Korishan
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Why to use Flux
- Thread starter Korishan
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italianuser
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Ehm... my soldering is perfect even without flux 
You need a good and clean tip and a good quality tin.
But, yes, flux does make the job smoother
You need a good and clean tip and a good quality tin.But, yes, flux does make the job smoother
OffGridInTheCity
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I believe my solder has flux in it. No need for extra fluxing - just 100w iron + solder. 2023 wraps up 6 years and the earliest solder joints are doing well - no corrosion or issues on any of the cells.
Have used kester - https://www.amazon.com/gp/product/B00DE2QVIG/ref=ppx_yo_dt_b_search_asin_title - consistently thru the years.
Have used kester - https://www.amazon.com/gp/product/B00DE2QVIG/ref=ppx_yo_dt_b_search_asin_title - consistently thru the years.
100kwh-hunter
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Most solders has flux in them, risen core.
Also the two metals both have their own jobs.
Especially tin, this makes the surface tension in molten condition smoother/liquid and lowers the overall melting point of solder wire
Lead alone will flow easier and gives a stronger joint, but without tin, it will not flow in small pesky corners.
Tin alone will have a hard time to flow, it will be more of a sitting blob and will not give you the ductile strength that lead does.
Pure tin solder flows very neat into those peasky corners, but to much tin on a joint will turn into a blob.
In the newer "lead free" solders, because lead is poisenes.....they use bismuth antimony copper and what ever more.
Tin has a relative low melting point, but can just as lead absorb copper, however tin can be heated save up to 2200C before evaporation.
Lead becomes dangerous after just its molten point (350C) at 450C, here the damping point is starting, evaporation starts at just 550.
Copper has a melting point of 1150C but it can be absorb by lead under the 500C but takes time.
Tin will do it faster at a higher temp.
Antimony will melt around 600C and evaporation will start at 650C it will not blend with tin, it needs a binder copper.
Side note; if you have only tin copper solder, that could also means you have copper powder mixed with tin, just to make the tin more harder.
Heat this to long and the copper will float at the top, just like lead and tin will separate after to long in liquid state.
In this the antimony is the binder/harder.
Antimony will oxidise very fast when RH is higher than 60% and is very brittle and rises the melting point of solder.
Those two (lead and tin) can not be used without each other.
They take the best out of each other, just like a perfect marriage.
NO not like horse and carriage.
Btw in that video, it could also be done with a soldering iron that was cooling down.
And i believe they used a high lead solder.
Flux is needed only in plumber jobs or soldering jobs that are to big.
Cost is a big factor, again tin.
Lead needs flux, high lead solders need flux if they dont have any in them.
Flux is also used to combine to metals to stay together when in molten state.
Again, lead and tin will separate after been heated for to long, flux will teach them a lesson to stay together.
Btw if you have old solder with a resin/flux core in it and it is 2 years unused, throw away the first 0.5 meter.
Resin will harden over time and loose his capabilities of "cleaning" the surface area.
That is basically what flux is doing, cleaning and smooth out the surface tension.
After soldering with high lead solders, some fluxes give also a small protection because they leave a "skin" on the solder.
Just like fresh rolled steel, it won't oxidise.
This was a bit elementary/basic of my knowledge of some metals and how they react.
Btw i buy my solders on ali ex, the cheapest per kilo i can find, but must have a resin core and around a 40/60 tin lead ratio minimum up to max 60/40 tin lead.
Somehow if i see the price of offgridinthecity's solder per pound....i think i am very glad that i still have two kilo's left, bought 3 years ago.
Also the two metals both have their own jobs.
Especially tin, this makes the surface tension in molten condition smoother/liquid and lowers the overall melting point of solder wire
Lead alone will flow easier and gives a stronger joint, but without tin, it will not flow in small pesky corners.
Tin alone will have a hard time to flow, it will be more of a sitting blob and will not give you the ductile strength that lead does.
Pure tin solder flows very neat into those peasky corners, but to much tin on a joint will turn into a blob.
In the newer "lead free" solders, because lead is poisenes.....they use bismuth antimony copper and what ever more.
Tin has a relative low melting point, but can just as lead absorb copper, however tin can be heated save up to 2200C before evaporation.
Lead becomes dangerous after just its molten point (350C) at 450C, here the damping point is starting, evaporation starts at just 550.
Copper has a melting point of 1150C but it can be absorb by lead under the 500C but takes time.
Tin will do it faster at a higher temp.
Antimony will melt around 600C and evaporation will start at 650C it will not blend with tin, it needs a binder copper.
Side note; if you have only tin copper solder, that could also means you have copper powder mixed with tin, just to make the tin more harder.
Heat this to long and the copper will float at the top, just like lead and tin will separate after to long in liquid state.
In this the antimony is the binder/harder.
Antimony will oxidise very fast when RH is higher than 60% and is very brittle and rises the melting point of solder.
Those two (lead and tin) can not be used without each other.
They take the best out of each other, just like a perfect marriage.
NO not like horse and carriage.
Btw in that video, it could also be done with a soldering iron that was cooling down.
And i believe they used a high lead solder.
Flux is needed only in plumber jobs or soldering jobs that are to big.
Cost is a big factor, again tin.
Lead needs flux, high lead solders need flux if they dont have any in them.
Flux is also used to combine to metals to stay together when in molten state.
Again, lead and tin will separate after been heated for to long, flux will teach them a lesson to stay together.
Btw if you have old solder with a resin/flux core in it and it is 2 years unused, throw away the first 0.5 meter.
Resin will harden over time and loose his capabilities of "cleaning" the surface area.
That is basically what flux is doing, cleaning and smooth out the surface tension.
After soldering with high lead solders, some fluxes give also a small protection because they leave a "skin" on the solder.
Just like fresh rolled steel, it won't oxidise.
This was a bit elementary/basic of my knowledge of some metals and how they react.
Btw i buy my solders on ali ex, the cheapest per kilo i can find, but must have a resin core and around a 40/60 tin lead ratio minimum up to max 60/40 tin lead.
Somehow if i see the price of offgridinthecity's solder per pound....i think i am very glad that i still have two kilo's left, bought 3 years ago.