled out. State There we go. Not a huge deal, That's not a big deal. It's practically going down to zero there.

So there you go. you do certainly need to be careful with cling because it can build up a charge and that is totally expected. So pros and cons of using cling wrap. Of course, the beautiful thing about cling wrap is that a it's cheap and readily available uh, from anywhere.

And also that it's super thin and very thermally transparent. So if you want the utmost in, uh, thermal transparency, cling wrap is an awesome way to do it. Yeah, just be careful though, Although there are ways to mitigate that. Um, with the cling wrap, you can actually uh, uh, wash the cling wrap and actually remove the static charge as well.

But if you are really concerned about ESD uh, for your particular scenario, using that thermal camera, there's other materials you can use. and you guessed it, these pink. ESD bags. Of course.

these also work a treat and are thermally transparent. Now these are made of uh, polythylene usually, but also polyphen material as well. You can get these and they are fully thin. thally transparent.

Probably not as good as the cling wrap. We'll test that in a minute. but yes, they do work. and look, they build up absolutely no charge at all.

That's the whole idea of anti static bags. They do not build up a charge and I've done a video on that which I'll link in down below. How they technically do not fully protect your devices they're just designed from ESD discharge. You can actually kill devices through these bags.

but anyway, that's a different video. But yes, they are thermally transparent. Here we go: I'll prove it. Here's my hand and I'll stick it in one of these pink SD bags and you can still see my hand.

look at that. Tada And of course this one. They're both visually, uh, seethrough. visually transparent as well, but also totally thermally or not.

totally. But they are thermally transparent and they don't build up a charge. Beauty And for those who will almost certainly ask, no, these Metalized uh. static shielding bags.

uh, are not thermally transparent. Let's have a look in there. Oh no, that was my handprint There we go. I Can leave my handprint on there.

Maybe I can flip it over and like that. but no. I can't stick my hand in there. Those are not thermally transparent.

Sorry. So is this uh Pink ESD bag thermally as transpar arent as the cling wrap? Well, let's try it. I've cut it into a single uh piece so it's not. uh, it's not a bag anymore.

it's just a single piece. and here we go: I will overlay it and you can see it come in there and it really? oh sorry. that was calibrated. It really does blur stuff out and uh yeah, it's not nearly as good.

You can see the maximum temperature go from uh 78. Here you can watch that go down to yeah. drops down a lot down to 63 so not that great. Now we'll do exactly the same thing with cling cling wrap here.

We go here goes the cling wrap 78 and as you can see, it only dropped down to 73 and you can see more detail in there. Definitely. So cling wrap does work better. And for those who want just the thermal image mode, okay, here we go.

We'll go with the cling wrap again and it's a bit. uh. here we go there we go. It really doesn't change that thermal image at all.

It really is very thermally transparent. That's why I Love the cling wrap for this purpose even though it might have a bit of ESD danger. And back to the ESD bag. Here we go.

it's coming across coming across and you can see that temperature drop a fair bit. And yeah, oh, the details there. but the camera? because we were using the MSX technology before so the detail is still there. But really? Yep, you got a lot more loss through that antistatic bag.