60/40 vs. 63/37 Solder

"William Sommerwerck" wrote in news:i1ovm1$ccb$ snipped-for-privacy@news.eternal-september.org:

maybe the price difference is due to "new and improved" rather than any other reason.

BTW,63/37 has the lowest melt point of all the tin/lead alloys. 361 deg F

--
Jim Yanik
jyanik
at
localnet
dot com

"William Sommerwerck" wrote in news:i1p4j1$t6b$ snipped-for-privacy@news.eternal-september.org:

91% is what CVS sells,I don't recall the price,though.

--
Jim Yanik
jyanik
at
localnet
dot com

No, eutectic solder has always been more expensive, and the reason has always been that tin is more-expensive than lead.

Exactly. That was my point, and MCM's error. I remember the little phase diagram in the Popular Electronics article.

Drug stores periodically have sales. You should be able to get a pint bottle of 91% for less than a dollar. No point in the 75% stuff.

ner

What kind of flux were you using? I want to try some tests, just laying down solder and flux gobs on 0805 SMD pads and measure the resistance. Then cleaning and remeasuring. (I've got a bunch of other 'fires' that I'm putting out so this may be a few days.)

George H.

The Meijer store here in Illinois has 99% isopropyl. It is normally about $1.25 for a 16 oz. bottle but occasionally they run sales of 2 for 1 at that same price. I stocked up with about a dozen bottles the last time they ran that sale. I avoid the lower % stuff because it is not always diluted with just water but sometimes oils and skin lotions. These are to be avoided for electronics work.

David

This is usually labelled "rubbing alcohol".

I prefer the hardware store stuff in the metal cans:

More expensive but always 99% (ignoring what moisture it absorbs from the air).

I have some rolls of solder around the shop that are not well labeled or identified. Rather than risk leaving corrosive flux on a board, I prefer to clean most everything.

--
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

I like 63/37 because some stuff I do I like it as low a temp as possible.

Deja vu. I worked for BFEC at NASA site, and went to NASA ssoldering school. I would guess 60/40 would be the norm.

greg

True. 60/40 goes through a semi-molten, plastic-like state, while

63/37 goes instantly from liquid to solid. The joint is not mechanically solid in this plastic state. It's not an issue with tiny components, that cool down rather rapidly. However, large components, that retain more heat, can product "cold" solder joints if moved while in the is plastic state.

In some cases, this plastic state is desireable. For example, pre-RoHS plumbers solder was 50/50 for both low cost and the ability to remain workable over a wider range of temperatures.

This got my attention: Some alloys, namely of lead and to some degree tin, contain small but significant amounts of radioisotope impurities. The radioisotopes undergoing alpha decay are a concern due to their tendency to cause soft errors. Polonium-210 is especially problematic; lead-210 beta decays to bismuth-210 which then beta decays to polonium-210, an intense emitter of alpha particles. Uranium-238 and thorium-232 are other significant contaminants of lead containing alloys. Oh swell.... something else to worry about.

--
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

Allmost all my soldering is repairs; cold joints seem more likely when you're fixing something.

Probably. I never had to solder, so I never went to school.

Which site? When? I worked from 1974 through 1978.

The boards were commercially made with water based flux. I had to fix them. They actually laid out the boards, which was a mistake.

greg

NASA standards authorize both.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

Did you ever change the klystron frequency from the control panel (there were six buttons along the bottom), rather than going out to the transmitter? If so, you used one of the improvements I installed.

"GregS" recommends for flux removal:

And then you accidentally plug the 120VAC into the 5VDC output of a voltage regulator, which promptly explodes and emits flames and smoke, and you just have time to say "oh wow, man, pretty fireworks" before the lights go out and the boss comes storming in saying "What the hell is going on in here? Why is that circuit board flaming like that? Someone grab the fire extinguisher!" Yep, ethanol works wonders, but it's probably not best for job security. I think I'll stick with the isopropanol.

I never ran that, but do recall them tuning them up. Something rings a bell though about mods. As the 80's rolled through everything was remote controled off site.

I do remember the time I pushed a button on one of the antenna motors, and everything went black for miles.

I also remember the time one would go outside and point at the falling Skylab, and the other person would try to move the antenna and lock on to it. What with the 1 degree beamwidth was impossible. We were using Norads predicts and they were too far off to be able to use. Somebody finally locked onto the spacecraft and finally got good predicts.

I also remember the time we tracked the moon with a wrench. For a while.

Big 85 ft.antenna made in Pittsburgh, as was much of the stuff made in the USA back then.

greg

protects

I just tossed solder like that into my solder pot.

--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

When the joint moves while in the plastic stage it is still electrically connected - when the joint moves with a eutectic mixture it cracks - the joint is very weak when still close to the liquid stage. With the non eutectic mixture the crystals of tin provide strength while the solid is cooling.

I might not have explained it very well, but I assure you, with total honesty, that the reason 60/40 was popular was the better reliability for point to point soldering and the reason 63/37 is now taking its place is that point to point has all but disappeared and the eutectic mixture gives slightly lower thermal stress.

Either that, or you believe or antecedents were morons, who while they knew about the eutectic mixture, were too stupid to use i,t or too clumsy to mix it, or they thought a few dollars extra per ton of solder was too much to pay for the good stuff.