[This isn't] Why lead free solder sucks...  [But it still sucks] - Page 1
Forum section: electronics / general

author: SilverSolder
author_rank: Super Contributor
timestamp: May 29, 2020, 09:30:59 pm
content: Why lead free solder sucks...

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: May 29, 2020, 09:33:41 pm
content: User name checks out.

author: nctnico
author_rank: Super Contributor
timestamp: May 29, 2020, 11:23:26 pm
content: This is not a lead-free solder problem but a production / design problem. You can have the exact same problems with leaded solder. Cold / heat cycles will cause any joint to crack. A rear-view mirror which is baking in the sun or freezing to sub-zero temperatures every day gets a lot of abuse. The cheap PCB material probably doesn't help either. Look at how the glue holding the component on the board has let go as well. The electronics shouldn't be in there. It is simple as that. But GM can do worse like mounting a single-sided board directly onto a diesel engine

author: SilverSolder
author_rank: Super Contributor
timestamp: May 30, 2020, 12:32:07 am
content: Lead free solder is less ductile than leaded solders - there is less "give". This is an issue when there are vibrations and mechanical shocks present... as with a rear view mirror.In my experience with repairs, bad solder joints is a more frequently occurring phenomenon with lead free than leaded - particularly if a board can flex.So for lead free, it may be better to design with many small stiff boards than one big wobbly one...

author: tooki
author_rank: Super Contributor
timestamp: May 30, 2020, 10:58:19 am
content: Quote from: SilverSolder on May 29, 2020, 09:30:59 pmOh man, are you just about to get egg on your face, smugly claiming this as a lead-free fail.That device was made withleadedsolder. How do I know?1. It was built in 2002, years before the RoHS restrictions went into effect.2. Automotive electronics are exempt from RoHS.Now, while the wholesale move of non-exempt electronics to lead-free has had the result of many exempt electronics being made lead-free anyway, car manufacturers are notoriously conservative, and wouldn’t have jumped on board so early.What it proves is that automobiles are a challenging environment for electronics. The failure mode shown is precisely why the passives manufacturers now make chip passives with flexible contact ends, so that board flex, vibration, and thermal cycling don’t cause the joints to fracture.And yeah, I still prefer leaded solder where I can use it, and I still think the RoHS restriction on lead in solder was the wrong decision. But it’s not proving to be the utter catastrophe that many claim it to be. Nor is lead-free as difficult to work with as so many claim — at least not if you buy quality solder. (The cheap 99.7% stuff really is harder to use, but a quality SAC305 works just fine.)

author: chriva
author_rank: Regular Contributor
timestamp: May 30, 2020, 11:17:09 am
content: Quote from: nctnico on May 29, 2020, 11:23:26 pmThey did the same with the gasoline version of SAAB 9-3 Second gen, a bunch of Opel / Vauxhall, Bentley and some other weird cars with b207 varieties. ALL of them suffer from dying ECUs.Weirdo thing with multilayer flexible pcb and BGAs all over the place.

author: SilverSolder
author_rank: Super Contributor
timestamp: May 30, 2020, 01:01:04 pm
content: Quote from: tooki on May 30, 2020, 10:58:19 amOops!Should have know better than to jump to conclusions.... many previous bad experiences with lead free solder misbehaving leads me to a plea of temporary insanity!This particular style of rear view mirror has failed in several cars I've owned. Normally I just replace them. This time, I'm about to attempt a repair for the first time and hadn't actually opened it yet...

author: Domagoj T
author_rank: Frequent Contributor
timestamp: May 30, 2020, 01:17:56 pm
content: Now you just have to explain your user name.BTW, when you guys hear silver solder, do you understand it as referring to soldering electronics? To me, that term is synonymous with brazing (high temp soldering, using silver alloys) but almost exclusively for mechanical connection, not electrical.

author: SilverSolder
author_rank: Super Contributor
timestamp: May 30, 2020, 01:28:50 pm
content: Quote from: Domagoj T on May 30, 2020, 01:17:56 pmIt refers to electronics solder with a small percentage of silver content, for soldering contacts/leads with silver plating (to avoid leaching the silver out). - I had been using it on the day I signed up for EEVblog so it was the first thing that sprung to mind when asked for a user name!e.g.https://www.amazon.com/Kester-Solder-24-7150-0018-ELECTRONIC-SILVER/dp/B01N44GDE4

author: Domagoj T
author_rank: Frequent Contributor
timestamp: May 30, 2020, 01:45:21 pm
content: Oh, I know about soldering electronics with alloys containing small amounts of silver.Silver brazing I'm referring to uses significantly higher silver content (for example, the stuff I use is 45% silver, 25% zinc, 30% copper). It also has higher melting point (660°C).