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#1
Posted to rec.audio.pro
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Solder (again)
I hate lead-free solder and all the stress to components, tools, and PCB
that rework entails when repairing gear. Ideally I clean off the crappy stuff as best possible, and re-solder with regular 60/40. But what if I didn't clean off the lead-free ? What are the implications of a blend of lead-free and leaded solder, electrically, physically, and chemically ? geoff |
#2
Posted to rec.audio.pro
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Solder (again)
Geoff wrote:
------------ I hate lead-free solder and all the stress to components, tools, and PCB that rework entails when repairing gear. Ideally I clean off the crappy stuff as best possible, and re-solder with regular 60/40. But what if I didn't clean off the lead-free ? ** When replacing components, it is easy enough to clean up the old Pb free solder and use fresh 60/40 to get a shiny and reliable joint. Same goes for cracked solder work that plagues so much gear theses days. What are the implications of a blend of lead-free and leaded solder, electrically, physically, and chemically ? ** Unknowable, cos you never know Pb free alloy was used on the PCB - makers should all be forced to label PCBs with that info. However, when the result looks dull and crystalline, it is a poor quality joint. ..... Phil |
#3
Posted to rec.audio.pro
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Solder (again)
On 5/02/2018 6:35 PM, Phil Allison wrote:
Geoff wrote: ------------ I hate lead-free solder and all the stress to components, tools, and PCB that rework entails when repairing gear. Ideally I clean off the crappy stuff as best possible, and re-solder with regular 60/40. But what if I didn't clean off the lead-free ? ** When replacing components, it is easy enough to clean up the old Pb free solder and use fresh 60/40 to get a shiny and reliable joint. Same goes for cracked solder work that plagues so much gear theses days. Short of abrading off the pads with a glass-fibre scratcy-brush-pencil thingy (don't ya hate those invisible shards that stick in yer fingers ?), always will be a remaining tinning of whatever came first. And wires already tinned with Pb-free and too short to snip and re-tin ? Or if just too lazy ? What are the implications of a blend of lead-free and leaded solder, electrically, physically, and chemically ? ** Unknowable, cos you never know Pb free alloy was used on the PCB - makers should all be forced to label PCBs with that info. However, when the result looks dull and crystalline, it is a poor quality joint. Just like Pb-free at the best of times .... geoff |
#4
Posted to rec.audio.pro
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Solder (again)
geoff wrote:
------------- But what if I didn't clean off the lead-free ? ** When replacing components, it is easy enough to clean up the old Pb free solder and use fresh 60/40 to get a shiny and reliable joint. Same goes for cracked solder work that plagues so much gear theses days. Short of abrading off the pads with a glass-fibre scratcy-brush-pencil thingy (don't ya hate those invisible shards that stick in yer fingers ?), always will be a remaining tinning of whatever came first. ** IME, using flux impregnated "solder wick" does the job well enough. BTW: I only discovered fibre pens last year and am still discovering good uses. Cleaning up green corrosion on PCB tracks from leaking Ni-Cd memory batteries is one - then you need to clean the residue off with a PCB cleaner spray. ...... Phil |
#5
Posted to rec.audio.pro
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Solder (again)
On 5/02/2018 7:54 PM, Phil Allison wrote:
geoff wrote: ------------- But what if I didn't clean off the lead-free ? ** When replacing components, it is easy enough to clean up the old Pb free solder and use fresh 60/40 to get a shiny and reliable joint. Same goes for cracked solder work that plagues so much gear theses days. Short of abrading off the pads with a glass-fibre scratcy-brush-pencil thingy (don't ya hate those invisible shards that stick in yer fingers ?), always will be a remaining tinning of whatever came first. ** IME, using flux impregnated "solder wick" does the job well enough. BTW: I only discovered fibre pens last year and am still discovering good uses. Cleaning up green corrosion on PCB tracks from leaking Ni-Cd memory batteries is one - then you need to clean the residue off with a PCB cleaner spray. They are amazing, even on gold-plated stuff can be controlled so as to not cause (too much) damage. Not as coarse as brass or steel ones. But the minute fragments that crumble off get everywhere, and even days later can end up embedded in digits and palms, and seem impossible to find/remove. But as so short they seem to find their own way out after a half-day or so. geoff |
#6
Posted to rec.audio.pro
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Solder (again)
Geoff wrote:
I hate lead-free solder and all the stress to components, tools, and PCB that rework entails when repairing gear. Ideally I clean off the crappy stuff as best possible, and re-solder with regular 60/40. But what if I didn't clean off the lead-free ? What are the implications of a blend of lead-free and leaded solder, electrically, physically, and chemically ? It depends, because all the lead-free formulations are different. But if you don't get a nice shiny joint, suck it off and do it again. The 60/40 or 63/37 should be nice and shiny and you can tell that it isn't crystallized and weak inside from the look of the joint. The lead-free joints will look dull and you can't really tell if they are good or not without x-ray inspection. If the contamination of lead-free stuff into the leaded solder is enough of a problem, it will cause the joint to look dull. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#7
Posted to rec.audio.pro
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Solder (again)
geoff wrote:
On 5/02/2018 6:35 PM, Phil Allison wrote: Geoff wrote: ** When replacing components, it is easy enough to clean up the old Pb free solder and use fresh 60/40 to get a shiny and reliable joint. Same goes for cracked solder work that plagues so much gear theses days. Short of abrading off the pads with a glass-fibre scratcy-brush-pencil thingy (don't ya hate those invisible shards that stick in yer fingers ?), always will be a remaining tinning of whatever came first. Put leaded solder on over the lead-free crap. Suck it off with the Soldapulit. Then solder the joint properly. If it looks dull, suck THAT off with the Soldapulit and try again. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#9
Posted to rec.audio.pro
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Solder (again)
Don Pearce wrote:
It is possible to make a decent joint with lead-free solder, even when you are gap-filling. This is a seven second video I made for our factory, showing them how to solder the pin of an F-type connector to a pcb https://www.youtube.com/watch?v=F7038fKlO2s It IS possible, the problem is that without special equipment you can't really tell if it's decent or not. The guys at the factory can check it for good fill, but I can't. And because it's more brittle, you have to be more careful about designing for strain relief, making sure connectors are physically secured, etc. You can make it reliable, but it's more work. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#10
Posted to rec.audio.pro
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Solder (again)
On 5 Feb 2018 12:46:32 -0500, (Scott Dorsey) wrote:
Don Pearce wrote: It is possible to make a decent joint with lead-free solder, even when you are gap-filling. This is a seven second video I made for our factory, showing them how to solder the pin of an F-type connector to a pcb https://www.youtube.com/watch?v=F7038fKlO2s It IS possible, the problem is that without special equipment you can't really tell if it's decent or not. The guys at the factory can check it for good fill, but I can't. And because it's more brittle, you have to be more careful about designing for strain relief, making sure connectors are physically secured, etc. You can make it reliable, but it's more work. --scott Certainly in my application both pin and PCB were very securely anchored. The screws right alongside the connector were really that close for RF performance reasons, but they certainly make for a good reliable solder joint. d --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
#11
Posted to rec.audio.pro
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Solder (again)
On 05 Feb 2018, Phil Allison wrote in
rec.audio.pro: I only discovered fibre pens last year and am still discovering good uses. Cleaning up green corrosion on PCB tracks from leaking Ni-Cd memory batteries is one - then you need to clean the residue off with a PCB cleaner spray. Is this what you're referring to? I've never seen those before. They look like they could be useful for a number of things. https://www.amazon.com/Cleaner-RISEP.../dp/B071HW43DN |
#12
Posted to rec.audio.pro
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Solder (again)
On 05/02/2018 19:49, Nil wrote:
On 05 Feb 2018, Phil Allison wrote in rec.audio.pro: I only discovered fibre pens last year and am still discovering good uses. Cleaning up green corrosion on PCB tracks from leaking Ni-Cd memory batteries is one - then you need to clean the residue off with a PCB cleaner spray. Is this what you're referring to? I've never seen those before. They look like they could be useful for a number of things. https://www.amazon.com/Cleaner-RISEP.../dp/B071HW43DN I've been using one like this for about ten years now, though to be fair, I don't do much in the way of circuit board repairs nowadays. :- https://www.amazon.co.uk/Modelcraft-...SF7KZZJ05C0KC2 -- Tciao for Now! John. |
#13
Posted to rec.audio.pro
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Solder (again)
John Williamson wrote:
------------------------ I've been using one like this for about ten years now, though to be fair, I don't do much in the way of circuit board repairs nowadays. :- https://www.amazon.co.uk/Modelcraft-...SF7KZZJ05C0KC2 ** Looks identical, but being sold as a hobby tool. Costs about around A$6 for the pen or 10 refills from a local electronics parts wholesaler. ..... Phil |
#14
Posted to rec.audio.pro
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Solder (again)
On 6/02/2018 8:49 AM, Nil wrote:
On 05 Feb 2018, Phil Allison wrote in rec.audio.pro: I only discovered fibre pens last year and am still discovering good uses. Cleaning up green corrosion on PCB tracks from leaking Ni-Cd memory batteries is one - then you need to clean the residue off with a PCB cleaner spray. Is this what you're referring to? I've never seen those before. They look like they could be useful for a number of things. https://www.amazon.com/Cleaner-RISEP.../dp/B071HW43DN Duuno if the same principle, this this: https://uk.rs-online.com/web/p/pcb-c...ushes/0514868/ The individual strands are extremely thin/fine. geoff |
#15
Posted to rec.audio.pro
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Solder (again)
On 05 Feb 2018, geoff wrote in
rec.audio.pro: Duuno if the same principle, this this: https://uk.rs-online.com/web/p/pcb-c...ushes/0514868/ The individual strands are extremely thin/fine. It looks like the one I referred to is a specialized one for fiber optic connectors. For general electrical contact cleaning the simple pencil style would probably be as good or better, and for 1/4 the price. It looks similar to a mechanical pencil - when the tip wears down, you push more of the cartridge out. Eventually it's used up and you replace the cartridge. Right? |
#16
Posted to rec.audio.pro
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Solder (again)
On 6/02/2018 1:21 PM, Nil wrote:
On 05 Feb 2018, geoff wrote in rec.audio.pro: Duuno if the same principle, this this: https://uk.rs-online.com/web/p/pcb-c...ushes/0514868/ The individual strands are extremely thin/fine. It looks like the one I referred to is a specialized one for fiber optic connectors. For general electrical contact cleaning the simple pencil style would probably be as good or better, and for 1/4 the price. It looks similar to a mechanical pencil - when the tip wears down, you push more of the cartridge out. Eventually it's used up and you replace the cartridge. Right? Yep. geoff |
#17
Posted to rec.audio.pro
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Solder (again)
geoff wrote:
On 6/02/2018 1:21 PM, Nil wrote: On 05 Feb 2018, geoff wrote in rec.audio.pro: Duuno if the same principle, this this: https://uk.rs-online.com/web/p/pcb-c...ushes/0514868/ The individual strands are extremely thin/fine. It looks like the one I referred to is a specialized one for fiber optic connectors. For general electrical contact cleaning the simple pencil style would probably be as good or better, and for 1/4 the price. It looks similar to a mechanical pencil - when the tip wears down, you push more of the cartridge out. Eventually it's used up and you replace the cartridge. Right? Yep. You will lose it or some kid will borrow it long before the cartridge is used up. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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