Soldering the Tek way
hackaday.com
hackaday.com
Tektronix was the first to make oscilloscopes where the screen was calibrated, and you could measure voltage reasonably accurately. Earlier scopes just let you see the general shape of a waveform. So Tektronix had to develop components and techniques to make electronics behave consistently, over a wide range of temperature and humidity, in portable instruments.
Unlike wellers and other soldering irons they don’t use a PID loop. They exploit the curry effect of the alloys their tips are made of and pump 2.6 MHz RF into the handle which keeps the tip heated the entire time with zero delay, even when contacting huge copper pours. The downside is that you have to change the (expensive) tips to change the temperature, but the upside is that it’s capable of delivering much more heat. Since the iron is capable of heating so fast, temperature control doesn’t really matter because it can melt the solder long before damaging nearby chips.
If you’re not using a solder oven, that’s the best option. It’s expensive but it’ll make a night and day difference to your soldering work. I’ve got a Metcal that’s almost 25 years old that still runs like a champ, is compatible with tips sold by Metcal and Thermaltronics, heats better than any soldering iron I’ve used since, and is easily repairable if it breaks.
I pugged my Metcal into a power meter the other day. The instant you the tip touches copper, the power jumps from ~4W to ~40W. The power goes back down as soon as the solder melts.
If you can not find good deal on a Metcal, JBC irons are ok. Probably 80% as good soldering experience and often have a better (shorter) handpiece.
Key benefits:
* JBC tips are cheaper, and clones are widely available that are just as performant and even cheaper ($10/tip)
* JBC tips have adjustable temp; you can argue this isn't useful, but if you typically solder leaded but need to desolder something unleaded then this is a problem since you need to bump temp to desolder properly.
* You mentioned this already, but handpieces are shorter generally. In my opinion this makes a huge difference to soldering experience, especially as I get shakier in my older age.
When I asked for a soldering station I could use in the lab, I saw a lot of JBC machines around. I said “could I get a JBC?”. He said “oh the JBC is a Ferrari. I don’t think you need a Ferrari. I’ll get you a Metcal. That’s the Toyota of soldering irons.”
I can’t comment on exactly what he means, but he seems very experienced and has good things to say about JBC.
The Metcal does not have adjustable temperature, the temperature is set by the tips you choose. So it only has one "speed" and this reduces the risk of cooking the board.
Both Metcal and JBC are good, ultimately it turns into a sort of Vim vs. Emacs sort of thing, aka personal preference.
However, lead free tin-silver-copper (SAC) solder is fairly easy to work with. You need a hotter soldering iron at around 300°C, and if soldering PCBs preheating the board to 80-100°C may be needed for good results. It may also take a bit longer for the solder to propagate flow and wet, since the surface needs to be hotter.
If you’re using additional flux or non-fluxed solder you’ll need to check it for compatibility, that should be on the data sheet. Most fluxes are fine, but I’ve seen a couple that say not to use with some lead free solder formulations.
The main downside to SAC lead free solder is the higher temperature required which can overheat some components, particularly capacitors and ICs in my experience. It’s a case of being careful to keep the heat duration as short as possible.
Personally I went back to lead solder and manage my exposure with ventilation and HEPA filters.
For hobby work, I've switched to lead-free simply because that's what 99% of the boards I work on we're originally soldered with, but I still have some leaded solder around. That being said, it can be used safely, I cast my own bullets which generates a far larger amount of lead particulate and my blood lead levels were not at all elevated when I had them checked 2 years ago. But since it bioacumulates, you do want to keep exposure in mind.
Metallic lead is dangerous if inhaled or ingested, but not a big concern for momentary contact with your skin as metal, especially given most modern solder is only 40% lead.
Your body will remove a small amount of lead, so hobby soldering is unlikely to cause long term problems.
This is proven to work via hair-tissue mineral analysis before starting therapy, during, and after.
I'm not going to debate them though, I'll just dump my values, it might help someone.
My job involves soldering at least once a week from through-holes to SMDs(mostly), 1.6mm to 0.8mm pcb thickness, from 1206 smd to 0402 (imperial) sizes. From flimsy 0402 resistors to beefy 1cm² all metal casing inductors from hell.
To do all this I use a JBC soldering station with C245 and C210 tips. I also use a non-brand hot-air station for TSSOP ICs with exposed pad on the underside for heat transfer. Sometimes I use a hot-plate as well, and a reflow oven while we're at it.
On the JBC:
For leaded solder: 350ºC on both C245 and C210 tips. I do increase it to +/- 360ºC on occasion to solder near big stubborn ground planes on the pcb. Less than that is impossible without pre-heating because I can't afford to spend more than a few seconds on each soldering op, both because have other things to do and because I can't overheat components. Overheating is also dependent on the time you spend on each component. Might bump it up to 380ºC on those inductors and switch the tips to beefier ones like the chisels and the knives.
For unleaded SAC: 360ºC to 380ºC on those same tips, and I might bump it up to 400ºC again on those inductors.
On the hot-air station:
For leaded: 275ºC
For SAC: 282ºC
On the hotplate: 240ºC for both SAC and leaded. (Mostly repair work after pcbs come out of the oven.)
On the oven: It's a temperature curve and I only use leaded solder paste. Peak at 240ºC.
NOTE1: All the soldering wire I use is flux cored. I tend to use extra flux a lot (Chipquik SMD291), even if it's not really necessary. But on lead-free SAC it's always obligatory.
NOTE2: We don't have any fancy setup where I work and it's overall barely professional in my opinion. Pre-heating is not used much if at all so, I don't have any temperature values to share in that regard.
NOTE3: The SAC solder wire I use is Sn99Cu0,7Ag0,3 EVO11 from CYNEL. I like the brand but I feel the need to try other formulations for different use-cases so I can get away with using lower temperatures on specific temperature sensitive components. On leaded I don't feel that need at all.
Can you tell us what exactly do you solder at 320ºC and what is the exact type of solder you use and/or Pb and Sn percentages?
Also, is your pinecil calibrated? And which tips do you use at that temperature?
Anecdotally, what usually happens to me at lower temps is the tip and/or the solder wire sticking a bit while I'm soldering which I take as a sign that the liquid solder won't flow correctly and that I have to spend more time giving it heat from tip, than I should.
I only bump it up to 400 C because that was the default, I never use it for more than two or three seconds so the temperature hasn't mattered much. I haven't noticed solder stick, it just sometimes fail to melt properly with large ground planes, so that's when I bump the heat.
Lead does bioaccumulate so continual exposure to low levels is dangerous, but unless you’re soldering all day every day it’s not likely to be dangerous.
If you’re a factory and have multiple wave soldering baths operating it’s a different story.
I mentioned it for completeness because someone else would if I didn’t.
I use Канифоль/rosin flux as well and use a fume extractor. Rosin flux is the most common for flux-cored solder in my experience.
But a few times a year is unlikely to be an issue, soldering health effects are in people who do it for work.
Not all types of flux work well though, my local store sells something that has no labels but seems to be very aggressive and works exceptionally well, the more common no clean types don't do anything at all.
Tips are definitely eaten a lot faster than leaded, but it's not exactly a huge expense when they're like a dollar or two for a 10 pack on aliexpress.
Turn your iron up (I use 675) and ensure you’re touching the pad first, it’s a much larger heat sync. Lean the tip of the iron up to the component leg, give it a second and then feed solder into the other side of the leg, letting the leg of the component melt the solder and flood the joint. I use flux if I’m really worried about the joint, the fluid transfers heat better. There should be a clear fillet arcing between the pad and leg of the component, solder should be wet 100% around the pad and gracefully blend into the component leg. The joint should not look sandy or dirty or have bad surface finish.
I felt a little puzzled about this but then it hit me that you probably meant Fahrenheit.
To spare others the conversion: 675 °F is roughly equal to 350 °C.
I think the resistance to the idea has two roots. First, there's a lot of old-timers who just didn't like the idea of the government meddling with their hobby, so they go out of their way to convince others to use leaded solder.
Second, the first years of the switch were painful. You needed to upgrade some equipment, the early alloys were not performing great, there were problems with tin whiskers (which aren't specific to lead-free soldering, but were apparently happening more commonly), etc. But these days are gone. The industry has moved on.
Also, you can buy pure lead in 1000 lb quantities (and leaded solder) at places like [https://www.rotometals.com/] with no paperwork.
For leaded Kester44 is my favorite.
Set the iron temp to the datasheet of the solder...then never touch it.
For larger pads use larger tips...a lot of people get into trouble cranking things out of range.
On a related note, I've had terrible luck with any of the Chinese solders off of places like Temu or Banggood. Even the lead ones were junky.
2) Flux and thin solder. Solder should contain flux too. Use solder paste whenever possible and keep it refrigerated when not in use as it dries out
3) you need a high wattage iron and usually a thicker tip with more heat capacity. A slightly higher temp helps a little, but the wattage helps it stay a consistent temperature from the start to end of the joint.
4) when designing boards use ENIG and not HASL
5) remove any old solder before attempting to add more to a joint (older than a day or two).
6) sometimes an air gun on a arm helps too on thick copper
7) get really good lighting with a mix of diffise and directional sources. Brighter than you’d think
if you're super paranoid, D-Lead hand soap is a fantastic product: https://esca-tech.com/product/d-lead-hand-soap/ -- I use it post-shooting to wash my hands of lead and residues from firearms.
Leaded isn't actually a significant health risk for you, so you might as well go with that. It's not like you are going to breathe in lead. It's a problem for the environment in general, and you do not want to consume it, but it isn't that unsafe. A bigger problem is that you should never use leaded solder to repair boards that have been soldered with lead-free, which means pretty much every board out there that has been manufactured in the last 20-30 years or so.
I have a setup in my garage with a vent fan connected to a dryer vent and a rubber flexible hose I can put near the solder station. I also hook it up to my 3D printer enclosure if I'm doing ABS.
I am unlikely to every try this, but curious: Why is that, what would happen?
The best way I can describe lead-free solder is like using some old and really crappy leaded solder. It can get kinda gummy and ugly, but usually only when you touch a joint for the tenth time.
The way to make lead free solder flow and work like leaded is simple: flux. Flux pens are alright, but your world will be forever changed by gel flux in a syringe. Clean up with rubbing alcohol and a toothbrush or paper towel.
Modern solder alloys are pretty good. Just don't buy the cheapest thing you can find. Always, always get your solder from a good manufacturer like MG chemicals. Also buy fluxed (not no-clean) solder wick from those guys.
I used to be in the "just use lead" camp, but there's really no benefit. I've been exposed to far more than enough lead in my career. Lead-free is totally fine.
Some people fret about solder whiskers, but I'm unconvinced that this is a real problem worth discussing. It seems to be myth more than a practical problem that anyone but NASA should care about.
Just use good lead-free. It's only trivially worse than leaded. It's fine.
(One trick that can be very helpful is pre-heating: e.g. placing a board on a hot-plate at ~150C or so, or using a hot air gun to do the same. This means the iron doesn't need to heat a much. But of course this makes placing and holding the components more difficult)
There is a USAF Technical Order for this, issued by the Navy and shared with the Marine Corps:
https://www.robins.af.mil/Portals/59/documents/technicalorde...
Cleaning the joint before and after was key. We used isopropyl alcohol in a push-down dispenser bottle, and acid brushes where we cut the bristles down to about 1/4" inch.
Another poster asked about lead-free solder, and the military is using it now but has concerns over tin whiskers.
This was the longest video I have watched on Youtube in ages. The lack of intrusive ads was refreshing.
People say they don't last, but I have had an incredible amount of difficulty getting regular tips tinned and conducting heat efficiently.
No combination of tip tinner, flux or cleaner has ever fully resolved it for me.
If your iron cannot support a regular tip, it's likely that it cannot get enough power to the tip to sustain the heat being pulled from it (copper will just expedite this). You can try a beefier tip (or load up a tip with wet solder which can kinda give the same effect) or you can get a higher power iron.
I've been soldering for 15 years with all manner of irons, I've never needed a copper tip, but I often need more than your standard hakko or weller. 400C on a the hakko is not at all close to being equal to 400C on a Metcal for instance.
The symptoms are pretty obvious: even if the iron was underpowered, melting a thin piece of solder wire should be pretty much instant. My issue has just always been getting the tip to a shiny solder finish with all the recommended tools...just doesn't work once that iron layer oxidizes initially.
EDIT: Although thinking about this now, actually the way you get rid of mill-scale is with white vinegar so maybe that's my actual answer: white vinegar for a couple hours, then rosin flux and then into the solder bath. Hopefully won't remove the entire iron coating on the tip since otherwise...copper tips again.
I wouldn't want to do the above too often and it's probably not the recommended way, but I seem to have gotten away with it by not being too rough with the screwdriver. Potentially worth a try if the tip is a write off otherwise.
Once it is tinned, clean and tin the tip before turning off after every use (but you probably already know that).
Ended up reviving the tip with very careful application of 600 grit sandpaper. Not as good as new, but got at least a few years of use on it.
Literally everyone who gets one goes “oh so that’s what soldering is supposed to be like”
Also might be crap solder. Get some decent Felder or Multicore stuff. Leaded is easier to work with and harmless if you wash your hands and don’t lick your PCBs. Silver bearing leaded from Felder is what I tend to use. But it’s about $70 a roll
Edit: I see that you have a Hakko. Buy genuine tips. Or replace it with a different iron. The cheaper Hakkos are terrible.
Rosin is also used on violin bows to increase friction, and it’s the white powder you’ll see gymnasts and baseball pitchers apply to their hands to improve grip.
Rosin vapour is a lung irritant, so avoid breathing it by using a fume extractor, and for some people it can cause contact dermatitis.
Yes it’s horribly sticky, that’s the worst part about it really. Isopropyl alcohol will dissolve it.
Other technologies like glues and crimping have their uses but are less reliable, higher resistance, or difficult to automate.
This may change but there’s little demand. Glues have lower conductivity and are harder to remove, mechanical connectors are bulky and not as strong.
If you’re applying fluxed solder directly there’s not much point applying separate flux to clean metal. Of course the flux will boil off pretty quickly so you need to use extra if you’re doing something where the solder wire doesn’t directly touch the components, or if the metal is old or previously soldered.
The only advantage to non-fluxed solder for most hobbyists is being able to choose your flux, but for most of us rosin is fine and fairly non-toxic.
But besides breadboards you're kinda stuck with facilitating a clean soldering setup, which is fairly easy - if you're really worried build a gloved-box. I just wear a respirator and open a window