A question to the knowledgeable regarding solder

Steve2381

Senior Member
I would like to ask the advice of those that know.... solder.
I have been using good old Maplins solder for years, and its not all that great. Time to get some decent stuff.

But... HOW MANY TYPES!

I need to order a disgracefully expensive Blue Oled display, and this company are the only suppliers, so I may as well make the order up to the £50 minimum for free shipping.

Which of this mind bending array of solders will suit me best? I am looking for something - small enough for SMT work, so I assume around 26swg (0.018" / 0.45mm).
I understand Rosin free is better (what is water soluble?) and 60/40 mix - 1-2% flux.
Search for this and I come up blank, so I must be missing something.

This is the solder page:

http://uk.mouser.com/Tools-Supplies/Soldering/Solder/_/N-b11qq?FS=True

Any guidance gratefully received.
 

Brian M

Member
I always used 40/60 and found the lead free to be a complete waste of time (especially in the field). As usual, I am pushing CPC Farnell, (trade Counter in Preston) open 7 days a week, free delivery on orders over £5 and a very comprehensive stock of components, tools etc.

Look at this page:

http://cpc.farnell.com/jsp/search/browse.jsp?N=411+2005+212239&Ntk=gensearch&Ntt=60/40+solder&Ntx=mode+matchallpartial&getResults=true

Up to now, I don't think I have sustained any significant brain damage, but there again ??

Lead free is here:

http://cpc.farnell.com/jsp/search/results.jsp?N=411&Ntk=gensearch&Ntt=lead+free+solder&Ntx=mode+matchallpartial&suggestions=false&ref=globalsearch&_requestid=286947
 

hippy

Technical Support
Staff member
The stuff I usually use at home seems to be similar to SD00961 1.2mm from Brian M's top link but alloy marked as "SAVBIT No 1" on the reel. Seems to be tin/lead/copper mix, 5-core 362 flux. That has served well for many decades and has been fine for veroboard and through-hole PCB construction. I wouldn't want to go larger diameter, but slightly smaller would probably be better.

It was being given away so I just accepted it. Not sure how I would choose what's best if I were buying other than by trying different sizes and different alloys but "Multicore" is a brand I've been happy with. It possibly is a case of too much choice being a bad thing!
 

Steve2381

Senior Member
Thanks guys.
Mouser isn't the greatest (and certainly not the cheapest) supplier. I use Farnell and the Picaxe store the most a. Perhaps I will get the solder from Farnell instead.

The Blue 4x20 Oled display I need is only available from Mouser. I have emailed the manufacturer directly and they won't supply to me. The LCD 4x20 I currently have in a project just isn't cutting it.

The display is £23+vat +£12 delivery. Pretty damn expensive - £40 for a display. However if you hit £50, its free delivery, so you may as well bump up the order.
 

Buzby

Senior Member
SAVBIT was the trade mark originating from years ago, because the solder included some copper in it's mix, supposed to reduce erosion of the copper soldering bit.
Then the bits started to be iron plated, which reduced erosion because the iron didn't react, meant the SAVBIT idea was not really needed.

I still use it, the lead free stuff is far too pernickety about temperature and cleanliness !.
 

MartinM57

Moderator
I find 0.7mm fine for SMD/SOIC (0.05" spacing) chips etc. I've considered 0.45mm occasionally, but then see the price...

My current fave is a 500g reel of 0.7mm Multicore 5 core ERSIN 362

I tried some 63/37 on recommendation from here I think - Omega Fast Flow 2% - and it spits its flux all over the place (yes, I tried all sorts of iron temperatures, which I can control to 1 degree resolution, possibly accuracy as well ;)), so that only gets used when flux-spit doesn't matter.
 

Hemi345

Senior Member
I have a few different brands and types of solder and keep coming back to Radio Shack's "High Tech Silver-Bearing solder". Diameter 0.015", Rosin Core Silver-Bearing (62%-tin, 36%-lead, 2%-silver) Solder: http://www.radioshack.com/product/index.jsp?productId=2062725
The flux cleans off easily by spraying the board with 91% isopropyl alcohol.
The 60/40 and lead-free I've tried are a PITA to work with compared to it.
 

WHITEKNUCKLES

New Member
The Best at 26SWG ? but £49.30 for 250g and that is a low price.

Multicore Smart Solder Wire SN62 505 26SWG 0.46mm 250g - a silver loaded wire (62/36/2 tin/lead/silver)
Sn62Pb36Ag2 material, 179°C melting point, suited to hand soldering of surface mount components.

http://www.rapidonline.com/Tools-Equipment/Multicore-Smart-Solder-Wire-SN62-505-26SWG-0-46mm-250g-85-6505/?source=googleps&utm_source=googleps&IncVat=1&gclid=CLaYj426_8ACFdSWtAodVw8Ayw


Mouser have as similar specification and much cheaper at only £26.53 per Lb

http://uk.mouser.com/Search/CompareProducts.aspx
 

srnet

Senior Member
I've considered 0.45mm occasionally, but then see the price...
For SMT stuff I use the 'Mechanic' el cheapo solder from eBay.

0.3mm, 63/37, 40g for around £4.50, which is a lot of solder for SMT use.

Now well proven for space useage, but I bet they dont know.
 

geoff07

Senior Member
Interesting question.

The school where I help out with their practical electronics class used to use resin-cored lead/tin as most people do, or used to do.

Then they were expected to use lead-free, which they tried. But they gave up on it because it led to too much teacher intervention to fix things.

So now they use lead/tin without the resin because 'it is a hazard'. They do use a flux pen, though I don't think the joints flow particularly well.

Is this a common practice? Is the concern real? or only real for continuous industrial use? The kids only have to make and solder a small board so it is a brief exposure. Exposure for staff isn't particularly notieceable and then is only for brief parts of the school year.

Personally I use lead/tin with resin (an ancient Maplin roll with a faded label so I can't read the spec), and rather like the smell. The replacement roll that I shall start shortly is Ersin Multicore 362, alloy 60EN (presumably 60/40).

Only yesterday I spent a lot of the lesson tracing a dry joint that I feel would not have happened with cored solder. This matters because it costs them time, and time ultimately means marks.
 

tmfkam

Senior Member
Looking at the safety sheets for 60/40 solder with rosin flux...

Unless you are eating it (in large quantities), in a very confined area with no ventilation and have an existing breathing related disorder or rubbing it into the hands while eating it is unlikely to cause any problems.

Only once students have mastered soldering with 60/40, try them with lead free!
 

Steve2381

Senior Member
Thanks all for the replies. Looks like there are a lot of options. My Maplins solder has done me well to be fair. and pretty well priced (no idea what spec it is now... label long since gone), but its too think for SMT.
I may spread my bets and get a couple of smaller rolls of different types and see what results I get.
Certainly don't care whether its ECO or me friendly! I will die of something else... not assembling my occasional Picaxe projects.
 

Dippy

Moderator
Yes, there are many types. We haven't tried them all I'm sure.:)
Most people stick to their preferred type.

I've tended to use 60/40 or the other variation with silver - from Ersin.
And also lead/tin from Warton Metals.
(I admit I use leaded solder paste for SMD at home. Full of flux)

All of them were excellent, wetted nicely, shiny, well-shaped blobs and didn't spit.

I had bad experience with cheapo no-brand lead/tin and lead-free.
Spitting and poor joints.

As a result I've never based my choice on 'cheapness' - a big roll will last years.
If it's awful then you are stuck with it for years - or you have to buy some better stuff.


How you treat fumes is up to you at home but, if possible, get something to suck or blow the fumes away from your breathing orifices.
Other than lead fumes there are some nasties in the smoke, regardless of how 'nice' it smells.
 

Jeremy Harris

Senior Member
I think I've fixed more bad solder joints in the last few years since lead-free solder became the norm than I have in my previous 40 years of electronic tinkering. The stuff is very, very prone to dry joints and cracking, the latter seems to be the biggest problem as lead-free solder has a higher Young's Modulus and tends to crack due to temperature cycling or if subjected to mechanical stress, whereas conventional tin/lead solder is far more forgiving.

Given the very low exposure risk from solder at the hobby/educational level I'm a bit surprised at the way lead-free is being demanded. The primary risk from it comes from using tin/lead in industrial scale molten bath soldering, where significant amount of lead could get into the air from the baths. It's not really a risk from hand soldering, though, I suspect some of the fluxes and solder-through coatings on some boards present a greater risk.
 

nekomatic

Member
I assumed the move to lead-free solder was more about reducing harmful substances in electronic waste than reducing hazards in manufacturing - although both are desirable.
 

John West

Senior Member
Lead-free solders I've used require the surfaces to be soldered be absolutely free of oxides. That's usually easy to achieve in a manufacturing environment, but not so easy in a hobby environment, so I use leaded solder for my projects (here in the USA.) Unlike a manufacturing business, I go through only about a pound or two of solder a decade, and I never toss out the circuits I've built. When I pass away, some poor soul can haul it all to the hazardous waste recyclers. It will be an hour's worth of work for someone in return for a lifetime of convenience in soldering for me.
 

BeanieBots

Moderator
It's another one of those regulations that's lost it's way!
The intent was to reduce the amount of lead going into landfill.
Companies that had not used up all their old stock are now not allowed to use that stock.
It must therefore be put into landfill. (completely missing the point).
 

nekomatic

Member
If you're talking about stock of leaded solder, a quick Google shows that there are plenty of companies willing to recycle it - the lead and tin can be separated chemically.
 

Goeytex

Senior Member
In 2005-2007 when I was on contract developing a product for military application, the military specifically forbid the use of non leaded solder and specified 63/37. This was because of tin whisker failures in some mission critical systems related to the use of early RoHS solder. Not sure if anything has changed.
 

BeanieBots

Moderator
I was mainly referring to product (eg PCBs) but I'm sure plenty have done the same with their old reels of solder too and 'contaminated' solder stations.
Further to Goeytex's comments, aerospace is exempt due to the brittleness (and hence probability of fracturing) of lead free.
 

Dippy

Moderator
I'm sure there are many (RoHS type and others) documents that explain and provide info on the lead-free debate.

There are a number of industries that have exemption and can use leaded solder.
Some manufacturers of certain components offer non-RoHS options on components.
There are gallons of documents on the subjects of tin whiskers, brittleness and all sorts of metallic growths (e.g. silver dendrites).
It has been known about for decades.
It's a real concern in the industry that I work in.
 

john2051

New Member
Hi,
this reaction where solder connections 'grow' whiskers. Is this why some products are coated both sides with a sort of conformal coating?
Is this a similar process to the shorts that develop in nicd cells?
I tried some supposed high quality lead free solder, and its use resembled the high melting point solder we used to replace the dropper resistors
in valve radios. The other thing I noticed was that the soldering iron bit would not tin with ordinary 60/40 solder after using lead free, has anyone else
found things like this?
If lead free soldered joints oxidise sooner, should there be a lot of people who have bought expensive electronics equipment that has used lead free?
Apologies for the number of queries, but there seems so many contradicting opinions in a google search.
thanks john
 

Dippy

Moderator
'Tin whiskers' in my industry are a big concern, fortunately we are exempt and can use lead/tin.

As far as I have seen the lead-free requirement is purely H&S , I can see no physical benefit of lead-free.
Tin whiskers can grow from any tin surface, not just a solder joint.
I have seen tin fur developing on pure tin plated screening boxes.
But the growth and time periods involved seem unpredictable and there has been a lot of research on this matter.

There is plenty of argument about whether a (spray on) conformal coating helps much.
Some engineers say the thin plastic coat is easily penetrated by whisker growth but I haven't seen any evidence.
I really can't say for sure, though 'gut feeling' suggests it should help a bit.

The mechanism of tin whisker growth is different to other metallic growths like the 'ferns' that grow from (for example) silver plating.
These are referred to as 'dendrites' and are definitely stimulated by external ambient conditions.
For example, in an atmosphere where sulphur compounds are present, the silver dendrite growth will be greater.
Most (all?) metals can suffer from dendrite growth to a degree - inclduing gold.

Dendrites grow like normal crystals whereas, based on the documents I have seen, tin whiskers seem to grow brom the base.
I would guess that the growth in batteries is a crystal/dendrite mechanism.
I don't know but the use of the word 'whisker' probably confuses the issue.

Anyway, hopefully you won't have a problem in hobby projects that only last a couple of years.


Your soldering iron...
This could be because the flux in the lead-free solder has left a cooked laquer layer on your bit.
Tin will (when heated) alloy with lead-tin easily.
There are so many variables including cheap&nasty fluxes.
Get a proper cleaner. Don't use sand/glass paper or a file.


I don't understand your last question, but manufacturers have to comply with regulations which dictates which solder they can (should) use.
I'm sure there will be exceptions depending on who makes the equipment...
 

john2051

New Member
Hi Dippy, sorry about the wording of my last question. I was trying to ascertain how these lead free problems
will cause headaches for radio amateurs who have spent many tens of thousands of pounds, or even consumer
electronics for that matter, and its long term effects on failures, but I suppose this crosses into the 'crystal ball realm'.
I agree about the possibility about fluxes causing iron bit not to tin, I tried the wet sponge, and a small tin of solders
paste/iron bit tinner/cleaner but so far no joy.
Thanks john
 

Steve2381

Senior Member
Well I ended up getting a 1lb roll of SN63/PB37 2% core, 0.20" That is 63% tin and 37% lead, 0.5mm diameter.
Only used it a couple of times so far, but seems pretty good and didn't cost the earth (think it was £22).
Thanks for all the advice.
 

Dippy

Moderator
Good choice Steve.... proper 'brand name' stuff or from you-know-where?

John:
Is that that paste stuff that comes in a small tin? Old hacks say that the modern stuff isn't as good as the old stuff.
Have you tried the brass woolly stuff or a brass wire brush?

I've had nightmares cleaning tips - especially after a Far Eastern lead-free solder from Map***.
As a result I'm happy to spend the extra couple of quid for a good solder (wire or paste).
Good solder with regular (as in 'often') wet-sponge wipe should be enough.

Solder paste (proper 'big name' manufacturer) has an enthusiastic flux which I've used to clean and pre-tin.
But it's expensive and a new tip is only a few quid.

Tin Whiskers are odd.
I've seen 15 year old equipment run 24/7 with little ones (2mm) and a similar device left in a cupboard with nothing.
Cross-sectional micro-photos show them erupting, mostly from surface imperfections.
Power, heat, humidity...? Who knows?
The same equipment had silver dendrites 15mm long.

So, yes, a 'risk' and as equipment and lead/track pitches get smaller then the risk gets higher.
But as most consumer stuff gets binned for the 'new game' or the 'i-Phone x+1' then it doesn't show up.
Or maybe is mis-diagnosed?
I really don't know.
 

Steve2381

Senior Member
Got it from Mouser (purely to make the order up to minimum for free postage so I could get my Oled display).. Made by AimSolder in Canada.
My Maplins solder is OK for general bashing I suppose... but I find it kills my soldering iron bits pretty quickly. This new stuff is for the more precision projects I have on the go.
All I use to clean the tip on my variable temp soldering iron is a damp sponge.
 

john2051

New Member
Hi again Dippy, The little tin I have with solder paste/flux is made by Ersin, and I would think its at least twenty years old. Yes some of the lead free solder I tried was from Map***!
Think I will stay with this thin 60/40 ersin savbit solder, the only gripe being it leaves flux all over. Fortunately it dissolves readily in isopropyl alcohol. I've also had problems with
some solders (or flux) eating bits away quicker than you would expect.
I recently bought an antex rework station with hot air and a fifty watt iron. Nice, but spare elements are £38.00!
Apologies for jumping in on this thread, regards john
 

techElder

Well-known member
The only procedure that I ever found for keeping the soldering tip "clean" was to develop the habit of wiping the tip on a wet sponge twice while rolling it in the hand to get both sides.

It was key to NOT do this when putting the iron back into the holder; only when taking it out of the holder to use.

It was a quick double wipe, and I doubt it affected the tip temperature much. We always had temperature-controlled irons. Weller brand. Name brand solder.

My technicians learned to do this on the first day; all day long. I had several techs working at the same time. The irons came on in the morning and stayed on all day. We all did this for decades. Rarely was there a problem with the tips not staying tinned. (Also changed the tips at least annually for new tips.)
 

geoff07

Senior Member
We have discussed the tin whisker problem before. NASA has lost satellites, attributed to this cause (and published evidence from their investigation). On a more prosaic level, if you try to restore an old radio using new-old-stock OC42 transistors, you will find perhaps half of them have failed in storage, attributed to tin whiskers (from the tin coating on the inside of the can). But they have had perhaps 40 years to grow.
 

John West

Senior Member
Texasclodhopper, you and I use the same tip care technique. I teach it to my soldering class students. My primary use tip has lasted over 3 years but is starting to pit, so it won't last much longer.
 

techElder

Well-known member
It always works, but you already know that! My home soldering tip has not been changed in 10 years that I know of and probably a year or so more than that. I took the iron when I sold the business in 2005!

In a business setting, it was deemed cheaper to just change the tips about once a year.

Texasclodhopper, you and I use the same tip care technique. I teach it to my soldering class students. My primary use tip has lasted over 3 years but is starting to pit, so it won't last much longer.
 

Hemi345

Senior Member
Did you ever use the lead-free stuff and have the tips hold up that well? I ran out of my favorite 62/36/2 solder so I was using some lead-free stuff and it destroyed the tip within a couple months. I've been using a tip cleaner and tinner after each soldering stint to try to make this one last till I can buy another roll of my favorite solder again.
 

jensmith25

Senior Member
I use an Antex temperature controlled iron - the one with the adjustment in the handle and it's great (about £50 so not cheap but much cheaper than Weller) They have tips specifically for use with lead free solder and I find they last very well. I use a brass scourer to clean the tip which was recommended to me.

Because I sell what I make I have to use lead free but the better ones are very good now. I use a lead free, rosin free solder called Omega II from Wharton Metals and I've found it to be pretty good. Nice shiny joints but it can get more sticky resin on it than other's I've tried, but for my stuff it doesn't need cleaning. For me, I'm happier using a rosin free and extracting the fumes.
 

Dippy

Moderator
I regularly clean my tips too.
And I've also had good results from solder made by Warton Metals.

Our blokes at work solder to standards by RR. I'll try and interrogate them as they solder day in and day out and probably solder more in a day than I do in a year.
 
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