"Fight" if you want: Don't make it personal but argue against my points, bring evidence, show me things I'm not seeing, and seek to educate.
I hope this thread can be a "crucible" where all assumptions are burned away and the only thing left is the facts.
My target is through-hole electronics (up to 24V) with a little bit of SMD work
I've been soldering this way for a couple of years, and before that I did all sorts of crazy experiments (like soldering PCB "art" with sections of solder cut from the roll and melted with a zippo)
I have 20/20 vision and good attention to small detail, especially while I'm learning
I prefer the principles of
"you can argue with what I believe, but you can't argue with my experience"
"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away"
Ok, now down to the topic.
I don't like solder with any type of core. I prefer to use separate flux. The reason is that the fumes come from the flux, and it's handy to be able to adjust the flux as-needed. I also feel like flux breaks down the solder tips, but I have no evidence of that.
For tinning I will dip the lead in flux, apply the right amount of solder to the iron, and then touch the molten solder to the lead until it wicks to the desired length.
For through-hole soldering I will dry-fit the component, apply flux either just to one side of the PCB or to the hole and lead separately, load the iron with solder, then touch the iron to the hole/lead and keep it there for a couple seconds as the solder burns the flux away and wicks in to the hole. If I've loaded the right amount of solder it gets that characteristic ideal solder joint shape (concave fillet), and there are zero signs of cold joints. The surface of the lead and the solder are smooth, have no tiny gaps and the hole is fully covered.
Since getting my TS-100, I've been setting it to 260C and using leaded solder, but I usually just follow the "set it high enough that the solder melts nicely against the tip" method, so that temp changes based on the specific solder I use. Ideally I'm not using a temp that will damage the components even if I leave it there for >6 seconds.
Cons:
Sometimes if I add too much flux in the hole it will bubble out from the solder for a bit. This is not ideal, but leaving the iron on it for an additional few seconds will typically vaporize it all. I just take the iron away slightly after the bubbles stop.
The flux is messy. While I enjoy the zen of the alcohol and toothbrush method, I can sometimes end up with conductive flux under components (like those tiny screw terminals) and that is frustrating until you learn not to do that.
It's possible that this method is slower and possible it's faster. I am not at a practice level where I can determine and it does not feel significantly different so while I will get fast through practice regardless I don't feel held back.
I don't see any problems. With regular flux-core solder, additional flux often helps.
There are (at least) 3 categories of flux for electronic soldering.
Regular-old rosin core solder is ugly but it's non-conductive and it doesn't (usually) have to be cleaned. (That probably isn't true in RF circuits.) I don't think alcohol is a "proper" cleaner. I think the freon-based "toxic waste" solvents rosin flux is no longer (widely) used in industry. I believe rosin flux is the "easiest" (most effective) flux but I haven't done that much experimenting.
Water-soluble flux is corrosive and it should be cleaned. This is the most common flux used in industry. Most components can be submerged in water. In PCB manufacturing deionized water is used but tap water is OK as long as the board is dried before powering it up.
No-clean flux leaves a non-conductive clear residue. It can be cleaned with alcohol, but it doesn't "easily" dissolve in alcohol so there may be better solvents. But of course, the idea is that it won't be removed.
[b}P.S.[/b]
I believe it's the flux that makes solder paste, paste, rather than solder-powder.
This is exactly the steps we did to tin the wire ends when called for. We used a commercial small solder pot with a section for liquid flux and a heated small solder pot to dip the wire into.
When I bought into the company, the thru hole production was done by an inserter machine that formed the leads, inserted into the circuit board, clipped the leads and crimped to hold them. Then the competed board went to the wave solder machine which used liquid flux to coat the bottom of the board and then moved it to the solder wave for soldering. Boards were then hot water washed.
So, in effect, you are using the industrial methods on a limited, individual basis.
Suggestion. Put your board into your kitchen dishwasher and clean it that way. We had that method as a backup to the commercial board washer.
Good luck!
So, in effect, you are using the industrial methods on a limited, individual basis.
It's mind-blowing to me that the method that I've figured out over the years is basically an industrial method!
For the dishwasher: I'm concerned about the dissolved solids in the local tap water, but I will try it out on some sacrificial boards to see if I'm wrong
Flux is flux (as long as it is the correct type). IMHO Whether you have it in the core or an application is irreverent. I choose to use solder of different diameters so the flux is kinda controlled for the application.
My only comment is your solder tip setting is a little low to get a fast clean solder connection. I use about 350 °C (at least that is what my solder station indicates). For a through hole strip header type of connection I think it takes me 3 seconds. This reduces the heat conducted into the component. I have some technical backing for my method as the folks who taught me to solder were trained at the Redstone Military installation.
I got a 3 litre unit (with heater) years back for around $70.00 @ Amazon.
I place the PCBs in a water filled zip plastic bag that is then immersed in the water in the Ultrasonic tub. This keeps the tub pristine for my wife to clean her items, eye-ware, jewelry. . . . However, the tub is stainless steel so it is easy to clean.
I avoid having potentiometers, sound devices and similar mounted on the PCBs when tub cleaning, they are added after.
The only thing that seems "questionable" about your method is the "apply solder to tip, then tip to board" bit. That isn't "wrong" per se (it's even a recommended technique for fine-pitch SMT stuff_, but it seems like it would be awfully slow for the common case of having a PCB with a hundred or so nicely-lined-up pins to solder (say, a couple of 40pin DIPs and 32pin memories.) Normally I'd set the board up so the pins ran vertically, put the iron in one hand and the solder on the other, and go blip, blip, blip down the row of pins - iron to board/pin intersection, solder to the other side. Done.
It seems like it would be slow and awkward to apply the solder to the iron tip every pin (or couple of pins) instead. Maybe this sort of scenario (hundreds of pins of DIPs) just isn't so common anymore...
(although, where do you even FIND sold-core solder? Digikey's choice of solid solder seems to be ONE, unless you want to buy 200lb at a time (and still not much better.)
Are the PCBs through hole plated, if so don't bother soldering them.
If not through hole plated, use wire through the hole and solder either side, a better solution to trying to rely on solder in a non plated hole. (All industrial PCBs I have had across my work bench that are double sided but not plated through, use a soldered wire connection.
Are you making your own PCBs or getting them made?
With respect to flux, each to his own.
With respect to wearing out soldering tips, I think the TS-100 can do it, and that is go into hibernation/sleep mode at a lower temp to preserve the tip.
You can't argue with good results. All engineering is always about managing competing priorities. Good, fast or cheap, pick any two.
Any guidelines that disagree with your own process do not mean you are "wrong" if your end results work as expected. Opinions are like rectal orifices; everyone has one, and they all stink.
Based on this thread I'm going to try upping the iron heat and give some time to get used to it. I do like the idea of heat for less time.
One thing that turns me off from it is how quickly the solder on the tip oxidizes at higher temps. If I go slow I find that I barely have to clean the tip even while doing rows of headers.
Re the vertical rows: I can definitely see how someone could be faster than me with a hot iron in one hand and a strand being fed from the other. I'm not that much slower once the flux is applied though: I keep the solder within reach of the iron, do one pin, 'scoop' some solder from the end of the coil, touch that to the pin, scoop the next, and so-on. No need to adjust my body position between pins.
although, where do you even FIND sold-core solder?
Despite how great this thread has been so far I definitely feel like there might be some pushback on this one... The coil I'm using right now is Dura Pure 50/50. Grabbed it from the hardware store and it's chonky. A 'general purpose solder', the applications are listed as "roofing, sheet metal repairs, automotive applications and stained glass repairs" but there is no flux/rosin and it's 50% tin + 50% lead so . I went looking for "just a mixture of electronics-friendly metals. no impurities, no nonsense." and I found it. My next one might be different depending on what's around when I look.
Thanks for that TomGeorge. I have noticed that some boards are not plated through the hole, but didn't yet make it part of my workflow to adapt to each type. That's going to level me up a bit I can tell.
Are you making your own PCBs or getting them made?
Usually ordering them from PCBWay when people way more experienced than me upload their designs.
go into hibernation/sleep mode at a lower temp to preserve the tip.
Oh! I had totally neglected that function but it definitely fits my workflow so I'll see what needs fiddling.
Ah. Your technique certainly removes some of the dependency on having "fine" solder for small pins, since you're melting it before it gets anywhere near the pins...
. I went looking for "just a mixture of electronics-friendly metals. no impurities, no nonsense." and I found it. My next one might be different depending on what's around when I look.