Rework technique, pitting and killing pads. HELP! PLS.

[y_not]

I have been practicing my desoldering technique on old boards, I'm getting quite speedy at removing caps.
However, I'm facing some problems I need to resolve before I'm successful enough in my technique to safely move on to real boards for repair.

Firstly I'm using an 800F 1/8" chisel tip, which is a Weller PTC8.
I'm using MG Chemicals 835 RA Liquid Flux in a Bonkote Pen.
Kester 44 Rosin Core Solder 63/37.

I use the rocking method, 1st adding a little fresh solder to each joint. Without flux, some joints melt, some don't. So I just always flux them. On the second board I was fluxing them twice, once before adding solder and then again after. I didn't do this on the 1st board, just fluxed once. Just experimenting.

Here's the problem.
1st board was a 13 year old cheap pos GVC socket A board out of a Micron barebones system. I hate those things, so I made it my 1st victim. I mean guinea pig.
On this one I noticed pitting, like etching of the fiberglass layers of the PCB.
The tracks held up fine and the pads were mostly OK, with some spots where it pitted under the pad, slightly compromising it but not lifting or breaking it.

I had almost zero issues with the filter caps, I believe due to the large copper ground plane right on the surface. There was no detectable pitting there, but I haven't fully cleaned it yet. Waiting to take some pics before I do.
It has a very matte finish on the solder mask of the rest of the board with semi inconsistent color and a rather light, almost faded pigment in its green PCB coloring. It just looked really poorly made in that regard, not surprising. So I figured it just couldn't stand up to the heat.

Then I switched to an old, slightly newer, Intel manufactured P4 Skt478 845 chipset board out of an old Gateway. Beautiful, quality Intel solder mask. Quite shiny and a good, consistent green color. A quality PCB base that I have learned to recognize over the years. Something you'd see on a modern, high quality board.

Again, outside of the VRM area, this board was way, way worse!!
I literally annihilated nearly all pads of just about every cap I did. The VRM caps were fine and some 25mm-30mm caps.
Although I did get some green solder mask that stripped off of the copper around the VRMs.

The smallest caps were the worst, about 3mm dia. as they had clinched leads and not knowing what to do about that, I just worked them out. *squeak squeak*
These were very hard to get to melt, flux was a must. Not to mention I kept having to reposition the iron around each lead joint at 1st contact to find optimal thermal contact so it'd melt the solder. Again, I think it was the clinched leads that were my enemy here.

There was lots of pitting and very few pads survived intact, literally just a small crater left behind at the through hole. No sign of a pad. Lol
Total dwell time toward the end as I got better at it was probably about no more than 8-10sec.
Those were also damaged, so I can't imagine it was due to the tip being too large or hot. Then again, the caps were really small.

I didn't have any blackened areas, no blackening of the flux, but it did get a deep amber brown.

My 1st thought was that It's my flux being too active and eating the board. But then again it is supposed to be equivalent to the flux in the core of my Kester wire. Not to mention it seems others use it on PCBs successully.
I'm certainly not applying any pressure to speak of. Although I don't have a board holder and not sure what to do about that without spending big bucks.
Then I thought, well, maybe It's too much heat being applied. I could maybe see that with the tiny little caps on the Intel board, they got so hot I couldn't hold them and had to let them cool by moving to another cap. The big ones I don't get. As on the GVC board I tried the little PTA7 1/16" tip, total fail, not enough heat reserve and major pitting, worse than all of the other joints. Then I tried the next size up, the PTB7 3/32". NIGHT AND DAY difference!! But still not quite enough for the VRM caps, where the PTC8 tip really shined. Maybe on these old boards I should be using the PTB8 tip, which I haven't tried yet.

I just really don't know, I'm doing something wrong and without killing even more worthless boards to figure it out, which isn't so much a problem, but I only have so many, ya know? HAHA!
I figure I'll save myself any further torture and frustration, by asking you fine knowledgeable folks for your thoughts on the matter.


Thank you so much for all your help and the collective knowledge of this board!

Ps. Sorry for the long post, needed to describe the situation in as much detail as a could. So it'd make sense.

[y_not]

Re: Rework technique, pitting and killing pads. HELP! PLS.

Would photos help?

[momaka]

Re: Rework technique, pitting and killing pads. HELP! PLS.

First question that comes to mind is what soldering iron/station are you using and at what temperature setting (if it has any control)?

Other than that, I'm not sure what else to suggest as your techniques seem fine. Perhaps some pictures may help.

I've used the MG Chemicals 835 RA/RMA liquid flux too, and I think it's quite alright. I like Kingbo paste flux better, though. It stays active for much longer than the MG Chem. 835 liquid flux.

For solder, I usually use lead-free solder (95% Tin, 5% Antimony), but I don't recommend you do the same (I use it just because I found a big spool of it in our garage). The only thing I like about it is that it doesn't have a rosin core, so I have to add flux to the joints manually and this gives me more control over when and where I want the flux.

For temperature setting, I prefer to use around 320-350C for the caps around the CPU VRM and 300-320C for the other caps. Sometimes when I'm lazy to change settings, I just do it all at 350C and that's fine too. For soldering iron, I have one of those cheap Chinese digital soldering stations, but it uses cartridge tips with the heating element built-in the tip, so it has very good temperature control. Such a station is not necessary, but I find it very easy to use, though. The tip I'm using is 5 mm chisel shape.

One thing that may help you is to add lots of solder on the tip before removing the cap. Another thing I can suggest when using the "rocking"/"walking" method, especially for caps with clinched/bent leads, is to first push the cap towards the board (after heating the joint, of course) as if you are putting the cap in. As soon as you do that, then start pulling the cap out.

Ps. Sorry for the long post, needed to describe the situation in as much detail as a could. So it'd make sense.

Don't need to be sorry. I actually prefer long detailed posts like this.

[y_not]

Re: Rework technique, pitting and killing pads. HELP! PLS.

Sorry about that, thought it was a giveaway from the tips I was using. Silly me!
It's a Weller WTCPS magnastat station.
Its temp is controlled by the tip, regulated by a Curie magnet tuned to cut off at a particular temp threshold, thereby disengaging the magnetic heater switch, then re-engaging when the magnet cools.

As for tips, they're all in Fahrenheit, so in my post whatever I listed as the tip p/n, contains the size on the 3rd character and the 4th, last character, is a number which indicates the tip temp. Temps are 6, 7 and 8, for 600F, 700F & 800F respectively.
Mostly using the 800F tip.

The tip I primarily used is a 3.2mm chisel tip, they are all chisel tips. But It's measured as 1/8", being I'm a Yankee.
It's quite large and heats the joints rather quickly. 1-2sec maybe. It was recommended by Ratdude.
It sounds like you're using a Hakko knock-off of the new yellow and blue type stations.

Yeah, no lead free for me. Lol
The lead doesn't scare me.... it's safe to eat it right off the spool, right?
Yeeesss... cool!!! Someone who can finally confirm that this flux is OK and isn't super human, titanium cutting, laser eye STRONG! HAHA

Don't need to be sorry. I actually prefer long detailed posts like this.

Thank you so very much for your kind and sincere words. I'm a very precise and detailed person, with the gift of language and writing, which comes through in my posts, at least to an extent and sometimes gets me in trouble. Ie. People not wanting to read them, let alone respond to them. Sometimes I get scorned for my "books" I write. HAHA!
Thank you so much for taking the time to read and respond.

Ps. I'll try to set the time aside to take some pics. I love doing it, but I have been struggling with some health problems as of late. We geeks are kind of a messed up bunch, goes with the teritory.

[momaka]

Re: Rework technique, pitting and killing pads. HELP! PLS.

Sorry about that, thought it was a giveaway from the tips I was using. Silly me!

Strange, I did Google the tips, but didn't get a clue to what soldering station it was for. (Yeah, my researching skills suck ).

It's a Weller WTCPS magnastat station.
Its temp is controlled by the tip, regulated by a Curie magnet tuned to cut off at a particular temp threshold, thereby disengaging the magnetic heater switch, then re-engaging when the magnet cools.

As for tips, they're all in Fahrenheit, so in my post whatever I listed as the tip p/n, contains the size on the 3rd character and the 4th, last character, is a number which indicates the tip temp. Temps are 6, 7 and 8, for 600F, 700F & 800F respectively.
Mostly using the 800F tip.

800F is way too high. Probably the reason why you're burning the boards so much. Somewhere along the lines of 600F to 700F would be much better (ideally around 660F). But I have a feeling your tips won't have enough heat reserve at those temperatures. And given the mechanism of your soldering station, I think it is just too slow to respond to tip temperature changes. By the time the magnet cools down, the tip can become too cold.

Don't get me wrong, your Weller is a really nice soldering station in terms of quality and performance. But it just doesn't offer the same heat control of more modern temperature controlled soldering stations.

It sounds like you're using a Hakko knock-off of the new yellow and blue type stations.

No, but I've used one (a fake Hakko FX-951) at my friend's repair shop and they work very well. Almost as good as the real Hakkos, actually. The only difference is the built quality, which really is night-and-day difference. The fake ones use shoddy plastic for the cartridge tip holder and the tip tends to get loose very often. The solder joints on the boards inside those fake Hakkos are also really horrible. Probably why so many of them are DOA or die after a while. But because they use cartridge tips with built-in heating elements, they perform very well and have excellent heat control.

The station I'm using is a Circuit Specialists CSI-2900 soldering station (Aoyue 2900 clone). Uses the same cartridge tips with built-in heating element as the fake Hakko above. The built quality is a little better than the fake Hakkos, IMO. Regardless, it works great too.

The lead doesn't scare me....

Me neither. I have leaded solder as well, but I'm starting to run out - hence why I'm saving it only for "special occasions" .

Someone who can finally confirm that this flux is OK and isn't super human, titanium cutting, laser eye STRONG! HAHA

It has a really nice smell, though (IMO), so I don't mind when I breathe it in occasionally. I don't know if that's a good thing or not, however .

Thank you so very much for your kind and sincere words. I'm a very precise and detailed person, with the gift of language and writing, which comes through in my posts, at least to an extent and sometimes gets me in trouble. Ie. People not wanting to read them, let alone respond to them.

No problem, hope my posts can help.
...
I have a feeling I have the same gift/problem as well . To be honest, though... one of the reasons it took me so long to reply to your post was because I'm in the middle of doing some renovations right now, and every night when I get on BCN, I say to myself "let me read this person's post and answer their question", but when I see the big wall of text, I postpone it for a little later, then eventually get tired and never read/answer the post. This is the same reason why I don't post that much in general, anyways - I just need time to type my wall of text when I reply .

[y_not]

Re: Rework technique, pitting and killing pads. HELP! PLS.

Strange, I did Google the tips, but didn't get a clue to what soldering station it was for. (Yeah, my researching skills suck ).

Lol, I'll say!
You're too funny! HAHA :P

800F is way too high. Probably the reason why you're burning the boards so much.

I wondered as much. I was just following Ratdude's lead and a few others. Then again, we were talking about lead free rework, not leaded, which is what I started off with for testing. Oops! Also, even though Ratdude has the same iron design that I do, his doesn't have the reserve transformer since it isn't a station. Just the direct plugin to wall type.

Somewhere along the lines of 600F to 700F would be much better (ideally around 660F). But I have a feeling your tips won't have enough heat reserve at those temperatures. And given the mechanism of your soldering station, I think it is just too slow to respond to tip temperature changes. By the time the magnet cools down, the tip can become too cold.

I have a PTC7 tip, same as the one I'm using, just runs @ 700F. I haven't tried it yet, still in the package and honestly I can't wait to try it out, as that 800F tip is oooonnneee hiiiiggghhh maintenance puppy. Whooooiiiieeee!
Now I'm all hyper cause I wanna go try it out, but my shop is 100deg. Booooo!

I think people tend to underestimate these stations until they have used them and at least given them a fair run. They have a bucketload of heat output and they regulate it very fast and quite well.
Not to be confused with the performance of the seemingly identical looking digital temp controlled Weller stations, sans temp control knob on this one. They couldn't be more different and the performance to boot.
Thermal mass, heat reserve, as well as tip temp recovery time, far exceeds the new and improved Hakko FX888 station. Sure, this can't quite compete with the newest and latest designs, like yours, where the heater is in the tip, but they aren't supposed to, not at their price point. $200 vs. $800+??? YIKES!!

Don't get me wrong, your Weller is a really nice soldering station in terms of quality and performance. But it just doesn't offer the same heat control of more modern temperature controlled soldering stations.

That's exactly why I bought it. It's American made and It's built to last a lifetime. Not to mention it's actually affordable. How's about $70 sound for new old stock?
For hardcore smd work, no argument there, at least from what I have been told. No 1st hand experience though.
Do keep in mind that it is actually temperature controlled and regulated and is nothing like those cheap unregulated irons. The only difference between it and other ceramic barrel heater, temp controlled irons is that there's no knob to adjust as the tip you use determines the temp. The only bad thing is if you need to change the tip mid job, you have to hot swap the tip, which really isn't too bad. But is that not so different from having to change tip types, or size, mid job on a digitally controlled station?
Plus, being that it isn't digitally regulated, there's no calibration to be performed. I saw that as a plus for someone like myself who just wants to do this for fun and for the experience.

No, but I've used one (a fake Hakko FX-951) at my friend's repair shop and they work very well. Almost as good as the real Hakkos, actually. The only difference is the built quality, which really is night-and-day difference. The fake ones use shoddy plastic for the cartridge tip holder and the tip tends to get loose very often. The solder joints on the boards inside those fake Hakkos are also really horrible. Probably why so many of them are DOA or die after a while. But because they use cartridge tips with built-in heating elements, they perform very well and have excellent heat control.

Well that doesn't sound like fun and definitely just the thing I wanted to avoid in my choice of tool. Everything I read said the Aoyue made knock offs were hit and miss in reliability, build quality, etc..
I just don't understand why the Chinese can't put just a little more pride into their work... baffles me to no end.

The station I'm using is a Circuit Specialists CSI-2900 soldering station (Aoyue 2900 clone). Uses the same cartridge tips with built-in heating element as the fake Hakko above. The built quality is a little better than the fake Hakkos, IMO. Regardless, it works great too.

That's AWESOME it works so well. I know there are some good non-namebrand units out there, it's just that my fear has always been that I'll get stuck with some POJ and I'm too honest of a guy to unload it on someone else without full disclosure and thus less money, thus a loss.

I'm cornfuzzled! You said yours isn't a Hakko knock off, but it uses the same tips and isn't made by Hakko, so doesn't that make it a knock off?
Or was it that when you replied and said: "no, you weren't using a Hakko knock off", that you were just simply differentiating between the really badly made Aoyue units that I was likely referring to, which I was, and the unit you have?

Me neither. I have leaded solder as well, but I'm starting to run out - hence why I'm saving it only for "special occasions"

Aaah, OK. Yeah, why be afraid of it? Even baking soda can be dangerous, everything can if you aren't smart with it. But you know, there's still lots of it avail for purchase, especially here in the US?

It has a really nice smell, though (IMO), so I don't mind when I breathe it in occasionally. I don't know if that's a good thing or not, however .

Oooohhh, aaaahhhh, yuuuummm! Tell me about it, yeah, it does. It smells downright tasty! Who knows, I might run out early. Flux cocktails anyone?

No problem, hope my posts can help.
...
I have a feeling I have the same gift/problem as well . To be honest, though... one of the reasons it took me so long to reply to your post was because I'm in the middle of doing some renovations right now, and every night when I get on BCN, I say to myself "let me read this person's post and answer their question", but when I see the big wall of text, I postpone it for a little later, then eventually get tired and never read/answer the post. This is the same reason why I don't post that much in general, anyways - I just need time to type my wall of text when I reply .

Oh yes, they have been a great help. Thank you for taking the time to stop and help. I know how valuable and important time is to each one of us.
Wow! Gee, sounds like I have that same problem. I eat up so much time on my various forums with my various interests, it can be downright overwhelming. The OCD can really eat you up if you let it. Sometimes I just can't spend the time to read things and respond, I have to stop myself, because I know that in order to do a thorough job, it'll take a while.
So some days/nights, I just don't even go into my forums, saves me the agony of being eaten alive by it. Not that I don't enjoy it, it's just the struggle of it interfering with other responsibilities, such as sleep and work for one. DRAT!
I'd have so much more time if I didn't need sleep. Lols

What are you remodeling can I ask? I'm currently working on leveling a 15' diameter patch of dirt for my temporary pool. I would have just put it up the same as last year, but the dirt had settled and the rocks were poking through because of my lack of sand. So doing it right this year, getting SOOOO hot though!!

Ttyl,
Thanks so much!
Tony.

[momaka]

Re: Rework technique, pitting and killing pads. HELP! PLS.

I have a PTC7 tip, same as the one I'm using, just runs @ 700F. I haven't tried it yet, still in the package and honestly I can't wait to try it out, as that 800F tip is oooonnneee hiiiiggghhh maintenance puppy. Whooooiiiieeee!

Yeah, with the temperature that high, tips tend to degrade real fast. One reason why I try to stay under 600F. Only motherboards with thick ground/Vcc planes around the CPU need higher temps. But even then, I don't think I went much higher than around 650F

Now I'm all hyper cause I wanna go try it out, but my shop is 100deg. Booooo!

Great! Just 500F more and you'll be able to recap boards without an iron
My friend's old shop used to be like that too. Usually hung in the upper 80s and 90s. Everyone hated it in the summer except for me - I love the summer heat!

I think people tend to underestimate these stations until they have used them and at least given them a fair run. They have a bucketload of heat output and they regulate it very fast and quite well.
Not to be confused with the performance of the seemingly identical looking digital temp controlled Weller stations, sans temp control knob on this one. They couldn't be more different and the performance to boot.

In that case, then it's probably the tip that is too hot.

Sure, this can't quite compete with the newest and latest designs, like yours, where the heater is in the tip, but they aren't supposed to, not at their price point. $200 vs. $800+??? YIKES!!

$800+??? My station is $60 at Circuit Specialists . The tips are more expensive, though - around $12 a pop (even the Chinese ones), but it's worth it IMO because they are tougher than the exposed heating element ones. Before I got my station, it used to be in my friend's shop, and sometimes people forgot it there fully turned on for days in a row, with the tip left at 350C .

I've also used this station as well:
http://www.jbctools.com/cd-b-solderi...5-gama-10.html
Now this is a dream-come-true station. That thing is so nice that I could probably solder even with my feet if I wanted to. Of course, it's quite pricey (around $500, I think), but worth every single penny if you want super-accurate heat control and excellent reliability.

For hardcore smd work, no argument there, at least from what I have been told. No 1st hand experience though.

The Chinese stations are okay for sodering/desoldering small SMD components, but tend to suck a little for doing BGA pad clean-up. For that, the JBC above makes a night-and-day difference.

The only bad thing is if you need to change the tip mid job, you have to hot swap the tip, which really isn't too bad. But is that not so different from having to change tip types, or size, mid job on a digitally controlled station?

Yeah, it's more or less the same. The cheap stations that don't use the cartridge tips with built-in heating elements are the worst, though, because there really is no easy way to change the tip when it's hot. Not to mention that there's a high chance of breaking the heating element since it becomes exposed. With mine, it's easier - just pull the tip with a silicone pad and put the new one on. I'm sure yours is designed well too, so you don't have that problem.

Plus, being that it isn't digitally regulated, there's no calibration to be performed. I saw that as a plus for someone like myself who just wants to do this for fun and for the experience.

Yeah, it's a simpler mechanism, so it's much more reliable.

Well that doesn't sound like fun and definitely just the thing I wanted to avoid in my choice of tool. Everything I read said the Aoyue made knock offs were hit and miss in reliability, build quality, etc..
I just don't understand why the Chinese can't put just a little more pride into their work... baffles me to no end.

I don't blame them. You can't pay someone $1 per day (or even less sometimes!) and expect them to turn out pro-quality work.

My station is quite shoddy too. The tip holder, for example, is extremely loose and sometimes the tip looses power (followed by annoying beeping from the station to warm me of that). But the built-in heating element is all that makes it worthwhile.
Surprisingly, my station does have a huge transformer in it, unlike the cheap Hakko knock-offs. Hence why I still think it hasn't burned out.

I'm cornfuzzled! You said yours isn't a Hakko knock off, but it uses the same tips and isn't made by Hakko, so doesn't that make it a knock off?

lol
With my station, the Chinese simply "designed" it around the tips that the genuine Hakko uses. As for the station itself, it's made by Aoyue (and rebadged by Circuit Specialists), but it doesn't look like a Hakko, so it's not really a Hakko knock off (did I make your head spin now? ). The exterior design is rather... primitive. But I like it - it's simple to use.

Oooohhh, aaaahhhh, yuuuummm! Tell me about it, yeah, it does. It smells downright tasty!

No really, doesn't your smell like pine trees? Mine does, and everytime I solder with that flux, I feel as if I'm walking in a pine forest... Or have I been breathing the fumes for too long now?

Sometimes I just can't spend the time to read things and respond, I have to stop myself, because I know that in order to do a thorough job, it'll take a while.
So some days/nights, I just don't even go into my forums, saves me the agony of being eaten alive by it. Not that I don't enjoy it, it's just the struggle of it interfering with other responsibilities, such as sleep and work for one. DRAT!
I'd have so much more time if I didn't need sleep. Lols

Yeah, that's how I feel too.

What are you remodeling can I ask?

Bathroom...
changing the shower faucets, shower tiles, floor, sink, sink cabinet, and sink faucet. The Throne will remain unchanged, though