Ideal Solder Temperature
- Thread starter Yamaha5000
- Start date
Electronics solder must be eutectic to avoid differential solidification in solder joints, which will quickly lead to crystallized and cracked solder joints. Much as if every single one was a "cold joint" where the solder wasn't melted properly.
Brazing solders are not all eutectic, and I use Harris 8 solder (6% sliver in pure tin) for "tin" lining copper pans (much harder and only a little lower melting point). Very difficult to get a shiny finish, it's usually matte because the silver crystallizes first, but that's not an issue, it's only there to keep the food from contacting the copper and it wears better than pure tin.
Lead free solders contain bisthmus, cadmium, copper, and other elements with the tin. typically similar melting temps, and eutectic formulas.
Harris 6 solder is 4% sliver in tin and eutectic. I'd not use it for electronics, there is no real gain in connectivity, it's much harder to remove and requires higher temps to solder. Will work fine, but the significantly higher solder temp will cause trouble de-soldering, especially with a "solder sucker" which may not get hot enough.
Brazing solders are not all eutectic, and I use Harris 8 solder (6% sliver in pure tin) for "tin" lining copper pans (much harder and only a little lower melting point). Very difficult to get a shiny finish, it's usually matte because the silver crystallizes first, but that's not an issue, it's only there to keep the food from contacting the copper and it wears better than pure tin.
Lead free solders contain bisthmus, cadmium, copper, and other elements with the tin. typically similar melting temps, and eutectic formulas.
Harris 6 solder is 4% sliver in tin and eutectic. I'd not use it for electronics, there is no real gain in connectivity, it's much harder to remove and requires higher temps to solder. Will work fine, but the significantly higher solder temp will cause trouble de-soldering, especially with a "solder sucker" which may not get hot enough.
Semanon
Super Member
@Skywatcher. Not aimed at you, just a general comment to the universe. I was still peeved at the “proprietary” solder formula. Ersin has 5 cores, but they’ll tell you exactly what makes your solder up and where to use each. I’ll listen to some music and calm down. 
BTW, I use Ersin because I bought several pounds of it from a ham operator who was clearing out some space. I bought enough to last a lifetime, and it was a fraction of his stash.
BTW, I use Ersin because I bought several pounds of it from a ham operator who was clearing out some space. I bought enough to last a lifetime, and it was a fraction of his stash.
Semanon
Super Member
Good point about the labeling. There goes its professional applications.
Chances are that is IS someone else’s solder. They can’t even be bothered with consistent labeling. But if you can’t compare, you can’t comparison shop
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Exactly... Some people need a specific % of certain metals for specific reasons. To me, when someone won't tell you what % of what is in "their" solder tells me they are indeed buying it "off the shelf" putting their own label(s) on it. They don't want to let THAT cat out of the bag. And when they "change labels" and tell you it is to "prevent counterfeiting" it (to me) means it's "nothing special"... Only so many "U.S.A." manufacturers make solder... Pros want to know what they are using and will only buy actual "professional" solder complete with datasheets and provide MSDS safety literature that are required by law. Especially containing lead and other metals..@Skywatcher. Not aimed at you, just a general comment to the universe. I was still peeved at the “proprietary” solder formula. Ersin has 5 cores, but they’ll tell you exactly what makes your solder up and where to use each. I’ll listen to some music and calm down.
BTW, I use Ersin because I bought several pounds of it from a ham operator who was clearing out some space. I bought enough to last a lifetime, and it was a fraction of his stash.
same here,
Kester "44" for "audio" duty. For any fancy work (e.g. inside a Tex or other lab equipment) I use Stannol with high silver content
right on!......Kester "44" 60/40 for quick in and out and minimal dwell time. No need for exotic boutique solder. Some argue the esoteric word put on a product means "magic sound"..Is it nice solder? For sure, but it's not magical. On these old vintage boards and traces, the lower the melting point, the better. Do one channel with "esoteric", and the other with Kester "44" 60/40, and I guarantee you'll never hear any difference.
I've been trying to work on my soldering technique which means some experimenting. Pulled the motherboard out of an old VCR and started on that. Basically, I was working to keep my dwell time -3 seconds. I found that 680f got me in and out about the best w/o doing any visible damage to the board. 700f went a little faster and likely the best once my skills improve.
In another life I installed and serviced CCTV equipment. Nothing like standing on an extension ladder assembling/soldering pin connectors for a huge pan-tilt in 10 degree weather. Had to block the wind to keep the iron hot enough to melt the solder while hanging on for dear life. Everyone had a winter iron as well as a summer one with the winter iron being the hottest you could find. I experimented with a butane powered thing that worked great until I dropped it into Boston Harbor while working on a pole camera at the end of a pier. A year earlier another guy had dropped a pan-tilt, housing, and camera from the same pole into the water. Losing that iron sucked but coulda been way worse.
In another life I installed and serviced CCTV equipment. Nothing like standing on an extension ladder assembling/soldering pin connectors for a huge pan-tilt in 10 degree weather. Had to block the wind to keep the iron hot enough to melt the solder while hanging on for dear life. Everyone had a winter iron as well as a summer one with the winter iron being the hottest you could find. I experimented with a butane powered thing that worked great until I dropped it into Boston Harbor while working on a pole camera at the end of a pier. A year earlier another guy had dropped a pan-tilt, housing, and camera from the same pole into the water. Losing that iron sucked but coulda been way worse.
The Fuxtor
Addicted Member
Most of the time I have the iron set to 600-700, but old fragile boards with stubborn joints I cool off a bit. Rely on a touch of new solder and/or flux.
Yep! Many times adding a "touch" of new solder makes a big difference. Especially on very old solder joints. The drop of new solder transfers the heat much quicker than the old.
Nobody is mentioning the importance of tip size and flux in combination with temps.
Imho iron tip size and the use of flux is every bit as important as the exact temp used, if not more so. A larger tip and flux will transfer the heat faster and overpower the heatsink properties of the connection in question faster than it can be shed, resulting in an overall lower heat soak than when trying to simply use more heat with a small "dry" tip.
For all work that needs a larger tip and/or higher temps I use some flux, either liquid or paste depending on the size of the work spot. Anything directly on a/the ground plane usually needs higher temps, a larger tip, flux, in combination.
For most work I run the station at 360°c with a slender shaft 2.2x1.2mm tip. For some spots I will run that up to 370°c, very occasionally 380°c. If I am limited in tip size because of space but need to apply more heat to quickly liquefy a joint I use flux first, higher temp second. usually I can get on and off a small (0.8mm lead) connection in 3 seconds or less. "Wetting" the connection with a small drop of solder on the iron speeds up soldering, for de-soldering I use liquid flux as needed, extra solder to wet the connection just means that there is more solder to be removed.
For larger leads/connections I use a 2.8x1.5mm fat shaft chisel tip, usually at the same temps. Flux as needed
For very large connections, such as large filter cap tabs, I'll go with a very fat shaft 4.8x1.5mm chisel tip @ 370-380°c. Flux always. Only for very large fat difficult connections do I go up to 400°c. Paste flux always!
I tend to use wick to remove solder on larger connections, a hand sucker has limited removal capacity in this case and tends to splatter solder that I have to track down and remove. Paste flux smeared on the wick helps a lot. (I don't have a power de-soldering gun yet).
If I can't remove all of the solder inside of a few seconds I move on to another work spot and come back after the area has cooled. The object is to find the best working option between a large heat soak from a prolonged application and the repeated thermal shock from several actions. With large caps I de-solder the + side first because that can usually be done (more) quickly and removes some of the ability of the cap to transfer heat internally from + to -. Then I work the ground side, which usually has a much greater ability to shed heat. Flux and a large tip is a must here.
Depending on the quality of the tips that one uses, 400°c can destroy tips fairly quickly.
YMMV.
Cheers,
James
Imho iron tip size and the use of flux is every bit as important as the exact temp used, if not more so. A larger tip and flux will transfer the heat faster and overpower the heatsink properties of the connection in question faster than it can be shed, resulting in an overall lower heat soak than when trying to simply use more heat with a small "dry" tip.
For all work that needs a larger tip and/or higher temps I use some flux, either liquid or paste depending on the size of the work spot. Anything directly on a/the ground plane usually needs higher temps, a larger tip, flux, in combination.
For most work I run the station at 360°c with a slender shaft 2.2x1.2mm tip. For some spots I will run that up to 370°c, very occasionally 380°c. If I am limited in tip size because of space but need to apply more heat to quickly liquefy a joint I use flux first, higher temp second. usually I can get on and off a small (0.8mm lead) connection in 3 seconds or less. "Wetting" the connection with a small drop of solder on the iron speeds up soldering, for de-soldering I use liquid flux as needed, extra solder to wet the connection just means that there is more solder to be removed.
For larger leads/connections I use a 2.8x1.5mm fat shaft chisel tip, usually at the same temps. Flux as needed
For very large connections, such as large filter cap tabs, I'll go with a very fat shaft 4.8x1.5mm chisel tip @ 370-380°c. Flux always. Only for very large fat difficult connections do I go up to 400°c. Paste flux always!
I tend to use wick to remove solder on larger connections, a hand sucker has limited removal capacity in this case and tends to splatter solder that I have to track down and remove. Paste flux smeared on the wick helps a lot. (I don't have a power de-soldering gun yet).
If I can't remove all of the solder inside of a few seconds I move on to another work spot and come back after the area has cooled. The object is to find the best working option between a large heat soak from a prolonged application and the repeated thermal shock from several actions. With large caps I de-solder the + side first because that can usually be done (more) quickly and removes some of the ability of the cap to transfer heat internally from + to -. Then I work the ground side, which usually has a much greater ability to shed heat. Flux and a large tip is a must here.
Depending on the quality of the tips that one uses, 400°c can destroy tips fairly quickly.
YMMV.
Cheers,
James
Arc deTriamp
Member
I don't know about most solder for electronics, but apparently 60/40 is not actually eutectic, while 63/37 is eutectic.
https://fctsolder.com/eutectic-solder/
https://ae5x.blogspot.com/2019/12/eutectic-or-non-eutectic-solder-does-it.html
However, 60/40 is very close to eutectic, which means that cooling solder passes through the plastic region very quickly. 60/40 may also be slightly better at "wetting" soldered surfaces, and is apparently less expensive.
In the end, whether you choose 60/40, 63/37, or a silver bearing solder such as Cardas or Wonder Solder, the quality of results is mainly dependent on your soldering technique, which includes using a sufficiently high iron temperature and appropriate tip to permit rapid heating of the work and solder flow. As pointed out elsewhere, thanks @Bratwurst7s, rapid heating of the work area, over less time, reduces the amount of heat that flows to adjacent areas, preventing traces from being lifted and damage to components.
Another reason that the iron temperature should be considerably higher than the melting point of the solder, is to activate the flux. The flux (whether in core or added) needs to get hot enough to work properly, and quickly. The flux helps the solder to flow and allows you to make a good joint in less time, reducing the heating of the components and board.
In my own limited experience, I find that iron temperatures between 680 and 700 seem to work best. If I am desoldering, the temperature will be at the high end of the range, and I add fresh solder to improve the heat transfer and lower the melting point of the old solder. If I am assembling, I generally lower the temperature somewhat. Larger solder joints require iron temperature at the high end, otherwise it takes too long to heat the material, melt the solder, and activate the flux. As long as you are not making cold solder joints, it is safer to work faster rather than slower.
https://fctsolder.com/eutectic-solder/
https://ae5x.blogspot.com/2019/12/eutectic-or-non-eutectic-solder-does-it.html
However, 60/40 is very close to eutectic, which means that cooling solder passes through the plastic region very quickly. 60/40 may also be slightly better at "wetting" soldered surfaces, and is apparently less expensive.
In the end, whether you choose 60/40, 63/37, or a silver bearing solder such as Cardas or Wonder Solder, the quality of results is mainly dependent on your soldering technique, which includes using a sufficiently high iron temperature and appropriate tip to permit rapid heating of the work and solder flow. As pointed out elsewhere, thanks @Bratwurst7s, rapid heating of the work area, over less time, reduces the amount of heat that flows to adjacent areas, preventing traces from being lifted and damage to components.
Another reason that the iron temperature should be considerably higher than the melting point of the solder, is to activate the flux. The flux (whether in core or added) needs to get hot enough to work properly, and quickly. The flux helps the solder to flow and allows you to make a good joint in less time, reducing the heating of the components and board.
In my own limited experience, I find that iron temperatures between 680 and 700 seem to work best. If I am desoldering, the temperature will be at the high end of the range, and I add fresh solder to improve the heat transfer and lower the melting point of the old solder. If I am assembling, I generally lower the temperature somewhat. Larger solder joints require iron temperature at the high end, otherwise it takes too long to heat the material, melt the solder, and activate the flux. As long as you are not making cold solder joints, it is safer to work faster rather than slower.
I have been buying the same solder that we use at work, 60/38/2, with the 2% being copper. 1mm diameter. It is supposed to melt at 183° to 190°c, normally I work at 360°c/680°f to 380°c/716°f. Been using it for the last 15 years with no problems.
https://www.newark.com/edsyn/ss1250/solder-wire-fsw32-flux-1mm/dp/35M4001
Cheers,
James
https://www.newark.com/edsyn/ss1250/solder-wire-fsw32-flux-1mm/dp/35M4001
Cheers,
James
YY1
Addicted Member
Had an occasion to solder some 20 ga wire yesterday to swap out the power connector on a tablet I was trying to revive.
(swapped out the very difficult to find one for one from a dead laptop that I have a ton of actual power supplies for)
I found my iron was previously set to 685 F.
After also removing the completely dead and error generating battery, and doing a factory OS restore... now that tablet works!
Gonna use it as a music playback device and backup file repository.
(swapped out the very difficult to find one for one from a dead laptop that I have a ton of actual power supplies for)
I found my iron was previously set to 685 F.
After also removing the completely dead and error generating battery, and doing a factory OS restore... now that tablet works!
Gonna use it as a music playback device and backup file repository.
exwhyzed
Active Member
I recently found out from purchasing solder on Mouser/Digikey that solder has a shelf life...i believe its the flux in the core. I've been using a roll for 5+ years and i thought it was ok. I just tried a new roll of MG Chemicals solder, that is rated for 2 years, and the solder practically jumps right into the joint and is perfect and shiny every time.
So i think having fresh non-expired solder is also a good thing to keep in mind. Its very easy to lose track of the expiry date as its not usually printed on the roll.
So i think having fresh non-expired solder is also a good thing to keep in mind. Its very easy to lose track of the expiry date as its not usually printed on the roll.
The expiration date (DOE) on Kester solder represents the manufacturer’s warranty period, or the time frame wherein Kester will replace a defective product (shelf life).
Otherwise, Kester states their solder has an indefinite working life when stored in a dry, non-corrosive environment between 10-40°C (50-104°F).
I'm not saying an old roll is just as good as a new roll, just echoing the product manufacturer's policy sheet.
My company regularly trashes unused, packaged solder rolls as soon as the DOE arrives, I rescue them and use them for myself.
Otherwise, Kester states their solder has an indefinite working life when stored in a dry, non-corrosive environment between 10-40°C (50-104°F).
I'm not saying an old roll is just as good as a new roll, just echoing the product manufacturer's policy sheet.
My company regularly trashes unused, packaged solder rolls as soon as the DOE arrives, I rescue them and use them for myself.
Some do, some don't specify. But lead/tin will last for years unless in a harsh environment such as salt air. It will get an oxidized coating on it and that is what makes it not work so good. Unwrap a layer to get down to the clean stuff. But I use it up so fast mine is always "fresh"..
When one roll is down to about half or so, I order another one in.