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Re: RoHS question
Jim,
There is a raft of information on tin whiskers at one of the NASA sites: Some really great (scary) photos As you can see on the NASA site, there actually were several communications sat failures due to whiskers. The one that most people remember is the Galaxy 4 Panamsat. That is the one that was carrying most of the pager traffic in the US. I worked on equipment that went on the replacement sat. If ever there was a customer that was jittery and over protective about tin, that one was it. He was right! As to how the tin got onto the sats, you will see several examples of things that were overlooked. "Everybody" knew that the leads on the ICs, transistors and most electronic parts were tin plated, so we had them solder dipped. We went out of our way to make sure the terminal posts we bought were solder plated, or solder dipped. When we inspected some of the terminal posts that looked odd for solder plate, we found that some were tin plated. At that point we stepped up our inspection for the finish, and we found that the suppliers were ignoring the solder requirement, and sending tin finish because they were in stock. Other structural hardware sometimes was tin plated. Several corrective actions were taken to replace them. Conformal coat does not protect against tin whiskers. The whiskers are really sharp, and push through the coatings. They also take on all kinds of odd shapes, and have been seen to curl over and touch each other. They also can break off, and become lodged in areas that are not coated. Harvey |
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Re: RoHS question
Yes, we're in violent agreement.
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Unless you're a manufacturer, RoHS (or whatever your local flavour is) isn't a problem. Space vehicles are exempt from these regulations, I guess they figure not many of them are going to wind up in a landfill. For the tin whiskers, the problem wasn't lead-free solder, it's the tin plating on the copper tracks, something even hobbyists do. I think they nickel plate stuff like spacecraft PCBs now. Dunno if there is a chemical solution to do nickel plating on copper like you do with tin, but electroplating nickel is really easy. Tony -----Original Message-----might tinker with the product. It applies only to manufacturers. We - hobbyists- can repair even brand new RoHS compliant gear using tin-lead solder if wein pure (or almost pure) tin solder was documented back when vacuum tubes werethere to fix a connection that's growing a whisker that has caused a shortcircuit even if the short hasn't caused permanent damage. RoHS solder formulationmany whales.sort of thing.of us.
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Re: RoHS question
Jim Higgins
RoHS isn't a requirement that applies to consumers, incl hobbyists who might tinker with the product. It applies only to manufacturers. We - hobbyists - can repair even brand new RoHS compliant gear using tin-lead solder if we want to.
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RoHS is an EU thing dating from early 2003 that expanded industry wide because industry wants to do business with the EU. I have no idea how the low/no-lead portion of it was ever incorporated into products made for applications in space... since the problem of "tin whiskers" (Google it) in pure (or almost pure) tin solder was documented back when vacuum tubes were king and solid state didn't exist - in the early part of the 20th century. We (the USA) have had at least one satellite failure and one nuclear plant malfunction due to tin whiskers. In the case of a satellite - even a big expensive commsat as was the case - it's not really convenient to go up there to fix a connection that's growing a whisker that has caused a short circuit even if the short hasn't caused permanent damage. RoHS solder formulation has improved since those days and conformal coating over completed boards takes care of any remaining risk. Conformal coatings in consumer products make repairs much more difficult. Jim H Received from Tony Smith at 10/28/2020 04:43 UTC: RoHS doesn't bother a lot of people, even if you're repairing old gear where the tracks fall off if you look at them funny you're still allowed to use leaded solder. They're full of lead and god only know what so redoing a couple of joints in lead-free isn't going to save too many whales. |
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Re: RoHS question
开云体育RoHS doesn’t bother a lot of people, even if you’re repairing old gear where the tracks fall off if you look at them funny you’re still allowed to use leaded solder.? They’re full of lead and god only know what so redoing a couple of joints in lead-free isn’t going to save too many whales. ? It’s not all that complicated, just mainly nit-picking pedantic pen-pushing stuff.? I work in IT dealing with money, so I’m used to that sort of thing. ? If you making laptops or whatever you get a statement from whom you buy solder, PCB, wire etc from that says how much lead is in it.? You staple all those together and send it off to the EU and say “our laptops are made from this” and everyone is happy.? Of course this means you can’t buy the cheapest solder from Honest Johns Alibaba shop and things are a bit more difficult if you actually make solder, but that’s not most of us. ? Tony ? ? From: [email protected] <[email protected]> On Behalf Of Dave
Sent: Wednesday, 28 October 2020 4:12 AM To: [email protected] Subject: Re: [homebrewpcbs] RoHS question ? Tony, ? Looks complicated but as Jim said I (we) shouldn't even worry about it as hobbyists. Dave On 10/27/2020 5:08 AM, Tony Smith wrote:
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Re: RoHS question
开云体育Tony, ? Looks complicated but as Jim said I (we) shouldn't even worry
about it as hobbyists. Dave On 10/27/2020 5:08 AM, Tony Smith
wrote:
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Re: RoHS question
Thanks Jim. That sorts out all of my questions and thoroughly answers them. I will stick with what I have as I have plenty to last forever.
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Dave On 10/27/2020 9:35 AM, Jim Higgins wrote:
Received from Dave at 10/26/2020 23:23 UTC:I bought some USB cables and noticed the RoHS sticker on them and never really read much about the standard so I have a few questions. It states something about 0.1% lead is allowed but in the case of cables, does that take in the whole weight of the cable?? |
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Re: RoHS question
Thanks for the reply Tony. That is what I wanted to know as I have a lot of regular 60/40 and some 63/37 that ought to last me forever. I also see no need to overheat or burn up my pcb's when using the higher temps with lead free solder.
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Cheers, Dave On 10/26/2020 6:52 PM, Tony Smith wrote:
It doesn't really matter what the item is, the lead (or whatever) percentage |
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Re: RoHS question
Jim Higgins
Received from Dave at 10/26/2020 23:23 UTC:
I bought some USB cables and noticed the RoHS sticker on them and never really read much about the standard so I have a few questions. It states something about 0.1% lead is allowed but in the case of cables, does that take in the whole weight of the cable?? No, it's based only on the weight of the components that are expected to contain lead... in this case the solder used can contain only 0.1% lead. Actually ROHS stands for "Restriction of Hazardous Substances" and it refers to a dozen or so other substances, not just lead, and the allowed percentage of each varies according to the substance involved... but we're just talking lead in this case. Or on a circuit board, how is the math actually based for the allowable limit of lead in the solder. It's based on the weight of the solder alone. And last but not least, I have never ever used no lead solder. Is is a good idea to buy some for future reference in case of reworking something that followed the standard? If you're a commercial enterprise, repairing an ROHS product with non-ROHS solder would be a be no-no. In the case of a hobbyist making things for himself and a few friends I wouldn't touch ROHS solder... not even for repair of ROHS products. In general it doesn't wet the parts nearly as well as tin-lead solder does so you're more likely to get a good joint with tin-lead... and wetability aside, during a repair you're also far less likely lift a PCB pad due to the higher temperature ROHS solder requires. And if yes, are all no lead solders the same or do the have choices using differing amounts of the ingredients to make it? They're not all the same. Neither are all lead containing solders. Jim H |
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Re: RoHS question
开云体育Ah yes, I did mean I still use the leaded stuff, maybe I should stop chewing it. ? And at least in Australian, you can buy it easily enough and it’s $10/roll cheaper than lead-free, so yay for us I guess. ? As far as RoHS, Wikipedia has a reasonable write-up: .? Huh, there’s 10 things on the list now. ? Weighing by individual materials eliminates cheating.? Say your cable is a metre long, weighs 1000 grams and the solder joints have 2 grams of lead, at 0.2% it’s double the limit.? No problems, just make the cable twice as long.? You still have the same amount of leaded solder but now 2 grams of lead in a 2000 gram cable is 0.1%, so it passes!? Everyone happy! ? Under RoHs both cables have 40% lead in the solder, so you need to sort that out. ? They don’t make the limit 0% because easier said than done, plus a tiny little bit of lead in steel & brass makes it easier to machine. ? Tony ? ? ? From: [email protected] <[email protected]> On Behalf Of Roy via groups.io
Sent: Tuesday, 27 October 2020 1:06 PM To: [email protected] Subject: Re: [homebrewpcbs] RoHS question ? I think you meant to type, "leaded" instead of, "lead free" - your 2nd link is to classic 60-40 Sn-Pb solder. Some of the early Pb free solders were genuinely unpleasant to work with, enough so that whoever did the plumbing in my house chose to silver braze everything instead of using whatever Pb free soft solder was available locally. |
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Re: RoHS question
I think you meant to type, "leaded" instead of, "lead free" - your 2nd link is to classic 60-40 Sn-Pb solder. Some of the early Pb free solders were genuinely unpleasant to work with, enough so that whoever did the plumbing in my house chose to silver braze everything instead of using whatever Pb free soft solder was available locally.
Roy |
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Re: RoHS question
It doesn't really matter what the item is, the lead (or whatever) percentage
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is applied to each material used. So the cable is made of copper, steel, solder, a few different plastics and each of these needs to have under 0.1% lead. Kinda makes sense when you think about it, although documenting it would be "fun". For hobbyist it doesn't matter much what you use. Lead-free solders seem to have improved, I was at my soldering something at a friend house and only after I'd finished I noticed the solder was lead free. I think, like many things, the "lead free is terrible!!" rantings and raving are from people just repeating what they've read on the internet. Pretty sure it was this stuff: , tin with 0.7% copper. Whatever it was, it worked like normal lead-free, I'm sure there are alloys that are terrible. That said, I use lead free because I've still got heaps of it left. And besides, why switch when it's still cheaper: Tony -----Original Message-----math actually based for the allowable limit of lead in the solder. And last butnot least, I have never ever used no lead solder.the same or do the have choices using differing amounts of the ingredients to |
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RoHS question
I bought some USB cables and noticed the RoHS sticker on them and never really read much about the standard so I have a few questions. It states something about 0.1% lead is allowed but in the case of cables, does that take in the whole weight of the cable?? Or on a circuit board, how is the math actually based for the allowable limit of lead in the solder. And last but not least, I have never ever used no lead solder. Is is a good idea to buy some for future reference in case of reworking something that followed the standard? And if yes, are all no lead solders the same or do the have choices using differing amounts of the ingredients to make it?
Thanks Dave |
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Re: Flux Pens
开云体育RS deliver worldwide, but the shipping might be expensive outside the UK. Other distributors sell Ersin products. Leon
73, Leon G1HSM |
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Re: Flux Pens
开云体育Thanks Leon, ? So you have to order it from the UK? Does Loctite make that stuff? Dave On 10/24/2020 12:27 AM, Leon via
groups.io wrote:
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Re: Flux Pens
Thanks Roy,
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? I looked at the link and they mention "hydroscopic" in "post soldering residues. I think they mean "hygroscopic" and if so, why would that be a good thing to have the residues attract moisture? Just curious. I am sure it works great. Dave On 10/23/2020 8:48 PM, Roy via groups.io wrote:
I'm pleased with a MG Chemicals rosin flux pen - it's not refillable. |
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Re: Flux Pens
Thanks Harvey,
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? I have a bunch of the Kester 186 RMA flux but I think it is the "no clean". I may look for a refillable pen with the 186 already in it and go from there. Dave On 10/23/2020 7:17 PM, Harvey White wrote:
I use a Kester 186 flux pen.? I've used it on lead solder (which is all I use), HASL boards (nominal Chinese made), and ENIG (used to use Oshpark, but the boards were too expensive). |
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Re: PCB through hole activation for copper plating
The problem was not lack of solder inside the eyelet, the component leads soldered fine with solder filling up the eyelet. It also soldered well to the bottom layer.
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Once the eyelet channel filled up with solder there was no motivation for it to flow further across and down over the edge to finally join the top layer of the PCB. The slit provided a path to reach the top layer without having to flow over the top. Bertho -----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Donald H Locker Sent: Saturday, June 13, 2020 20:42 To: [email protected] Subject: Re: [homebrewpcbs] PCB through hole activation for copper plating More likely provided the capillary wick necessary for the solder to follow. With the plain barrel eyelets, the solder would have to wick up the center hole or between the eyelet and the substrate - one gap is too large and the other is too small (as well as having a non-wettable surface facing the eyelet.) The slit provides a wettable, narrow channel for the solder. Isn't surface tension wonderful! Donald. -- *Plain Text* email -- it's an accessibility issue () no proprietary attachments; no html mail /\ <> On 2020-06-13 4:40 p.m., Lee Studley wrote: @ Bertho: That's an very interesting note. Thanks for sharing that. I |
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Re: Flux Pens
I use a Multicore flux pen. They are sold by RS Components. Leon On 24 October 2020, at 02:48, "Roy via groups.io" <roylowenthal@...> wrote: I'm pleased with a MG Chemicals rosin flux pen - it's not refillable. ?<??> Roy |
Leon
Bertho