Hand soldering technique - Page 1
Forum section: electronics / general

author: KL27x
author_rank: Super Contributor
timestamp: November 01, 2015, 11:44:13 pm
content: Made a video of how I hand solder a pcb, using a huge bevel tip and liquid flux. This is why I have a reflow oven, but I never use it!Before watching this, note that I did absolutely no practice run or retakes. I did minimal setup. I edited for max upload size, but I made a point of leaving in most all the bobbles/mistakes (mostly occurring right off the bat, trying to figure out how to solder without a microscope for the first time in forever).http://vid18.photobucket.com/albums/b103/klee27x/Sloppy%20drop%20Super%20Short_zpsl5m6olh2.mp4The component density on this board is very low, so I have no trouble using a 3mm bevel tip. For tighter layouts, I might preferentially use a 2mm tip, and I may invert the tip to hold the solder drop above the pcb. Anyway, the point being that the bevel tip holds a lot of solder and can get some jobs done much faster. And can get most other jobs done just as well. This technique works on SOT23-3, and most all passives and any flatter SMD components with some exposed lead.Hand-soldering, there is are no stressful moments. Nothing that can't be fixed on the fly. No paste washup. No boring post-inspection. And no breaking out the heat gun to fix crooked ICs. Overall, I'd say stencil pasting usually wastes more time and increases error rate, for me, personally. (And this includes my attempts with much larger boards/panels.)Anyway, I think a few of you might learn a new trick, here. Excuse the disgustingly loud breathing throughout the video. The camera is practically up against my face.

author: Muttley Snickers
author_rank: Unknown
timestamp: November 02, 2015, 12:08:14 am
content: Thanks for posting the video, an excellent job and you make it look so easy.There are two things that I have struggled with all of my life the first being hand writing and the second being soldering, both of these activities cause mild tremors in my right hand which has been broken may times at the wrist joint, once a customer was watching me tin some wires and the tremors started and they asked me what was wrong, I explained to them that the oscillation soldering technique is the best method and takes many years of practice to master, I got away with it.Many ThanksMuttley

author: mrpackethead
author_rank: Super Contributor
timestamp: November 02, 2015, 12:17:35 am
content: Your soldering technique is similar to the "drag" method thats taught, and well used. You get even better results using a "hoof" tip, which is similar to the bevel, except the bevelled edge is concaved into a dish. Its all about surface tension, dragging the solder from pin to pin.I do this from time to time, when needed or replacing an IC. as for placing R/C and hand soldering thats absolutely what a stencil and oven is for ( along with the IC's ).. there is a lot in correctly stenciling a board and if its not done right, it does cause problems... Stenciling and reflowing is how 1000's of boards are made every minute of the day.. so it does have some merit.Quote from: KL27x on November 01, 2015, 11:44:13 pm

author: KL27x
author_rank: Super Contributor
timestamp: November 02, 2015, 12:39:16 am
content: Quote.... using a PNP machine. When I get a PNP machine and a project worth setting it up, I will use a stencil.Hand soldering might even take a little longer, if you have your hand-pasting/placing method down pat. That's just the time it takes to get the board into the oven. But after hand-soldering a board under the microscope, I do not need to do any post-inspection. I have inspected each and every connection as it was made. My speed is higher and error rate lower, this way, when including inspection and rework of a reflowed board.I have played with toaster ovens, real ovens, hand pasting, stencil pasting. And in the end I had a little fun and wasted a lot of time. Personally.QuoteI can't buy a dished tip for my iron. But part of the magic of the tip in the video is the "F" in CF. It's tinned face, only. This allows the surface tension to suck up excess solder out of the joint, without leaving a little trailing doohickey, even when the tip is massively loaded. This is what gives the CF tip part of it's bridge-sucking and pad-cleaning ability. Regular bevel tips work ok, but tinned face only is on steroids.QuoteThanks very much! It looks even easier (it is!) under a microscope!I felt like I had a lot more tremors than usual. There's something about working under a microscope that calms your nerves down. Seeing gives you some kind of instant feedback mechanism, or something. And it IS easy. The flux and solder surface tension do all the work. The way the drop touches the pads is very similar to how wave soldering works without making a mess of things.As far as the drag soldering, sometimes I get a tremor trying to position the iron. But once the tip is resting against the pins, it's all good.

author: nanofrog
author_rank: Super Contributor
timestamp: November 02, 2015, 02:13:32 am
content: Quote from: KL27x on November 02, 2015, 12:39:16 amHakko does make them for the FX-888/D.900M-T-3CM(3mm)900M-T-2CM(2mm)Seems the smaller 2CM is getting hard to find in the US for some reason (doesn't sell well maybe).FWIW, they work even better for drag soldering than a hoof, but it's not as versatile.

author: sleemanj
author_rank: Super Contributor
timestamp: November 02, 2015, 02:35:48 am
content: Since this is a soldering thread, I've been using a hooked/bent type tip for my 900 series iron lately, I quite like it, you can use the point, or the sides easily, and the curve makes it easier to get into certain positions with a more comfortable working angle (subjectively). Tip type: 900M-T-I (actually, nope, maybe that's the knock-off-chinese-code, Hakko's bent series seem to be T-J not T-I)

author: mrpackethead
author_rank: Super Contributor
timestamp: November 02, 2015, 04:08:34 am
content: Quote from: KL27x on November 02, 2015, 12:39:16 am

author: KL27x
author_rank: Super Contributor
timestamp: November 02, 2015, 06:25:28 pm
content: QuoteI have yet to come across a leaded IC that can't be done 1000x more reliably with drag soldering. Well, a 0% error rate vs 5% is actually more than 1000x difference. Yes, you may have to fix bridges with drag soldering, too. But that adds another two seconds. Not a whole additional process. And the one time in 100 the chip goes crooked in the oven and you need hot air to remove it, it really takes all the time you ever saved and throws it out the window. The finest pitch QFP I have come across is the same pitch as SSOP/TSSOP at best. I don't see anything special about QFP, in particular. Do they make QFP's down to MSOP pitch? Even with MSOP, I find drag soldering superfluously fast, easy, and reliable.For the uQFP no lead parts, I have had the best luck with pretinning and refluxing the pads, personally.QuoteYou must be really good at that. I bet you have some tips to share.I have only ever tried stencils on my larger quantity boards. And there are some additional quirks to batch processing, for sure. I would set up a stenciling jig and paste up 4-8 boards at a time, depending on cirumstances (this takes up a lot of space!). Then populate and bake them. Rinse and repeat, and keep going while the paste was out and the stencil dirty, until I had done as many as I could stomach for the day. And including the inspection and rework and managing the physical boards in various stages and the space, and the cleanup/maintenance, it was barely a wash, at its best. And a terrible waste, at its worst.I can see how with a team of assemblers in an assembly line, it could be way more efficient considering the need for less equipment and skilled labor, and more efficient use of skilled labor. But a hobbyist can't train/assign a minimum wage unskilled laborer to paste and repaste boards until they are right, nor to clean up the mess, after. While he is doing those jobs, his microscope and soldering iron and skilled solderer/inspector are not being utilized.There is also workflow and inventory management. A huge advantage for a 1-man operation is you don't need to dedicate a large block of time and space to hand-soldering. You can start/stop at any time without screwing up your efficiency and workflow. You can batch process boards, certain components and/board areas at a time, no problem. Everything you do is permanent and inspected and can be left for days/weeks for later completion. Or if it's a simple board with minimal different components, you can complete one board, or panel of boards, at a time, and have minimal space/organizational requirements. You don't have a bunch of pasted boards that have to be completed today. You don't create piles of inspected boards and uninspected boards that must be carefully stored and labeled. Youbdont have to stop to setup one different component cut tape, every few boards. Every board in any stage is obvious by looking at it.There is also a matter of waste. With hand soldering you can pre-assemble all the dirty cheap passives on a pcb and only order and assemble the expensive ICs on demand. You don't need to stay on top of components inventory. If you run out of X component, you can finish the rest while that component is being shipped. How many of your boards end up getting used? For me, I would estimate 30% of my boards end up as waste. It's a matter of bulk efficiency. Ordering extra boards, just in case, is sensible, due to both cost and turnaround time.Time is money to me, too. And stencil pasting is wasting my time. If it is not wasting your time, as an individual hobbyist, you are much better at pasting or much worse at soldering than me. Or your boards have the density of a modern cellphone. The biggest BS is that is passed around is that if the paste/placement isn't perfect, don't worry. The part will realign automatically. If you are not perfect, the parts will usually realign and not bridge or tombstone. That is still a problem that sucks time for inspection and rework.I do agree that stencils are more useful for passives. I am interested in giving stencils another shot, but I will be removing the ICs from the paste layer.QuoteI mostly use CF tips for SMD work or a mix of SMD and thru hole. Regular bevels or blunt conicals are my preference for extensive thru hole. Fine conical for those tight repair jobs. And a knife tip for SMD rework of passives. I have used a bent conical at a jobsite, and it's neat because you can use it sort of like a knife tip to rework passives. Maybe I'll add one to my collection.I find it curious that Hakko describes the bent conical as specifically a tip for removing bridges. I suppose you turn it flat against the pins to do that, but I can't see it working any better than a knife tip or large chisel tip at removing bridges, i.e. fairly mediocre.

author: mrpackethead
author_rank: Super Contributor
timestamp: November 02, 2015, 10:02:06 pm
content: QuoteYou must be really good at that. I bet you have some tips to share.It seems to work; but theres a few things you need to make it all work;(a) you need good quality pcb's that have flat surfaces. OSP or ENIG. Using HasL just leads to trouble, as the boards are not gasketed well.(b) PCB's need to be fresh. Anything over 90 days i'll not use in production, thats for sure. If they are older than that, at a miniuum bake them at 60C for 5-6 hours to ensure they are completley dry.(c) use a good quality stainless laser cut stencil.(d) Use good quality and fresh paste. For small qunaitys at home. Zeph phaste is a good choice a wee bit expensive, but it is very forgiving(e) Make sure everythign is clean.. Did i say make sure everythign is clean.(f) Getting your apatures correct is critical.. Not just for prototyping but for produciton as well.(g) Good stencil printer and a good reflow process.QuoteNor shoudl a professional. The paste up is the most critical part of the entire process. Get it wrong and everything goes wrong. Tombstones, bridges etc etc. Get it right and you hit 99.99% good work.QuoteI disagree, but thats ok, what ever works for you.QuoteI do this for a job, so guess its not a hobby any more. If i was quicker to hand solder i would be doing it. I do sometimes drag solder an IC, if im replacing it during prototyping or a repair.QuotePasting needs to be consistent and done properly. Placement is less critical, though you do want to get things as best you can.Quote

author: KL27x
author_rank: Super Contributor
timestamp: November 02, 2015, 10:44:02 pm
content: You are using a PnP machine. Obviously, said machine increases your overall efficiency. And also, your large and expensive machine is useless without paste. That gives you some bias. I bet a manual PNP like that is ideal for one-off prototypes with a high parts count. I have seen video of this machine in action, and it really looks to be a peach. Of any machine I have seen, this would probably be the very first one on my list, before any CNC machine.I solder with a stereomicroscope, which a lot of hobbyists do not have. I do not have a PNP machine, which some hobbyists do have. I also have some mad soldering skills. That gives me a particular bias.I agree to disagree, as well.FWIW, I'm more than a hobbyist, too. For me, design, programming, and assembly (of my own work) are a business. But I have no employees.QuoteThese are the only kind I have tried, with frames. I have resorted to using hand lapped end-grain cutting boards, cut to size, for the pasting. I have used fresh MG solder paste in the syringe. Jigs to hold the board in place. I suppose my credit card squeegee might be the weak link. I do fine on the passives, but am only batting 75%, on a good day, on the pasting of the ICs.QuoteThis is the curious part. With the finer ICs I got problems of too little paste and too much paste even on the same board. For this reason, I have thought perhaps thinner stencils material than stainless steel could be better, so the paste doesn't cling to the sides of the stencil.QuoteMy previous attempts include 1 each of HASL and ENIG. The HASL was much better, but that is probably because the ENIG was a flex board. Even if the paste is right, the IC doesn't always reflow, correctly. Taping the boards down before reflowing would have added even more hassle to the process that was already easier for me to hand solder. Also, I never figured out how to make a jig for positioning the flex boards relative to the framed stencil.QuoteThis is a biggie. Even if you get 99.99% perfection with a good paste and place. And assuming you can tell a good paste from a marginal paste 100% of the time. Likewise, you can have the ability to never misplace a part. Let's say you have only 20-100 components on your board. Does this mean you are confident enough to actually ship your (smaller, at least) boards without any visual post-inspection?The post inspection is the biggest problem I have. You have already viewed each part with your Dyna machine as you placed it. But because stuff can happen during reflow, you typically still need to look at each and every part, again, right? And while placing your parts with the Dyna machine, and if you see a sketchy paste on an otherwise great board, or if you have a mishap while placing, how can you easily deal with that? Do you have a system for marking that component for later inspection/rework? Is there an easy way to wipe up and repaste that pad without screwing up the workflow? For me, looking for bridges and tomb-stones in 99.99% good boards is infuriatingly infuriating. It's like trying to find a lifeboat in the middle of the pacific. Even if I stare right at it, I might not see it. Then there's another issue with reflow on the ICs. Sometime the IC, or part of the IC (tilt), can float on top of the paste. And it might connect, fine, but there's no visible toe filet, no flash of solder on the top of the pin. This adds more grief to the process.When hand-soldering, you can quickly and easily fix problems in the moment. Board 100% inspected when done. You have spent 4x as much time (and more focused, purposeful time, rather than staring-into-space-until-your-eyes-glaze-over time, only to be intermittently disrupted with a need for rework and then to have to remember where you left off) looking at the board under magnification, but your overall time spent assembling might be around the same. This is of course dependent on your board, your equipment, and your skills.Thanks for participating in the thread. Your use of the Dyna PnP and your extensive assembling experience gives you a unique perspective, which is appreciated.

author: mrpackethead
author_rank: Super Contributor
timestamp: November 03, 2015, 01:39:22 am
content: Quote from: KL27x on November 02, 2015, 10:44:02 pmA manual PNP....QuoteIts not that large, and it certainly was'nt expensive.. I was really really lucky and got it on ebay, and the freight cost me more than the machine...But they are about 5000 Euros last time i looked new. You could copy some ideas out of it and build a pretty good DIY machine though. I had a similar idea machine previous but it was a pile of junk. As for bias, maybe, but it does give me a place to talk from experience. And yes, i also from time to time, put parts on by hand in a manner that is very similar to what your video showed.QuoteIts actually pretty handy for also doing small runs ( say 10 or so on a panel, as its quicker to set up and run than the full machine ). And yes, if you are doing prototypes, (1 off ).. this will be miles faster than an automatic machine in most cases.. The fact that you can twist the part around to get correct oritation is really helpful. Something you cna't do with a vacumn pen easily.QuoteI have a mantis inpsection scope, as well. And from time to time i use it to solder under, particulary if its an ugly part..c) use a good quality stainless laser cut stencil.These are the only kind I have tried, with frames. I have resorted to using hand lapped end-grain cutting boards, cut to size, for the pasting. I have used fresh MG solder paste in the syringe. Jigs to hold the board in place. I suppose my credit card squeegee might be the weak link. I do fine on the passives, but am only batting 75%, on a good day, on the pasting of the ICs.Yup.. You need a pretty stiff steel stencil. you can buy some good ones on Alibaba for a few dollars though.. two passes's is all you should need.QuoteThis is the curious part. With the finer ICs I got problems of too little paste and too much paste even on the same board. For this reason, I have thought perhaps thinner stencils material than stainless steel could be better, so the paste doesn't cling to the sides of the stencil.QuoteMy previous attempts include 1 each of HASL and ENIG. The HASL was much better, but that is probably because the ENIG was a flex board. Even if the paste is right, the IC doesn't always reflow, correctly. Taping the boards down before reflowing would have added even more hassle to the process that was already easier for me to hand solder. Also, I never figured out how to make a jig for positioning the flex boards relative to the framed stencil.QuoteThis is a biggie. Even if you get 99.99% perfection with a good paste and place. And assuming you can tell a good paste from a marginal paste 100% of the time. Likewise, you can have the ability to never misplace a part. Let's say you have only 20-100 components on your board. Does this mean you are confident enough to actually ship your (smaller, at least) boards without any visual post-inspection?never, nothign leaves here without being fully functionally tested. And typical boards for me run to 300-400 parts... You can tell good paste from bad, its not really that tricky..QuoteBut it only happens rarely if you'd done your work well.QuoteFive years ago, i was were you were, largely hand assembling parts with tweezers, iron etc etc. It was'tn an easy thing to migrate to what i'm doing. It takes time and mistakes to learn from, but it does work, and it saves me time. Your mileage might vary. With reflowing, its the small things that make a big difference, between success and failure.

author: KL27x
author_rank: Super Contributor
timestamp: November 03, 2015, 02:57:40 am
content: Great input on the Dyna. I would love to have one of those machines.Great input in general. Thanks!For the fun of it, I did the confidence interval on number of parts vs accuracy rate, using a 99.99% success rate per part. Moot point, since your figure was not meant to be taken as accurate, I know! But just to put things into perspective on the relative need for a structured post-inspection:20 parts = 99.80% of the boards should pass without inspection50 parts = 99.50%300 parts = 97.4%400 parts = 96.0%

author: mrpackethead
author_rank: Super Contributor
timestamp: November 03, 2015, 05:10:10 am
content: So, this is pretty much how it works, we know that most of the time things go well. A cursory visual inspection will pick up most issues.However Every board is functionally checked before it ships. ( mostly they have to get programmed as well ), so if there is a problem we will know about it because it doesn't work.The DIMA are really good..[quote author=KL27x link=tFor the fun of it, I did the confidence interval on number of parts vs accuracy rate, using a 99.99% success rate per part. Moot point, since your figure was not meant to be taken as accurate, I know! But just to put things into perspective on the relative need for a structured post-inspection:20 parts = 99.80% of the boards should pass without inspection50 parts = 99.50%300 parts = 97.4%400 parts = 96.0%

author: lovemb
author_rank: Contributor
timestamp: November 10, 2015, 12:43:06 am
content: I don't have any problem with hand-soldering, but would like to say that after I saw this video of this guy soldering with the bevel tip, I bought it immediately. Obviously bevel tip shouldn't be used for everything, but I rarely switch from it. After I started using the tip, I gotperfectresults just like in the video.Bevel tip also makes it also easy to remove excessive solder in a pad/pin. I simply got in love with it.https://youtu.be/5uiroWBkdFY?t=120

author: KL27x
author_rank: Super Contributor
timestamp: November 10, 2015, 12:49:05 am
content: ^That vid is what prompted me buy the 3mm CF tip for my iron. Is pretty bomb. I still use my 2mm tip more often, but that's probably more due to familiarity. If you haven't already, give the flux and blob method a try. The bevel tip is key to holding a lot of solder without dropping it all on the first joint.QuoteAlso, if you haven't tried one, give the tinned face only tip a try (also hear good things about the hoof tips). It is like the regular bevel on steroids when it comes to sucking out bridges.*My first soldering iron was a Radio Shack firebrand. I was disappointed in one regard when switching to a "real" iron with an ordinary tip. No bridge sucking power. In retrospect, I was constantly creating my own tinned face tip by filing and tinning only one flat spot on the tip of my Radio Shack iron.