General > General Technical Chat

Missing items to buy for my soldering kit

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Cubdriver:
I first started getting Digi Key catalogs when I began playing with electronics in the mid-late 70s.  Back then they were the size of a very thin magazine.  The last printed catalog I received was thicker than a phone book.  Mouser has been around just as long.  Both are very reputable vendors, I've been using them off and on for 40+ years, and used them almost exclusively for both work and hobby purchases for the past 25 years.

Just order a roll of 63/37 Kester 44 from one of them and be done with it.

-Pat

EPAIII:
I have no desire to get into a big, long argument over this. I thought the purpose of this thread was to help the OP who asked a question and I was offering what I had.

You have your techniques and I have mine. You have your experience and I have mine. I do not want to dispute that yours work for you. And I certainly do not want to tell you that there is only one way of doing something and you are not doing it right. Can't you grant me the same? And let the OP and others who read this pick and choose and experiment with one, the other, or some combination of both. Or other ideas posted here. Who knows, they may actually find something that works better than any advise posted here. And then he/they can share it with all of us. There's more than one way to build a mouse trap.

I have learned things from this thread. I have learned a great amount from this board and from others I have participated on. I hope you have too. 




--- Quote from: tooki on August 22, 2022, 10:09:47 am ---
--- Quote from: EPAIII on August 22, 2022, 09:32:29 am ---Well, I guess I have been put in my place. Nothing there that anyone could ever argue with. NOTHING at all!

--- End quote ---
Or you could try to learn something… Or if you think I’m actually wrong, explain your position.

--- End quote ---

Boris_yo:
I will be using this solder and solder flux paste from China which according to AndyBeez is used for a single part repair but I will use it for removing through-hole soldered mouse switches.

EPAIII:
Well, others here may jump on my opinion again, but for the most part I see no reason for using flux when removing or unsoldering parts. You just heat the joint, if it is a through-hole component you use either vacuum or solder wick to remove as much of the old solder as you can, and then you remove the part.

Flux is a cleaning agent which is used to remove any oxidation or other undesirable chemical which is on the surface of the parts and which would prevent the solder from attaching to that surface. Sometimes the old solder will not melt when the iron is brought into contact. In those cases applying a small amount of rosin core solder between the iron and the old solder will allow the rosin flux to clean the old solder and the small drop of fresh solder will provide a good path for the heat transfer. All of this should only take two to three seconds. If heat has been applied for over five seconds, STOP and look for the reason why. Just applying heat to a PCB will eventually cause the foil to de-laminate from the board and you will have a bigger repair job than you started with.

On the idea of cleaning the soldering iron tip with a dip into a paste style flux, perhaps I did not give enough detail. I find that I can run on and on so I try to keep my posts as short as possible. What I do is first dip the hot iron in the flux for a few seconds (2-5 seconds). Then I will finish cleaning it by using one of the pads of metal ribbons that are sold for this purpose. Those pads are like the scouring pads used to clean pots and pans but with larger sized brass ribbons.

https://www.mouser.com/ProductDetail/Weller/T0051384099?qs=sGAEpiMZZMtyU1cDF2RqUH2NFvQyI8sgys%252BG5vvqc0M%3D

This, plus the heat of the iron does a very nice job of cleaning the iron's tip. Then a small amount of rosin core solder is applied and it immediately wets to the tip, covering it so it is ready for use. I do this immediately before I am going to use the iron/tip. But I only do it once in a work session, if that much: I do it only when it is needed.




--- Quote from: Boris_yo on November 10, 2022, 02:06:47 pm ---I will be using this solder and solder flux paste from China which according to AndyBeez is used for a single part repair but I will use it for removing through-hole soldered mouse switches.

--- End quote ---

EPAIII:
You keep harping on my improper technique. I would like to see a video of just how you remove a 16 pin DIP IC from a plated hole PCB by use of the pin wiggling technique. NO EDITS, of course! 

Personally, when doing that I prefer to use the large size solder sucker tool to quickly remove most of the solder AND THEN heat each pad (only the pad, not the pin) for a few seconds while using a small screwdriver or other tool to move the pin toward the center of the hole. Remove the heat and let it cool before taking the screwdriver away. That breaks any small amount of solder film left behind.

The vacuum iron leaves no place for any other tools to wiggle the pin. If you try to wiggle the pin with the vacuum iron, because of the lower vacuum pressure you wind up with a much larger amount of residual solder bridging from the pin to the side of the hole and when you remove the iron, the pin just snaps back to the side of the hole just before the molten solder freezes. Then you need to add more solder and try again. But then, of course, I am doing it wrong. So I want to see that video. NO EDITS! OLD IC with OLD SOLDER on plated holes and complete removal with no broken pins or lifted foil. Show me, please.

I think it would be interesting if we both were working in the same shop on the same type of boards. And we kept track of how long repairs took and how many boards needed repairs on the foil during our use of these techniques.

On that Pace video, it is a good video. But I noticed one thing when they were demonstrating de-soldering the DIP style ICs. While most DIP ICs have the pins angled to the outside, probably so they do not fall off the boards while the boards are being populated and moved around the factory to the wave soldering machine, the pins on the ICs in the film were straight down the middle of the holes. They only touched the plated holes at one or two small areas on their thin dimension. That would be on the component side of the board, just where they enter the holes. Two almost microscopic areas of contact. It is no wonder that the solder was completely removed with the suction. Unfortunately most, dare I say all of the ICs that I have had to remove had their pins angled to the outside so their flat side was in contact with the hole at the foil side of the board. That produced a much larger area where residual solder could remain. And DID remain. I call FOWL on that video!

PS: I did not deliberately try to misquote you. I guess I assumed that in today's world if you are having trouble with de-soldering components, they they are in plated holes. Non plated holes do make the job a lot easier. I believe we can agree on at least that.




--- Quote from: tooki on August 21, 2022, 05:46:37 pm ---
--- Quote from: EPAIII on August 21, 2022, 06:15:18 am ---I haven’t used a real one, or don’t know how to use it?

I have used, well TRIED to use, a Hakko, which I understood is a respected brand.

--- End quote ---
Hakko is a real one, so I'm gonna go with "don't know how to use it". Bear in mind that correct technique is required and isn't necessarily obvious, and takes practice to get right. Desoldering is also just plain a more fickle process, and part of doing it right is recognizing right away that additional help is needed, such as supplemental heat.



--- Quote from: EPAIII on August 21, 2022, 06:15:18 am ---Perhaps it's not. But I found that I spent far more time clearing if of bits of extracted solder than actually removing solder with it. And, no matter how I used it, there was always some residual solder after the extraction.

--- End quote ---
There's no question that desoldering irons are needy little divas that demand careful ongoing care and maintenance. But treated well, they perform very well.


--- Quote from: EPAIII on August 21, 2022, 06:15:18 am ---I did not observe any greater volume of air being sucked in when I triggered it and after a second or two of suction the tip would cool to the point where the solder solidified and would not melt again until the vacuum was turned off. I did try wiggling the part for that second or two but that did not improve the removal by much.

--- End quote ---
Then the technique wasn't right. When done properly, the joint is completely molten before suction is applied. You start moving the pin, when it's completely loose (indicating complete melt) you trigger the vacuum, and the initial rush is what sucks away all the solder. Then you keep moving for a second or two for the cool air to cool the joint down, preventing readhesion. Compared to not moving the pin around, it should be a dramatic difference: with movement, the pin should be completely free, and the component should just fall out when all the pins are done.


--- Quote from: EPAIII on August 21, 2022, 06:15:18 am ---Perhaps the Pace is better. I don't know as I have not used one. If it works for you, then by all means, stick to it with my blessing.

--- End quote ---
I haven't used a ton of desoldering system brands myself yet: Weller, Pace, Den-On and Ersa. Of those, the Pace and Den-On have performed the best.


--- Quote from: EPAIII on August 21, 2022, 06:15:18 am ---Anyway, our OP is interested in inexpensive methods. I rather doubt that he will buy either a Pace or a Hakko or any other de-soldering station in that price range. A really good, high end, piston style solder sucker costs around $20. I have been using this brand for over 50 years and they are, IMHO, the best.

--- End quote ---
Agreed. I just think it's important to understand the limitations of solder suckers on plated through-holes, which nowadays are nearly universal. Non-plated through hole is easy. Plated is not.

I agree that the Edsyn solder suckers are the best. Though I also have had good results with my tiny Engineer one, which performs better than expected because the silicone tip, which can form a much better seal around the pin, prevents most of the suction going to waste, so to speak.


--- Quote from: EPAIII on August 21, 2022, 06:15:18 am ---"Continuous vacuum is really the only reliable, halfway gentle way to desolder through-hole components...".

--- End quote ---
You snipped off the most important part of that sentence, which makes me think you didn't take note of it: I said "Continuous vacuum is really the only reliable, halfway gentle way to desolder through-hole components from plated through-holes." Emphasis on the "plated". On non-plated holes, where you have a pad one one or both sides, but the hole itself has no copper cladding, a solder sucker works well. But on plated holes, after using a solder sucker, it's almost inevitable to have a tiny meniscus of solder keeping the pin adhered to the side of the hole. Unless the pin was perfectly centered in the hole when it was soldered, and the solder sucker is able to overcome residual capillary action, you will still end up with a solder bridge to the pin. And if the pin is snug against one side of the hole wall, which is very common, then it's going to remain adhered.

The motion of proper continuous-vacuum desoldering ensures the pin can't remain adhered.


--- Quote from: EPAIII on August 21, 2022, 06:15:18 am ---This requires a longer time that the plated hole is subjected to the high temperature.

--- End quote ---
Slightly. But it ensures you're not later fighting an only partly-desoldered pin. And we're still only talking seconds. If a joint refuses to budge within 3 seconds, you abort, regroup, and first ensure you had proper thermal contact (people are AWFUL about forgetting to tin their desoldering iron tips!) and figure out how to add supplementary heat, like hot air, a preheater, or a soldering iron from the other side, so that you can then achieve a full melt within a few seconds.


--- Quote from: EPAIII on August 21, 2022, 06:15:18 am ---I have seen PCBs where that heat for a longer time is almost a complete guarantee that the foil will be lifted from the board. Were they a poor PCB?
--- End quote ---
That can happen with top-quality boards if they're overheated or if pressure is applied while at soldering temperatures. Again, proper technique...


--- Quote from: EPAIII on August 21, 2022, 06:15:18 am ---Of course they were. But they were made by a major manufacturer and had to be repaired so there was no choice. The heat and fast suck of a piston style solder sucker was the way to go to prevent that damage.

--- End quote ---
Proper technique, man... no matter which tool you use, you have to use proper technique. You can mess up a board with a desoldering iron, and you can mess up a board when desoldering with a solder sucker. (In the former, by applying heat for too long, or applying pressure while hot. In the latter, by applying force to the board after the sucker fails to completely free a pin. I've seen both.)

In summary, your reply really leads me to believe you don't know proper technique for a desoldering iron. (You are not alone in this.)

Watch this ancient, but extremely informative video from Pace. All of it is useful, but Part 5 (17:00-22:22) is the key method: [url]https://youtu.be/IqE1KA0OAnM?t=1022[/url]

--- End quote ---

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