EEVblog #317 - PCB Tinning Myth Busting

[digsys]

For all high current PCBs, I use minimum 3+3oz, most of the time 4+4oz, Top and bottom.
Then leave the solder mask exposed for 80% of the Cu strip, makes a HUGE difference
with heat !! Also allows me to Solder a thick wire the full length for heavier currents.
I add two "stake" holes at each end in case I need to do it. This set up easily carries 20A
with very little Cu heating. PLUS, I always add a two isolated ~3" strips along an edge
for testing, one exposed, and one masked. It verifies the quality of the PCB.

[Ed.Kloonk]

On Dave vs. Mike competition I get the impression Mike wants to know the answer and the video is a bonus, Dave wants to make a video and the answer is a bonus

How do you figure?

For example you spend about 1:30 talking about 4 wire measurement and more a bit later, Mike covered it in about 20 seconds.

Mike documents what he did and the results with the video. You spend more time explaining why and how you did which is for the sake of the video.

Showing what you did is required to understand the results, talking about why and how doesn't get better or faster results.

I am not critical of either approach just commenting on the difference.

The difference to me is the 90 seconds to explain that is all good stuff to a knuckle dragger such as myself. It's a slipery slope if we were to ask Dave to tell the "cut to the chase" viewers to, in fact, cut to the chase. I've been sitting here today with a bottle of plonk, playing catch up after a long week. I've enjoyed watching the videos up until this time.

There is one thing I noticed though, there is some long black pole leaning up against the bench on Dave's right. Wondering if this is some personal security instrument that Dave keeps in case of surprise ninjas or something..


 

[EEVblog]

For example you spend about 1:30 talking about 4 wire measurement and more a bit later, Mike covered it in about 20 seconds.
Mike documents what he did and the results with the video. You spend more time explaining why and how you did which is for the sake of the video.
Showing what you did is required to understand the results, talking about why and how doesn't get better or faster results.
I am not critical of either approach just commenting on the difference.

I like talking about the how and why, much to the disgust of the 3 minute attention span viewers 
I think it's what makes my videos personable, but as always, YMMV vary as the viewer. It's not a deliberate choice I make for the sake of "better video", it's just my natural style.

Dave.

[rohitdesa]

You'll notice (and I think Dave pointed it out too) that the solder on the board shown in the video (not the vero board, the other one) was no really consistent. It was narrower to the left. An interesting technique that manufacturers use to get more consistent results is to have multiple thinner un-soldermasked on the PCB track. The image will explain it better. Its from an old UPS I have. Visible on the top is a track with multiple parallel unmasked lines. And on the bottom are traces where the woule trace is unmasked.

I suppose the thicker unmasked areas are less consistent because during wave soldering the solder collects in globs and the weight of the glob is more than the force of adhesion to the copper, so the liquid solder falls off. With multiple narrower unmasked zones, you'd obviously have to have a wider overall trace if the same lower resistance is required, but it would be more repeatable.

[SeanB]

Older soldermask would have wrinkling on large surfaces of tinned copper, so that is often why there were multiple tracks and crosshatched ground planes.

[digsys]

GK, for the same reason, would it make sense to route multiple parallel traces instead of a big solid single one, similar in spirit to Litz wire, or do you run into other problems if you do that?

In all honesty I have no idea. Can't say that I've ever seen that done either.

Being flat and thin, a copper trace is already better suited for skin effect, we wind HF S/Mode Inductors with copper ribbon.
Having lots of thinner tracks is a waste of area and has no remedial value.

[siliconmix]

is heating the copper twice or three times going to anneal the copper somewhat and change it's resistance ? .just a a thought

[free_electron]

I like talking about the how and why,

Keep that up ! That is the true educational aspect. Blindly repeating things is for monkeys. The web is already full if mind-numbingly dumb copycats of copycats of badly copied of parts-reduced becasue their function was misunderstood designs.

[ejeffrey]

is heating the copper twice or three times going to anneal the copper somewhat and change it's resistance ? .just a a thought

Not much.  Technically it makes some improvement but unless your copper is very badly work hardened it won't make any difference.  Heating is more likely to change the conductivity through oxidation, and possibly chemical reactions involving any impurities in the copper.

[siliconmix]

maybe ejeffrey .here's an excellent url on the subject
http://pcdandf.blogspot.co.uk/2012/03/keepin-it-smooth-how-surface-roughness.html

[ejeffrey]

Thats for RF.  Surface roughness has zero impact on DC/low frequency losses.

[siliconmix]

 to get an accurate measurement both samples must be the same .the same ambient temperature.same meters .

[McMonster]

I saw Dave's Twitter entry about Polish subtitles to this video so I wanted to check it. It's mostly correct and acceptable, but I've spotted a few errors and disparities. Also it omits completely some important parts of what Dave actually says.

Is there a way I can edit or submit my corrections? Can't see any option like this in the YouTube interface.

[SgtRock]

Greetings EEVBees:

--Now maybe Dave can do an experiment to confirm whether or not the light in the fridge goes out when you shut the door. Just kidding. Excellent video. I finally learned how to do a four wire resistance measurment. Bonus!

"Wish in on hand and whiz in the other, and see which one fills up first."
Gator Dundee 1948 -

Best Regards
Clear Ether

[EEVblog]

I saw Dave's Twitter entry about Polish subtitles to this video so I wanted to check it. It's mostly correct and acceptable, but I've spotted a few errors and disparities. Also it omits completely some important parts of what Dave actually says.
Is there a way I can edit or submit my corrections? Can't see any option like this in the YouTube interface.

Yes, you can download the subtitles from here:
http://www.universalsubtitles.org/pl/videos/UzjoXbTCkgld/info/eevblog-317-pcb-tinning-myth-busting/
No idea how to edit them.
I can re-upload (no one else has the access), but herein lies the problem with this subtitle business - how am I to know which one is more accurate?
You may have spotted a few errors and disparities, but how do I know which one is actually better?
Who do I trust? 

Dave.

[Monkeh]

Who do I trust? 

Dave.

Whichever one speaks English the most fluently. Assuming they're translating to their native language, anyway. If they can't string together a simple sentence without errors, they can't translate worth a crap, either.

[Rick]

Who do I trust? 

Dave.

Whichever one speaks English the most fluently. Assuming they're translating to their native language, anyway. If they can't string together a simple sentence without errors, they can't translate worth a crap, either.

Not true. The guy may have perfect command of English but may not speak Polish in the same way or he may be unable to translate into Polish properly. Say someone born in USA or UK for example. Ask them to translate a test of 200 words. You will know. That's how they do.

[Monkeh]

Who do I trust? 

Dave.

Whichever one speaks English the most fluently. Assuming they're translating to their native language, anyway. If they can't string together a simple sentence without errors, they can't translate worth a crap, either.

Not true. The guy may have perfect command of English but may not speak Polish in the same way or he may be unable to translate into Polish properly. Say someone born in USA or UK for example. Ask them to translate a test of 200 words. You will know. That's how they do.

Please read my post again. I did address that.

[Rick]

Yeah that's right. As I told you, they may think they speak Polish properly but may be they are not. But I made a mistake about the test. You get them translated into Polish then you need a translation back into English (but this time the translator needs to be a confirmed one). If your sentences changed then you know who is wrong. They do those back translations a lot especially the agencies who do not master the target language.

Speaking English and translating into Polish is an entirely different business. Even speaking Polish and translating into Polish is an entirely different business. Speaking does not mean being able to translate.

[Monkeh]

Yeah that's right. As I told you, they may think they speak Polish properly but may be they are not.

If it's their native language I should hope they can speak it properly.

Speaking English and translating into Polish is an entirely different business. Even speaking Polish and translating into Polish is an entirely different business. Speaking does not mean being able to translate.

If you can speak both languages fluently you should be pretty capable of translating between the two.

I do believe I've just hit your language barrier.

[Rick]

Sure you must think you are always right. I am doing this to earn my life (not from English) so may be I know something about it.
Even if you speak both languages fluently you cannot always translate from one to the other, ask any translator he will tell you.

[Monkeh]

Sure you must think you are always right. I am doing this to earn my life (not from English) so may be I know something about it.

No, I just think you're misinterpreting what I've said. And your English seems to confirm that. So, let's try again: If you can't speak English properly, what chance do you have of translating it into any other language?

Even if you speak both languages fluently you cannot always translate from one to the other, ask any translator he will tell you.

Perhaps not, but if you can't speak one of them properly, then you certainly can't translate from it!

[McMonster]

There's a relatively simple solution that yelds good results, peer review. I'll put my corrected version somewhere on the forum for the other people speaking Polish to give their opinions. Yes, I'm aware of the confidence problems in this area, but this way of thinking can ultimately lead only to abandoning any translations at all.

And from my experience translating to one's native language is much simpler, English has the advantage that it is so widely know and simple that a lot of people (especially working in technical fields, like me) can't even try to avoid it.

[EEVblog]

Someone from the Polish electronics forum http://www.elektroda.pl did the first translation.
They are talking about doing some others as well.
I'm happy to upload any attempted translations, but peer reviewed ones are always better of course.
You can't obtain better results than when nerds fight it out  %-B 

Dave.

[McMonster]

I once considered translating your videos more regularly as you post them, but this was more or less at the time when you started doing feature length electronics movies as your blog entries. But if someone helped me this could actually be a good idea.