# What type of solder do you prefer for flashlight electronics?



## vestureofblood (Jan 31, 2010)

I have actually just almost finished my first full roll of solder. It went a long way, but now it is time to re-up. The solder I have been using is the lead free electrical solder with a rosin core, and says its silver bearing. This type seems to work ok most of the time, if I recall it was about 6-7$ a roll at Home Depot.

What type of solder do you prefer, and why?


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## AnAppleSnail (Jan 31, 2010)

Mainly avoid "lead-free" solders. It's not such a hazard to your brain if you work in a ventilated place, but it's SO much more likely to crack.


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## Th232 (Jan 31, 2010)

A big +1 to what AAS said.

Interesting bit of information: With RoHS certification, medical devices are exempt from the "no lead-bearing solder" requirement. Why? Reliability. I believe Pb/Sn solder is also used in critical military equipment instead of Pb-free for that same reason.


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## purduephotog (Jan 31, 2010)

Funny, because I'm having serious problems soldering today.

I just received a bunch of emitters and went to tin the contacts- and the solder beaded up. In fact I couldn't get it to flow no matter what I did- which means... who knows.

At least I bought an extra just in case. Right now I have 60/40 rosin core from Radioshack.


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## TooManyGizmos (Jan 31, 2010)

Did you apply a flux/cleaner to the area first ?


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## Billy Ram (Jan 31, 2010)

I use both. I use 60/40 for most jobs and lead free for higher heat joints. The lead free silver bearing solder makes a stronger bond.
Billy


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## vestureofblood (Jan 31, 2010)

Billy Ram said:


> I use both. I use 60/40 for most jobs and lead free for higher heat joints. The lead free silver bearing solder makes a stronger bond.
> Billy


 
The joints I have made with this do seem to be very strong when its done properly. Most of the time when I have a joint break its because the wire breaks off, or if I got the pad too hot and the solder pad comes off the board. It seems to me that this type of solder needs to be very hot to wet properly, and can be temperamental. Meaning if every thing is not just exactly right ( ie very hot iron, good amount of flux, tip very clean and tinned), it wont melt properly. Of course part of it too is that I may need a little more practice.


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## Lynx_Arc (Feb 1, 2010)

not sure they sell it any more but kester 60/40 is what I would buy but I have plenty of solder a 1 lb roll goes a long way


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## 65535 (Feb 1, 2010)

60/40 or 63/37 is the way to go, the latter being a eutectic blend which has no intermediate phase between solid and liquid so it is less likely to form a "cold joint."

Rosin core is a a fine solder, I prefer low rosin content vs. high content because a dab'll do ya.

Another option a lot of people like is a paste or liquid flux applied separately, that allows soldering of certain materials that don't always bond well with rosin flux. 

Personally for 99% of work the 60/40 rosin core is all you'll ever need.


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## vestureofblood (Feb 1, 2010)

65535 said:


> 60/40 or 63/37 is the way to go, the latter being a eutectic blend which has no intermediate phase between solid and liquid so it is less likely to form a "cold joint."
> 
> Rosin core is a a fine solder, I prefer low rosin content vs. high content because a dab'll do ya.
> 
> ...


 
I have some flux paste, it does help sometimes. I mostly use it on larger joints, or when assembling large copper parts for heatsinks. I also use it to clean the tip of my iron once in a while, after I file it when it has gotten to the point my sponge cant do the job.

So far it seems like the census is the 60/40 tin lead, which happens to be cheap on ebay right now.


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## Benson (Feb 1, 2010)

I use rosin-core 62/36/2; it's basically the same as 63/37 with 2% silver added to allow soldering silver or gold plated connectors. Apparently precious-metal leaching into the tin is a problem when using pure Sn/Pb solders.

Flux paste is a must when tinning bare wires, etc; once all surfaces are tinned and cleaned (excess flux can be corrosive and/or conductive when baked on!), the rosin core is generally enough to make good joints, and doesn't leave enough residue to need cleaning afterwards.


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## 65535 (Feb 1, 2010)

Benson said:


> I use rosin-core 62/36/2; it's basically the same as 63/37 with 2% silver added to allow soldering silver or gold plated connectors. Apparently precious-metal leaching into the tin is a problem when using pure Sn/Pb solders.



That seems like an ironic situation considering that if the precious metal leached into the solder you'd have a alloy similar to 62/36/2 anyways. Strange goings on, I've never had an issue with gold plated, silver, plated, or nickel plated joints.


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## Benson (Feb 1, 2010)

65535 said:


> That seems like an ironic situation considering that if the precious metal leached into the solder you'd have a alloy similar to 62/36/2 anyways. Strange goings on, I've never had an issue with gold plated, silver, plated, or nickel plated joints.



Yeah, but it leaves you a layer where there was supposed to be gold plating and there's... nothing? And so your joint falls apart. Or something like that, I guess. :shrug:

I don't really know about it, but I heard you're supposed to use silver-bearing solder for gold and silver joints, and it's OK to use everywhere else, so I just use it everywhere.


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## purduephotog (Feb 1, 2010)

TooManyGizmos said:


> Did you apply a flux/cleaner to the area first ?



I've used flux, and I've used some flux that I use to sweat copper pipes. Neither had any impact on the gold pad and getting the solder to flow- just forms a bead.


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## kuksul08 (Feb 1, 2010)

I started trying to solder for the first time with 98% tin solder (and some silver). I couldn't figure out how people could do it...

Then, thanks to CPF, I discovered 63/37 rosin cored solder, and have been using that since.


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