Solder quality

[netdudeuk]

I've been using the cheap Chinese lead solder for a while and I get mixed results.  Some joints are gorgeous.  Smooth and shiny.  Others are dull and not so slick and need reflowing.

My Hakko tip is clean and at 350 degrees.

I've found that Chem-Wik desoldering braid is far better than the cheap stuff I was using.  Does the same apply to solder ?  Which are the best brands to go for in the UK ?

Yes, I've see one thread with a few solders on the Veroboard but that just mostly shows poor joints.

Thanks

[dom0]

350 °C sounds too much for me for leaded solder. I usually use 250 °C, 350 °C only for really fat ground planes or tinning thick wires. 405 °C for road runner.

I personally use Felder Sn60 Pb40 F-SW 32 at 0.8 mm thickness, costs something like 8 € for 250 g. Not sure about availability in UK, though, although I think that the brand doesn't matter much as long as you get Sn60/Pb40 with proper flux in it. OTOH solder is one of the cheaper things for us, why bother saving a few cents here?

[mariush]

Get some quality solder, Farnell has some good brands like Multicore, Kester, Stannol

I think their UK "retail" (aka small purchases) version of the site is this one http://cpc.farnell.com  but there's also http://uk.farnell.com if that one doesn't work.

There's 63/37 solder which is great and there's 60/40 solder, which is more "user friendly". 
The 63/37 is eutectic, which means it turns from liquid to solid almost instantly, once the temperature reaches a very narrow temperature range (maybe a couple of degrees C). It makes for better solder joints.
The 60/40 solder stays liquid for a higher temperature range so it takes more time to turn to solid, so it's easier for amateurs and it makes it easier to work with lousy soldering irons.
Between these, I'd still recommend going with 63/37 even if it's more expensive.

There's a third and fourth option, 62/ 36/ 2  where 2 means 2% silver (Ag) or Copper (Cu).
The Ag version is more suited to soldering surface mount components like tiny resistors or capacitors (some surface mounted components have silver in the ends which mixes with the solder for better connection.
The Cu version... i think it's designed with added copper because it makes soldering iron tips last longer... there may be other benefits but I'm not aware of them or I don't remember them now.

Here's some suggestions :

http://cpc.farnell.com/multicore-solder/609961/solder-wire-crystal-400-0-71mm/dp/SD01822  (about 2.2% flux)  250 grams
http://cpc.farnell.com/multicore-solder/610008/solder-wire-crystal-510-0-71mm/dp/SD01827 (about 2.8% flux)  250 grams
http://cpc.farnell.com/multicore-solder/609985/solder-wire-crystal-400-0-71mm/dp/SD01823  (500g , more value for money)
http://cpc.farnell.com/multicore-solder/qlmp22/solder-lmp-22swg-250g/dp/SD00061  (250g, with 2% silver)

I would also recommend investing in some liquid flux. While the solders above all should have a a good amount  no-clean flux in them, sometimes extra flux helps and too much flux is almost never a problem.

[netdudeuk]

Thanks for the replies guys but the question is, is it actually better than my cheap 63/37 ?

I have used a flux pen and it does sometimes make for a better joint but I'm working on a through hole project with loads of IC socket pins and the tip is pretty ragged up now and the pins stop a nice distribution of flux.  I've watched SMD soldering videos with the flux pipette or whatever being used but not sure that it would be any use to me.

[mariush]

I would say yes, if it's some no-name Chinese solder , then the ones I recommended should be much better.   The flux amount (inside the solder wire) could vary, or there could be areas where there's no flux, you may have portions of solder that aren't quite 63/37 ... and so on.

The Multicore solders in particular advertise having 5 separate "strands" of flux spread through the wire diameter, so that when you bring heat the flux spreads more evenly on the work surface and has a chance to work before it evaporates.
IMHO it's worth investing some money on a good solder.

Note that the diameter of the solder wire is also important.. the ones I linked to are around 0.7 mm which is a decent diameter, I personally have and use 0.56mm diameter solder (multicore 63/37) and I like it a lot for soldering pins and surface mounted components.

Lower the heat of your iron to around 280-300c, get some paper handkerchiefs/napkins , clean the tip of the iron with the napkins to remove the crud and apply a bit of solder, then apply a bit of fux where you're going to solder and proceed to solder pins until you feel a new tip cleaning is in order.

Skip the first minute or so as you won't have leads so oxidated to require rubbing with abrasive material, flux in the solder should be enough for that. Watch the soldering technique:



Again you may skip the first minute if you want to.... this is a bit overkill ("avionics" grade, paranoid etc) but it demonstrates the proper way of cleaning tip, applying some solder to prevent oxidation and so on.. it's a good process to do before going through a lot of soldering.

[nanofrog]

I've found that Chem-Wik desoldering braid is far better than the cheap stuff I was using.  Does the same apply to solder ?  Which are the best brands to go for in the UK ?

Absolutely. Brand wise, Multicore is widely available in your market (no experience with Stannol AFAIK, but hear good things about it).

FWIW, Kester has better availability here in the US, so is more common vs. Multicore. Other top quality brands would be American Iron & Metals (AIM), Indium, and Alpha Metals (Cookson). Not sure on availability in the UK though. 

Generally speaking, I'd go with:

• 3.3% of flux
• RMA if it's mostly new stuff, but if there's age to anything you're working on, such as repair, you'd be better off with RA instead (will cut through the oxidation) if you want to keep it to one roll.
• 63/37 for general purpose
• 0.5mm/0.020" to 0.6mm/0.025" wire diameter for general purpose (also note, the smaller the diameter, the more expensive it gets for the same roll weight)

You'll likely need to dig into the datasheets to decipher which roll is which (rosin <R, RMA, RA>, no-clean, water soluble, and flux core size terminology). Wire diameter at least is more straight forward (mm, inches, or both).

[netdudeuk]

I like the eutectic nature of the 63/37 solder but the big sellers don't seem to be big on that alloy. For example, those Farnell links are all 60/40.

I should have added that I'm working on one of these FR4 prototyping boards that's have single PTHs.

The sockets are tacked on at the corners and I'm doing point to point wiring with Kynar wire, so that's a PITA anyway, especially as I'm doing data and address buses with several wires connected to some pads.

If the IC socket pin is sticking though, applying flux with a pen gets tricky.  It's a lot easier with those three hole pad boards.  More room to apply the flux and more room to tack on multiple wires.

[mariush]

I like the eutectic nature of the 63/37 solder but the big sellers don't seem to be big on that alloy. For example, those Farnell links are all 60/40.

The 62/36/2  Sn/Pb/Ag  solder is also eutectic, and has melting point even lower at 179c (63/37 is at 183c). The last link is to this kind of solder... but as you can see they're more expensive.

Yes, I've noticed 63/37 are rarer these days. I can usually buy them from one of the sellers that ship cheaply in Europe (TME.eu , Farnell, RS Online)

[netdudeuk]

I've just found this (Omega Rosin Free 63/37 2% Flux Fast Flow Solder)

http://www.rapidonline.com/tools-equipment/omega-rosin-free-63-37-2-flux-fast-flow-solder-22swg-500g-85-6154

Anyone know if this would be better than the cheap Chinese flux, with the advantage of no rosin ?

[nanofrog]

I've just found this (Omega Rosin Free 63/37 2% Flux Fast Flow Solder)

http://www.rapidonline.com/tools-equipment/omega-rosin-free-63-37-2-flux-fast-flow-solder-22swg-500g-85-6154

Anyone know if this would be better than the cheap Chinese flux, with the advantage of no rosin ?

No idea with it, as I didn't see anything stating what the flux actually is (suspect it's a no-clean, but can't be sure). Personally, I'd skip it without further information.

Worst case, you'd be able to get 63/37 from Farnell (US stock, so there's a 15.95GBP shipping fee). Multicore MM00975 (RMA) or Kester 24-6337-0010 (RA) displayed on Farnell's UK site when I searched at any rate. Digikey would be another source that would ship US stock to the UK.

[neslekkim]

On Farnell there are lot of 60/40 solder with UK stock, but only one 63/37, wonder why.

And according to the datasheet for the Omega solder it seems like it's no-clean type.

[nanofrog]

On Farnell there are lot of 60/40 solder with UK stock, but only one 63/37, wonder why.

Didn't see any 63/37 on Conrad either. What gives? 

[ttt]

I've been using the cheap Chinese lead solder for a while and I get mixed results.  Some joints are gorgeous.  Smooth and shiny.  Others are dull and not so slick and need reflowing.

I did the same thing for a while and resorted to cheap stuff from EBay. Turns out the difference is dramatic: I will never buy cheap solder again. I thought of doing an in depth comparison at some point but here is a comparison I put together quickly (luckily I had not thrown away all of the Chinese solder I had):

#1 Generic Chinese Roll 63/37 .3mm #1
#2 Generic Chinese Roll 63/37 .3mm #2
#3 AlphaFRY 60/40 .0625"
#4 AlphaFRY 60/40 .032"
#5 Oatey 60/40 .0625"
#6 MG Chemicals 60/40 .032" (2.2% flux)
#7 MG Chemicals 63/37 .040" (2.2% flux)
#8 Kester 66/44 .015"

All have rosin core. See the result in the pictures. Kester and MG chemicals wins hands down. The Oatey is about as bad as the Chinese one when you see it in person. The Chinese solder is extremely "gummy", so is the Oatey. I've had other Chinese solder in the past, they all look the same. There must be some impurities in this stuff.

The Rosin flux I used in the second row is from MG chemicals.

Temp was set to 300C. Though it makes zero difference on the finish, 275C and 325C look the same.

[nanofrog]

#1 Generic Chinese Roll 63/37 .3mm #1
#2 Generic Chinese Roll 63/37 .3mm #2

#5 Oatey 60/40 .0625"

Those ^ are some rather nasty looking joints.

FWIW, Oatey focuses on plumbing products rather than electrical, but that's quite surprising to me. Are you sure it's not actually Sn40/Pb60 (Oatey does make that particular alloy; here)?

Granted, 60/40 will have a duller appearance than 63/37 all things being equal (working temp, joint size, and cooling time), but that's too drastic IME. And it shouldn't be grainy (disturbed joints have a wrinkled appearance).

[netdudeuk]

Thanks for doing that.  I've found some MG Chemicals 63/37 0.032 and was just about to buy and then noticed that that solder in the examples doesn't seem to have fully flowed over the pins.   Or is it just my eyes ?

[ttt]

FWIW, Oatey focuses on plumbing products rather than electrical, but that's quite surprising to me. Are you sure it's not actually Sn40/Pb60 (Oatey does make that particular alloy; here)?

You are right, the Oatey IS Sn40/Pb60, you can see it on the label (now that I think of it I have no clue where it came from :-). Given that the Chinese solder looks similar and clearly says 63Sn/37Pb what does that mean? As I said before I've tried similar solder from EBay with similar results. Might be worth buying more samples to see if it's a common rip-off.

I am talking about stuff like this:

http://www.ebay.com/itm/0-3mm-10G-63-37-Rosin-Core-Flux-1-2-Tin-Lead-Roll-Soldering-Solder-Wire-/400707527667
http://www.ebay.com/itm/0-3-MM-63-37Rosin-Roll-Core-Solder-Wire-Tin-Lead-Flux-Solder-Welding-Iron-Reel-/400675900639
http://www.amazon.com/0-3mm-Lead-Spool-Soldering-Solder/dp/B0094FZ0KC
http://www.amazon.com/Rosin-Solder-Leaded-Electronics-0-8mm/dp/B007N6RQC4

[ttt]

Thanks for doing that.  I've found some MG Chemicals 63/37 0.032 and was just about to buy and then noticed that that solder in the examples doesn't seem to have fully flowed over the pins.   Or is it just my eyes ?

It's probably just my crappy soldering 

[nanofrog]

Thanks for doing that.  I've found some MG Chemicals 63/37 0.032 and was just about to buy and then noticed that that solder in the examples doesn't seem to have fully flowed over the pins.   Or is it just my eyes ?

Flow itself looks good to me.

MG Chemicals makes good flux and solder IME (on equal footing with Kester, Multicore, AIM, and so on). They don't offer as many variations as other manufacturers though. Even Multicore has cut back on their lead alloy offerings.

If you can find it, AIM (American Iron & Metals) or Alpha (Cookson) make some excellent quality products as well, and at least here in the US, tend to be a tad less expensive vs. Kester.

You are right, the Oatey IS Sn40/Pb60, you can see it on the label (now that I think of it I have no clue where it came from :-). Given that the Chinese solder looks similar and clearly says 63Sn/37Pb what does that mean? As I said before I've tried similar solder from EBay with similar results. Might be worth buying more samples to see if it's a common rip-off.

I thought that was the case from what I saw in the photo, but couldn't be sure. And the appearance is far too similar between the cheap Chinese sourced solder and the Oatey to be a coincidence IMHO, but held off making a comment until I was sure on the Oatey's actual alloy.

As per why this could happen, the position of Sn and Pb can be either way; electronics tends to go Sn followed by Pb, but it seems the position of the metals used is not universal. So I could see how that could get Sn60/Pb40 swapped with Sn40/Pb60 (possibly by mistake)

That said, it's far more likely based on greed IMHO, as tin (Sn) is more expensive than lead (Pb). Now take it a step further; "60/40 is close enough to 63/37" in terms of where the numbers for the alloy fall, and less scrupulous vendors slap both labels on a single alloy (further increase their profits on the 63/37 labeled rolls they ship). So put both together, and voila; you get Sn40/Pb60 with a Sn63/Pb37 label slapped on it. All done to fulfill the goal of lining one's pockets as quickly as possible, ethics be damned.

It's probably just my crappy soldering 

Yes it is.       

For prototyping, what you've done with the quality solder samples is sufficient IMHO. My one suggestion, cut back on your solder a bit so you form a fillet in the joint (curve between the solder on the pad and where it makes contact with the wire lead). Also keep the iron in contact with the pin/lead as you remove the iron (this is what pulls solder up the entire lead; goal is to have solder covering all of the lead, including the end where it's trimmed off). 

Plenty of free resources that have photos or illustrations of what this is might help (covers other stuff that might be useful).  You don't need to be able to meet NASA/mil-spec/avionics standards, but if you can manage say 80%, you're doing extremely well (focus on the joint appearance; you can skip the "clean solder wire of oxide with alcohol soaked Kim wipe before soldering" types of steps). Necessary for their particular applications as a CYA, but not necessary for bench use/consumer products.

[netdudeuk]

The MG options include RA and no clean flux, stating that cleaning is optional for the RA, which I thought was mandatory ?

I'd prefer the best joint possible but as most of what I do is on prototyping boards with loads of point to point Kynar wiring, I don't really want to have to start scrubbing away to clean off the flux.

As an aside, I have an anti-static brush that I bought to clean off flux with my Maplin PCB and Flux Cleaner but it looks like the latter dissolves the former    Is there a non-animal based brush option suitable for PCB cleaning ?

[nanofrog]

The MG options include RA and no clean flux, stating that cleaning is optional for the RA, which I thought was mandatory ?

Two totally different things (between this and what I mentioned).

What MG Chemicals and other solder manufacturers are talking about in this case, is flux residue. You don't have to clean the residue off for rosin or no-clean flux.

I was talking about where you're supposed to clean off oxidation from the wire itself prior to even making a joint as per avionics/NASA/Mil-Spec requirements (solder wire is cut from the roll first, wiped down with a lint free tissue soaked with isopropyl alcohol, then used to make a joint; any remaining bit is tossed into a recycle container). Which is on the extreme end of requirements, not what most of us are doing (just soldering up experiments on a bench; nothing that human lives would rely upon for survival types of projects).

Hope this clears things up.

I'd prefer the best joint possible but as most of what I do is on prototyping boards with loads of point to point Kynar wiring, I don't really want to have to start scrubbing away to clean off the flux.

Isopropyl alcohol is commonly used for the task, and is inexpensive. You can also increase it's cleaning capacity by adding small amounts of either xylene or acetone if necessary (always test in a small, inconspicuous spot to see if it's going to remove the solder mask or legend).

You can also substitute ethanol, methanol, or denatured alcohol for isopropyl alcohol (may also be called IPA or isopropanol).

As an aside, I have an anti-static brush that I bought to clean off flux with my Maplin PCB and Flux Cleaner but it looks like the latter dissolves the former    Is there a non-animal based brush option suitable for PCB cleaning ?

Rather aggressive stuff...   Hogs hair and horse hair are common (flux brushes in particular), and will work with the above chemicals (alcohols). But there are polymers made for the task as well that will hold up to the more aggressive cleaners.

Search for "ESD brush" on eBay for example. As per quality brands, look for Menda (example), and Gordon Brush for example (be prepared for some sticker shock). Not sure of any brands exclusive to the EU market, so others may be able to offer alternatives.

Personally, I like finding military surplus for bargains (example). Even though the shipping costs may seem high, do be aware of their cost if purchased elsewhere. They're ~20USD each in the US (here).  And if you buy multiple lots, you can get it to as little as ~1.75GBP per brush if you buy them all (assume VAT still needs to be applied).

[netdudeuk]

Thanks for the reply.  My first point as in isolation from your previous comments though and related to the fact that they are using the RA flux in some solders but there is a comment stating that cleaning is optional, which I didn't think was the case for RA flux (http://en.wikipedia.org/wiki/Soldering#Flux), unlike the 'regular' rosin one.

So, the RA type would be better, if I didn't have to clean it away.

[nanofrog]

Thanks for the reply.  My first point as in isolation from your previous comments though and related to the fact that they are using the RA flux in some solders but there is a comment stating that cleaning is optional, which I didn't think was the case for RA flux (http://en.wikipedia.org/wiki/Soldering#Flux), unlike the 'regular' rosin one.

So, the RA type would be better, if I didn't have to clean it away.

Ah, OK now I know where you got that.

Best practice is to read the manufacturer's datasheets. 

FWIW, I can't recall any RA product that must be cleaned off for corrosion prevention, so I'd say wiki's incorrect on this point. Only type that must be cleaned to prevent corrosion, is water soluble (nasty stuff, recommend avoiding it entirely for hobbyist use).

[netdudeuk]

Ok, so I ordered one of these -

http://www.circuitspecialists.eu/leaded-solder-wire-roll-0-81mm-dia-454g-sn63-pb37-4885-454g/

It has tin & lead in the right ratio (to meet the eutectic need) and RA flux for better cleaning.

I would have preferred the 0.6mm stuff but that's out of stock.

If I don't get consistently smooth and shiny joints guys, you'll just have to PayPal me the cash 

[nanofrog]

Ok, so I ordered one of these -

http://www.circuitspecialists.eu/leaded-solder-wire-roll-0-81mm-dia-454g-sn63-pb37-4885-454g/

It has tin & lead in the right ratio (to meet the eutectic need) and RA flux for better cleaning.

I would have preferred the 0.6mm stuff but that's out of stock.

If I don't get consistently smooth and shiny joints guys, you'll just have to PayPal me the cash 

That will certainly work.  So if you don't get nice shiny joints, it's your fault! 

Do keep in mind that 0.032"/.81mm is a little bit on the thick side. Fine for thru-hole and tinning wire, but you won't have the control you would with a smaller diameter. Not well suited to SMD should you find yourself working with that, other than perhaps the largest packages.

[netdudeuk]

Ok, so I ordered one of these -

http://www.circuitspecialists.eu/leaded-solder-wire-roll-0-81mm-dia-454g-sn63-pb37-4885-454g/

It has tin & lead in the right ratio (to meet the eutectic need) and RA flux for better cleaning.

I would have preferred the 0.6mm stuff but that's out of stock.

If I don't get consistently smooth and shiny joints guys, you'll just have to PayPal me the cash 

Do keep in mind that 0.032"/.81mm is a little bit on the thick side.

Agreed.  I'll just have to push it into the job twenty five percent slower than I usually would