[Robotgroup] lead free soldering advice

[Leslie Filip]

If these explode better than the regular electrolytic ones then I  
would like to buy a few to experiment with.

Mr. Poo-Poo


On May 24, 2007, at 10:25 AM, douglasee at att.net wrote:

> another interesting feature of RoHS is "PCB free" water-based  
> electrolytic capacitors.
>
> the first few designs that got into the field wound up exploding  
> after a few years on service. Dell, HP, IBM, NCR, Wincor, just  
> about everybody got snagged by this problem.
>
> The water-based electrolytic has a tendency to express hydrogen gas  
> over time, especially if the operating temp exceeds 50 C. These  
> caps then start to expand until they look like ball-park franks in  
> the microwave. As the hydrogen is released, the value of the  
> capacitor starts to change drastically.
>
> This is what happens when you get "design by legislation"
>
> -de
>
>
> -------------- Original message from Edwin Wise  
> <edwin at simreal.com>: --------------
>
>
>>
>> On 24 May 2007, at 2:21 AM, Ed Xavier Gonzalez wrote:
>>
>>> Makes me wonder why European manufacturers are trying so hard to  
>>> push
>>> RoHS so brutally, specifically when it comes to lead.
>>
>> Yeah, it's not going to be pretty with electronics failing all over.
>> The whiskers are mostly a problem with analog or low-voltage,
>> delicate systems... they are extremely fine! But dang, they can grow
>> _long_ too (I saw pictures). Amazing stuff.
>>
>>> If corrosion begins forming immediately after the lead-free  
>>> solder is
>>> applied, then an overcoat of lacquer or some other clear surface
>>> treatment that prevents oxygen from passing through would need to be
>>> applied...
>>
>> Apparently overcoating doesn't work either (according to this article
>> I read). They fingers grow anyway, and they are so sharp they just
>> burrow their way through. As far as I've heard, there's no cure yet,
>> though the industry is working with different solder formulations to
>> try and minimize the problem.
>>
>> Edwin!
>>
>>
>>
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