Lead free soldering!

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I have chosed lead free for my current project and it started out just fine... however after just a few solderings the tip starts to oxidise really badly.

Any of you guys have experience with lead free?

I use a WSD-81 Weller station with the WSP-80 pen and have tried Kester 275 and Almit SR37. Both solders work fine as long as the tip are new and shiney so the soldering in itself works fine but holy smoke how bad the tips look after only 10-20 solderings. The wetting ability of the tip goes out the window in no time.

I would apreciate tips on how to use the tips ( :) ) both how to make them last longer before they get all black from oxides and also how to remove the oxide.

After reading on the net and talking to the swedish importer of Weller and Almit I have started to get some ideas on how to make things work better. Time will show..


/Peter
 
Have a cloth, an old cloth dampened with watter...not too much

And clean the hot tip skidding it into the cloth... the point of course.

Skidding it over the cloth and turning... you may clean 120 degrees each time.... so... automatically you will repeat 3 movements and ready to go.

Never use knife or sandpapper to clean your tips.

I have not experience with special solder types...cleaning between solders you will never have your soldering iron tip dirty...and this will turn into your mind something as one needed step after soldering...will be automatic...you will make it almost without think on that.

Will just think when you forget the cloth, or natural sponge... than you will scratch the table and will remember that forgot something.

Soldering supports use to have space to put those pieces of absorbing material.... with some watter they will turn heat resistant (a little bit resistant)

regards,

Carlos
 
Peter,

Are you selling your units commercially? If they are just for you, why do you need Pb-free solder? Why not just go back to 63/37 fast-flow solder and get rid of the problem?

I also have a WSD81/WSP80 combination and I am very worried to see how quickly the tips deteriorate...

I fully support the reduction of cadmium and mercury in consumer appliances, but banning a few grams of lead is a bad move from what I can make out. Firstly, you have the issue of tin whiskers in fine pitch PCBs, secondly, the higher temperature and lack of flowing abilities make it near-impossible to rework Pb-free PCBs.

My suspicion is that, by banning leaded solder, much more waste electronics will be created, causing far more environmental damage than prevent. One engineer I know who's been in the game since the '60s (he was an original Leak engineer!), thinks that banning leaded solder is a classic example of what happens when bureaucrats, with no knowledge about the industry over which they legislate, are given free reign to make rules...

I'd love for someone to tell me the problems with Pb-free are a storm in a teacup, and that the issues are over-exaggerated - please, please tell me it isn't that bad... I recycle everything I can and I'm all for saving the environment, but Pb-free will cause more damage than it prevents IMHO.

Meanwhile, post your opinions here - I'd like to get a debate going with the people who make the solder: http://www.indium.com/drlasky/entry.php?id=673



Justin
 
What annoys me so much is that the amount of lead being leaked into the soil from waste electronics is miniscule, compared to the amount of lead being leaked into the soil and water by simple erosion of lead flashing on many buildings!

I think if they are going to make RoHS lead free cover electronics, then it should also cover the building trade - any building with lead flashings should have to have it removed within 5 years.

By the look of it, such flashing is being removed anyway - by theives who are then selling the lead onto the scrap market!
 
Carlos,

have you ued LF solder? Thanks for advice but the problem is that the normal procedure that you use with standard solder does not work with LF. Wiping the tip on a damp sponge is not recomended since the LF solder wipes of to easy as compared to standard solder. Without the coating the tip oxidise quicker. It's also more important to use the right flux. I have good experience with standard soldering and can produce high quality works at a fast pace with that.. it's when I switched to lead free the problems started.


Justin,

no soldered products commercially. I was curious to use it even though I agree that the environmental problems is open for debate. I am aware of tin whiskers and I'm also a little worried about the higher temperature especially for small sensitive parts.


/Peter
 
Been doing some experiments with lead free soldering over the last weeks (luckily at works expense.) We are using Weller TCP Magnastat based irons and we have also noticed that the tips are not lasting anywhere as long as they did with leaded solder. Tips were typically lasting months with leaded solder, even when being used every day. Now, with lead free solder, some tips are only lasting a week.

We have also tried around 10 different lead free variants of solder and IMHO not one comes anything close towards the lead/silver we have used before in respect of wetting, finish and ease of use. One of the ‘better ’ solders we found is this Multicore 99.7/0.3 309 Rosin based solder , and then only with additional flux.

Don’t want to teach anyone to suck eggs but some tips, hopefully someone will find useful:
• When using a solder tip for the first time, keep tinning and cleaning it, until it is up to full working temperature. This really does ease the initial ability for the tip to ‘wet’. Haven’t tried it myself but attempting the tinning and cleaning as the iron warms up may help your wetting issues.
• When placing the iron back into its holder, always add a little bit of solder to the tip, so it doesn’t get left dry. So don’t clean the tip before putting it away, only when you using it.
• Lead free solders don’t appear to mix well, with each other or leaded solder. If you change from one type/make to another it can make the iron difficult to wet. If doing re-work make sure the item your soldering has as much of the original solder removed as possible.
 
I've used lead free for most the time I've actually soldered. I find it works great on veroboard (which I often use) but was dissapointing on a normal PCB. Just using an Antex 18W iron, solder has silver content. Having used lead solder and my 30W iron for some larger connections I find that it does indeed give a shinier result, actually mirror like. When I next do PCB's I'll have to get some normal leaded stuff; is the fast flow stuff the best then?
 
Peter,

we tried Multicore SAC 305, whilst it did give a reasonable finish, its wetting abilty was lower than quite a few of the other lead free solders.

Another tried was the Stannol 95.5/3.8/.7, which is similiar in compostion to the SAC 305 spec. This was better then the average lead free and has proven to be a good all rounder. Although when the next Farnell order goes in we will give the previously mentioned solder a long term trial.

These are the only two silver based solders we have tried and from this small sample, the silver does not appear to offer the same advanatages (of wetiing and general usablity) in everyday soldering, it offered in lead based solders.
 
I hadn't even thought about the implications for 'scavengers', Jaycee... Good point.

What's more, aside from flashing, car batteries and CRTs are exempt - how much lead do they use compared to a gram or two in a typical piece of audio's solder?

Reworking is what worries me the most. Hardly a day goes by without me seeing a posting at a group such as this one, complaining of issues with soldering. With only a year and a few months having elapsed since ROHS became compulsory, we won't have witnessed too many rework situations yet... I have yet to try my De-non SC7000 on Pb-free solder yet, but at £50 a tip, I'm pretty worried about the implications if it gets damaged after a few applications... Considering a tip lasts me months with leaded solder, that's another issue where a few grams of lead creates a need for much more metal in replacing the reworking tip...

I fail to see what good EU membership does for anyone in the UK - the politicians still have enough autonomy to make disastrous and catastophic decisions, with the genuine man-in-the-street having to abide by petty EU legislation, with an agenda dictated by multi-national corporations who have the lobbying power in Brussels. Heads it's wrong, tails it's wrong.

If anyone else would care to post an opinion at the Indium blog, I'd be grateful. With all the research they should have put in, if anyone can calm my fears, it should be them...

Justin
 
After some advise from venso.se the Swedish importer of Weller Almit and other brands and some reading on the net things have improved greatly.

The surface tension is different with LF solder which seems to result in a much to clean tip after you wipe it on the damp sponge. Better is to use "wooly-metall" becasue it leaves a tad more in on the tip, enought to protect it from heavy oxideformation. However, I didn't find that propduct yet but I did buy a salmiakstone. I had never used that before but I could read on the net that those where used to remove oxides from tips when solder/flux/sponge wasn't enough.

So now I can keep a nice clean tip much longer and the wetting ability is very much improved. I hardly use the sponge at all.. just rub the tip on the salmiakstone and off goes the coloration and oxides. Now I can concentrate on soldering again instead of worrying about the tips. Strange though that some tips work better than others with the salmiakstone.


Oh, I should add also that part of the problem was the damp sponge but also the multicore tip tinner/cleaner I used which seems to create as much problems as it solves. The flux residues oxidise and become burnt at the tip.

So, without having used that "woolly-metall" yet my advice to those who expereince problem with LF soldering is to use it in parallell with the salmiakstone and be careull with the sponge and the tip tinner/cleaner.


Off to work, time to produce some solder fumes! :)

/Peter
 
Did some reading on the Nasa website. It seems like tinplated metalls, electroplated, is the real problem. Soldering with an alloy with at least 3% lead is considered to be acceptable.

Seems like whiskers may be no problem with SAC solder that contains Sn96.5%/Ag3%/Cu0.5% but they do not adress this specifically.

edit: even silver, gold, aluminum, zink, cadmium, indium and lead can form whiskers it seems.


/Peter
 
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