Mouse Posted January 14, 2016 Share Posted January 14, 2016 Hi there just a quick question, my wife bought me a model aircraft for christmas and i have to do some soldering on the power distribution board, and i am confused as to wether i need to use flux or not. one shop has said i do not have to use it because non leaded solder does not need it, another shop has said that non leaded solder is no good and has given me some leadded solder but has also said to use a paste flux for very thin wires only but when i watch build blogs for this model on the internet most people use a liquid flux. Could you good people give me your oppinion on this. Thank you Bill. Quote Link to comment Share on other sites More sharing options...
trebor Posted January 14, 2016 Share Posted January 14, 2016 You will find a better flow of solder using flux as long as its not the corrosive type. It cleans the surface to be soldered. Quote Link to comment Share on other sites More sharing options...
Phil Green Posted January 14, 2016 Share Posted January 14, 2016 Lead-free solder is a Bad Thing. Its responsible for gazillions of equipment failures and remains banned for medical electronics. Get some 60/40 cored lead solder, this has a channel of flux inside the solder and with clean connections should be all the flux you need. Once you've finished up, clean off any remnants of flux as it can be corrosive. Just a point of interest, a 'power distribution board' suggests a larger, more complex model - have you flown RC before? just thinking it might not be the best introduction, maybe save it as a second model after a trainer. What exactly have you got there? Cheers Phil Edited By Phil Green on 14/01/2016 19:15:15 Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted January 14, 2016 Share Posted January 14, 2016 Leaded solder is "banned" but can still be used in military or medical equipment or any "safety critical" equipment which kind of tells you everything you need to know really. I don't find lead fre solder as good to use as good old 60/40 but it does work OK. Most solders you buy are cored in that they contain flux inside the solder itself....when the solder melts the flux is released to help the solder flow properly.... Quote Link to comment Share on other sites More sharing options...
Allan Bennett Posted January 14, 2016 Share Posted January 14, 2016 As a rule I find that extra flux (there's flux in the solder wire) is not necessary with small, clean, electrical items. Each part should be tinned first, before offering them together; that means applying some solder so that they're completely coated. I only use a separate flux with larger items, such as undercarriage wire legs, or untinned printed circuit boards. Your power distribution board may be in the latter category so, if so, would benefit from light cleaning with very fine emery paper, and a thin smear of flux before tinning. Quote Link to comment Share on other sites More sharing options...
Phil Green Posted January 14, 2016 Share Posted January 14, 2016 Posted by Steve Hargreaves - Moderator on 14/01/2016 19:54:09: Leaded solder is "banned" ...only for commercial use, its perfectly legal for us to use it as hobbyists. Posted by Steve Hargreaves - Moderator on 14/01/2016 19:54:09: I don't find lead free solder as good to use as good old 60/40 I'd go beyond that and say its evil ! In repair work I find that many faults turn out to be lead-free joints gone bad. Horrid stuff ! Quote Link to comment Share on other sites More sharing options...
Shaunie Posted January 14, 2016 Share Posted January 14, 2016 Yup, unleaded solder is the work of the devil but is a legal requirement for consumer electronics unfortunately. The important thing to remember is that attempting to repair unleaded boards etc with leaded solder is a bad thing. Given the choice use leaded but if the joint is unleaded then repair with unleaded. If you want to flux beforehand I use these **LINK** Shaunie. Quote Link to comment Share on other sites More sharing options...
Stuart C Posted January 14, 2016 Share Posted January 14, 2016 Reading this, I thought that I would check up on what I use. Its Ersin MultiCore - and has five flux cores in 18 swg leaded ribbon. How much lead, the package does not say. Purchased in UK - made in Malaysia! Could be anything, but it does the job and claims to be non-corrosive. Quote Link to comment Share on other sites More sharing options...
Phil Green Posted January 14, 2016 Share Posted January 14, 2016 Ersin Multicore is the longest established, most reliable, most common 60/40 and beloved by electronics people the world over. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted January 14, 2016 Share Posted January 14, 2016 That's why I put "banned" in inverted commas Phil.... 60/40 still widely available from Maplins CPC etc. Ersin Multicore uses Rosin flux I believe (rosin is a type of resin derived from pines) been around for donkeys years. Also worth looking at LMP or Low Melting Point solder....as you might guess this has a relatively low melting point (useful as it helps prevent you melting any plastic in the vicinity of your iron) but the main benefit for me is that it goes from liquid to solid instantly...there is no "pasty" stage like with many other solders...a bit of movement during the pasty stage can lead to a very unsatisfactory joint. Be warned though LMP solder isn't cheap..... Quote Link to comment Share on other sites More sharing options...
onetenor Posted January 14, 2016 Share Posted January 14, 2016 Ersin solder is the dog's diddlies. Non lead solder needs a hotter iron aas it melts at a higher temp. This is often the reason for poor joints. Insufficient heat to get the solder flowing properly. If you need to repair a lead free solder joint use a solder pump to remove as much of the old solder as you can. Scrape the joint area with the tip of a sharp knife tip,flux it and wait a few minutes before applying the iron and solder to the joint. Hold the iron on for a few extra seconds after the solder flows. That should be OK then as long as you don't move / shake the joint until it cools. Use the same routine with LMP solder . Leaded is banned for use on things like potable water and other consumables which could come into contact with it . Quote Link to comment Share on other sites More sharing options...
Braddock, VC Posted January 14, 2016 Share Posted January 14, 2016 Before I add my twopennorth, I must say that soldering for me isn't repairing or making electronic equipment, simply joining servo leads, soldering battery connectors and also making wire undercarts and low skilled bits like that. I started using lead free with poor success until I bought an iron designed for lead free. Since then I have found lead free soldering a joy compared to previously, even deans plugs are a doddle. I assume the solder I use has internal flux and my results seem to bear that assumption out. Edited By Braddock, VC on 14/01/2016 23:46:54 Quote Link to comment Share on other sites More sharing options...
Allan Bennett Posted January 15, 2016 Share Posted January 15, 2016 I keep reading about the supposed evils of lead-free solder but, having used it for several years now, I have yet to find what they are. I've not had a failure on any of my joints using it. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted January 15, 2016 Share Posted January 15, 2016 There was a story in the photo magazines that when the rule that only lead free solder could be used in manufacturing that Hasselblad were going to stop making cameras. I see that they are still making them so I wonder what the answer was there. I always buy lead/tin solder, cored with flux. It doesn't need any extra flux normally but sometimes it can help with big joints in heavy guage piano wire Quote Link to comment Share on other sites More sharing options...
Geoff S Posted January 15, 2016 Share Posted January 15, 2016 Posted by Phil Green on 14/01/2016 21:26:26: Ersin Multicore is the longest established, most reliable, most common 60/40 and beloved by electronics people the world over. I agree, though my current batch of 60/40 isn't Ersin I must have used a few rolls of it in the past 60 odd years. I can't see my needing to buy any more now as I've just started a new reel. The one to avoid for electrical work is Arax Multicore which has an acid flux which works for steel soldering etc. I sneaked a few inches of Arax into my Radio Servicing Exam soldering test back in 1958 just in case I needed it. I actually used it to solder an earth wire onto the tiny steel chassis we were given. I still passed Geoff Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted January 15, 2016 Share Posted January 15, 2016 Ah yes but the earth wire probably fell off shortly after your exam Geoff.....eaten away by the acid flux.... Quote Link to comment Share on other sites More sharing options...
Kevin Wilson Posted January 15, 2016 Share Posted January 15, 2016 Posted by Braddock, VC on 14/01/2016 23:45:58 I started using lead free with poor success until I bought an iron designed for lead free. Since then I have found lead free soldering a joy compared to previously, even deans plugs are a doddle. I believe that lead free solder has a higher melting point. This explains why VC had greater success with a specific iron and why I struggle with my old Weller temperature controlled iron. Of couse sparking up a good old thermal balanced 25w+ iron gets the leadfree muck flowing enough to replace it with 60/40. For electrical connections on clean surfaces (essential imho) 60/40 flux cored is all that is necessary. Soldering non electrical connections is another matter entirely and necesitates a different approach dependant on what materials you are joining. Quote Link to comment Share on other sites More sharing options...
Geoff S Posted January 15, 2016 Share Posted January 15, 2016 Posted by Steve Hargreaves - Moderator on 15/01/2016 12:47:30: Ah yes but the earth wire probably fell off shortly after your exam Geoff.....eaten away by the acid flux.... Yes but I why should I care as, according to the certificate I probably have hidden away somewhere, I'm a Certified Radio Service Engineer? Forget the 'Certified' for a bit and remember that 99% of the radios I repaired still had valves and you'll appreciate it doesn't stand for much Even the manufacturer (Murphy Radio) whose service department I worked in hasn't existed for decades. Come to that, none of the companies I've ever worked for, except Rolls Royce, are still in business including the then giant GEC. Even Royce's seem to be on shaky ground! Plus ca Change! Geoff Quote Link to comment Share on other sites More sharing options...
Mouse Posted January 15, 2016 Author Share Posted January 15, 2016 Hi there Thank you for all the reply's, After reading all the posts I have one another question, I have some Ersin 5 core multicore leaded solder, is this what some of you good people have recommended as mine does not say what the ratio is. Also to answer phil green, it is a hexcopter I am building and the li-po leads are connected to one of the frame boards and power is sent through the board to various points where the esc's are then soldered, it makes for a far neater instulation than having wires run everywhere. Thank you Mouse. Quote Link to comment Share on other sites More sharing options...
Andy48 Posted January 15, 2016 Share Posted January 15, 2016 That'll do nicely Mouse. Quote Link to comment Share on other sites More sharing options...
Geoff S Posted January 15, 2016 Share Posted January 15, 2016 It will indeed, Mouse and no other flux necessary. Geoff Quote Link to comment Share on other sites More sharing options...
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