What is 5 Sn/95 Pb solder for? - Page 1
Forum section: electronics / projects

author: Forced Perfect
author_rank: Contributor
timestamp: February 21, 2014, 04:40:50 pm
content: I picked up a spool of solder the other day on eBay simply because it was a brand new, name brand, unused spool for only $5 with free shipping. I figured whatever it is I could find a use for it at that price.Turns out it is 5% Tin / 95 % lead solder. This stuff is "ALPHA Energized Plus" rosin core. From what I have read (http://alpha.alent.com/~/media/Files/CooksonElectronics/TB%20EnergizedPlusWRCUSAPESM1079%20%20120126.pdf) it is a super strong flux for soldering difficult or unusual metals in MIL-SPEC applications.Does anyone have any experience with this stuff? I'm just curious what it is normally used for as 95% lead seems really high and it's difficult to find any information on it as searches usually result in 95% tin lead free products.

author: CaptnYellowShirt
author_rank: Frequent Contributor
timestamp: February 21, 2014, 05:31:49 pm
content: RoHS protest solder?

author: Forced Perfect
author_rank: Contributor
timestamp: February 21, 2014, 05:34:35 pm
content: Quote from: CaptnYellowShirt on February 21, 2014, 05:31:49 pmDamn right. Screw lead free. I'm going all the way, baby.

author: Monkeh
author_rank: Super Contributor
timestamp: February 21, 2014, 05:55:30 pm
content: For attaching leads to components which won't come off when soldered normally.

author: uwezi
author_rank: Unknown
timestamp: February 21, 2014, 08:42:10 pm
content: Quote from: Monkeh on February 21, 2014, 05:55:30 pmThat's it: melting range 301-314°C (574-597°F for the US)

author: Forced Perfect
author_rank: Contributor
timestamp: February 21, 2014, 08:44:30 pm
content: Quote from: uwezi on February 21, 2014, 08:42:10 pmInteresting. Could come in handy at some point, I'll hang on to it.Hey, I live in the US but I sure as hell use metric.

author: uwezi
author_rank: Unknown
timestamp: February 21, 2014, 08:50:26 pm
content: Quote from: Forced Perfect on February 21, 2014, 08:44:30 pmNo pun intendedI live in Sweden and have to deal with imperial units and screws all the time

author: Forced Perfect
author_rank: Contributor
timestamp: February 21, 2014, 08:52:16 pm
content: Quote from: uwezi on February 21, 2014, 08:50:26 pmYeah, I know what you mean. I moved here from Canada a few years ago and in my job I get asked the weather all the time and tell them in °C all the time and they give me odd looks. Oh well, one day they'll get on board with the rest of the world.

author: uwezi
author_rank: Unknown
timestamp: February 21, 2014, 09:00:25 pm
content: I just looked closer at the label: exp-date Oct-14 ...What happens to solder beyond its expiry date - and is this valid also once the solder has been applied to the circuit?

author: Forced Perfect
author_rank: Contributor
timestamp: February 21, 2014, 09:03:36 pm
content: Quote from: uwezi on February 21, 2014, 09:00:25 pmFrom what I read it is for the flux - which of course isn't used after the solder has been heated. The documentation says to send it to them for testing if you have expired solder. Implying it can still work beyond its date.Honestly, I don't think it is going to suffer any major problems after the date - especially since it isn't even open (although it's not actually air tight).There is some guy on eBay selling the same brand (but 63/37) which expired 5 years ago and I didn't notice any negative marks on him saying he sold them crappy solder.

author: uwezi
author_rank: Unknown
timestamp: February 21, 2014, 09:08:31 pm
content: Most of the time I am using lead-free solder nowadays - not because I have to for my own projects or even at work at the university, but just because it feels better.However I have some leaded 63/37 solder left, which I got from my uncle more than 25 years ago, and it still is perfectly fine. But I guess for mil-spec everything has to specified and traceable...

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 21, 2014, 09:10:00 pm
content: Quote from: uwezi on February 21, 2014, 09:00:25 pmProbably surface oxidization.I use solder that's >10 years out of date with no issues.Worst case you may need to chuck the first layer on the roll if it's really ancient.

author: CaptnYellowShirt
author_rank: Frequent Contributor
timestamp: February 21, 2014, 09:13:45 pm
content: Quote from: uwezi on February 21, 2014, 09:08:31 pmHave you made a pact with the devil? How much did this power cost you?

author: grumpydoc
author_rank: Super Contributor
timestamp: February 21, 2014, 09:35:01 pm
content: QuoteAbsolutely no idea but this ->http://www.datasheetarchive.com/dl/Datasheet-080/DASF005098.pdfgives a clue that it might be used for solder bumps on flip-chip packages.Could also be used for low temp applications as it's probably ductile at low temps (see theWikipedia articleon solder).And I guess (again from the wikipedia article) that if Pb90Sn10can be used for car radiators and fuel tanks then Pb95Sn5would be suitable for that as well.

author: tszaboo
author_rank: Super Contributor
timestamp: February 21, 2014, 10:13:02 pm
content: It is a hard solder, not for electronics joints normally.The best use is to replace the label and prank colleagues with it. Highly recommend it!

author: guipoletto
author_rank: Contributor
timestamp: February 21, 2014, 10:14:18 pm
content: Quote from: CaptnYellowShirt on February 21, 2014, 09:13:45 pmSome year and a half ago, i bought about 2 kilos of sacx0307 for 5 bucks each(500g).Compared to the 67/37 solder that in brazil costs about 30 dollars for 500g, it was a nice deal.don't get me wrong, it is a wonderfull solder once you get used to. Looks different, and can be a real bitch when soldering on moving parts.But Lead free is definitely NOT the choice for electronics works. If you ever happen to solder a power mosfet (power vias plated trough) with the green stuff, forget about getting it out. it somehow binds to the copper in the vias. real nasty stuff for electronics repair.On the other hand, if you happen to be repairing your dad's glasses, lead-free will bind to almost any metal, and have good mechanical stability once youabsolutely not shake it during solidificationBottomline, lead free is better for everything except electronics(just my opinion).

author: CaptnYellowShirt
author_rank: Frequent Contributor
timestamp: February 21, 2014, 11:00:59 pm
content: Quote from: guipoletto on February 21, 2014, 10:14:18 pmI don't know if its the same effect, but I have run into similar desoldering problems. My solution was to add leaded solder to the SAC joint and then wick/suck it all out. Once a little bit of Pb gets into the joint, it seems to behave like a regular 60/40.

author: Forced Perfect
author_rank: Contributor
timestamp: February 21, 2014, 11:05:53 pm
content: Quote from: CaptnYellowShirt on February 21, 2014, 11:00:59 pmYeah, that trick works really well. I have been using it on this Mini-ITX board which has suspect caps on it. I can't seem to heat the joints all the way though (the board is probably 8 layers) and adding a little of my 63/37 really helps. Especially with desoldering after I get the part out - those teeny tiny holes won't desolder at all without it.

author: GreyWoolfe
author_rank: Unknown
timestamp: February 21, 2014, 11:07:05 pm
content: Quote from: NANDBlog on February 21, 2014, 10:13:02 pmThat could be another post for the electronics stuff up thread!

author: uwezi
author_rank: Unknown
timestamp: February 21, 2014, 11:10:33 pm
content: Quote from: Forced Perfect on February 21, 2014, 11:05:53 pmJust out of curiosity: have you tried to add some lead-free solder? In my experience it does have about the same effect. The problem could be that the melting range is quite narrow for the lead-free alloys and adding just some more thermal mass will keep it liquid just long enough to get the part out.

author: guipoletto
author_rank: Contributor
timestamp: February 22, 2014, 12:08:23 am
content: Quote from: uwezi on February 21, 2014, 11:10:33 pmIf it is a cap, sometimes it will work, but anything with enough thermal runaway (like caps directly soldered to a power plane, on the other side of the plated hole), that can be a real pain, and i've cooked some boards trying to get them out, so i never lead-free solder any of that. if it comes pre-soldered, than it's time to do some voodoo before trying anything. hehe.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 22, 2014, 01:04:58 am
content: Quote from: grumpydoc on February 21, 2014, 09:35:01 pmHmmm, interesting. I wonder if they use low-alpha Pb for that. Which makes me wonder, could the 95/5 be low-alpha as well? Supposedly that stuff is kind of sought after. Because, alpha particles (due to Pb210 impurity, which ultimately arises from U238 decay) cause bit flips in digital circuits, which is obviously a problem. Not sure if they're now using more plating layers beneath the solder to address that, or what.QuoteYes, I would imagine so. The main difference is, Sn63 is eutectic, meaning it solidifies almost instantly as the temperature crosses the melting point. Plain old 60/40 is close, laziness really I guess (and cheapness, since tin is more expensive than lead...).Quote from: NANDBlog on February 21, 2014, 10:13:02 pmNo, hard solder (braze, actually) contains primarily copper or silver, or other higher melting metals. Melting under 800F (~400C?), it's technically still soft. Although I would argue it should be context-dependent: try "soldering" that lead with regular solder and I dare you to find where the bond is -- it's more like lead 'brazed' with solder alloy.I can't argue with the prank usage thoughAs for the solder itself... not much electrical value. It's too hot for FR-4, and most irons will strain to reach those temperatures. The rosin may be interesting: just any old formula should burn up quickly at that temp, so I wonder if it's a special low-volatile blend or something.Tim

author: SeanB
author_rank: Super Contributor
timestamp: February 22, 2014, 05:49:45 am
content: Most common use was to solder high power resistors to tag boards so that they could run at close to red heat without melting the solder joints. You can have a ceramic power resistor in a white boat running at close to white hot before that solder will melt from the conducted and radiated heat. Was very often used in valve sets and in older Tek scopes for that purpose.

author: LukeW
author_rank: Frequent Contributor
timestamp: February 22, 2014, 08:02:24 am
content: Wikipedia has a big table of different solder alloys, and what their composition, basic properties, melting points and typical uses are.http://en.wikipedia.org/wiki/SolderThis might be of interest.