Soldering Wires: Myth or Fact?

[dzkfraser]

What do you find desirable about 63/37, compared to 60/40? Thinking about ordering some, so I thought I'd ask.

The 63/37 is eutectic - It has the lowest melting point and goes from liquid to solid quickly - Is just easier to work with

 

[njcanuck]

I've read that regular lead solder is not that great of a conductor, especially compared to the copper that it is used on. Therefore, it is important to establish a good wire-to-lug connection (2 or 3 wraps) before soldering. The primary purpose of the solder is to hold the connection in place, not to conduct electricity.

Not sure how this applies to printed circuits, tho? I guess the conductivity of solder is still 'good enough'.

 

[N8Nagel]

Solder is in fact good enough. Your interconnects may be 3' long so they need to be copper. The solder joint between the copper and the RCA pin should be a fraction of a mm at most so the higher resistivity of solder is dwarfed by the much longer length of the copper conductor; the length of the copper will determine the overall resistance of the assembly. Also resistance is not as bad as L or C in signal apps, resistance will just attenuate while L or C cause other effects (attenuating some frequencies more than others for example)

 

[rothwellaudio]

I've read that regular lead solder is not that great of a conductor, especially compared to the copper that it is used on. Therefore, it is important to establish a good wire-to-lug connection (2 or 3 wraps) before soldering. The primary purpose of the solder is to hold the connection in place, not to conduct electricity.
Not sure how this applies to printed circuits, tho? I guess the conductivity of solder is still 'good enough'.

No, I don't think that's correct. The conductivity of solder is plenty high enough but if you try to check for continuity in interconnects (or anything) by putting a probe onto the soldered joint you might get a high reading. That's because the flux forms a thin insulating layer on the surface of the joint, not because the solder itself has a high resistance.

 

[Hyperion]

It is simply good practice to make a mechanically sound joint before soldering, it doesn't have a lot to do with conductivity. Except that when you make the solder joint on a wire-to-lug joint that HAS been made mechanically sound - the wires/lugs to be soldered are much less likely to move during the making of the joint - thus making a good joint first time.

 

[C0deXeus]

I never thought Kester 44 is so expensive at Malaysia:
Price at US: http://www.all-spec.com/Catalog/Soldering-Rework/Solder/Solder-Wire/24-6040-0027-16600#undefined2

Price at M'sia: http://my.element14.com/webapp/wcs/...&langId=83&storeId=10188&gs=true&st=Kester 44

I think it's still worth to give a try

 

[Blue Shadow]

That is a good price for solder, $21 and change for a pound. Price changes based on the price of metals but this is a good deal.

You link in Post 16 is for a very thick solder. I would not consider that a good one to use on electronics but Kester makes their 44 in many different sizes. Most here would want a solder between 0.5 and 0.8mm for regular work on stereo gear.

I don't know if the Kester is significantly better than a good quality solder you can buy at a fair price, and I don't know what you have available in Malaysia at those fair prices.

 

[E-Stat]

AFAIK, they have not solved the tin-whisker problem with lead free solder.

I'm thinking that Audio Research has using their RoHS compliant custom silver solder. Advance to about 8:30 in the first of the two following videos.

 

[ConradH]

There are certainly a bunch of solder brands and though Kester, Alpha and a couple others "own" the USA market, I suspect they aren't the only good choices. Not a recommendation, but here's some more- http://wonderfulengineering.com/best-soldering-wire/

I once knew a professional contract PCB assembler. The only solder she'd use was from these people- http://www.interflux.com/en/solder-wires

 

[NAD80]

Been using Kester 60/40 since 82 for leaded use. 959 flux. Using Kester unleaded for ROHS. PITA to use. Higher temps, Using 959T flux for unleaded. Doesn't flow as well as the leaded. 95% of what I do at work is ROHS. Wish we had a desoldering station for lead free like the old Weller type. The newer Pace handle type clogs easy from the solder. The lead free solder attaches itself to the glass tube to the point you can't remove it or just breaks the glass tube. Just have to replace the glass tube more than once a year .

 

[C0deXeus]

That is a good price for solder, $21 and change for a pound. Price changes based on the price of metals but this is a good deal.

You link in Post 16 is for a very thick solder. I would not consider that a good one to use on electronics but Kester makes their 44 in many different sizes. Most here would want a solder between 0.5 and 0.8mm for regular work on stereo gear.

I don't know if the Kester is significantly better than a good quality solder you can buy at a fair price, and I don't know what you have available in Malaysia at those fair prices.

I just received reply from Element 14 company saying that those selling at their site are 24 series, not 44. Yes, $21 is a good deal but that's the price in US. Due to the currency inflation between dollars and ringgits, price has gone through an increase (approx 30-40$)

I was quoted by an authorized Kester distributor- Solcrester saying that Kester is phasing out 44 series so they doesn't keep stock anymore. They did recommend me to use Kester less rosin more resin type of soldering wire since this type is easier to clean off the flux if necessary. Didn't name the model thou.

I've Googled for almost all soldering companies in Malaysia and Kester seemed hard to find. Maybe will use Mekko by Asahi solder.

 

[C0deXeus]

Kester 44 63/37 or 60/40 is hard to beat. The main reason low percentage silver solder exists is because copper dissolves slightly in solder. When you solder very fine wires, the added silver prevents thinning of the wires. It also prevents damaging the ceramic component strips used in old Tek oscilloscopes. It does give a very nice shiny joint and is a nice touch if you can afford it. The cost seems way higher than the small amount of silver used would justify.

There are various other brands you'll run into. Multicore and Multicore "Sav-bit", Alpha Reliacore, all of which work well.

If I build a board from scratch, I use a "331" flux solder. That can (must!) be washed off with water and makes for a very neat job without messing with alcohol or solvents. The flux can't be left on the board as it will cause corrosion and leakage. Use hot water, soap and a toothbrush. There are also "no-clean" fluxes like "245" that are OK with clean parts and leave a bit less mess than "44".

AFAIK, they have not solved the tin-whisker problem with lead free solder.

I was wondering to try out the 245 series but after some research did...I told myself to forget it...
http://www.circuitnet.com/experts/73284.html

One of the other important considerations not mentioned so far, is solder melting point, especially for those of us working on older (pre- 2006) equipment, the bulk of which will usually have been designed for, and produced with, a leaded solder.

The 'normal' 60/40 or 63/37 leaded solder products, used extensively before lead-free solder legislation, are the lowest melting solders - while, as far as I'm aware, all of the lead-free and silver containing solders are higher melting point products. The higher temperatures involved with lead-free products may seem 'trivial' and easily handled by modern, often temperature controlled, soldering irons / stations, but the potential problem lies in the higher thermal stresses applied to older pcb traces, that were not designed for the higher melting solders. Excessive temperature can easily lead to trace damage, delamination, etc. - and while pcb quality obviously varied over the years, and between different manufacturers, few if any of the earlier pcb's were designed for the elevated temperatures required by the lead-free products, so 'caution' is called for.....

Everyone will have their own preference, but personally, I tend to use desoldering braid to remove old solder, or initially a solder sucker for larger quantities, and then desoldering braid - I think it's not only effective at wicking away the old solder, but also provides a measure of thermal heat-sinking that helps minimise (potential) damage to pcb traces. I normally resolder using lead-based solders, for personal use, but understand that there may be different constraints for professional restorers.

This info is far more than helpful. I was going to use lead-free solder on a 30+ years old PCB. Though previously it was used lead free(not me, a guy who repaired the burst right channel) I will just assume a joint or two. Not a big problem since I will substitute a better part and resolder

 

[ConradH]

I was wondering to try out the 245 series but after some research did...I told myself to forget it...
http://www.circuitnet.com/experts/73284.html

This info is far more than helpful. I was going to use lead-free solder on a 30+ years old PCB. Though previously it was used lead free(not me, a guy who repaired the burst right channel) I will just assume a joint or two. Not a big problem since I will substitute a better part and resolder

That's a great thread on the benefits of cleaning or not. I'm in the cleaning camp, regardless of what flux system is used. Kester 44 leaves a lot of rosin and can be difficult to clean with alcohol. When I do a small repair I try to clean each joint with a Q-Tip and alcohol. If the board was already covered in flux, I leave it alone- count all the old TVs and other stuff that ran for decades with a pound of flux inside! (I have been known to fully clean a factory board, but it's a pita, especially the old Dynaco boards.) The 245 seems easy enough to clean if you like. The 331 is an entirely different animal. It must be cleaned, no exceptions. My usual method is hot water, soap and a fingernail brush, scrubbing in all directions and thoroughly rinsed. The end result is very nice and can be given a spray of clear acrylic if desired. IMO, the average person doing just repairs should stick with a traditional RMA flux because it has a long history of success, cleaned or not.

 

[C0deXeus]

I will still prefer 44 series. 245 series has the no-clean ability and makes flux cleaning more difficult than 44. Flux on 44 is chemically inert if you don't clean it. Flux on 245 is another long story.

 

[Bill Ferris]

just dont forget if removing lead free and replacing with leaded it doesn't mix very well if at all .. plus you need to apply and wipe off leaded solder to your iron tip 3 times after removing lead free and then using leaded and visa versa .
hope that isnt too confusing ..

Perfectly clear petehall347.. I prefer to stay away from lead free applications/repairs where possible.. Though, I recently found "silver solder" to be excellent for soldering the pressed in nuts for the feet on the bottom of a Fisher receiver bottom that had popped out.. I reset the splined nuts, then placed the bottom on blocks of wood, & then placed my early fifties badass big 300 watt and 80 watt Weller iron`s flat sides close to the pressed in nut and let them cook for a while until the area was hot enough to evenly flow the higher temp silver solder.. Worked rather well and is much stronger than if I would have tried to use straight 60/40 solder.. Nice how NASA & and the US military electronics are exempt from lead restrictions !!

 

[Oasis8]

As someone has suggested already, the joint should be physically a good connection, relying on the solder to conduct is not a good approach.

 

[ferninando]

for 50yrs have always used 60/40 rosin core exclusively and will not use anything else

 

[evoroadster]

I too have 50+ years of rosin core 60/40 use and don't plan on changing anytime soon.

 

[DEAFASABAT]

Ersin 60/40 multi core whatever gauge.. Simply the best !!! Superior wetting action.. Kester when I have no Ersin Multicore off site, but RAT SHACK`s "solder like substance", only in last resort desperation !! Glad I bought many 1lb spools of Ersin multicore red spool in the 2 different gauges in the early nineties when I had 5 local music stores to repair for before lead prices/quality went out of control.. HA !! my work shop is probably a Potential HazMat super clean up site !!! Ask me if I care ?? Mercy Sakes Alive on all of this.. By the nature of my disability(left side hemi paresis since 11/19/81 medical malpractice & I`m very well paid) which means I have been placing solder in my mouth since that time to effect thousands of daily repairs since then !! Oh well, I also smoke Winston regular cigarettes since 1980(but not in my house or work shop and am turning 62 this year !!! Ersin multicore even tastes sweeter than other brands of solder !! Hey Kids--- don`t try this at home.. OKB

Sn / Pb solders other than 63/37 have three physical states: Solid, plastic, and liquid. When using 63 / 37, known as eutectic solder, there is no plastic state between melted (liquid) and solid. This helps to eliminate compromised joints due to even very slight movement or vibration while a non-eutectic solder is in its transitional plastic state as it cools.

Such bad joints are often referred to as "cold joints" but in actuality are caused by poor wetting action, contamination on the surface of the solder and / or component lead, terminal, etc. to be soldered, movement of joints during the plastic state, overheating of the solder
(melted solder alloy will experience a separation of Sn and Pb into its unalloyed metals after a little as 3 seconds, depending on iron tip temperature and mass). And / or any combination of the preceding conditions.

There is no such thing as a "cold joint", as once solder melts it is not cold.

Successful soldering is satisfying to do, but bad soldering is always a pain in the @$$. Too much re-working, with an increased possibility of damaging components, wire insulation, and printed wiring boards. So just learn to do it right and enjoy...

Regards, -DAAB-

 

[loopstick]

The RS stuff is thin and easy to use and I have a couple folks that want silver solder when I work on their gear. They can probably hear the difference.

No. They can't.