RoHS soldering wire

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Tobe
Posts: 665
Joined: 16 Feb 2018, 06:19
Location: Varberg or Stockholm, Sweden

RoHS soldering wire

Post by Tobe »

I'm having a hard time with the RoHS soldering wire w/o Pb/Lead, are there any tricks that I have to catch up?
I don't feel it to float and I have tried all kinds of settings on my soldering station.
Cheers,

Tobe
Martin
Posts: 744
Joined: 16 Feb 2018, 14:11
Location: Warwickshire

Re: RoHS soldering wire

Post by Martin »

The stuff with lead in it is much easier to use. Very hard to use the lead-free multicore stuff in a home environment.

Even the commercially soldered lead-free boards are known to be less reliable than the leaded ones. Over time, the lead-free tin grows spikes which then short parts of the circuit.

Lead wasn't banned from solder because of any risk when soldering - the reason for the ban was to stop lead leaching into groundwater when old electronics end up in land fill. The risk to the person soldering comes from the flux, not the lead - and that's the reason you should take steps to avoid breathing the fumes.

I use a computer fan, powered from a 3-cell LiPo when soldering. I 3D printed a shell to hold the fan, and it sucks the air through some filter material I bought on-line. I stand it on the desk behind where I'm soldering, and it produces a gentle air current that takes the smoke into the filter rather than up into my face. The filter probably doesn't catch much of the flux smoke, but at least the smoke is going away from me rather than towards.

solderFan.jpg

If you must use lead free, then it's even more important than usual to keep everything spotlessly clean - the PCB, the components, the soldering iron and the solder itself. Use plenty of flux - the watery stuff that you apply using a thing that looks like a marker pen, or the stuff that comes in bottles that can be applied like nail varnish works well. You need a soldering iron with accurate temperature control, set to a higher temperature than when using solder that contains lead. I usually set my iron to about 350 C for lead-based solders, and close to 400 C for the lead free ones.

I've also used lead-free solder paste - I think it contains bismuth. That melts at a lower temperature than the lead solders, and although it's really intended for use with hot plates and reflow ovens, you can use it for normal soldering with an iron, though it's messy to apply, and messy to clean off any paste that you don't actually melt. Normally you melt all the paste - it starts off looking like grey toothpaste, but once it's been heated up, the flux turns into smoke, as usual, and the solder has the normal silver colour.
Attachments
SolderingFanCase.zip
The STL for the soldering fan case. It prints, 'face down' without support. There are some supports built into the design to help with the printing of the filter grid - but these are designed to be easily snapped off the finished print.
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Tobe
Posts: 665
Joined: 16 Feb 2018, 06:19
Location: Varberg or Stockholm, Sweden

Re: RoHS soldering wire

Post by Tobe »

Thank you Martin, I'm getting to the end of my regular soldering wire and at least here in Sweden you can't buy anything else that RoHS so I have to get to the lead free wire.
It's hard to teach an old dog to sit 😕
Cheers,

Tobe
Martin
Posts: 744
Joined: 16 Feb 2018, 14:11
Location: Warwickshire

Re: RoHS soldering wire

Post by Martin »

You can still buy solder with lead from China using AliExpress. What happens if you buy that in Sweden; does it get confiscated?

Although there's no lead in the smoke when soldering (the temperatures are far too low) you should be careful to wash your hands after soldering - especially before you cook or eat anything.

Watch out for the smoke from the lead free stuff - it's even worse to breathe than the leaded, because the flux is more acidic.
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Mike_K
Posts: 669
Joined: 16 Feb 2018, 06:35
Location: Hertfordshire

Re: RoHS soldering wire

Post by Mike_K »

You can still legally and easily buy lead/tin solder in the UK, try Farnell 817533. It's only restricted for commercial/industrial use, but it's nearly always specified for military and aerospace and I believe medical products have certain exemptions as well. And for private use, there are no control restrictions at all, unless you are going to sell a product.

If you are going to buy lead-free solder, always buy solder with a silver and copper content, it cost double to tin/copper solder, but has a lower melting point, flows more easily and is less prone to growing the dreaded "whiskers" (tin crystals that grow as small spikes and as they're conductive, can short out circuit boards). You need a hotter and a higher wattage soldering iron and I've found thinner diameter solder allows the iron to keep at a more constant temperature. And as Martin says, the flux is more of an irritant than that used with lead/tin solder.
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kalle123
Posts: 35
Joined: 02 Feb 2021, 07:06

Re: RoHS soldering wire

Post by kalle123 »

Same problem here in Germany.
Ordered three reels a 250g Cynel professional from Poland last December.
Paid ~ 30€ incl. shipping. (Make the order in €, not in PLN)

https://botland.store/166-tins-and-solder-pastes

And be careful with that 60/40 from China. Ordered two 500g reels from Aliexpress.

Same behavior like in this video at 3:28 https://www.youtube.com/watch?v=2PipqGVuc5o

br KH - I am to old to switch over to lead-free. ;)
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