Recognizing lead-free solder

Gawd knows mate. The politicians probably didn't think of that one.

About 50C higher. Hang on, you said " SnSb or SnAg " ! Where do you think you're going to find those ?

Graham

Georgia ?

How about starting with an Alloy Temperature Chart??

Kester Lead Free Solutions

NPL: UK's National Measurement Labs

BTW, Kester lists 5 eutectic solder alloys on this chart -- can you find them?

It has been recommended by the creators of the half-arsed RoHS directive, that manufacturers mark their boards with the alloy that has been used. To date, I think I have probably seen about 2 or 3. In general, boards made with lead-free, look as though every joint is bad ( and often, this is pretty much the case !! ). Instead of the joints having a shiny appearance, and being domed or meniscus-shaped, they are dull and grey, decidedly 'crystalline' looking, and tend to be volcano-shaped, with straight sides.

Pretty much any commercial equipment from the big far east manufacturers - Pan, Sony, Hitachi etc - built in the last two or so years, can be assumed to have been built in lead-free.

When you get a lead-free board for repair, as well as finding your fault, which may well be joint-related, check the solder joints on anything large such as connectors, power transistors, heatsinks etc. It's also worth checking the soldering on any LSIs fitted to the board - particularly the rows of legs on the downstream side of the soldering process, which is often marked on the board by an arrow. Give anything suspicious, a good rocking. Bad joints just don't look the same as with leaded solder. I have had components just come out in my hand, leaving behind a perfect-looking volcano of solder. This is because the manufacturers run their solder process plants at as low a temperature as they can, to avoid damage to LSIs etc. With the known inferior wetting properties of lead-free, this tends to result in insufficient heat to properly solder components with a high thermal inertia. SM LSIs seem to suffer as a result of the inferior flowing properties of lead-free, resulting in poorer capilliary 'draw-in' of the solder, under the legs.

As Graham says in this thread, 50 deg C hotter is about right. The difference in actual melting temperature, is around 30 - 40 deg, depending on the exact mix. As a matter of interest, the recommended alloy for general bench rework, is Tin-Copper-3% Silver. This has a melting point about 10 deg lower, and apparently, rather better wetting properties, but I can't vouch for this, not having tried any yet.

Arfa

Yes...

Thanks -- just what I was looking for.

Actually, that gives the melting points, which weren't hard to find in the first place. What I'm looking for is advice about how to set the temperature-controlled iron.

Thanks -- that's useful!

Dead easy - lead free solder joints fall apart in less than a year!!!

Any chance the half-arsed RoHS directive was thought up by the stuck up gits who pepper the countryside with 12bore lead shot?

OK. You mean the mind-less idiot knob on the current soldering stations?

Personally my range is 650 to 750 degree -- the KEY is to stay in the range and then select the proper tip SIZE (1/64" to 1/4" in 1/32 or 1/64" increments) and PROFILE (screwdriver, conical, single flat) -- as well as solder. Works well for 63/37 Tin/Lead eutectic and 60/40 alloy.

For the Weller WTCP, I still use 700 degree F tips, PTA, PTB for screwdriver, the other 3 tips that I occasionally use depending upon the work (reach, SMD, etc) are: PTH, PTL, PTS

I do know some people who jump to 800 degree for the no-leads -- depending upon formulation being used.

For Lead free solder, call Alpha/Cookson Electronics (Jersey City, NJ) and have them send you a sample of:

96.5% TIN; 3% SILVER and 0.5% COPPER in the .020 diameter either with a 3.3% flux or WRAP2 flux

g. beat

Most shot used in clay shooting is no longer lead, I seem to recall. Anyway, the point is that if it is, it is not recycled, so remains lying where it is. Solder accounts for less than 1% of the world's mined lead, over 80% going to car battery manufacture. The car battery industry have managed to organise virtually 100% safe recycling, so are allowed to carry on using lead on this basis, and the contention that there is no suitable alternative. With the coming of the WEEE directive shortly, end of life electronic equipment will have to be safely recycled in much the same way, so where's the difference ? If the car battery people can do it, I'm sure that the electronic people can also do it with less than 1/80th the volume.

The point about the RoHS directive as it stands with regard to leaded solder, is that it is forcing a changeover from a mature, tried and tested technology, which had reached the point of almost perfect reliability, to a less than satisfactory alternative, with at best, woolly reasoning to try to justify it. This is well understood by such people as the US military, who refuse to use the stuff, the avionics industry, who have obtained exemptions, and the medical instrument industry, likewise. Any ecological advantage from the poisoning angle, will probably be outweighed in the long run by the additional energy budget worldwide to run all those solder production lines and hand soldering irons 50 degrees hotter, and all the extra recycling brought about by electronic equipment being junked earlier due to owners getting fed up with all the intermittent problems from bad joints ...

Just keep your fingers crossed that avionics are not finally forced down that route, coz that'll be the day that I stop flying.

Arfa

Some good points there, I didn't know lead was no longer used for 12bore shot - any idea what they use instead?

Regardless of the WEEE directive, lead was originally mined out of the ground and one way or another it will eventually end up back there, also I had always held the opinion that the common solder alloys were substantially less toxic than lead on its own, if this is true then the manufacture of lead/tin solder actually reduces the availability of lead wherever it ends up at end of life.

One thing I have been trying to find out if anyone knows, is how much lead the petroleum industry procured annually for TEL additives before leaded petrol was discontinued, the figures I read somewhere (can't remember where, or how much!) were huge - thousands of tons of lead converted into exhaust particulates to be inhaled, washed onto agricultural land and into the water table, I suspect that lead in solder is insignificant compared to previous usage of TEL!

On Thu, 15 Jun 2006 23:48:02 GMT, "Arfa Daily" put finger to keyboard and composed:

I wonder how much lead is in a typical CRT? BTW, I googled for "lead free CRT" but got very few hits.

- Franc Zabkar

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Please remove one 'i' from my address when replying by email.

"ian field" wrote in news:M4Fkg.13160$ snipped-for-privacy@newsfe3-win.ntli.net:

Yes, but the lead coming out of tailpipes was widely distributed in the air, whereas electronics that wind up in landfill dumps just sit there for a long time and continuously leach their chemicals into the nearby ground, whence it flows down into water tables and gets into drinking water. I'd prefer my drinking water lead-free, thank you.

First to Jim two posts above. You are missing the point. The electronic waste will no longer sit in landfill, because the new WEEE directive, in Europe at least, will make sure that the equipment is recycled, and any lead content removed. Electronic equipment in landfill will soon become a thing of the past. Anyway, just how soluble is lead in water ? I'm not too sure, but I expect some clever chemistry graduate will tell us. In the past, water was delivered to all households in the UK via lead pipes. In a lot of older properties, it still is. Certainly, the house that I grew up in had lead pipework. I am not aware of people of my generation all dying of lead poisoning, or having suffered intelligence lowering due to lead-induced brain damage. In fact, since lead piping has been being removed here, the kids have been getting progressively thicker ... !! I have heard people say that delivering water via lead pipes is of no consequence, because the pipes quickly get an internal coating of limescale, that insulates the water from the lead, but some areas of the country have very soft water, with little or no calcium content, so I'm not sure that this argument " holds water " ( ouch !! ).

Even if lead is soluble in water, I can't imagine that it is extremely so, and I would have thought that water treatment plants would have removed any in their raw input, or could be made to do so fairly easily. Of much more concern, I would have thought, must be the organic fertilizers and such that get into the water supply. I don't know what the situation is your side of the pond ( I'm assuming you are US based ) regarding landfill. All we ever hear over here, is that your glorious leader is not a very eco-friendly guy, but I'm sure from what I've seen on my frequent visits, that isn't the case amongst the general population.

To Franc. I'm not sure what the percentage of lead is in the lead-glass that is used for CRT faceplates, but as far as I am aware, it's another technology that has been deemed not to have a viable alternative, so has been granted an exemption from the RoHS directive. Total recycling of this glass should be possible, with no lead-to-environment contamination. As well as the faceplate glass, I seem to recall that there is some issue also, with getting a vacuum-proof seal between the CRT pins and the glass, that involves possibly some other hazardous substance covered by the directive. Interesting stuff. If anyone has any strong objections on the grounds of this being off-topic, say so, and I'll stop raising new points ...

Arfa

I have a friend who owns a clay range. A few years back, there was a big thing locally about shot from his range ending up in a wheat field behind. This also lead to complaints on the noise issue. As far as I recall, they changed over to a different cartridge, that has a non-lead shot content, and a lower velocity powder charge, which cuts down on the noise, making more of a soft whumph noise than the previous sharp bangs. I haven't seen him for a while, nor been to the range, so I don't know what the effects of this have been on the sport, but I will try to find out, if you like.

I think that the issue with ' out of the ground / back to the ground ' that's usually quoted, is that it came out of the ground as a naturally occuring ore, but goes back as refined lead. But I'm still not convinced that this whole thing is not just an eco smokescreen, keeping beaurocrats in a job. I'm sure that there are much more hazardous substances getting into the eco system, than lead from solder.

Arfa

Arfa

"Arfa Daily" wrote in news:MkHkg.23791$ snipped-for-privacy@newsfe3-gui.ntli.net:

I believe the lead in CRT glass does not leach out. It's probably the monitor electronics is where the lead is coming from. Also,it's not just the faceplate the lead-glass is used,as the lead is intended to attenuate X-rays which I believe scatter BACK from the target.

--
Jim Yanik
jyanik
at
kua.net

See:

The proceedure is to test for leaching using moderately acidic water (Ph = 5.0) and to literally pulverize the glass to accellerate the leaching (See Method Phase I). As expected this yielded the worst case results at about 3 times the US limits.

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# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558            jeffl@comix.santa-cruz.ca.us
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# http://www.LearnByDestroying.com               AE6KS

A bit more on the topic:

Is this Ban Really Necessary? A Critical Investigation of the CRT Ban. |

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# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558            jeffl@comix.santa-cruz.ca.us
# http://802.11junk.com               jeffl@cruzio.com
# http://www.LearnByDestroying.com               AE6KS