Missing items to buy for my soldering kit

[Boris_yo]

Hi. I made a photo of what I have for soldering. My locals told me that since I ordered from Aliexpress both soldering wick and solder wire lack flux. They said that they learned that stuff like this ordered from China lacks flux. It is mentioned 2.0% Flux on my soldering wire so I don't know but solder wick mentions no flux which defeats its purpose due to lack of capillary action.

I guess that lack of flux makes solder harder to adhere and affects conductivity as well. When I attempted to solder a wire the solder just didn't stay properly and after slight nudge of wire the solder came off.

Another thing they told me is that soldering tip became oxidized because I didn't apply solder in the process and didn't clean after working with it. They were right. They said I should buy a thick solder wire 1.0mm with flux rosin and apply on soldering tip.

I later learned about solder tinner which for dipping of soldering tip. It seems like a better option than applying solder wire every few minutes on soldering tip to prevent oxidation. In this case should I buy it in addition to soldering wire? I just don't know how to apply soldering wire on tip that I have. It's just small and not flat that solder can stay on. It will just fall down from the tip.

Another thing is, flux is also sold separately. I saw one in a mini-can where you dip soldering tip and another one is sold in syringe that you drop on a joint where you want to solder. Do I really need to buy soldering wire if I already have one (without flux/rosin) and just buy flux in a mini-can? Can I dip soldering wire in it and solder?

There is soldering paste sold as well. I am soldering very rarely when I need to fix small stuff. I need minimum items to do the job. What would you recommend me? Since I have only 1 soldering tip, should I buy a set of solder tips? I think working with a flat tip is easier to keep solder from dropping. Thank you.

[nvmR]

Hey Boris,

I would recommend that you get a soldering iron with adjustable temperature, for example this one:
https://www.aliexpress.com/item/32434361333.html
and along with that several tips and a cleaning wire, for example:
https://www.aliexpress.com/item/32969829786.html

I am working with quality solder from Kester, purchased on amazon, which is leaded and contains flux.
Go over Dave's tutorial on soldering, and make sure to try to apply the solder to the target and not to the iron. Apply solder to both surfaces individually, and then just heat them up together to connect.

Happy soldering

[Boris_yo]

Hey Boris,

I would recommend that you get a soldering iron with adjustable temperature, for example this one:
https://www.aliexpress.com/item/32434361333.html
and along with that several tips and a cleaning wire, for example:
https://www.aliexpress.com/item/32969829786.html

Hello

I saw solder wire on reels and I saw twisted solder wire in tubes. Is there any difference other than form in which they are contained? Is it a matter of personal preference?

Which soldering wire would be your preference from this screenshot?

I remember how someone had to drip liquid flux on microchip and use heater to detach it for replacement. Is this flux in a bottle also used for other purposes that I would find need for?

[AndyBeez]

Not sure there is such a thing as Tin-Palladium solder?
Any tin-lead solder on a reel is economic - small tubes cost more per meter. 1mm multicore is a good general purpose solder. For SMD working, 0.5mm is recommended.

Understand solder paste has a shelf life, which is why some people keep their paste in the fridge. Unless you are going to use paste in the next 12 months, don't buy. A bottle of liquid flux is very usefull - liquid flux improves the performance of solder braid.

If you're serious about your hobby, (you must) invest in a temperature controlled solder station - with a set of shaped bits. Some stations have hot air guns too. Like this...

[Cubdriver]

The difference between reels and tubes for a given solder is just quantity.  As for type, I’d strongly recommend going with a known, established brand like Kester or Multicore.  My go-to is Kester 44 in 63-37.  I’ve heard too many tales of sketchy solders from China and simply don’t trust it.  This is more often than not a 'you get what you pay for' area, and worth splurging a bit.  Bad solder or flux will be endlessly frustrating.

Regarding irons, I’m less up to speed on current offerings, though I hear a lot of talk about the KSGER T12; it seems to be popular.  A temperature regulated iron is much easier to use, and typically safer for what you’re using it on.

-Pat

[EPAIII]

Boy, where to start? OK, first I have never purchased anything from Aliexpress and probably never will.

If you want to save money, buy name brands from good suppliers. None of the items in your photo are saving you any money. They are costing you more both in currency and in time.

The soldering iron shown looks like a real cheap one. Perhaps it can be used if the user has enough skill to know how to use it. I have been soldering, both as a hobbyist and as a professional, for over 60 years and can tell you that I would have trouble using that iron.

The tip in your photo is hard to see clearly. IMHO, the best tips are plated. The bare copper tips are both harder to use and the copper will slowly dissolve in the solder making a replacement needed. The plated tips last for many years - I even have some that are many decades old and still working just fine.

The flux is noticeable by it's absence. GET SOME! It is not optional. And a tin of rosin flux will last for many, many years.

From what I can see of the solder I am not impressed. For electronic work solders have a core of rosin flux. This usually brings a sufficient amount of flux to the point of use. The best ones have multiple flux cores, usually five.

Solder wick is not my first choice for removing old solder. I prefer the solder suckers. They are better than the wick or the vacuum pumps connected to the hollow tip of the iron. Why? Because the solder suckers apply a sudden and intense vacuum which removes the melted solder quickly. Vacuum pumps apply the vacuum over a longer period of time: sometimes that works and sometimes not. And solder wick depends on capillary action. But so do most solder joints so it is a tug-o-war between the solder wick and the joint you are trying to remove the solder from. Most of the time it winds up being a tie with some solder left in the joint. Then you need to wiggle the wires or connection to try to break that remaining connection. The solder sucker removes almost all the solder with one quick stroke.

Your difficulties with the solder not sticking to either the iron tip or the joint are caused by a combination of the solder you are using and technique. GET A NAME BRAND OF SOLDER, like Kester. And get a soldering iron which used plated tips. Temperature controlled irons are best and can be purchased for under $50. I have a Weller WTCP that is around 45 years old and still going strong. It has no controls as the temperature is selected by the tip in use. They are popular in many shops as the techs can not just crank up the temperature at will. A few years ago I purchased a second one for a second bench in my office. It is a digitally controlled, Tenma model and seems to work as well as the Weller. It also has interchangeable tips.

Use: The age old advice for soldering is to clean the joint, apply flux, heat the joint, and finally apply the solder which should run into the joint immediately when it is applied. That is good advise. BUT, it seems to assume that a torch of one sort or another will be used. For electronic work I have found that heating the joint with a soldering iron can be problematic. A typical joint between a PCB and a wire or pad on a surface mount component can be hard to heat at the same time. One will get hot and the other not so much. So solder may flow, but you do not get adhesion to both surfaces. That means a bad joint. So how is this done quickly and reliably?

First, the tip of the iron MUST be tinned. This means that the tip must be clean. And then flux is applied to the tip. And finally solder is applied to the tip. With a plated tip, at that point the solder will quickly melt and wet the surface of the tip. A reasonably sized drop of solder will not fall off the tip: it will cling to it, even if you try to flick it off with moderate force. If you are using a bare copper tip, getting this adhesion of the melted solder may be more problematic. Added flux can help as using a small brass brush to "work it in". In either case, the tip MUST be properly tinned before attempting to solder anything with it.

Next, even with a properly tinned tip, it can be difficult to transfer enough heat to both sides of a joint at the same time. A bit of flux on the joint can help. But the biggest help I have found is to have a small drop of solder on the tip of the iron. This solder will start to wet to both sides of the joint and this metal-to-metal-to-metal contact will transfer the heat quickly.

So the modified procedure that works best for electronic soldering is clean the joint, flux the joint (often skipped), APPLY A SMALL DROP OF SOLDER TO THE IRON TIP, touch iron to the joint, and finally add solder to the joint. Some may argue with this, but it is the best sequence that I have found.

The flux on the joint is often skipped because electronic parts usually have tin or solder plating already on them. So the base metal below that plating does not need to be cleaned with the flux. And even if it is a bit dirty, the flux in the solder is often enough to clean it. But applying some does no harm and I suggest that a beginner do so.

Surface mount parts are another story. While the larger ones can be soldered with careful use of the above techniques, as they get smaller other techniques are needed. I suggest you start with more traditional solder connections and leave surface mount components for another day. There are a lot of videos available that illustrate different techniques for them.

[EPAIII]

You ask about using the solder you already have and dipping it in the flux. Dipping in a liquid flux will not get enough on the solder to do any good. Soldering paste, which is my first choice, will not stick to the outside of the wire well so, again, probably not a good option.

If you are determined to do it the hard way I suggest applying a small amount of a paste flux to the JOINT, not to the wire.

And the iron tip can be dipped in the paste type flux. I do that often to clean it. In my decades of soldering I have never even had any liquid flux for electronic soldering. If I did use it I would want one of those needle style bottles to apply small drops. And be sure it is a liquid flux intended for electronic work. Acid flux should never be used for electronic or electrical work.

[AndyBeez]

FYI liquid solder flux comes in syringes as a semi paste and in bottles with a paint on brush as a true liquid. See attached. Generally, the paste is used for detailed single part repair with a soldering iron. The fluid is used for flooding areas such as IC pins when using hot air.

Desolder braid never has enough flux; add a small amount of either type to the braid to make it 'pull' solder away faster.

And if all else fails, a tin of Rosin Flux will last ages

Solder tips come in a range of styles, with each specific for a type of solder weld. I have never used a point tip as the heat leaches away from the end too fast. Any flat tip is more efficient. In soldering, the 'thermal mass' of the tip is muy importante.

As for lead free solder, this requires high iron temperatures (300+), which can erode cheap soldering iron tips in minutes! Beware.

( Disclosure: I have used all of the pictured fluxes with good results )

[Boris_yo]

The tip in your photo is hard to see clearly. IMHO, the best tips are plated. The bare copper tips are both harder to use and the copper will slowly dissolve in the solder making a replacement needed. The plated tips last for many years - I even have some that are many decades old and still working just fine.

Thanks for soldering advice.

I have attached a close-up photo of solder tip. Do you think it is plated?

And the iron tip can be dipped in the paste type flux. I do that often to clean it. In my decades of soldering I have never even had any liquid flux for electronic soldering. If I did use it I would want one of those needle style bottles to apply small drops.

Paste type flux like this one or you meant tip tinner in a tin? AndyBeez posted above rosin flux in a tin which I think is similar to this one that I posted now.

[Boris_yo]

FYI liquid solder flux comes in syringes as a semi paste and in bottles with a paint on brush as a true liquid. See attached. Generally, the paste is used for detailed single part repair with a soldering iron. The fluid is used for flooding areas such as IC pins when using hot air.

Desolder braid never has enough flux; add a small amount of either type to the braid to make it 'pull' solder away faster.

And if all else fails, a tin of Rosin Flux will last ages

So liquid flux and rosin flux in a tin can are different fluxes? I can't use rosin flux in a tin can on a chip that I want to disassemble using heat gun?

Can I clean soldering tip in rosin flux that is in a tin can instead of in tip tinner in a tin can?

[AndyBeez]

It's all Rosin (tree resin) just at different purities with various solvents to make it more or less solid-thru-liquid. Pure rosin is crystaline, liquid fluxes are a lot of IPA. Hence liquid fluxes boil off their solvents very quickly - which means you need to work fast. Gel(atine) fluxes have a longer workability time but, can leave a mess to clean off.

So... also add a small bottle of isopropyl alcohol to your soldering kit for cleaning both pre and post soldering.

[Ian.M]

Unfortunately flux is no longer all pine Rosin.  A lot still is, or is synthetic rosin equivalent or modified purified rosin based, but you'll also encounter synthetic resin based flux that cant be fully removed by the solvents commonly used for rosin fluxes, and so-called water washable fluxes, either modified rosin (pre-saponified?) or low VOC organic acid based.   The water washable fluxes (and other organic acid fluxes intended for electronics) are fine for production use but are totally unsuitable for repair workshop, development lab, or DIY use as no one who's not in the PCB assembly business has the high pressure near-boiling water jet board wash machines required to get their residue out from under ICs and off the board properly and any trace residue of acidic fluxes is a circuit-destroying corrosion time-bomb! 

The trouble with liquid fluxes if you are in a hurry is the solvent boiling driving the flux away from the joint.  However with a little more patience, you apply the flux and let it dry some and thicken up before you start soldering.  It doesn't take long (seconds or minutes at most) for a thin film of liquid flux to dry till its tacky to the touch, at which point it stays where you need it when you apply heat.  The solvent does *NOT* help the fluxing action as its all evaporated and gone by the time the joint reaches the melting point of solder.

Beware of any mineral acid or chloride containing fluxes. Their application is plumbing and sheet metal work, never electronic and electrical assembly as even slight traces of their residue will quickly rot wires, tracks and component leads.   Many paste fluxes in tins are this type and unsuitable for electronics.

Edit: clarifying types of acid flux

[tooki]

Solder wick is not my first choice for removing old solder. I prefer the solder suckers. They are better than the wick or the vacuum pumps connected to the hollow tip of the iron. Why? Because the solder suckers apply a sudden and intense vacuum which removes the melted solder quickly. Vacuum pumps apply the vacuum over a longer period of time: sometimes that works and sometimes not. And solder wick depends on capillary action.

If you think a solder sucker is better than a continuous-vacuum desoldering system, then you haven’t used a real one, or don’t know how to use it. (And some, like Pace, do in fact create a sudden high vacuum before continuing with a lower continuous vacuum.) Continuous vacuum is really the only reliable, halfway gentle way to desolder through-hole components from plated through-holes. Neither wick nor a solder sucker can clear the solder between a pin and the plated hole. Continuous vacuum does, because you suck out the molten solder and keep the pin moving while the continuous vacuum cools the pin and plated hole, preventing them from re-adhering to one another.

[tooki]

Can I clean soldering tip in rosin flux that is in a tin can instead of in tip tinner in a tin can?

No! Despite what EPAIII says, soldering flux isn’t intended for cleaning your tip at all. (And note that tip tinner is very harsh, and should only be used on tips that resist being tinned with your regular solder.)

Just use good quality solder, whose flux core will allow the tip to tin properly.

As for the rest: stop fucking around with garbage supplies from China. Your sanity, and the components you intend to use, aren’t worth it. Even “expensive” solder is still cheap because you use so little of it. Who cares if a 500g reel costs $50 if it lasts you 5+ years? My favorite solder so far is Kester 63/37 with type 44 flux core.

And watch this soldering tutorial, if you understand it and follow it, your soldering will improve: https://youtube.com/playlist?list=PL926EC0F1F93C1837

[EPAIII]

[ Specified attachment is not available ]That tip does not appear to be plated. The plated area would have a silver like appearance while the area above it may be tarnished after use. Here are three tips you can compare it to. The left and center ones have been used and the line between the plated area and the rest of the tip is fairly clear. The third one has not been used and while the entire tip appears to have a silver like color, if you look close you can see the line between the plated area at the tip and the rest of it.

The tip in your photo is hard to see clearly. IMHO, the best tips are plated. The bare copper tips are both harder to use and the copper will slowly dissolve in the solder making a replacement needed. The plated tips last for many years - I even have some that are many decades old and still working just fine.

Thanks for soldering advice.

I have attached a close-up photo of solder tip. Do you think it is plated?

And the iron tip can be dipped in the paste type flux. I do that often to clean it. In my decades of soldering I have never even had any liquid flux for electronic soldering. If I did use it I would want one of those needle style bottles to apply small drops.

Paste type flux like this one or you meant tip tinner in a tin? AndyBeez posted above rosin flux in a tin which I think is similar to this one that I posted now.

[EPAIII]

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. 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. 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.

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.

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.

https://www.tequipment.net/Edsyn/DS017/Desoldering-Irons/?Source=googleshopping&/?utm_content=Soldapullt&utm_term=&utm_campaign=Shopping&utm_source=Bing_Yahoo&utm_medium=cpc&msclkid=45ac84dfbea11a52cf0ae7de76a8418d

Properly applied they remove at least 99% of the solder in a thru hole on a PCB. I have seen other brands that are very similar in size and action.

There seems to be a rash of smaller ones on the market today. They use a smaller volume and a smaller spring. Therefore they have a weaker action. I have tried using some of the smaller ones and do not recommend them. I can easily understand how your Pace with a vacuum pump may be better than them.

"Continuous vacuum is really the only reliable, halfway gentle way to desolder through-hole components...". This requires a longer time that the plated hole is subjected to the high temperature. 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? 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. At least on the first repair: after that all bets were off.

Solder wick is not my first choice for removing old solder. I prefer the solder suckers. They are better than the wick or the vacuum pumps connected to the hollow tip of the iron. Why? Because the solder suckers apply a sudden and intense vacuum which removes the melted solder quickly. Vacuum pumps apply the vacuum over a longer period of time: sometimes that works and sometimes not. And solder wick depends on capillary action.

If you think a solder sucker is better than a continuous-vacuum desoldering system, then you haven’t used a real one, or don’t know how to use it. (And some, like Pace, do in fact create a sudden high vacuum before continuing with a lower continuous vacuum.) Continuous vacuum is really the only reliable, halfway gentle way to desolder through-hole components from plated through-holes. Neither wick nor a solder sucker can clear the solder between a pin and the plated hole. Continuous vacuum does, because you suck out the molten solder and keep the pin moving while the continuous vacuum cools the pin and plated hole, preventing them from re-adhering to one another.

[EPAIII]

And yet, after a dip in my tin of rosin flux and a quick wipe on a wet sponge, my tips are clean. And ready for use. Flux cleans metal. That is it's entire purpose. To clean the metal so that solder can adhere to it.

Been doing it for 50+ years and I still have and use the ORIGINAL tips on my Weller soldering station. Today they are still as good as new. So if there is any harm in it, I can not see it.

Please notice that NO ONE here is talking about an acid flux. Acid flux has absolutely no place in electronic or electric soldering. It should not even be on the same workbench.

Can I clean soldering tip in rosin flux that is in a tin can instead of in tip tinner in a tin can?

No! Despite what EPAIII says, soldering flux isn’t intended for cleaning your tip at all. (And note that tip tinner is very harsh, and should only be used on tips that resist being tinned with your regular solder.)

Just use good quality solder, whose flux core will allow the tip to tin properly.

As for the rest: stop fucking around with garbage supplies from China. Your sanity, and the components you intend to use, aren’t worth it. Even “expensive” solder is still cheap because you use so little of it. Who cares if a 500g reel costs $50 if it lasts you 5+ years? My favorite solder so far is Kester 63/37 with type 44 flux core.

And watch this soldering tutorial, if you understand it and follow it, your soldering will improve: https://youtube.com/playlist?list=PL926EC0F1F93C1837

[Boris_yo]

And yet, after a dip in my tin of rosin flux and a quick wipe on a wet sponge, my tips are clean. And ready for use. Flux cleans metal. That is it's entire purpose. To clean the metal so that solder can adhere to it.

Please notice that NO ONE here is talking about an acid flux. Acid flux has absolutely no place in electronic or electric soldering. It should not even be on the same workbench.

Okay. I will look for rosin flux free of mineral acid and free of chloride. I will skip tip tinner since it can be harsh on non-plated tip.

[tooki]

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

"Continuous vacuum is really the only reliable, halfway gentle way to desolder through-hole components...".

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.

This requires a longer time that the plated hole is subjected to the high temperature.

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.

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?

That can happen with top-quality boards if they're overheated or if pressure is applied while at soldering temperatures. Again, proper technique...

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.

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: https://youtu.be/IqE1KA0OAnM?t=1022

[tooki]

And yet, after a dip in my tin of rosin flux and a quick wipe on a wet sponge, my tips are clean. And ready for use. Flux cleans metal. That is it's entire purpose. To clean the metal so that solder can adhere to it.

Been doing it for 50+ years and I still have and use the ORIGINAL tips on my Weller soldering station. Today they are still as good as new. So if there is any harm in it, I can not see it.

Dipping into the flux is inferior to tinning with flux-core solder for three reasons:
1. it harms the flux.
2. it results in excess flux residues on the tip.
3. it doesn't "flush" away old solder. The solder on the tip gets oxidized from being heated, but also gets contaminated with dissolved copper, gold, etc from the joints. (Especially in rework.) Flushing with fresh solder eliminates that. 

[james_s]

That soldering iron takes me back to my childhood, it's much like the ones Radio Shack used to sell in the 80s and 90s. They are not very good by modern standards but they do work if you are careful.

As for solder, just forget all the cheap junk, buy a roll of Kester or other reputable brand 60/40 and you'll be set. I got nearly 10 years out of the last 1lb roll I bought so the cost spread out over time is very low.

[tooki]

That soldering iron takes me back to my childhood, it's much like the ones Radio Shack used to sell in the 80s and 90s. They are not very good by modern standards but they do work if you are careful.

Hehehe yep. I, too, started with the Radio Shack 30W fire stick. Then I "graduated" to the 15W grounded one (whose superior tip shape meant it performed better).

[Boris_yo]

As for solder, just forget all the cheap junk, buy a roll of Kester or other reputable brand 60/40 and you'll be set. I got nearly 10 years out of the last 1lb roll I bought so the cost spread out over time is very low.

Are there other ways to determine if solder is a quality one besides brand name and whether it gives off China-made vibes? I see many brand names on Amazon that have good rating.

Also does quality solder matter when it comes to solder something simple like kitchen timer versus PCB board of TV or air conditioner?

Is this even more more critical where beside elecrical conductivity there is also data transfer and communication like motherboard? Are there special solders specifically for that last one? Just curious.

[Cubdriver]

As for solder, just forget all the cheap junk, buy a roll of Kester or other reputable brand 60/40 and you'll be set. I got nearly 10 years out of the last 1lb roll I bought so the cost spread out over time is very low.

Are there other ways to determine if solder is a quality one besides brand name and whether it gives off China-made vibes? I see many brand names on Amazon that have good rating.

Also does quality solder matter when it comes to solder something simple like kitchen timer versus PCB board of TV or air conditioner?

Is this even more more critical where beside elecrical conductivity there is also data transfer and communication like motherboard? Are there special solders specifically for that last one? Just curious.

About the only way to find out is to buy some and try it.  That said, trust us - just buy a spool of the good stuff (Kester or Multicore) and be done with it.  Those will have good quality fluxes and well controlled alloy proportions, and they just work. It’ll be cheaper in the long run to buy the good stuff right out of the gate, rather than the false economy of buying one or more of the cheap ones, wasting time and effort discovering that they’re crap, then buying the good stuff.

To my knowledge there are no special solders for data transfer, other than just using good solder.  There are some speciality solders, such as alloys containing silver (used many years ago by Tektronix on their ceramic terminal strips, for instance), and some low temperature alloys for very special applications, but for normal electronics, normal solder will do.

-Pat

[tooki]

As for solder, just forget all the cheap junk, buy a roll of Kester or other reputable brand 60/40 and you'll be set. I got nearly 10 years out of the last 1lb roll I bought so the cost spread out over time is very low.

Are there other ways to determine if solder is a quality one besides brand name and whether it gives off China-made vibes? I see many brand names on Amazon that have good rating.

Given that Chinese vendors have proven themselves readily willing to cheat the ratings (by buying positive reviews or by simply fraudulently taking over an old listing for some unrelated, but positively rated, product), I wouldn’t trust Amazon reviews for Chinese items farther than I can spit.

Also does quality solder matter when it comes to solder something simple like kitchen timer versus PCB board of TV or air conditioner?

Is this even more more critical where beside elecrical conductivity there is also data transfer and communication like motherboard? Are there special solders specifically for that last one? Just curious.

Yes, quality matters: bad solder won’t flow properly. Solder quality depends fundamentally on two things: 1. the alloy and 2. the flux.

Quality manufacturers have tight control over the alloy, keeping detrimental impurities to a minimum and ensuring it’s all been alloyed correctly. There are rumors that the Chinese even recycle reclaimed solder to make new solder wire, meaning that contamination is included, and the actual alloy is poorly controlled. (Note that recycled solder does exist from top quality manufacturers, but they aren’t just collecting molten solder in a wok and reusing it right away. It’s a proper process with results indistinguishable from virgin metal.) FYI, two major solder contaminants are copper and gold, which dissolve into the solder while molten. Gold in particular is really detrimental to joint quality, which is why in military/aerospace, gold-plated components first have to have the gold removed before installation.

As for flux, this is where, even among top quality brands, there are huge differences in performance, and why a huge assortment of flux types are offered. A weaker, gentler flux will work perfectly on brand-new components and boards, but won’t cut through the oxidation of stuff that’s been stored longer. A more sctive flux will work well on those. Additionally, some fluxes “spit” more (bubble and spray droplets of flux around the board) than others. (Multicore and Stannol, two now-independent brands that had been merged for a few years and thus have similar products, tend to spit more in my experience.)

Three people, myself included, have advised you so far to not waste your time, money, and sanity on cheap solder. I don’t think this point can be emphasized enough. You use so little solder that even “expensive” stuff isn’t that expensive.

My favorite brands so far have been Kester (a very well known American brand, whose type 44 flux is more or less the gold standard in flux core, being active enough for almost anything, yet whose residues are inert enough to not require cleaning), Felder (a lesser known German manufacturer, whose products are quite aggressively priced but which perform very well in my experience), and Tamura-Elsold (a Japanese-German manufacturer whose products are the only ones allowed by the European space agency, but which are very hard to find available for purchase).

As Cubdriver said, there really aren’t any solders selected for special electrical properties — solder alloys are selected for mechanical, chemical, and metallurgical compatibility. As a hobbyist, you really don’t need to worry about that: just get a top quality 63/37 leaded solder if you can, 60/40 leaded if 63/37 isn’t available, and Sn100+ (tin with a minuscule amount of germanium, etc) if you can only get lead-free. (Sn100+ is the only lead-free alloy that, other than needing a higher temperature, really looks and behaves like leaded solder.)

Non-exhaustive list of quality brands:
Kester
Felder
Tamura-Elsold
Multicore/Loctite
Stannol
AIM
Indium
Almit
ChipQuik
MG Chemicals
Radio Shack (surprisingly!)
SRA
Weller
Asahi


As for flux types: rosin is the traditional kind, of which the aforementioned Kester 44 is IMHO the finest example. Nowadays, especially with lead-free, “no-clean” solders are very popular. (They’re called such because their residues are less conspicuous; rosin flux’s amber residues are visible but harmless.) They generally aren’t quite as active as rosin, and should you decide you do want to clean them, no-clean flux residues can be significantly more difficult to remove. Finally, there are water-washable fluxes, which are essentially acid fluxes similar to the ones for plumbing: DO NOT get water-washable! It demands absolutely flawless cleaning without exception and without failure, as even the tiniest amounts of residue will cause corrosion down the line. Plus, they categorically cannot be used on anything where flux can wick into a place it cannot be cleaned, such as stranded wire, where flux wicks under the insulation.