Soldering question...

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Don't use plumbing flux, it is acidic and can eat into the copper wires. Electrical flux like rosin is not acidic.
Which is of course exactly how it works very effectively on copper pipe.I have used this technique on stubborn joints for years without issues. You certainly do have to make sure you use it very sparigly, and clean properly afterwards, otherwise yes you would have issues in future. But for instances where all normal techniques have not worked, this has never failed me. If access for cleaning afterwards is an issue then you can use it as a preparation beforehand. I also find that the moern lead free solders are nothing like as effective, unless everything is spotless. Ì treasuure a stock of old lead solder for those more challenging situations 🙂
 
You can still buy lead based solder for both plumbing and electrical / electronic's . For avionics, medical and mil specs then I believe you can only use lead based solder which does say something for lead free!
 
You can still buy lead based solder for both plumbing and electrical / electronic's . For avionics, medical and mil specs then I believe you can only use lead based solder which does say something for lead free!
Have seen it for elecrical use, didnt know you could still get it for plumbing. Fortunately i still have enough rolls of the good old stuff to see me out!
 
Ive a question about soldering, in case anyones an expert... Im trying to repair some failed electrical joints in some speaker drivers. They have two delicate wires that go into the voice coil under the central dust cap/dome, but they have perished through oxidation i think in damp storage.

I want to solder a new connection to these wires that go into the voice coil, but i cannot for the life of me get any solder to stick. I have gently abraded with a stanley blade, fine sand paper, and heat to try and get rid of any possible coating, to no avail. Using flux and tried a couple of types of bog standard solder with a cheapo soldering iron.
Im stumped. If i can just make a reliable electrical connection (has to withstand being wobbled vigorously at many frequencies) i think i can salvage these drivers and they are decent, full recone kits are laborious and expensive so it would be great to avoid that. So im hoping i just need bettert solder/flux/iron?
I find if it’s clean and fluxed it will flow I usually used cored solder on wiring ( solder with flex inside) good luck
chas
 
didnt know you could still get it for plumbing
Yes with plumbing you can use lead but not on potable water supplies. What some plumbers do is to roll lead solder onto the spool saying lead free. We have had lead solder for decades, I cannot recal any deaths as a direct result of plunbers using lead solder, there are still a lot of houses with lead pipes and the only joint failures I have had, have been with lead free. You are probably inhaling more toxins and such just by walking through London than the lead used in pipework has delivered to the population.
 
Yes with plumbing you can use lead but not on potable water supplies. What some plumbers do is to roll lead solder onto the spool saying lead free. We have had lead solder for decades, I cannot recal any deaths as a direct result of plunbers using lead solder, there are still a lot of houses with lead pipes and the only joint failures I have had, have been with lead free. You are probably inhaling more toxins and such just by walking through London than the lead used in pipework has delivered to the population.
Yes, sill have a lead main here. And at my dads cottage he still has a number of pipes with the big egg shaped lead joints. He's nearly 100 and still going strong. As for air pollution I seem to recall reading somwhere that if you drive a modern low emission, cat etc car through some cities the air coming out of the exhaust pipe can be cleaner than the stuff going in :)
 
You need to use the same time of solder as was originally used. I can’t remember at what stage lead-free solder was introduced, but its some years now, so if the joint was made with that and you’re using 60/40 lead/tin solder, or conversely, the joints were made with lead/tin and you’re using lead-free, they won’t mix. Well they will, after a fashion, but in my experience, the alloy created has a much higher melting point.

You can buy small bottles of non-corrosive liquid flux as is used in SMD PCB production. It works well with both types of solder.

The coil is itself is just a few turns of fine enamelled copper wire. Much depends on the age of the speakers, but as often as not, the wire is self-fluxing and when the enamel melts, the joint will solder without cleaning off the enamel or using flux. (assuming the solder is flux cored, as it usually is).

Hope that might help a bit.
 
Thanks everyone! Have ordered a nice new iron and ive got some plumbing flux now and will give all these things a go and report back.

As has been said just be aware plumbing flux tends to be rather strong and can be both water soluble (easy clean) and not so easy!

It will hopefully achieve what you want but should be neutralised or cleaned off to prevent future damage to the surrounding cone.
 
Some one has already mentioned it, but the fact you say the metal is silver coloured when yo removed the coating may mean it’s not copper…it may be aluminium…in which case it’s back to the drawing board
 
Ive a question about soldering, in case anyones an expert... Im trying to repair some failed electrical joints in some speaker drivers. They have two delicate wires that go into the voice coil under the central dust cap/dome, but they have perished through oxidation i think in damp storage.

I want to solder a new connection to these wires that go into the voice coil, but i cannot for the life of me get any solder to stick. I have gently abraded with a stanley blade, fine sand paper, and heat to try and get rid of any possible coating, to no avail. Using flux and tried a couple of types of bog standard solder with a cheapo soldering iron.
Im stumped. If i can just make a reliable electrical connection (has to withstand being wobbled vigorously at many frequencies) i think i can salvage these drivers and they are decent, full recone kits are laborious and expensive so it would be great to avoid that. So im hoping i just need bettert solder/flux/iron?
Hello,
It could just be your solder, use a solder which has flux in it. Take a look as RS Components for the correct solder
Regards
 
As has been said just be aware plumbing flux tends to be rather strong and can be both water soluble (easy clean) and not so easy!

It will hopefully achieve what you want but should be neutralised or cleaned off to prevent future damage to the surrounding cone.
Yes cleaning any residue is important, so it doesnt carry on working afterwards. So needs to be used vary sparingly and neutralised/cleaned with a dampened q tip or contact cleaner. I certainly wouldnt advocate using it routinely, but when you are in that last chance saloon situation, when the next move is to have to bin the thing, its well worth a try. Has got me out of a hole on many occasions. It is also useful for soldering dissimilar metals. I do regularly use it for soldering brass curb pins onto steel regulator arms in pocket watches. Have tried various specialist products, but have never found anything else that does the job as well.
It seems to me that this is a common problem with many modern products, be it flux/solder or for example weedkiller. Making them free from nasty ingredients is all very well, but often leaves you with a product which doesnt actually work as well as the old fashioned "dirty" version.
 
I’ve managed to solder headphone and speaker wires in the past by flicking a lighter flame over the end. Any coatings burn off, and you can scrape it clean, flux and tin it. They are quite delicate so be careful.
 
Back in my younger days and well before noise pollution police and asbo,s I had two 18” base bins home made of course. Every now and again 1 bin would drop out - I had to remove the back and literally climb in and re-solder this tiny wire back onto the coil. It would last a few weeks then fail again , In the end I could do the repair in a few mins - I used a standard soldering iron and some old resin cored solder -I think it came off the arc . I have a small refillable torch with a catalytic converter that heats a small soldering tip to a high temperature-it could be worth trying this method if all else fails. I’ll post a pic of my torch when I’m back at home .
 
I'm inclined to think the wire will be aluminium because of its light weight. The silver colour would tend to corroborate that. You can get special solder for that.
Re: enamel - it's entirety possible that it's plain enamel and not polyputthekettleon type, which doesn't melt and has to be scraped off.
 
I have often found that plumbing flux overcomes this sort of issue. Seems to be much more powerful. Just smear a tiny blob, maybe a mm round or less on the surface then use your regular iron. I would advise you clean thoroughly afterwards as its powerful stuff and if you leave any residue behind it will eat its way through your delicate wiring.
Wire corrosion is the formation of an oxide, flux does not REMOVE the oxide.
Whether the wire is copper, aluminium or other - they will either oxidise ( or in marine environments form chlorides )
Flux just assists in the soldering process by "wetting" between the base metal and the solder.
It may appear that you have formed a good fusion, but not so.
If the wire has ANY signs of corrosion - just replace it
 

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