J.N. Posted January 31, 2015 Share Posted January 31, 2015 I am genuinely puzzled with regard to the following question and it is not an attempt to instigate a protracted discussion. I was about to solder some gold plated connectors then thought to check if a dedicated solder/flux was needed (as with soldering stainless steel) and then call in at Maplins to buy the necessary solder. I looked up the internet and read an interesting article on the Wikipedia site. It was stated that soldering gold plated connectors had its problems in that the gold and solder melt into each other to a greater or lesser degree, leading to complications. I know it is all very technical and way above my retirement pension grade but I will be interested to know what is what. In the meantime I will solder the gold connectors with my normal resin cored tin/lead solder. Quote Link to comment Share on other sites More sharing options...
Depron Daz Posted January 31, 2015 Share Posted January 31, 2015 I just tend to use normal plumbers flux most of the time, never had any issue. I do have an expensive pot of electronic engineers board flux for SMD's but rarely gets used. Also the melting point of solder is many times lower than gold, so I can't see how they melt together at all? Edited By Depron Daz on 31/01/2015 11:58:27 Quote Link to comment Share on other sites More sharing options...
WolstonFlyer Posted January 31, 2015 Share Posted January 31, 2015 I use 2mm lead/tin flux cored solder. I bought a big roll from RS about 10 years ago and still have more than half left. I also use an electronics flux pen to add more flux where needed. I don't like plumbers flux for electronic, it is too thick and sticky for my liking.Soldering on the gold plated connectors is not an issue, it makes a very good joint, no special solder needed. Daz- Soldering works by the solder melting in to the surface of the other material at a molecular level, this forms a very strong joint.Edited By WolstonFlyer on 31/01/2015 12:29:30 Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted January 31, 2015 Share Posted January 31, 2015 Posted by Depron Daz on 31/01/2015 11:57:03: I just tend to use normal plumbers flux most of the time, never had any issue. I do have an expensive pot of electronic engineers board flux for SMD's but rarely gets used. Also the melting point of solder is many times lower than gold, so I can't see how they melt together at all? Edited By Depron Daz on 31/01/2015 11:58:27 Hi plumbers flux is highly corrosive and will eventually eat away at the copper wire unless washed off after soldering . Resin flux intended for electrical is Fine and I have never had a problem . Quote Link to comment Share on other sites More sharing options...
G-YRUS Posted January 31, 2015 Share Posted January 31, 2015 If modern plumbing fluxes were corrosive then they would corrode the copper pipe we use it on. And before somebody says they are washed out in water pipes, most are also suitable under the gas regs for natural and propane carrying copper gas pipes. Having said that I would not use them for electronics but battery connectors and under carriage wire etc its not an issue. It is good practice to wipe off any excess of used flux I would think. Edited By Biggles' Elder Brother - Moderator on 31/01/2015 16:57:49 Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted January 31, 2015 Share Posted January 31, 2015 My limited understanding is that high silver content solder is the best for gold - that's not silver solder before anyone gets confused! Maplins do one (to confuse matters they call it silver solder) but it's lead free so I'm not sure I'd recommend it! I still have a few inches of Deans Racing Solder which is supposed to be the "proper" stuff... Edited By Martin Harris on 31/01/2015 13:00:45 Quote Link to comment Share on other sites More sharing options...
Depron Daz Posted January 31, 2015 Share Posted January 31, 2015 In reference to the O.P's original statement, the gold doesn't melt at all. The solder obviously melts and bonds with the irregular surface of the gold connector, as you say at molecular level, which is what I was getting at. The only joints that I find get dirty are the negative joints, but that is a natural thing with negative. Hope I've explained that correctly. There was a fairly good thread on here about a year ago re the negative side of terminals getting dirty, and someone I believe explained the physics/chemistry side of things as to why it done this. I never did physics or chemistry at school, history and biology were my chosen subjects. Lol. Quote Link to comment Share on other sites More sharing options...
John Privett Posted January 31, 2015 Share Posted January 31, 2015 Posted by Depron Daz on 31/01/2015 13:30:45: In reference to the O.P's original statement, the gold doesn't melt at all. Indeed, just to put that into context, the melting point of gold is over 1,000 C. Traditional lead/tin solder melts at about 190 C and the horrible new stuff around 200-220 C. So for a soldering iron designed to melt solder at approx 200 C to reach 1,000 C would be quite a feat! Quote Link to comment Share on other sites More sharing options...
Stevo Posted January 31, 2015 Share Posted January 31, 2015 Normal Tin/lead solder, sometimes I flux the larger connectors with rosin flux, but mostly I flux the cable itself,as this is the most difficult to tin properly! Quote Link to comment Share on other sites More sharing options...
TigerOC Posted January 31, 2015 Share Posted January 31, 2015 Posted by J.N. on 31/01/2015 11:54:05: I am genuinely puzzled with regard to the following question and it is not an attempt to instigate a protracted discussion. I looked up the internet and read an interesting article on the Wikipedia site. It was stated that soldering gold plated connectors had its problems in that the gold and solder melt into each other to a greater or lesser degree, leading to complications. I know it is all very technical and way above my retirement pension grade but I will be interested to know what is what. In the meantime I will solder the gold connectors with my normal resin cored tin/lead solder. In chemistry terms this is referred to as electro-chemical corrosion. When 2 metals are mixed it leads to one metal degrading the other. This is how electroplating is accomplished. Another example is the degradation of aluminium components in automotive engines that have aluminium heads and iron blocks. In technical terms the more stable of the 2 metals will leach electrons from the less stable metal leading to it becoming a salt of the metal rather than the pure metal. The salt will form as crystals and either leach away as a liquid when combined with atmospheric water or a powder. This you will often see this on the battery terminals of lead acid battery. You will see a mixture of copper sulphate from the wire and lead sulphate. Since gold is quite a long way down in the periodic table and is a very stable metal it will have little effect on metals in solder in the short or medium term. Quote Link to comment Share on other sites More sharing options...
Erfolg Posted January 31, 2015 Share Posted January 31, 2015 The points that Tiger raises puts issues into perspective. Far to frequently issues are raised that although real, are not an immediate or medium term issues. Little of our equipment is going to last technically above 10 years. Perhaps the most significant advice provided for us, with electronic type issues, is that cored solders are the most appropriate. Many of us use lead tin solder, as the melting point is 20C lower than lead free, the best of containing silver. The reason being although 20c does not sound much. In reality it is a lot, as the possibility of damaging components particularly electronic and polymers (bits of plastic) increases significantly at these higher temperatures. I personally do solder lead free to lead tinned items, the purists will throw their hands up in horror. Telling us about the complex metallurgy and what might happen. On the other side of the coin, although the EU is wedded to lead free solder, you also see papers that have been written with respect to the long term stability of these alloys (joints). On that basis why worry, lead free does not come with a completely clean bill of health for stability and temperature issues. Cored solder is indisputable the best with electronics. Again as been said, passive flux such as Frys, often used in plumbing, is messy for electronics, great for what it is intended for. That is where materials are prone to fast oxidation, which are cleaned then protected with the flux. But leaves a sticky residue and probably more importantly obscures the small electrical joints, whilst soldering. As has been written, will work, and work well, but not convenient, and there is greater potential for messy residue. Outside of industry, much of what we agonise about is so theoretical as not to matter, for what we do. If you are my age, you will remember what your dad would do with a soldering iron stuck in the fire, looking for the colour of the flame surrounding the bit and then swiftly to work. No temp controlled iron, pretty dubious fluxes and solders. Yet our fathers did a very good job, essentially by just getting on with things. Our fathers had a sense of proportion which eludes us today. As for EU directives, who else but a EU bureaucrat and scientist would even think that a low wattage kettle would save energy, other than Ed Davey that is. The same issues surround many EU directives. So I have no worries about lead tin solders. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted January 31, 2015 Share Posted January 31, 2015 There is a phenomena knows as "Gold Embrittlement" & I recall it being considered an issue in the Defence Industry for military equipment. One reason why they often prefer to crimp connections rather than soldered. That said military equipment often needs to last 40 years or so which is significantly longer than most of our equipment will ever last so I just don't see this being a problem at all. Learn to solder, use resin cored solder for electrical/electronic joints....enjoy your hobby!! Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted January 31, 2015 Share Posted January 31, 2015 PS like Erf I prefer leaded solder but I picked up some samples of lead free at a recent Industry exhibition which have changed my mind somewhat..... Quote Link to comment Share on other sites More sharing options...
Chris Barlow Posted January 31, 2015 Share Posted January 31, 2015 Posted by Erfolg on 31/01/2015 15:15:37: If you are my age, you will remember what your dad would do with a soldering iron stuck in the fire, looking for the colour of the flame surrounding the bit and then swiftly to work. No temp controlled iron, pretty dubious fluxes and solders. Yet our fathers did a very good job, essentially by just getting on with things. Our fathers had a sense of proportion which eludes us today. Remember the old soldering iron well and after my father teaching me how to solder wires in an old CB radio I wouldn't trust him to solder a plug on an AA battery! Also my fathers sense or proportion and just getting on with it explains why his gate is fitted with butt hinges nailed to the gate post and why I wouldn't fix it when it started to fall apart! It's true we can get lost in technical details but I also think our standards today are a lot higher and achieving them easier with modern tools and materials. Back to the OP I have some Novak lead free solder (for RC cars) that I use for gold plated electrical connections along with traditional electrical flux. I do use white plumbers flux sometimes but clean it off with solvent afterwards as it does turn the copper wire green with a powdery surface! Quote Link to comment Share on other sites More sharing options...
Erfolg Posted January 31, 2015 Share Posted January 31, 2015 Unless the lead free solder has a higher silver content, then the 20C is just a conservative figure. I have tried lead free solder for a number of things, which has re-enforced my lead tin preferences. I have had some interesting conversations recently on the plumbing side, A few years ago with a plumber, connecting my new hob in, where he said he had gone to a higher temperature gas mix, due to failures with Lead free, that customers had done, and difficulties he had encountered. The second very recently, where I wanted a plumber to take out an old globe valve (which was passing when closed) in my daughters property and then insert a new stop valve in the Cu pipe. The first response was I am not confident that a lead clamp will work, I then suggested that why not wipe in a pb to Cu joint. The response then was I cannot get the right grade of Pb Tn solder. I said fortunately my farther has left a whole pile of the stuff (plumbers solder), I have it in my garage. Then it became a question of would it be legal, eventually a case he was not confident he could wipe the joint. So they now have a extra valve in the supply. I personally will continue to use Pb Tn electrical solder, as successful joints are far more probable, particularly where access is restricted or adjacent components is an issue. I find it very frustrating that many of the EU dictats come with the assurance that the performance of what ever, is as good or saves the environment,. Such as with low energy light bulbs. Institutions are leant on to agree. Then subsequently there is a retrospective acknowledgement that issues of poor performance, low initial lighting levels, production of light in unatural wave lengths for human eyes, damage to fabrics and even disposal issues, have now been improved to similar levels of performance as Tungsten Bulbs. Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted January 31, 2015 Share Posted January 31, 2015 Gold will actually dissolve (not melt) in molten solder, this can cause mechanical reliability, weakening and brittleness. To mitigate this, a solder is available that is mostly lead/tin, but also has a 2% silver component. Usually known as LMP (Low Melting Point) solder, usually with a flux core, it's the only solder I use on RC connectors. It has the added advantage that as it cools it changes directly from liquid to solid. It has no "pasty" state, like 60/40 solder does, so it's much less likely that any movement during cooling will cause a dry joint. Flux cored solder has the perfect flux inside it for the job at hand. There's never any need for other fluxes. Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted January 31, 2015 Share Posted January 31, 2015 I have had to edit one post - and then delete the perhaps justified, but over heated, response - on this thread. Remember that personal comments an insults are not allowed on here. If you can't discuss an issue without remaining civil to the views of other forum members then put simply - you're not welcome on here! So, let's all try to be polite and extend some respect towards other people's views - even when we don't agree with them and fact especially when we don't agree! BEB Quote Link to comment Share on other sites More sharing options...
Andy48 Posted January 31, 2015 Share Posted January 31, 2015 I do all my own plumbing, and having worked on an electronics assembly line for a year solid before moving on to production engineering I would say NEVER use plumbers flux, always resin cored solder when soldering connectors. Plumbers flux does corrode copper pipes where it is exposed to it. One only has to look at old plumbing connections to see the blue/green gunge when the plumber has not cleaned the joint after soldering. Used on connectors that same flux will travel up between the very thin strands of the connecting wire underneath the plastic sheath and will certainly corrode the individual thin wires. If you use cored solder together with a correctly rated soldering iron, and always tin both the wire and the gold connector first you should not have a problem Quote Link to comment Share on other sites More sharing options...
TigerOC Posted January 31, 2015 Share Posted January 31, 2015 Posted by Andy48 on 31/01/2015 19:46:26: Used on connectors that same flux will travel up between the very thin strands of the connecting wire underneath the plastic sheath and will certainly corrode the individual thin wires. This is good description of electrochemical corrosion. Plumber's flux contains ammonium chloride and ammonium salts are hygroscopic (attract water) thereby forming an ideal conductor for the passage of electrons from copper to tin and corrosion of the copper. The green gunk forming being copper chloride. Edited By TigerOC on 31/01/2015 20:02:32 Edited By TigerOC on 31/01/2015 20:03:18 Quote Link to comment Share on other sites More sharing options...
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