Author Topic: Rossmann's repair videos. Using tons of liquid flux for no apparent reason?  (Read 51926 times)

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Offline fubar.gr

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After having watched some of Louis Rossmann's repair videos, it seems like he's adding tons of liquid flux on whatever part he's repairing as a mater of course.

See for example on this video:

From 8:30 to 15:00 he adds flux like 5 times on the same spot, all over the place, then again at 19:00 he adds more flux and reheats with the soldering iron what looks like a perfectly soldered part.


Is there some valid reason for going overboard with the application of flux?

Online kripton2035

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just subscribing ... ;)

Offline Deathwish

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Works for Louis, good enough. I think he's funny as hell and tells it like it really is.
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Offline helius

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Flux reduces oxidation on pins and pads and enables solder to flow onto them to make connections, and it also conducts heat. But when it has been heated for a long time, it dries out and doesn't work any more. If you are reworking a difficult component you may need multiple applications.
At 19:00 he uses the soldering iron to give the joints a proper fillet, which was not present from hot air placement. Like the narration says, "perfectionism".
 

Offline Kjelt

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Is there some valid reason for going overboard with the application of flux?
No looks to me he does not have a small enough applicator tip for the flux. Just a standard one you would use on THC's.
I have about 3 different flux bottles with all kinds of small tips, needles, and brushes.
The problem is flux usually flows as mad all over the place, so a very tiny drop is enough.
On the other hand, you have to clean it up anyway at least if you want it too look nice, so who cares.
 

Online mikeselectricstuff

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you can never have too much flux
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Offline KL27x

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^ I keep hearing this, and I take it to heart. But I don't like any of the noclean fluxes I have tried. They are great, until you actually ever want to clean the board. Add alcohol, and watch the transparent "polymer" residue turn into schegma. Most of the time I don't clean off the residue, and I still can't stand this.

This maybe the reason the only flux that is mil-spec is rosin flux?

I would really like to find a rosin flux like what Indium uses in their solder. They say it's a purified rosin flux. It leaves something like regular rosin flux residue, but with a lot of the yellow/brown color removed. I'm using regular liquid RA, and lots of it. My bevel tip is normally operating with a crust of brown flux residue around the sides.

Quote
then again at 19:00 he adds more flux and reheats with the soldering iron what looks like a perfectly soldered part.
He even says this is not necessary while he's doing it. And it might look the same. But I can see why he might have done it. He flowed flux core solder onto the pads with an iron, using up some of the flux. Then he reflowed with hot air. So the solder could be a little bit crusty, theoretically. If he were doing a leadless IC like that, he probably would have added more flux BEFORE reflowing. He might have felt like something was missing, after the fact. :)

FTR, I am definitely not a perfectionist. Most of my SMD joints would make you laugh. Straightness doesn't matter, and anything from a concave filet to a grossly spherical bead is fine, so long as it's shiny and obviously flowed to both the lead and the pad. IME, you don't need a perfectly controlled amount of solder to be able to see that.
« Last Edit: November 22, 2015, 09:01:16 pm by KL27x »
 

Offline Howardlong

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I have to hand it to him, you do get warts and all. I can't imagine working with him though, if I had that kind of running commentary in the lab throughout the day it'd drive me nuts. No surprise he comes from NYC!

As a recommendation, a decent tweezer iron and some component kits are supremely useful.

I use stripped wire wrap (Kynar) wire for the type of PCB hack he did: with the wire he used you really need to tin it first to ensure it's stripped to melt the insulation off, not a big deal but it's an extra step. The insulation also can be quite noxious, but it didn't stop me when I was younger, I made many thousands of connections on stripboard with that stuff. The wire wrap wire is also silver coated so there's no problem with it tinning immediately.

The connector looked like it was contaminated either with oxidisation or grease, but he's right that trying to solder one pin at a time is generally a waste of time: just one at each end to get the connector initially placed then drag solder it and get the wick out.

Regarding the amount of flux, it's cheap I guess!

One thing is true though, we all have our own ways of doing rework like this. Ask three different people, you'll get different answers. Many rework methods are quite individual.

The best thing his videos show is that as long as you have enough bravado confidence, you can fix anything in SMD, and for that he's to be applauded.
 

Offline EEVblog

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After having watched some of Louis Rossmann's repair videos, it seems like he's adding tons of liquid flux on whatever part he's repairing as a mater of course.

Yep, common technique.
 

Offline Rasz

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you can never have too much flux
this!

fubar.gr its normal to ask that question if you never used good flux :) you gain 2 levels of soldering skill with one drop of the good stuff, just like drugs :-DD. This is one of the well known secrets of working with smd, and why so many amateurs are scared of qfn and other small/weird packages.
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Offline Shock

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Re: Rossmann's repair videos. Using tons of liquid flux for no apparent reason?
« Reply #10 on: November 23, 2015, 04:53:12 am »
It's a bit deceiving under the microscope, what looks like a ton of flux may be the size of matchstick head. Of course if you haven't repaired anything before this all looks like rocket science.

But I personally can't stand nutjob banter in any form, I've met so many idiots talking BS before, now I just switch off when they open their mouth or start repeating themselves.
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Offline Kjelt

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Re: Rossmann's repair videos. Using tons of liquid flux for no apparent reason?
« Reply #11 on: November 23, 2015, 09:25:17 am »
you can never have too much flux
There is always a maximum,  come'on, you can not solder normally if you have a cm of flux on top of the component.
IMO the blogger uses an excessive amount of flux in this video due to the large application tip/needle he uses, half of what he uses would still be more then enough to get the job done properly.

 

Offline DimitriP

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Re: Rossmann's repair videos. Using tons of liquid flux for no apparent reason?
« Reply #12 on: November 23, 2015, 10:02:01 am »
Naahhh...too painful to watch. Neeeext
   If three 100  Ohm resistors are connected in parallel, and in series with a 200 Ohm resistor, how many resistors do you have? 
 

Offline senso

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Re: Rossmann's repair videos. Using tons of liquid flux for no apparent reason?
« Reply #13 on: November 23, 2015, 10:18:53 am »
It's a bit deceiving under the microscope, what looks like a ton of flux may be the size of matchstick head. Of course if you haven't repaired anything before this all looks like rocket science.

But I personally can't stand nutjob banter in any form, I've met so many idiots talking BS before, now I just switch off when they open their mouth or start repeating themselves.

You should really, really watch is videos about why reballing and BGA rework in general is the evil himself..
And then proceeds to charge 350$ to repair boards with used components pulled from dead boards that he says he buys by the pallet at 20$ a piece, some of his soldering is a bit awfull, but its a good bed time rant to start sleeping.
 

Offline Howardlong

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Re: Rossmann's repair videos. Using tons of liquid flux for no apparent reason?
« Reply #14 on: November 23, 2015, 02:37:37 pm »
And then proceeds to charge 350$ to repair boards with used components pulled from dead boards that he says he buys by the pallet at 20$ a piece

In monetary terms, and in terms of using salvaged parts, that's not dissimilar to taking a car into the repair shop to fix a ding. I may be living on a different planet, but I don't think $350 for a specialised repair such as this is that bad. I wonder how many times it is just a resistor or chip replacement and how often it ends up being something more. Plus he's warranting the repair. I am sure he has to maintain a reasonable stock of spares in stock too to provide a quick tunraround undoubtedly demanded by the locale, and I'm very sure the rent there ain't cheap.  I am sure he's saved the butts of many a clumsy hipster who's dumped their decaf skinny latte over their shiny $3k Macbook Pro!
 

Offline Shock

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Re: Rossmann's repair videos. Using tons of liquid flux for no apparent reason?
« Reply #15 on: November 23, 2015, 03:37:40 pm »
And then proceeds to charge 350$ to repair boards with used components pulled from dead boards that he says he buys by the pallet at 20$ a piece

In monetary terms, and in terms of using salvaged parts, that's not dissimilar to taking a car into the repair shop to fix a ding. I may be living on a different planet, but I don't think $350 for a specialised repair such as this is that bad.

Secondhand zero ohm resistor soldered to your cars body. Fixed!
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Offline bookaboo

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Re: Rossmann's repair videos. Using tons of liquid flux for no apparent reason?
« Reply #16 on: November 23, 2015, 04:04:58 pm »
It's a bit deceiving under the microscope, what looks like a ton of flux may be the size of matchstick head. Of course if you haven't repaired anything before this all looks like rocket science.

But I personally can't stand nutjob banter in any form, I've met so many idiots talking BS before, now I just switch off when they open their mouth or start repeating themselves.

You should really, really watch is videos about why reballing and BGA rework in general is the evil himself..
And then proceeds to charge 350$ to repair boards with used components pulled from dead boards that he says he buys by the pallet at 20$ a piece, some of his soldering is a bit awfull, but its a good bed time rant to start sleeping.

With repair work are within your right to charge what it's worth to the customer not what it cost you. Don't forget about the times you get sucked into a black hole time warp on a repair whereby the fix seems just round the corner but you spend 10 hours over what its worth, or better still when you fail completely and can only ask the customer a fraction of what you should for your time.

 

Offline Howardlong

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Re: Rossmann's repair videos. Using tons of liquid flux for no apparent reason?
« Reply #17 on: November 23, 2015, 05:28:56 pm »
And then proceeds to charge 350$ to repair boards with used components pulled from dead boards that he says he buys by the pallet at 20$ a piece

In monetary terms, and in terms of using salvaged parts, that's not dissimilar to taking a car into the repair shop to fix a ding. I may be living on a different planet, but I don't think $350 for a specialised repair such as this is that bad.

Secondhand zero ohm resistor soldered to your cars body. Fixed!

But it wasn't fixed with just a zero ohm resistor, there was a specific high density connector that you won't get in rat shack, you'll need a stock of those, along with all those other parts. The point is, you have to make an estimate based on what it might cost. How are you to know if it's a zero ohm resistor, a re-seat of a connector, or a board replacement without actually performing the repair? Admittedly a few you'll win real easy, but most probably not. And if it had just been a zero ohm resistor, I'd have darned well wanted to know why that zero ohm resistor failed in the first place. And if someone's already had a go on the board, you never know what you're going to be left with.

Plus, as I mentioned, there's the cost of rent and other fixed costs and overheads. If you've never run a business, it's all too easy just to look at BOM costs and nothing else. Offering a same day service like this is not going to be cheap. And then there's the cost of the flux of course ;-)
 

Offline Shock

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Re: Rossmann's repair videos. Using tons of liquid flux for no apparent reason?
« Reply #18 on: November 23, 2015, 06:11:06 pm »
Thread is getting a little ridiculous, bookaboo is charging me a days labor on some other customers repair and Howardlong is charging me for a special high density connector for a resistor.

I'm starting to think I should have repaired it myself.
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Offline Howardlong

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Re: Rossmann's repair videos. Using tons of liquid flux for no apparent reason?
« Reply #19 on: November 23, 2015, 07:31:34 pm »
Thread is getting a little ridiculous, bookaboo is charging me a days labor on some other customers repair and Howardlong is charging me for a special high density connector for a resistor.

I'm starting to think I should have repaired it myself.

 :-DD

Good call!
 

Offline Fat

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Re: Rossmann's repair videos. Using tons of liquid flux for no apparent reason?
« Reply #20 on: November 23, 2015, 08:58:54 pm »
Yeah, he uses a lot of flux. Most videos he notes that he put too much on, but he's working by the piece and speed is everything.  I can't imaging the NYC rent he has to pay. He will flux, solder and add more flux. Makes me crazy that he's not cleaning it off between steps.  He goes a mile a minute and likes to rant, but that makes it interesting to me.

He's also here on the forum, under another name which I can't recall.

Fat
 

Offline AF6LJ

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Re: Rossmann's repair videos. Using tons of liquid flux for no apparent reason?
« Reply #21 on: November 23, 2015, 09:43:24 pm »
Flux is your friend when working on already overheated small pads.

Like some of the better things in life rework sometimes needs to be messy.
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Offline JoeO

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Re: Rossmann's repair videos. Using tons of liquid flux for no apparent reason?
« Reply #22 on: November 23, 2015, 09:44:21 pm »
It's a bit deceiving under the microscope, what looks like a ton of flux may be the size of matchstick head. Of course if you haven't repaired anything before this all looks like rocket science.

But I personally can't stand nutjob banter in any form, I've met so many idiots talking BS before, now I just switch off when they open their mouth or start repeating themselves.

You should really, really watch is videos about why reballing and BGA rework in general is the evil himself..
And then proceeds to charge 350$ to repair boards with used components pulled from dead boards that he says he buys by the pallet at 20$ a piece, some of his soldering is a bit awfull, but its a good bed time rant to start sleeping.
No one is forcing customers to go to his shop. 
They can always buy new laptop or send it to apple to get it fixed for a lot more than he charges.
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Offline c4757p

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Re: Rossmann's repair videos. Using tons of liquid flux for no apparent reason?
« Reply #23 on: November 23, 2015, 10:21:37 pm »
Damn he sounds like an unpleasant prick. How can you people watch this? |O
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Offline Rasz

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Re: Rossmann's repair videos. Using tons of liquid flux for no apparent reason?
« Reply #24 on: November 23, 2015, 10:34:57 pm »
There is always a maximum,  come'on, you can not solder normally if you have a cm of flux on top of the component.

reductio ad absurdum

IMO the blogger uses an excessive amount of flux in this video due to the large application tip/needle he uses, half of what he uses would still be more then enough to get the job done properly.

do you even microscope bro? this is apple, when you see resistors in the picture they are most likely 0201  :palm:
plus cleaning will remove any residue anyway, so why bother spending extra time pipetting "just enough"?

c4757p why ad hominem? just because someone is not like your favorite dewdiepie?

edit: most critique to Louis repair videos comes from _non-practitioning_ theoretical EEs that just know better because they read somewhere all about 'best practices' :)
« Last Edit: November 23, 2015, 10:48:01 pm by Rasz »
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