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EOL solder wire purchase

Hi,

Many years ago, I made what I *though* would have been my "last buy" of solder wire. Apparently, my estimated usage was off -- or, I have lived too long. :< Either way, I find myself having to repeat this exercise... (the real problem is that I have been using too much of it for "bigger jobs" instead of prototype fabrication, touch up/rework, etc.)

[Note I am not worried about solder *paste* -- I buy that as needed]

I figure I will need enough for ~500 (smallish) prototypes (several square inches of PCB, components both sides) plus miscellaneous wiring, cables, etc.

And, the sorts of things anyone "electrically/electronically inclined" encounters in day-to-day living (repairing appliances, TVs, etc.)

In addition to 0.028" and 0.015" 60/40 wire, recent experience suggests I purchase some larger diameter (0.062"?) for those uses that eat gobs of wire per connection (i.e., when you'd be feeding half a foot just for *one* connection!)

Suggestions as to how much of which sizes? And, is this truly a commodity product (cost being the only issue) or are there vendors to avoid/favor? (I've tended towards kester over the years -- but for no "real reason")

Digikey? Or, "anyplace local" (taxes vs. shipping fees)? Figure ~$30-40/pound for anything "non-esoteric"?

Thx,

--don

Reply to
Don Y
Loading thread data ...

More like close to fifty bucks for the good stuff. Ouch, ouch.

And yeah, it's commodity products. Kester makes a leaded no-clean in

0.062" but personally I haven't used their 8817 yet (well, maybe at clients without realizing it):

formatting link 

--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

Acceptable. It's been *decades* since I last made a buy so I'll accept some amount of "inflation".

Any ideas as to quantities I should target? E.g., figure

500 densely populated, double-sided boards in the 6-12 sq in (per side) range... (they are often much smaller than this but usually "stacked" to achieve a particular volume profile)

"No-clean" isn't important -- especially on larger diameters (where I might not even *have* to clean up!)

Thx!

--don

Reply to
Don Y

Anywhere that UPS or Fedex picks up or delivers is now considered local. Welcome to the global economy.

I suggest eBay: Plenty to choose from.

I use 0.031 for most everything, except for the really fine stuff, where I use 0.022. I also some heavier stuff (forgot the diameter) for soldering copper sheet. Skimming randomly, it looks like about $25 to $30 per pound for rosin core Kester solder.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558
Reply to
Jeff Liebermann

No idea but easy to find out, my wife uses the same trick to find if she can make another teddybear from a given amount of yarn of unknown length: Weigh your spool of solder on a very precise kitchen scale. Solder up a storm, note the achieved square-inches. Now weigh again.

[...] 
--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

Kester 44 flux is a fave--it's RA flux rather than RMA, which I much prefer, especially when using old parts, such as my 20-year-old inventory of many many values of RN55C resistors.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 USA 
+1 845 480 2058 

hobbs at electrooptical dot net 
http://electrooptical.net
Reply to
Phil Hobbs

Do NOT use "no-clean" as it (1) needs cleaning, and (2) makes for more problems than any other formulation.

Reply to
Robert Baer

AFAICT "no clean" flux for leaded alloys is just good old rosin flux.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 USA 
+1 845 480 2058 

hobbs at electrooptical dot net 
http://electrooptical.net
Reply to
Phil Hobbs

I beg to differ somewhat. There are no-clean fluxes with a rosin base. Usually, they're classed as ROL0 (Rosin Low activation). I don't believe they're available as a rosin core for roll solder but might be mistaken.

We used no-clean flux with 60/40 in various wave soldering machines back in the late 1970's and early 1980's. I hated it. No-clean flux tended to leave a difficult to remove residue. This residue drove me nuts with bed-o-nails test fixture contact problems and tuning drift effects on RF circuits which weren't protected by silk screening. UV inspection of the urethane waterproof conformal coating showed crappy adhesion to the flux residue. Under stress, the coating would flake off around the solder joints. The residue also appeared to be hygroscopic and caused problems with high impedance circuits.

While none of these problems are likely to appear in the OP's hand assembled or repaired PCB's, neither are the benefits of using no-clean flux in a production environment likely to be useful. Therefore, I suggest RMA (rosin mildly activated) for general purpose use where a solvent cleaning is sometimes forgotten, and RA (rosin activate) for repair work on ancient devices that are likely to be coated with oxides. All my roll solder is RMA. If I need more flux, I have a bottle and apply it with an included brush.

Why Clean No-Clean?

Why Should I Clean "No Clean" Fluxes and Pastes?

Flux specs table:

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558
Reply to
Jeff Liebermann

"Today, one of the most common reasons to remove no-clean fluxes is to prevent malfunctions in circuits with clock speeds over 1 gigahertz. "When you get above 1 gigahertz, the electrons are conducted on the outer surface of the conductor," says Stach. "If there's flux on the conductors, it can act as a conductor, too, and interfere with the signal.""

--

John Devereux
Reply to
John Devereux

I have never seen that happen and some of my RF and digital designs run transitions in the few hundred picoseconds. No problems. I assume what they mean with "conductor" is a trace. Those are supposed to be covered with solder mask and I don't see how flux can get underneath there.

Yeah, no-clean is a bit hygroscopic but other than that I haven't had problems with it. It's been many years now.

[...] 
--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

newark is a good place for solder.

Reply to
Cydrome Leader

I've never seen that either because most of my strip lines are 50 ohms and buried under a layer of green solder mask where the flux won't stick. What I have seen is the residue bridging between a solder pad and ground as in the annular ring around a pad. We would wash, rinse, dry, test, tune, and then watch the tuning and bias points slowly drift. Hit the PCB with a heat gun to evaporate the water, and all would be well for a few days. Add a little humidity (or test with a nebulizer), and in a few hours, the tuning and bias points would again drift. This problem was one of the reasons that the company went on a "design with low impedances" binge. High impedances and high Q circuits just weren't compatible with the flux processes of the day.

I personally contributed to making things worse. I substituted a washable flux but didn't have a proper production line board wash available. So, I used an ordinary dishwasher, which did a marginal job. Washable flux is loaded with acid, which needs to be washed well and immediately. The tuning and bias points didn't drift. Instead, the leads and some plating disappeared, etched off by the acid residue.

By coincidence, Fairchild Semi had just switched from Epoxy B to silicon epoxy PN style transistor packages. These had the unique property of opening a tiny gap around the leads during wave soldering, which allowed some flux into the transistor package. Everything looked normal until the completed radios emerged from burnin, where hundreds of dead transistors were found. Xrays of the dead transistors showed that the bonding wires had disappeared. We gave up on washable flux.

It really depends on the circuit. If you're doing high voltage, high Q, or high impedance designs, I suspect there will be problems.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558
Reply to
Jeff Liebermann

Even if it would stick it doesn't matter too much.

I have seen that with other fluxes, including some weird electrolytic effect. A client even saw it depelop some "whitish pus" between to IC pins. Never seen that with no-clean but, of course, if you have a very high impedance pads close to other conducting matter you have to even clean the no-clean. Which is harder to do than with other resin so this may be a situation where no-clean is not the best option.

That's one reason I use no-clean. I just donated a scope to a school and first I had to spend many hours repairing it. Turns out the mfg had not cleaned the flux. What a mess.

I always urge clients not to use wave-solder but use reflow instead. It prevents a lot of problems from happening.

Yes, but that also requires measures to be taken at the layout step. Got to be really careful with the solder mask. Sometimes we've even added silk screen there to make things thicker or build "dams".

--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

I can maybe believe a capacitance change if there is moisture absorbing crud between pads say. Or leakage in very high impedance circuits as Joerg says. But that is not at all what the article was suggesting AIUI.

--

John Devereux
Reply to
John Devereux

D'oh! Yes, great idea! I'll just have to find a precision scale (I don't use scales in the kitchen).

Thx!

--don

Reply to
Don Y

Many postage scales are very precise, even cheaper ones. Like mine which was cheap but measures down to one gram in metric mode. Otherwise ask a neighbor who is a gourmet cook. They usually have very fancy scales. Marble tray, smoked-glass floating see-through LCD on a gold-plated metal post, the works. We've got one but only because of a liquidation sale at a store.

McGyver method: Put a thin long plank on a pipe, making a see-saw. Mark center. Place a rock at one end and the fresh spool on the other so you have equilibrium. Now you know what 0.5lbs is. Mark distances from pipe. Solder. Place spool on the plank again, scoot until equilibrium. Mark new distance, determine with tape measure, calculate weight.

I bet the local Fedex depot or post office will also be friendly enough to perform a quick before-after weighing.

--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

Mine is intended for packages. I think ~40lbs at 0.1oz (maybe 0.2?) resolution (I would have to check to be sure -- I keep it packed away until needed, like most things, here)

I had a "precision balance" many years ago (e.g., the sort of thing you would encounter in a pharmaceutical laboratory for measuring actives and excipients -- like measuring the weight of individual grains of sugar!). But, it was *big* (i.e., takes a lot of space for the seldom used functionality it affords) so it was abandoned on one of the moves. I've not missed it...

(lab scales also tend to raise eyebrows with law enforcement professionals... best not to go there! :< )

Post office would probably work. I think they have a scale in the lobby. I would *hope* it can handle ~1 lb (smallish... no doubt intended for *letters*). I will check next time I find myself there (seldom). If I *know* I'll be there, I can bring a spool of solder wire with me and see if it "notices" several inches removed between weighings...

Reply to
Don Y

In the land of the free! What are you coming to?

Jeroen Belleman

Reply to
Jeroen

I bought some ebay "precision scales", quite cheap, did not pay much attention to what I was buying. I had some idea I would use them to count components, nuts or something. Claimed up to 0.01g resolution I think.

I was puzzled to get a CD in the post. I realise it is the weigh scale. Designed to look like a CD! WTF. They are built into a CD case, clearly designed so as to look innocent to visiting law enforcement!

I expect I am on a List now...

--

John Devereux
Reply to
John Devereux

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