Good lead free solder for hand soldering

[forrestc]

ok and you know good liquid flux for lead-free ? i remember in past i tryin something like that https://termopasty.pl/produkty/topnik-rf800/ and this flux was no good for lead-free rather for leadded soldering

I'm a fan of Indium TACflux 020B or 089HF.   089HF works well but you have to either clean it or make sure it's 100% activated before leaving it on the board.   020B is a little less active, but residues are safe even if they have not been activated.  Note activated means brought to soldering temperatures.   Generally I'll use 089HF when I'm 100% sure I'm going to be able to get all of the flux activated - tiny applications to a joint is a good example.   I use 020B when I'm not 100% sure, such as when debridging a joint where some of the flux may end up under the component and may never get removed.

Avoid any flux which says "water clean".  Water clean = must clean, and residues (even if heated) typically are active and will eat components over time.  There are a few out there which claim that residues are safe to leave, but they are few and far between, and haven't tried any I like.   Basically a "no clean" flux hardens to a plastic-like substance which is safe to leave on the board except in some critical applications.

[lfldp]

hehe exactly this was what i mean before , anyways in my case even extra flux manually added by me to solder wire could not help me to fix this problem because i soldering under fume hood and before i can put tip with extra flux to solder joint it evaporating faster ! so for me there should be extra flux added directly to solder wire , do anyone tryin solder wires made by amtech with syntech flux incliuded ? does these soldering wires are worst its price ?

The fume hood isn’t likely to make any difference whatsoever, in that the flux isn’t so much evaporating as it is burning off.

ok but in short i have problem like that - i can only correctly solder by lead-free wire if i smear pcb with externall flux so maybe the problem is with valid lead-free solder wire model ? soon ill try this SN100Ni+ maybe it will be ok to fix my problem

What temperature are you using? What kind of tip? What kind of joint? What technique? How old are the components? While external flux can make it easier to make nice joints, it really shouldn’t be necessary for THT soldering (and some SMD soldering).

i usually use 360c

OK. And what about the 4 further questions I asked?

today i received felder sni100+ and i can confirm this is exactly what i need! its flux works enough long and i didnt getting anymore joints with so called moustaches , the stannol sn100lc solder wire is totall crap in this case or i have expired one but anyways as i remember this solder wire works very poor from begining (one year ago) problem with this solder wire is like i said it lost very fast its own flux and i getting moustaches by it , also its flow is not even comparable with felder sni100+ ! thanks for previous recommendations , last question - does solder wire or its own flux have some kind of expiry date ? or it can be used even after few years ?

[lfldp]

ok and you know good liquid flux for lead-free ? i remember in past i tryin something like that https://termopasty.pl/produkty/topnik-rf800/ and this flux was no good for lead-free rather for leadded soldering

I'm a fan of Indium TACflux 020B or 089HF.   089HF works well but you have to either clean it or make sure it's 100% activated before leaving it on the board.   020B is a little less active, but residues are safe even if they have not been activated.  Note activated means brought to soldering temperatures.   Generally I'll use 089HF when I'm 100% sure I'm going to be able to get all of the flux activated - tiny applications to a joint is a good example.   I use 020B when I'm not 100% sure, such as when debridging a joint where some of the flux may end up under the component and may never get removed.

Avoid any flux which says "water clean".  Water clean = must clean, and residues (even if heated) typically are active and will eat components over time.  There are a few out there which claim that residues are safe to leave, but they are few and far between, and haven't tried any I like.   Basically a "no clean" flux hardens to a plastic-like substance which is safe to leave on the board except in some critical applications.

well ok thanks also for yours recommendations ill try also this flux and btw. the water washable flux so called water soluble they are no good for me and long time i stopped use them , offcourse they give much more less contaminated fumes than usuall flux but have one problem - they are very high active and could for example warp pcb especially if you soldering bga with them could also damage solder mask with wires easy for example the one ive using in past was amtech lf-4300 original one

[forrestc]

well ok thanks also for yours recommendations ill try also this flux and btw. the water washable flux so called water soluble they are no good for me and long time i stopped use them , offcourse they give much more less contaminated fumes than usuall flux but have one problem - they are very high active and could for example warp pcb especially if you soldering bga with them could also damage solder mask with wires easy for example the one ive using in past was amtech lf-4300 original one

I'm not aware of ANY solder pastes which are from reputable solder manufacturers (Kester, Indium, Amtech, etc.) which will warp the PCB or damage solder mask.   Eat away copper and cause corrosion and/or surface resistance failures, but not PCB warpage or solder mask.

Generally warping and/or solder mask damage has to do with improper (too hot or uneven) application of heat, or in the case of solder mask damage, mechanical "scuffing" of the mask when hot.   Now, with that in mind - using incorrect paste will often result in the operator having to apply too much heat to get a BGA off or similar, causing the damage you describe.  But it's not the paste, it's the heat.

Note that if you need to rework a BGA, you need to make sure you have a flux which will flow under the bga and still be active when it reaches the balls you need to melt.   The tacflux that I mentioned will do this, but you'll probably want to be careful to use the hot air to "push" the flux under the bga.

[tooki]

hehe exactly this was what i mean before , anyways in my case even extra flux manually added by me to solder wire could not help me to fix this problem because i soldering under fume hood and before i can put tip with extra flux to solder joint it evaporating faster ! so for me there should be extra flux added directly to solder wire , do anyone tryin solder wires made by amtech with syntech flux incliuded ? does these soldering wires are worst its price ?

The fume hood isn’t likely to make any difference whatsoever, in that the flux isn’t so much evaporating as it is burning off.

ok but in short i have problem like that - i can only correctly solder by lead-free wire if i smear pcb with externall flux so maybe the problem is with valid lead-free solder wire model ? soon ill try this SN100Ni+ maybe it will be ok to fix my problem

What temperature are you using? What kind of tip? What kind of joint? What technique? How old are the components? While external flux can make it easier to make nice joints, it really shouldn’t be necessary for THT soldering (and some SMD soldering).

i usually use 360c

OK. And what about the 4 further questions I asked?

today i received felder sni100+ and i can confirm this is exactly what i need! its flux works enough long

Glad you're happy with it!

Which flux? They sell the Sn100+ alloy with at least two kinds of flux.

last question - does solder wire or its own flux have some kind of expiry date ? or it can be used even after few years ?

Most manufacturers list an expiration date or manufacturing date on the package. They guarantee performance only until the expiration date or for a certain number of years after the date of manufacture. Super-critical customers like aerospace and military will discard the solder after that. But for normal use, it lasts forever. I have top-brand (Kester) solder I bought in the early 1990s and it still works like new. I don't have any solder wire younger than 2015.

The only thing that could be an exception (this is purely speculation on my part) is water-soluble fluxes. I can imagine that some of those are hygroscopic and could degrade in high humidity. Maybe someone else has experience with this?

Separate liquid or paste fluxes also last forever, well beyond their expiration dates.

What doesn't last forever is solder paste: since it's solder powder suspended in paste flux, the huge surface area of all those microscopic solder powder balls reacts with the flux and corrodes. Additionally, the flux itself can degrade (including by evaporation). All of this means that old paste won't stencil as cleanly, and even if it does, it won't perform as well as fresh paste. So while it's OK to buy solder wire in large packages that will last you for years, only buy as much paste as you can use in a year or two. And keep it in the fridge.

[lfldp]

hehe exactly this was what i mean before , anyways in my case even extra flux manually added by me to solder wire could not help me to fix this problem because i soldering under fume hood and before i can put tip with extra flux to solder joint it evaporating faster ! so for me there should be extra flux added directly to solder wire , do anyone tryin solder wires made by amtech with syntech flux incliuded ? does these soldering wires are worst its price ?

The fume hood isn’t likely to make any difference whatsoever, in that the flux isn’t so much evaporating as it is burning off.

ok but in short i have problem like that - i can only correctly solder by lead-free wire if i smear pcb with externall flux so maybe the problem is with valid lead-free solder wire model ? soon ill try this SN100Ni+ maybe it will be ok to fix my problem

What temperature are you using? What kind of tip? What kind of joint? What technique? How old are the components? While external flux can make it easier to make nice joints, it really shouldn’t be necessary for THT soldering (and some SMD soldering).

i usually use 360c

OK. And what about the 4 further questions I asked?

today i received felder sni100+ and i can confirm this is exactly what i need! its flux works enough long

Glad you're happy with it!

Which flux? They sell the Sn100+ alloy with at least two kinds of flux.

last question - does solder wire or its own flux have some kind of expiry date ? or it can be used even after few years ?

Most manufacturers list an expiration date or manufacturing date on the package. They guarantee performance only until the expiration date or for a certain number of years after the date of manufacture. Super-critical customers like aerospace and military will discard the solder after that. But for normal use, it lasts forever. I have top-brand (Kester) solder I bought in the early 1990s and it still works like new. I don't have any solder wire younger than 2015.

The only thing that could be an exception (this is purely speculation on my part) is water-soluble fluxes. I can imagine that some of those are hygroscopic and could degrade in high humidity. Maybe someone else has experience with this?

Separate liquid or paste fluxes also last forever, well beyond their expiration dates.

What doesn't last forever is solder paste: since it's solder powder suspended in paste flux, the huge surface area of all those microscopic solder powder balls reacts with the flux and corrodes. Additionally, the flux itself can degrade (including by evaporation). All of this means that old paste won't stencil as cleanly, and even if it does, it won't perform as well as fresh paste. So while it's OK to buy solder wire in large packages that will last you for years, only buy as much paste as you can use in a year or two. And keep it in the fridge.

Glad you're happy with it!

Which flux? They sell the Sn100+ alloy with at least two kinds of flux.

the one with 3,5% flux iso core "clear"

Most manufacturers list an expiration date or manufacturing date on the package. They guarantee performance only until the expiration date or for a certain number of years after the date of manufacture. Super-critical customers like aerospace and military will discard the solder after that. But for normal use, it lasts forever. I have top-brand (Kester) solder I bought in the early 1990s and it still works like new. I don't have any solder wire younger than 2015.

thats good information