MakeMineVinyl
Major Contributor
Rosin flux does smell pleasant, but don't overdo it.....please.
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Solder - unleaded or classic Sn60Pb38Cu2?
- Thread starter Shefffield
- Start date
It may be too late for that.Rosin flux does smell pleasant, but don't overdo it.....please.
Prana Ferox
Addicted to Fun and Learning
You can wash your hands and then walk outside and get hit by a car - but at least you'll have clean hands
OP
Shefffield
Member
- Thread Starter
- #44
Wow, that's far more feedback than I was hoping for. Thanks, guys!
I think I'll go with Stannol HF32, which seems to be still available from many online shops here in Germany.
Since someone was curious, I use an Ersa RDS 80 soldering station, so achieving and holding a sufficient temperature shouldn't be an issue.
I'm happy to have found such a helpful and knowledgeable forum!
I think I'll go with Stannol HF32, which seems to be still available from many online shops here in Germany.
Since someone was curious, I use an Ersa RDS 80 soldering station, so achieving and holding a sufficient temperature shouldn't be an issue.
I'm happy to have found such a helpful and knowledgeable forum!
The legislator creates the norm to protect us citizens. If they phased put Pb containing tin is because there was a viable alternative (what is more than evident).
From that moment it is the job of the concerned industry to find the even better alternatives (for instance in this case something even better than the lead solder). If it doesn't happen is beacuse there is no commercial interest or the current alternative is good enough.
This is what always happens in every field, if the legislator (all of us at the end of the day) does not kick the industry's ass nothing would evolve and we would all be living in houses full of asbestos and impregnated with chromium.
From that moment it is the job of the concerned industry to find the even better alternatives (for instance in this case something even better than the lead solder). If it doesn't happen is beacuse there is no commercial interest or the current alternative is good enough.
This is what always happens in every field, if the legislator (all of us at the end of the day) does not kick the industry's ass nothing would evolve and we would all be living in houses full of asbestos and impregnated with chromium.
MakeMineVinyl
Major Contributor
There's nothing inherently wrong with lead free solder when used on the circuits for which it is intended. That would be surface mount components stuffed by machine with the use of lead free solder paste. When doing manual soldering, lead free is simply out of its element and is difficult to work with, but that just translates to more work on the assembly line and occasional cold solder joints. There's no real need to develop any other solder type because lead free works for its intended purpose despite the added hassle.
If you're going for leaded solder, I'd go for 63/37 Sn/Pb as that alloy is eutectic, i.e., goes straight from liquid to solid. 60/40 Sn/Pb is another very common alloy. It has a small (5ºC) plastic region, so it transitions from liquid to 'goo' to solid. If you disturb the solder joint as it transitions through that plastic region, you'll have a cold solder joint.
There's no real point to using "silver solder" (62/36/2 Sn/Pb/Ag) unless you're soldering on silver clad connectors, such as many RF connectors. Sn/Pb solders dissolves the silver, which can result in bad solder joints. Adding a bit of silver (usually 2%) to the solder solves that. That said, I also don't think there's any harm in using the "silver solder" everywhere, aside from a possible greater hit to the pocket book.
I disagree that lead-free solder is out of its element in hand soldering, though I can certainly see how someone would arrive at that conclusion. One of the first lead-free alloys was SAC305 (96.5% Sn, 3% Ag, 0.5% Cu). That alloy is still used quite a bit for surface mounted parts populated by machine and you can get it in the form of wire solder as well. It's an awful alloy for hand-soldering. It has a very large plastic region and a high melting point. It doesn't flow nicely and requires a significant dwell time to wet properly. On top of that even a good solder joint made with SAC305 looks grainy (so it basically looks like a cold solder joint performed with 60/40), which makes visual inspection of solder joints harder.
There are more user-friendly lead-free alloys, however. I've come to really like the 99.3/0.7 (Sn/Cu) alloy. It's available under various trade names, such as Kester K100LD, AIM Sn100C, and a few others. This alloy is eutectic and performs a lot like 63/37 Sn/Pb leaded solder in my experience. The only drawback is the higher melting point of 227 ºC vs 181 ºC for 63/37 Sn/Pb. You can get germanium and bismuth doped versions of this alloy as well. Supposedly the Ge/Bi dopants help increase the surface tension so you get fewer solder bridges and such.
For those interested in more details on the various flux types and solder alloys, I do write quite a bit about it here: https://neurochrome.com/pages/choosing-solder
Breathing the flux fumes, although tempting, is generally not recommended. I use a Weller WSA350 smoke absorber to remove the flux fumes. It's basically a fan with an active charcoal filter. It's pricey, big, and loud but it does the job very well. One could get the job done with less though. An old PC fan with a charcoal filter could work well enough.
Tom
There's no real point to using "silver solder" (62/36/2 Sn/Pb/Ag) unless you're soldering on silver clad connectors, such as many RF connectors. Sn/Pb solders dissolves the silver, which can result in bad solder joints. Adding a bit of silver (usually 2%) to the solder solves that. That said, I also don't think there's any harm in using the "silver solder" everywhere, aside from a possible greater hit to the pocket book.
I disagree that lead-free solder is out of its element in hand soldering, though I can certainly see how someone would arrive at that conclusion. One of the first lead-free alloys was SAC305 (96.5% Sn, 3% Ag, 0.5% Cu). That alloy is still used quite a bit for surface mounted parts populated by machine and you can get it in the form of wire solder as well. It's an awful alloy for hand-soldering. It has a very large plastic region and a high melting point. It doesn't flow nicely and requires a significant dwell time to wet properly. On top of that even a good solder joint made with SAC305 looks grainy (so it basically looks like a cold solder joint performed with 60/40), which makes visual inspection of solder joints harder.
There are more user-friendly lead-free alloys, however. I've come to really like the 99.3/0.7 (Sn/Cu) alloy. It's available under various trade names, such as Kester K100LD, AIM Sn100C, and a few others. This alloy is eutectic and performs a lot like 63/37 Sn/Pb leaded solder in my experience. The only drawback is the higher melting point of 227 ºC vs 181 ºC for 63/37 Sn/Pb. You can get germanium and bismuth doped versions of this alloy as well. Supposedly the Ge/Bi dopants help increase the surface tension so you get fewer solder bridges and such.
For those interested in more details on the various flux types and solder alloys, I do write quite a bit about it here: https://neurochrome.com/pages/choosing-solder
Breathing the flux fumes, although tempting, is generally not recommended. I use a Weller WSA350 smoke absorber to remove the flux fumes. It's basically a fan with an active charcoal filter. It's pricey, big, and loud but it does the job very well. One could get the job done with less though. An old PC fan with a charcoal filter could work well enough.
Tom
Personally, always leaded/flux solder for THT - if not just to make your life 10 times easier desoldering if need be. I always dread desoldering non-leaded components, jams your nozzle near instantly (fr-301) because of the higher heat required & makes what could be a simple process an ordeal.
I like to fill a small jar with iso & a cup with q-tips for some of the general flux removal (one tip iso soaked, other dry/damp to wipe away larger buildups), and have a box of 99% prep pads around since they don't fray for a wipe down [can re-use the dry end of the q tip & a rubber band to avoid drying your hands].
SMD stuff like Tom said (or pick/place), definitely less advantageous & something like an electric plate/hot air rework/reflow oven along with unleaded paste is more than adequate for both soldering & removal.
Agreed on fumes though - there are a fair few open source solder fume suckers around (if you live in a "green-friendly" country/state you will likely have access to cheap inline fans) & can make something like [1], [2] - either will knock the socks off the basic computer-fan-connected-to-filter type of deal. [mild PSA: if you do buy one of the computer fan types seen in the following link, replace the filter with one HEPA rated asap]
I like to fill a small jar with iso & a cup with q-tips for some of the general flux removal (one tip iso soaked, other dry/damp to wipe away larger buildups), and have a box of 99% prep pads around since they don't fray for a wipe down [can re-use the dry end of the q tip & a rubber band to avoid drying your hands].
SMD stuff like Tom said (or pick/place), definitely less advantageous & something like an electric plate/hot air rework/reflow oven along with unleaded paste is more than adequate for both soldering & removal.
Agreed on fumes though - there are a fair few open source solder fume suckers around (if you live in a "green-friendly" country/state you will likely have access to cheap inline fans) & can make something like [1], [2] - either will knock the socks off the basic computer-fan-connected-to-filter type of deal. [mild PSA: if you do buy one of the computer fan types seen in the following link, replace the filter with one HEPA rated asap]
solderdude
Grand Contributor
Shouldn't but does.
So does the wetting material.
So does the wetting material.
Actually lead-free was introduced for RoHS compliance in the electronics industry. The idea is to avoid having a bunch of lead waste go to the landfills.
If you do set up a toaster oven for solder reflow, please don't use it for food after...
Tom
That's a really good point actually.
For toaster oven reflow (which I use for prototypes) I actually use 60/40 Sn/Pb solder. Even though I monitor the temperature in the oven during the reflow and am getting pretty good at hitting the prescribed reflow temperature curve by unplugging/re-plugging the oven at strategic points in the cycle, I still find SAC305 to be a pain to work with. Some joints flow fine. Others have solder granules held together by dry flux. 60/40 flows perfectly every time. ChipQuik makes 60/40 solder paste. It's available a the usual suspects: Mouser, Digikey, et al.
If you do set up a toaster oven for solder reflow, please don't use it for food after...
Tom
tvrgeek
Major Contributor
I an so glad to see this thread talk about easy and reliability not some magic about "silver" solder that some claim magically removes harmonics from recordings and gives 100dB SNR to vinyl.
Fortunately, I still have almost a full spool of good old Kester 60/40.
Fortunately, I still have almost a full spool of good old Kester 60/40.
Heh... Now about resonance control...
Happy New Year!
Tom
Happy New Year!
Tom
Weeb Labs
Addicted to Fun and Learning
Capitol C
Active Member
Completely correct. 63/37 is a eutectic. The following diagram is not hard to understand. The upper lines are where freezing starts when you lower the temperature, and the horizontal line at 183 degrees C is when freezing is complete. You get a double advantage at the eutectic, in that freezing is at the lowest possible temperature and it happens all at once at that temperature. I am surprised, however, to see that the diagram says 61.3, not 63--does anyone know why the solder is 63/37 instead of 61.9/38.1?
Maybe the flux changes things.
Tom
Tom
Great. You can stop wearing a seatbelt and drinking water and eating vegetables now.
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