Nichicon "Fine gold" caps a PITA to solder ?

[benh]

Hi Folks !

Just wondering if this is just me ... I grabbed a few bags of Nichicon "fine gold" caps from pedalpartsaustralia.com.au (I think stompboxparts has some too), and I've been somewhat struggling with soldering them :-)

I never had that problem before, it's odd... the leg sizes are no bigger than other caps but for some reason they behave like the fat legs of black diodes, ie, it takes a LOT of heating before the solder adheres to the leg. At that point, the cap itself becomes really hot and I already had to replace one that was acting as an open circuit, I suspect due to heat damage.

I normally solder at 380C using lead free solder, I've done it for years, and never had such a problem. I usually don't need to heat a component for more than 1s.

Am I doing something dumb here ? :-)

[jessenator]

Could it be oxidation on the leads or the board pads/vias?

Could also use some additional flux.

Even with flux core solder, I personally never feel it's enough and always use more—it's just part of the process now. The no-clean stuff can be removed with a little isopropyl alcohol, if you're concerned about it staying on the board. IMO, the best value is a tub of paste style flux. 

[jwin615]

1)try cleaning them with some isopropyl
2)could be ground plane sucking up heat.
3)like Jessenator said, lil flux

It very well could be the nature of the component as well. Maybe a thicker, more robust foil or something of the like that's being a heat sink.
Are these the caps they discontinued because they could get their magic foil any longer(along with the awesome QYX films)?

[jimilee]

What board are you soldering them in to?


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[benh]

What board are you soldering them in to?

I had the issue with several, including Anamorph, and recently TH's Tube Driver (madbean is out of Archibald and I wanted a second one :-) So I don't think it's ground plane sucking heat. It does happen with both legs and every time with those specific caps.

As for the other replies, I have been fairly 'liberal' with the flux pen but it might be a crappy one... I'll look into getting some paste.

That said I am not new to soldering and it's the first time I hit something like this. It could be oxidation of the legs I suppose. I'll see if cleaning them helps next time.

It does look like the cap itself is sucking all the heat :-)

I will sacrifice one or two on a bit of vero to see if I can find a magic solution. Maybe going hotter on the Weller for less time...

I might try with leaded solder too... I mostly switched to unleaded to appease my better half but it's been a while and no issue with Wurth, Panasonic or even other Nichicon caps. Only those fine gold ..


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[jimilee]

Try cutting the legs before you solder them instead of after. That will help a lot, too. I don't care for ground planes, they suck a lot of heat, too. I try not to use them in my boards.


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[jwin615]

Those were EOL 3 years ago. Very well could be a bit of oxidation by now.

[jessenator]

Those were EOL 3 years ago. Very well could be a bit of oxidation by now.

I wondered. Makes sense. Some of the ancient parts that go in the "verification builds" category suffer similarly.

[benh]

So in the end, shortening the legs, fine grit sandpaper, cleaned with IPA and plenty flux does the trick :-) they still need a bit more time with the iron on the legs than the other ones but it's not as crazy ... Hopefully they'll all work when I'm done with this build (Boom boom, only using the FG caps for the audio path 1uF's).



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[jimilee]

So in the end, shortening the legs, fine grit sandpaper, cleaned with IPA and plenty flux does the trick :-) they still need a bit more time with the iron on the legs than the other ones but it's not as crazy ... Hopefully they'll all work when I'm done with this build (Boom boom, only using the FG caps for the audio path 1uF's).



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Cool, glad you got it worked out.


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[jessenator]

I wonder if you could rig up a 3d-printed "rack"  (~1mm thick), feed the leads in, and have it sit over a small jar of vinegar, or some other weak acid to remove any oxidation. Quick wipe down to remove the excess vinegar before soldering. Not sure if it would work, but might be less labor intensive than sanding each one. I've used vinegar to clean up car wiring terminals (non-battery ones...) similarly.  I suppose the initial setup is a bit of a faff, but could have a rack with multiples, eventually save time?

[jimilee]

I wonder if you could rig up a 3d-printed "rack"  (~1mm thick), feed the leads in, and have it sit over a small jar of vinegar, or some other weak acid to remove any oxidation. Quick wipe down to remove the excess vinegar before soldering. Not sure if it would work, but might be less labor intensive than sanding each one. I've used vinegar to clean up car wiring terminals (non-battery ones...) similarly.  I suppose the initial setup is a bit of a faff, but could have a rack with multiples, eventually save time?

It's be easier to just not buy the caps with the  gold leads. Sounds like they're more expensive and more hassle.


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[benh]

It's be easier to just not buy the caps with the  gold leads. Sounds like they're more expensive and more hassle.

This :-) I'll go through the ones I have and then go back to my stock of Panasonics, Kemet and Wurth :-) (I still use those for the non audio path too, mostly Wurth)

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[lars]

RoHS compliant leads, perhaps? They have to be able to guarantee cold solder joints in order to hit their built-in obsolescence quotas...otherwise people might make things that function longer than five years.