Hi. Just a quick follow-up video on the PCB Tinin video I did last time and if you haven't seen it click here. you'll be able to watch it. It's fairly indepth.

had a lot of people ask. can I try it with leadfree solder? Well I didn't have any last time, but I've got some this time, hence why I'm wearing a green shirt. eh, green seems to be the color for lead free stuff, so let's give it a go. Repeat exactly the same thing we did last time for the lead one with lead free solder.

see what the differences are and here it is I Went down to my local J Car Store and picked up some Uh Durch by Sonar Tech which is an Electus company which is all affiliated with Jcar all owned by Gary Johnston Anyway, it's 99.3% tin, 0.7% copper so there's no lead in it at all. and uh, of course, um, it's got some copper in there, so that'll you know, uh, lower the resistance and uh, tin should be, uh, in theory lower resistance than the 6040 lead stuff we used last time. So let's give it a go. and it's green of course.

Got to love it all right? Let's get a baseline figure here. We're using the same Verab borders before, but we're using the strip on the other side bare 1 oz copper. It's definitely confirmed as 1 oz, just over 1 amp constant current. We're getting 52.8 86 molts, which is 52.8 m ohms or thereabout.

so we'll take that as our reference figure and then we can add uh, different layers of uh, lead free solder on here and see how much it drops by. All right, We'll start out here by doing a very thin coat so that we get a minimum Baseline and then a maximum Baseline as we did last time. So pretty much a minimum amount of solder that you can expect a wave soldering process to put on here. I Know we're not doing wave soldering, but it's going to be pretty close I Think so let's give it a go.

Just a quick safety tip. By the way, you'll notice that I was actually soldering what is effectively a live circuit here. I We're passing current through this thing and I'll sold her at the same time. That's generally a very, very bad idea unless you have a specific reason to do it like I was doing.

because why? your soldering iron I won't touch it. That's the hot end. Um, is M's Earth Reference: The tip is shorted to Main's Earth That means if you don't use a completely floating system while you're soldering, Bang You're Going to short it out to something. Really bad news? You don't want to do it.

So generally never, ever solder a live circuit unless you know precisely what you're doing. and it's floating. And by floating of course, I mean it's either battery powered or the supply you're using like this one is not mains. Earth Reference: It's got a floating output.

Here is the Earth Terminal right Here and it's got a shunt short in link on there, but I've disconnected that from the negative terminal. so this is now a floating power supply, but if that was connected to there, it would be Main's Earth referenced. and if you solder in a live circuit bang, All right. I've got a very thin layer of lead free solder on this thing and we're basically dropped down to, um, almost.

you know, around 46 molts or 46 milliohms. So basically, that is a 133% decrease. And before, with the Le stuff, uh, we got a 15% decrease. So um, you know, really, it's certainly in the same ballpark.

If anything, it's actually worse than the lead free solder. But I'm not going to claim that because it's all about the thickness and everything else. So you know, roughly, it's pretty much exactly the same. Let's give it a go again.

and uh, you'll notice it goes up instantly when I heat it up with the soldering iron Wham you'll notice it just jumps up in resistance. So let's coat it well. I've put on uh, as much solder I think as I did last time for the lead stuff I You know, but it's hard to tell exactly how much you've actually, uh, put on. But check it out.

26. 1 milliohms. So uh, roughly that is once again, a 50% decrease or just slightly over a 50% decrease. Exactly what we got last time with the lead free solder and well, in theory, um, that shouldn't have happened I think in theory, we should have had uh, a lower value I'm not sure by how much, but a lower value with the lead free solder, but we haven't we've got roughly the same.

um I'm going to try and put some more solder on now. I'm really going to try and pile it on. but like I said I think I kept it pretty much the same as last time, but there is going to be some error in there and I think I've put on the absolute Max I Can you know that really any wave soldering process would put on such a thickness track? Really? this is a 4.2 2 mm thick track and I I don't know how that shows up on camera, but that is a massive amount of solder on top of there. Um I think that's a lot more than what I put on the uh lead free.

uh, the lead one that's for sure. And there you have it. We've jumped to 14.5 Milli now or thereabouts. and uh, that is, uh, just over a 72 or 72 1 12% decrease.

So you know that is an absolute maximum amount of solder. I Think you could probably Phys. You might be able to get a bit more on there, you know you're really go insane, but I've never seen a wave soldering process put this amount of uh solder on such a small track before. So I think we're You know that's got to be the real extreme upper limit there.

So there you have it, that's lead free solda 99.3% 10 .7% copper. In comparison, rough comparison to the 6040 lead solder we did in the previous video, and in theory it should have higher conductivity. But I don't think the exercise that we did here can precisely show that uh difference because really, we' need a more you know, a much more rigorous uh method than this. We need to know exactly how much solder went on there with hindsight, probably should have weighed or measured the amount of so shoulder going on in both cases, and well, you know you could do this sort of thing until the cows come home.

But in the end, roughly ballpark figures uh, Rules of thumb that you can take Industry rules of thumb would be roughly anywhere from say, a 15% uh, decrease with lead free solder to say 70% tops with lead free solder. So I think there probably is a difference there with the lead free solder as you'd expect in theory, but you know we need more. much more accurate uh measurements to be able to quantify that. You know, get that actual uh value difference.

but H it's it's not. It's not going to be double. For example: I don't think it's double the lead solder so you know it's uh, it might have a difference with the track. uh, width as well because you then you get round into the solder and stuff like that.

that's all going to make a difference. So really need further experiments In terms of track width measure, you know, quantify the amount of solder put on there. Somehow you know, work out it, its thickness and its conductivity and all that sort of stuff. Uh, maybe we'll do some more videos on it I Don't know.

but I think we've got some good rules of thumb there. And by the way, for those in the previous video who seemed a bit confused when I was talking about percentage increases and percentage decreases, they're not the same. Like I mentioned, a 40% increase in resistance and a 28% decrease you? That's just the way the math works. You got to know the terminology of percentage decrease.

It's a specific term, percentage decrease and percentage increase. A 40% increase is not going to be a 40% decrease and it won't go into the whole theory of it. That's what we got. We got anywhere from a 15% to a 70 odd per decrease in resistance with the lead free solder.

Woo! Hope you enjoyed it. Catch you next time.