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[on:]

I've been using 96/4 lead free rosin core solder, 96% tin, 4% silver, in the .031 (or .032) size for many years now.

I used to get it from radio shack. Since that's the type they sold, thats what I started working with.  They started charging too much, so I found it for cheaper at harbor freight.  However it just comes in tiny tiny little tubes that I go through very rapidly.

I have searched many times on ebay and the web for larger quantities like 1/4 to 1/2 pound, but never seem to find it.  I find all sorts of other solders, or other formulas, like 99.3/.7, acid core, and many others, but never 96/4.  On a rare occasion I have found a 1lb spool for like $80 from some no-name place, but I don't trust buying that large of a quantity of an unknown brand.  I just want the same quality 96/4 I've been successfully using for many years, in 1/4 to 1/2 lb quantities, at an affordable price that's cheaper than buying tons of tiny tubes at a time, like maybe a 1/4 pound for $25.

Anyone know why its so hard to find?  Am I perhaps not using the best stuff, and other solder formulations may be better?

[Reply #1 on:]

You can get 1lb. for $98 and it's a well-known brand:

http://www.techni-tool.com/488CH7402

Frankly, I'm a fan of Kester's K100 -- much cheaper too:

http://www.techni-tool.com/488SO1331

--
The Ruggeduino: compatible with Arduino UNO, 24V operation, all I/O's fused and protected

[Reply #2 on:]

Strange to say this but leadfree is much cheaper at Sparkfun - 100g for $8  (about $36 / lb)
http://www.sparkfun.com/products/9325

[Reply #3 on:]

Tin Whiskers!

Some reasons to seek out the lead/tin solder.
http://nepp.nasa.gov/whisker/background/index.htm

http://www.designnews.com/author.asp?section_id=1389&doc_id=212417

Take this issue very seriously if you are designing commercial equipment.

I was aware of these issues in 1970 -- this is not news, however, with a sometimes pointless drive to "Green" products (taht aren't) you run into old familiar problems...

[Reply #4 on:]

96/4 Sn/Ag is an unusual mix, because most lead-free solders contain copper (only some contain silver as well). All the major distributors sell Sn/Ag/Cu solder, for example, http://www.digikey.com/product-detail/en/796065/82-126-ND/2498924.

[Reply #5 on:]

Lead solder gives off lead-oxide fumes - its a poison that causes permanent impairment of brain-function in children.  Some people may be happy to take the risk of poisoning themselves, but keep lead and lead fumes away from children for their sakes please.

Since the metal is soft it rubs off invisibly onto the hands too, and ordinary soap is no good at removing it (see barchart here: http://www.uniquetek.com/site/696296/product/T1262 )

Years ago I used lead/tin solder and now use lead-free (as lead/tin solder is illegal in Europe now), and there is no difference in performance, so long as you set your iron to the correct temperature.  I don't feel the need to scrub my hands raw after soldering and before eating now either!!

[Reply #6 on:]

...as lead/tin solder is illegal in Europe now...

Just to be clear, the thing that is illegal is to use leaded solder in the manufacture new equipment and then to sell that equipment in Europe. Leaded solder is still permitted when building prototypes and for hobbyist use - although retail outlets here in the UK tend to sell only lead-free solder now.

[Reply #7 on:]

dc42 (and others)

Lead / Tin solder is NOT illegal in the EU for "Fine Trace" boards. (I believe that people use .650 mm trace spacing for this standard.)

The problems with Tin Whiskers is serious enough that exertions are (routinely) granted for "fine trace" boards.

See here:
http://www.calce.umd.edu/lead-free/STMAKeyNote.pdf

Pg 19/29 for example.

See here as well:
http://www.sigcon.com/Pubs/news/10_01.htm

Whoever brought up the dangers of lead: Spare us the lectures on the dangers of lead. People in engineering and design are well aware of the dangers.

[Reply #8 on:]

Whoever brought up the dangers of lead: Spare us the lectures on the dangers of lead. People in engineering and design are well aware of the dangers.

And, of course everyone reading this forum is either an engineer or an experienced designer.

[Reply #9 on:]

I'll say that regardless of the solder type, buying and using a small fume extractor is a good idea. Not expensive and effective.

I plan on switching to lead-free as experience permits. Now that I have a reflow oven almost set up, making the switch may be within reach. I just have to verify that the heat up times are within spec as far as the profiles are concerned. I'll check on the solder sold by Sparkfun, thanks for the suggestion!

In the meantime, chelating soap is available from McMaster Carr and other outlets. Not that hard to use nor that expensive.

[Reply #10 on:]

Perhaps I may need to switch to a different type of solder, such as some of those cheaper options others mentioned.

I've just always used 96/4 because I know it worked and considering how many solders either don't say what they are made of, or list extremely cryptic details (that I'm sure I could understand if I spent 4 hours on google researching them, but haven't done that).  I was always afraid to using some sort of incorrect solder.

[Reply #11 on:]

I've just had my first experience with Kester 96/3.5/.5 solder paste and I am impressed. The paste did a better job of reflowing than the leaded solder paste I am accustomed to. Not only did the MCU lack solder bridges, the ADE7753 with its much finer pitch reflowed perfectly as well. The leaded solder usually required an additional pass with solder braid and some components like 5mm TQFP-32's  were very difficult to get done right.

I've put in an order for the same solder in wire form from Techni-Tool. Call me a happy camper.

[Reply #12 on:]

http://www.digikey.com/product-detail/en/SMDSWLF.020%204OZ/SMDSWLF.020%204OZ-ND/2177058
Chipquick is a fine brand...

Magic search term would be "sn96ag4"