EEVblog Electronics Community Forum
Products => Other Equipment & Products => Topic started by: Heindal on November 24, 2024, 03:04:45 am
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I wanted to know if the flux in the image attached to post is lead free. Been using it because thats what I can get here.
One thing I realised is the flux is conductive when in liquid form and its hard to remove when using it with smd components. For example I bathed a pcb with LQFP48 chip which i used the flux in and most of the flux was gone but some was left under the chip and under the legs of the pins.
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Why would flux itself ever contain lead?
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Terminology:
- Solder paste is a mixture of flux and solder balls.
- Flux is a reducing agent (Keeps solder shiny, stronger, stickier/wetter and easier to use).
- Solder balls are made of metals, some use lead.
Your photo is of solder paste.
The recipes for products like this are usually listed in their SDS (safety data sheet). Most countries require publishing these documents.
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What is the model number on your solder paste in the photo? SP-50?
I can find almost no information about it. Even the brand's website (https://www.nipponamerica.com/product-page/sp-10-sp-50) is useless.
If you can't find detailed and reliable info on the product then I would assume it's a greymarket import (whatever is cheapest) that gets a label slapped on. This almost guarantees it would be leaded (leaded solder is cheaper than lead-free as Pb is cheaper than Sn).
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it is flux, not paste. Some sellers online mistakenly describe flux as soldering paste idk why. It like a grease then heat turns it into a liquid. Idk why the label says paste
this is it https://latinafy.com/products/nippon-america-soldering-paste-10-grams/
Mine just has 50g (SP-50) instead of 10g(SP-10).
There is no tin in there. Paste is darker this flux is amber-colored.
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For historical reasons (and the different “traditions” of different vocations), the term “soldering paste” is commonly used by plumbers, sheet metal workers, etc. to refer to flux paste. (And because such pastes are normally corrosive, I would avoid using anything labeled “soldering paste” for electronics.) Sometimes, in those fields, the phrase is shortened to “solder paste” even though it is just flux.
In the electronics tradition “solder paste” (no “-ing”) means the solder powder suspended in paste flux. But on occasion, some vendors will use the term “solder paste” for flux. In my experience that tends to be companies that either aren’t specialized in electronics at all, or ones that are old-fashioned and a bit sloppy (like Nipponamerica looks like to me). As many such companies don’t understand that chloride-bearing electrical fluxes that are OK for electrical work and really old, large electronic parts (like in point to point wiring in old tube radios) are not OK to use on modern electronics, I would steer clear.
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Why would flux itself ever contain lead?
When lead-free soldering became important due to RoHS, tons of new products optimized for lead-free soldering processes were released, frequently with “lead free” haphazardly added to the product name to differentiate them from the conventional product. But what is meant is not “this product contains no lead, unlike the conventional product” (i.e. suggesting the conventional product contained lead), but rather “made FOR lead-free soldering” (implying the conventional product is not optimized for lead-free processes).
That’s why there are tons of “lead-free” fluxes, solder braids, etc.
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Terminology:
- Solder paste is a mixture of flux and solder balls.
- Flux is a reducing agent (Keeps solder shiny, stronger, stickier/wetter and easier to use).
- Solder balls are made of metals, some use lead.
Your photo is of solder paste.
Despite the labeling, the product shown clearly is flux, not solder paste.
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this is it https://latinafy.com/products/nippon-america-soldering-paste-10-grams/
Oof, that page’s AI-generated product description slop is… bad.
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Yeh the information on that flux is really lacking. it works but more worried about the fumes and exposure to it. Like if its okay on skin cause that flux gets stuck in places you dont want sometimes even after you clean it. Lol ngl im an EE and ive been fixing electronics for years and only fairly recently (like months) started to use flux because it makes things easier
Anyway whats your recommendation for a flux that wont poison you and easy to clean, also non conductive.
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I like ChipQuik SMD291NL. Its fumes are WAY more pleasant than most: it smells like roasted hazelnuts rather than burning acid like so many modern fluxes. It isn’t the most potent flux on the market, but so much nicer to work with. (It is also transparent amber when cold, not milky like many fluxes, and this is actually useful when applying under a microscope.)
As for skin contact, no matter what electronics flux you use, you should be washing your hands afterwards. For many fluxes, you may need to use alcohol to get it off.
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I like ChipQuik SMD291NL. Its fumes are WAY more pleasant than most: it smells like roasted hazelnuts rather than burning acid like so many modern fluxes. It isn’t the most potent flux on the market, but so much nicer to work with. (It is also transparent amber when cold, not milky like many fluxes, and this is actually useful when applying under a microscope.)
That description sounds like a rosin-based flux, and the MSDS (https://www.chipquik.com/msds/SMD291150G.pdf) confirms that it is.
In my experience rosin works just as well for lead-free solder as it does for leaded solder.
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Yep, but rosin gets processed somehow to make it tolerate higher temperatures. (The "NL" in "SMD291NL" means "no lead", and it there is indeed an SMD291 without the NL.)
However, the smell is nothing like plain rosin. (I've even made my own flux from pure rosin.) The smoke from SMD291NL is much milder than normal rosin fluxes, or even of just pure rosin itself. Rosin smoke smells like, well, a bit like pine trees. SMD291NL smells sweet like hazelnuts.