Strange string of failures - seems to be solder?

Started by MrStab, February 03, 2014, 08:53:06 AM

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MrStab

hi,

i'm definitely no pro, but i've built a lot of things with success and never have i had FIVE non-working projects in a row. i can usually trust my builds enough to use at shows and give away, but something really weird has started happening, and the only variable that's changed is the brand of solder i'm using.

i usually use this stuff: http://www.toolandfix.com/silverline-as15-solder-100g.html?gclid=CO6l3L6JsLwCFUQUwwodMisA9A - there's not that much info about it online and i can't find an empty spindle, unfortunately, but that stuff works fine for me. so, thinking there wouldn't be much difference, i decided to score this as part of an order: http://www.rapidonline.com/Tools-Equipment/Stannol-Solder-Wire-Pb60Sn40-1-0mm-100g-50-2436. both 60/40, non-RoHS stuff. supposedly.

in each of these 5 projects (2 overdrives, 2 phasers, 1 buffer/tremolo-to-be), there have been inconsistent anomalies with signal path and voltages. desperate after trying all the usual debugging techniques (even getting the right voltages... which would later change, same with probing), i discovered that randomly cutting between tracks - i use veroboard - often fixed some of these problems. temporarily, at least. my DMM didn't even detect continuity and i couldn't see any shorts whatsoever.

i'm at a loss. i have some of my usual solder en-route, but my confidence has taken a major blow here and i'm hopeful that it even is the solder to blame. if it is, it's surely flux-related(?). can anyone spot (or infer) any key differences between these products? this stuff seems a tiny bit more reluctant to melt on my 30W iron, just a tiny bit, although it's much more prone to being pasty. and the joints seem a bit less shiny. they dry a bit faster, too. the veroboard is tried & tested - i thought that could be the problem too, but nothing's changed there.

all this would make sense to me if these solders were of drastically different composition, but i'm not enough of a solder expert to work out this possible difference. i mean, 60/40 is 60/40, right? i'm after some peace of mind, more than anything!

thanks for any insights.
Recovered guitar player.
Electronics manufacturer.

duck_arse

can you post some pics of the GOOD working, bright, shiny, wetting (and clean) solder joints on a working build, and some pics of the bad, cold, grainy, clumping, (and clean) evil solder joints on a non-work? we need to be able to see the joints good enuff to compare them, but it sounds like not enuff or long enuff heat causing dry joints.
don't make me draw another line.

R.G.

From the pictures, you have been lead astray by the numbers.

Most times, solder composition is quoted as the % tin followed by the % lead. In the typical electronics solder, you get 60% tin, 40% lead. The "Stannol" stuff you got is advertised as 60% LEAD 40% TIN which is confusingly the reverse way to state the numbers.

There is a trick I used to show the difference in solder compositions. Get a steel plate (NOT A KITCHEN PAN!!) and place it above a gas burner. Place equal sized snippets of solder on it, side by side, then heat. If you know the composition of one of them, you can easily tell if they're different compositions or not by the time which they melt. All 60 tin/40 lead solders melt at the same temp. A tin 40 / lead 60 will be much higher.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

MrStab

Quote from: duck_arse on February 03, 2014, 09:40:18 AM
can you post some pics of the GOOD working, bright, shiny, wetting (and clean) solder joints on a working build, and some pics of the bad, cold, grainy, clumping, (and clean) evil solder joints on a non-work?

i'd have to unscrew a pedal to take a pic of the good stuff, but i can if you're still curious. i think RG has nailed it, though.

Quote from: R.G. on February 03, 2014, 10:06:02 AM
The "Stannol" stuff you got is advertised as 60% LEAD 40% TIN which is confusingly the reverse way to state the numbers.

*huge sigh of relief*! i didn't think to check which way round that ratio actually was. i'd come across another thread on the interwebs where someone had a problem with 70% lead/30% tin solder, which was apparently more suited for plumbing work, but i overlooked it without much thought. it's weird that i came across the Stannol stuff on an electronics website - maybe they themselves were led astray or it's suited for more macroscopic electronics applications?

thanks a lot for the info RG, and for offering to check it out, Duck.
Recovered guitar player.
Electronics manufacturer.

PRR

That listing had me fooled too.

The description says "flux covered"(?) but the package does NOT say flux anywhere.

You need flux (or other cleaning process) to solder electronics.

The high-Lead stuff "can" be used in electronics, but needs more heat. Which also means more oxidation. Which means a better flux. Which I don't think this stuff has.

I suspect it is plumbing solder. On heavy pipes you can use a strong acid flux, usually supplied in a separate tin, and torch it up hotter so you can use cheaper high-Lead solder.

Lead is much cheaper than Tin. Roofers use a LOT of solder (on copper or terne roofing) so they use a mostly-Lead "solder". Plumbers use considerable solder but can't work way-hot so they use a bit more Tin. Also both trades like a solder which goes "semi-solid" as it cools so they can smear it into the joint. In electronics we use so little solder that the price of Tin is small, we like low temperature, we like a solder which hardens "instantly" (63% Tin eutectic) or very nearly (60% Tin).

And we must have FLUX, usually Flux Core. There should be a pine-sap smell and smoke when you touch the end on a not-quite-hot iron. If it's not in the solder, then you need liquid flux and a fourth hand to apply it.
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MrStab

thanks for the further clarification, Paul. i'm totally stumped how that even wound up on the Rapid Electronics website, which - to the best of my knowledge - isn't plumber-oriented. as it happens, my drummer's a plumber. maybe i should give the rest to him.

talking of smell: i instantly knew things were "right" again when i melted my first piece of the right stuff this morning and smelled that familiar piney odour you mentioned. a vero layout which i lazily put together last night has just worked straight off the bat. you can actually see the core at the start of the reel with this stuff, which i can't at all with the misleading solder.

be wary, people!

Recovered guitar player.
Electronics manufacturer.

MrStab

#6
just have to share this: was idly chatting to a relative, who couldn't care less about all this, but she pointed out that i'd been "mis-lead". ha.
Recovered guitar player.
Electronics manufacturer.

mth5044

Sounds like you've been....

Quote from: MrStab on February 05, 2014, 01:01:55 PM
"mis-lead".



YYYYYYYEEEEEEEEEEEAHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

MrStab

lol! wish i'd had that CSI (?) guy to crack this from the beginning...
Recovered guitar player.
Electronics manufacturer.

PRR

I may have looked at the wrong site. However the link to Rapid shows a high-lead solder with urea flux, which is unfamiliar to me.

As for plumbing-- in the USA lead solder is banned for drinking water pipes. And there isn't near enuff in that roll to do a 4" cast-iron waste pipe (the classic "wiped" joint).
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KazooMan

Regarding that "piney odor".  Try to limit your exposure to flux fumes.  They are well known to be pretty strong respiratory tract irritants.  When i first got into the hobby of vintage amp restoration and building pedals I slowly developed a chronic lung problem.  It got much worse with time to the point that I eventually ended up using prescription medications such as steroid inhalers meant for those with chronic obstructive pulmonary disease.  I finally put two and two together when I noticed the problem was worse the day after a lengthy soldering session.  With my background as an organic chemist I knew I needed a fume hood to protect me from exposure.  I built one from scraps of wood and Plexiglas with an inexpensive bathroom exhaust fan sending the fumes out the window through a piece of flexible hose (like a shop vac hose).  NO more lung problems.  No more drugs.  No more chest pain.  No more shortness of breath.  I won't solder anything outside the hood anymore.

Here's a link to an article on the subject from the Weller soldering iron folks.

http://www.elexp.com/tips/Health_Hazards.PDF

Here's the fume hood.  Since I took this picture I have added some racks for screwdrivers and pliers, as well as a rod that supports a Dremel tool with a flexible shaft handpiece.  


MrStab

...and here was me thinking lead oxide was all i had to worry about - thanks for that, Kazoo. a worthy warning. it's pretty damn cold in my neck of the woods so i never have the window open, and i don't take any precautions, so maybe this is a much-needed wake up call. i already have (what i think is) chronic bronchitis from years of smoking various things, the genius i am, so it would've been too easy for me to just brush this off. i'd say i feel more nauseous than short-breathed after a heavy day's soldering, but i'd just attributed it to the fact i sometimes get so focused on projects that i forget to take breaks and eat lol.

i'm not at all handy with woodwork or anything like that, but i'm suddenly motivated to find a solution. i'm not the healthiest person to begin with.
Recovered guitar player.
Electronics manufacturer.

PRR

Lead fumes in hobby soldering, even factory soldering, are almost a non-issue. It's not hot enough long enough to make lead fumes. (Factory dip/wave soldering, with a hot-tub full of molten solder all day, is a very different case.)

Wash your hands after touching solder (raw or on boards), and don't eat (or smoke) while soldering.

Rosin flux sensitivity is VERY variable. Some people can snort flux fumes all day long.(*) Others choke-up in 15 minutes. It seems to be an allergy-- if you have it, it will only get worse. As Kazoo says, it can be debilitating.

I find flux irritating but not noxious. I prefer an air-flow to sweep the fumes away from my eyes and nose.

(*)A friend spent years 8-10 hours a day soldering the equivalent of 100 pedals a day. Actually TV tuners, but the iron and the solder were just the same, and the ventilation was not great.)
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