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how to solder a circuit board
Attention geeks, I need your help. I need to touch up a few little points on a circuit board in one of my cars. I have no training on how to use a soldering iron, but I own one and some solder-y stuff. Does it matter what kind of stuff I use? Lucky for me the points aren't that fine that I need to make. Do i melt some metal to the iron and then touch it? Or touch the metal to where I want it and then melt it? But wouldn't that melt the old one off? Thank you in advance for your knowledge. Sep 20 15 08:55 am Link Paolo Diavolo wrote: It matters. Get someone experienced in soldering to do it right. Too much heat and you can fry it. Not enough heat, wrong solder type, or wrong flux and you won't have a good solder joint. Sep 20 15 08:59 am Link I'm going to end up doing it myself because I am good at everything. Probably watch some youtube vids first but figured I would ask here too. just need to know tips like "too much heat and you'll fry it" and also what the flux, flux is? Sep 20 15 09:03 am Link dont use plumbers solder, its too heavy for circuits. you need the finer rosin core solder for electronics. get the soldering iron hot to where it will melt the solder when you toutch it to yhe tip. clean off the tip first by rubbing it on a damp paper towel, then apply a small amount of new solder. if you are soldering a newly striped wire to the board, then toutch the iron to the tip of the wire n feed a bit of solder by toutching the solder to the wire, to tin it. toutch the spot you need to solder till it melts the old solder, place the tinned wire on the spot, now feed in a bit of new solder till its noce n shinny n covered. take the iron off the spot but hold the wire still for a few seconds till the solder cools a bit. just work quickly and not longer than ot takes to melt the solder. thats all it takes. Sep 20 15 09:05 am Link The F-Stop wrote: thanks Sep 20 15 09:14 am Link Aside, I like the solder that has a bit of silver in it too. Joints just look cleaner and more shiny with it than standard rosin core that has a duller look. Radio Shack sells it for about $1 more than their standard rosin core solder. They do sell a practice soldering kit too for about $15. A wet sponge for wiping the tip is what is in my old Weller soldering station that must be 30 years old now. It was designed for soldering those small IC chips and has a really small tip. Still works. I'd guess for a car you'd need something along the lines of a 40 watt iron or more. Good luck! Sep 20 15 09:28 am Link If the metallic runs on the board are very thin, like less than 1/8th, use a low-wattage iron with a small tip as mentioned above. Otherwise, you'll destroy the adhesive holding the copper to the substrate. The trick is to have the right temperature at the tip of a well-tinned iron, then get on and get off the copper trace: don't let the tip linger on the metal trace. You can clearly see the solder melt, and if it doesn't melt almost as quickly as you touch the metal run (say, a second or two), something's not right - back out and figure out what's wrong. Sep 20 15 09:39 am Link Also, try to have a heat sink between the soldering and the actual electronic part. Some pliers holding the wire would do just fine. You can get parts you need for soldering at Radio Shack. Sep 20 15 10:05 am Link The F-Stop wrote: Plumber's solder is acid core. Electronic solder is rosin core. Sep 20 15 10:32 am Link Practice on some old scrap electronics to get the "feel" of it. Use rosin core solder less than 1mm dia. such as http://www.ebay.com/itm/191286499825 (don't use plumbing solder or flux paste) Use a temperature controlled and ESD safe soldering iron such as https://www.hobbyking.com/hobbyking/sto … duct=19240 (the random temperature soldering irons are nowhere near as good) Tip should be clean and shiny. Heat the joint and add solder. I assume you are probably reworking loose connector pins -- if it has been arcing you may need to file, scrape or drill/grind the metal connector pin surface down a little to clean off oxidation. Adding fine copper wire into the solder from the pins to the circuit board tracks may be useful as well. (green or red solder mask coating must be scraped off) Everything should be clean and shiny. Don't breath the metal dust (lead) Recoat with thin epoxy or similar to stabilize if wire is added. see also http://www.ebay.com/itm/141438319994 http://www.ebay.com/itm/5pcs-Diamond-Ne … 1143001869 http://www.ebay.com/itm/5-NEW-71-0260-P … 0484574107 http://www.ebay.com/itm/UV-Solder-Mask- … 1264006403 Sep 20 15 01:30 pm Link Only some franchise stores remain. RadioShack Begins Liquidation http://www.inquisitr.com/1824309/radios … e-for-now/ RadioShack would accept liquidation bids: lawyer http://www.reuters.com/article/2015/02/ … H320150206 Sep 20 15 01:41 pm Link Bad solder on a circuit board will look flat and dull. Good solder will be shiny. You want to heat up and remove the bad solder first. You'll need a 'solder sucker' - a simple trigger-activated plunger/sucker. Then you can replace the solder. I used to fix power supplies in the 90's. Oh, remove the electronics from any power supply or battery first. Sep 20 15 01:44 pm Link Jerry Nemeth wrote: Yeppers. And to the person who likes to use a little silver, well, I suppose it won't hurt but if you solder correctly (using regular old electronics stuff) the joint will appear nice and shiny. If it is cloudy, well, ya didn't do it right and now have what we call a cold solder joint (that will fail). Sep 20 15 01:53 pm Link Flux is a paste that you add to wires and joints to make the solder stick better. It's not technically necessary, but it makes the process much easier. It also puts extra non-conductive stuff in the solder joint, which reduces how well it works. Not generally an issue for high-current stuff like power, or basic stuff like blinkers(they're on or off), but it might be a problem in some applications. Resin core solder has something like flux built in. You'd never use flux with that, unless you were having a bear of a time, and connection quality isn't a big deal. Even then, more practice would be better. Silver core has no flux, but silver is the best affordable conductor, so it work the best once you get it on there. Using silver solder with copper wire(especially really good copper wire) can be hard though, because everything conducts so well. You absolutely need heat sinks, or else the whole wire will heat up in your hand before you can get it soldered into place. I have some little tiny aluminum clips I use. I also have a big heavy base with clip arms, and that works as a heat sink too. Not knowing what part of your car you're soldering, I'd be hesitant to suggest you learn now. Reconnecting tail lights is no big deal, but fiddling with sensors or the CPU could cost you an awful lot of money if you do it wrong. I learned by wiring guitars - if I screwed up, I just played something else until I had a chance to fix it. It's easy to do, but it's not at all easy to do well. To this day, I still can't properly wire a guitar with braided metal shielding around the cables without a lot of mistakes and awful solder joints. My joints are usually only good for about a month. Sep 20 15 02:06 pm Link Paolo Diavolo wrote: Flux is a paste (or sometimes already coated on a filler metal) used to prevent oxidation, or a fudged up joint. I'm a plumber though, can't really help you with a circuit board! Sep 20 15 02:07 pm Link I haven't soldered electronic components for like 30 years now (switched from h/w to software), but used to do it a lot. It's an art. It's not hard to screw up a circuit board with too much heat. The trick is getting enough heat to melt the solder correctly on the joint, but not too much. Watch a few videos from someone that knows what they're doing with soldering circuit board components. It matters what you heat (solder or lead), how much (like I said). It's an art to do it correctly. Sep 20 15 02:13 pm Link J O H N A L L A N wrote: Yeppers! Personally, I think the OP should find an old PCB and practice de-soldering parts (another art) and then re-soldering them. It is an art, but one that is very easy to learn and master with a little practice. Sep 20 15 03:01 pm Link Paolo Diavolo wrote: Most plumber's solder are acid core flux which will corrode electronic components. You want to use a temperature controlled fine-point soldering iron of 700 degrees and thin rosin core solder. Assuming there is a wire lead from the component you want to solder, and a copper trace on the board, place a small amount of solder directly to the iron and lay it so it heats the lead and the trace at the same time evenly. After about 2-3 seconds, the component and trace will be at the right temperature. Apply the solder directly at the point where the metals meet. Avoid applying any more solder to the iron - but, rather apply the solder to the metals you're joining. If the solder doesn't melt, the metal is not hot enough and will give you a bad connection. The solder should start to melt and be drawn onto the trace and the component lead. Sep 20 15 03:32 pm Link I fixed it! I feel on top of the world haha. like I can fix anything. Resoldering it turned the airbag light off in my car. amazing. It was a bad connecton by the map light that indicates if the passenger doesn't have their seat belt on. Apparently the airbag circuit runs thru this. Geez can you imagine how much it would have cost if I took my car to the dealership to diagnose an airbag fault? And what they wouldve charged to replace stuff? Freebie! Sep 20 15 03:54 pm Link Paolo Diavolo wrote: Congratulations! You didn't set the car on fire. Sep 20 15 04:03 pm Link Jerry Nemeth wrote: The car makes fire on its own. Sep 20 15 05:37 pm Link It's best to get rosin core solder that is lead based because it melts faster although I use tin based, works just as well for me once the soldering iron is hot. If this is the first time you're soldering ever, I would suggest get a piece of wire and practice your soldering before going any further. Once you have a soldering iron heated up, you have to 'tin' the tip of it, which basically means just take your solder and melt it over the tip of the iron to coat it, this prevents the tip from oxidizing and therefore makes it much easier to solder. The best approach to soldering is to melt a little bit of solder on each end of whatever you're soldering and then when you place those ends with the solder next to each other and place the soldering iron on the solder, they will fuse into each other, creating a bond. This is a very fast process, as the solder solidifies almost instantly, so definitely practice on something else first, if you're going to do it yourself. Speaking from experience, an electrical engineer. Nvm haha didn't see your post glad you were able to fix! Sep 20 15 11:25 pm Link A lot depends on how small are the points you are soldering? I would look on craigslist to find those who do chips clocking and modchipping. Sep 21 15 12:01 am Link Ok you need electronic solder with a 60/40 rating. Fine pitch if you can also .5mm Sep 21 15 12:10 am Link Thanks for all the tips guys. I successfully fixed the part yesterday. Sep 21 15 06:53 am Link congratulations! no big deal... a monkey can do it! Sep 22 15 01:12 pm Link For the next time something comes up, start doing some reading and watch YouTube videos. In particular, the series from paceworldwide on YouTube is quite good. https://www.youtube.com/channel/UCT5e-X … _9wF3CgY1w Their training videos are old, but still applicable. As with photography, it is a mixture of art and science. Experience counts. You need to build up a feel for how different materials accept the solder and know the right tool for the job. Don't overlook the safety matters. Wear eye protection in case of splatters and work in a well-ventilated area. Sep 24 15 08:44 pm Link Sep 24 15 09:09 pm Link i only solder guitar parts. and that's with a chisel tip. i wouldn't want to trust my rudimentary skills on a pcb. although, with a little practice, it probably wouldn't be that hard, but i'd use a fine tip iron. there's the right way to solder, and the wrong way. someone mentioned earlier to use some form of heat dissipation (an alligator clip is fine), and that's a good idea. i use those when i'm attaching capacitors to my pots, in the guitar. it never hurts to take the one extra step to ensure not frying something. Sep 24 15 09:24 pm Link Electronic parts are more heat tolerant than you might guess. Wave soldering machine technology https://www.youtube.com/watch?v=Ap-HY7qP9zE (entire bottom of board is flushed with hot rosin and then molten solder - that's why the usually green solder mask is there) PC Board Assembly - Wave Soldering Machine https://www.youtube.com/watch?v=inHzaJIE7-4 (most problems with failed joints are because of large differences in heat dissipation between different types of parts - makes it hard to dial in the "right" temperatures on the machines) Sep 25 15 05:20 am Link Lots of useful comments above. My comment: let the work melt the solder. Do not smear solder over the joint, rather heat the joint and let it melt the solder when hot. Sep 25 15 09:47 am Link |
