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how to hand solder smd aluminum electrolitic capacitor?

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Boncuk

New Member
Electrolytic caps are soldered manually the same way as any other component.

Just use a little portion of soldering tin (0.3 to 0.5mm thickness with resin core) Heat the the part (terminal) prior to heating the SMD-pad and shift the part into the correct position. Then solder the second pad and component terminal. Use some flux and reheat for equal tin distribution and maximum mechanical strength and conduction on both solder spots.

Boncuk
 

arhi

Member
thanks for the info but I don't get it :(

I do solder smd without much problems, but only when there are some pins I can work with, like sot or 1208 or 0806 ... but these aluminium capacitors are like QFN .. the pins are "under the device", there is nothing sticking on the side ?!?!?

so at the very beginning on your explanation "heat the terminal" is a problem, if I heat it what then? "fast put it to the pad hoping it will be still hot enough to stick" ?? and how to "solder the second pad and component terminal" then when darn terminal is under the device?!
 

colin55

Well-Known Member
The best way to solder these electro's is to bend the pins and remove the insulator and straighten the pins. Then solder the device as a "through-hole" component. You have to be very quick to prevent heating the rubber/plastic seal and allowing them to leak.
Otherwise you can bring the pins out sideways and solder them to the board.
 

ronsimpson

Well-Known Member
Most Helpful Member
Are you soldering to a PCB, or point to point in the air, or to a purf-board?
 

DirtyLude

Well-Known Member
One side is easy. You load one pad with a bit of solder, try to stay closer to the edge where you can put the iron on when you place the cap down. Place the cap down and heat the pad; Solder will melt and the cap is held down on one side. Second side. The contact are not totally hidden unde the cap, the stick out a bit. Heat the pad and the bit of contact with your iron and apply the solder, it will all come together.

Maybe I can make a video if I can find a board that I haven't populated.
 

arhi

Member
colin ... yeah that was my iniital idea but that requires non standard hole diameter, thin board, etc etc .. does not sound like fun at all :(

ronsimpson, to pcb

dirtylude, I think I understood you .. so if I understand you correctly, I make the pads on pcb bit larger, put some solder on pins, put solder on pads, heat one pad put cap over, then heat other pad from side and it should make the solder flow .. will try .. thanks for the tip... with regards to video, I'd sure like to see it, and I'm sure I'm not the only one :)
 

Sceadwian

Banned
Boncuk, those are SMD electrolytics not so easy to solder by hand.

No arhi you want to keep the electrolytic as cool as possible heating it too much will damage it, in fact I'd practice this a few times before you try to do the real one because too much heat will change the cap values possibly to the point it no longer functions.

What Buncuk was saying is use standard rosin core solder to tin the leads, get just a little bit of solder on there so you have something to work with. Then apply a little bit of paste flux to the leads and apply it to the PCB pads. Then go back in with the soldering iron and heat up each leg till the solder re-melts. You have to use a paste flux or you'll either get a bad solder joint or end up having to torch the part to get the solder to flow.
Colin's method will probably work best if you're not comfortable doing it that way.
 

DirtyLude

Well-Known Member
What PCB software are you using? Eagle footprint for nichicon capacitors is already pretty big. You get enough space to either side of the capacitos to just solder down the tiny little exposed contact if you need to.
 

arhi

Member
ah clear ... the "tiny" part of the leg that sticks is "standard" :) ... I'm using these first time now so was not sure if that was standard or I was just lucky with this batch :D

thanks all

dirtylude, I'm using all sort of software :D .. from eagle via dos pcad and tango going by proteus (ares) all the way to altium designer :) ... but mostly it is ares.
 

be80be

Well-Known Member
Those are made for reflow not hand solder at all. Put solder on the tab and the pad set the cap in place and heat the tab will set them.
 
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