Any tricks to desoldering using a cheapo solder sucker?

[Xoc1]

Adding more solder helps, as this adds fresh flux and the extra solder aids the heat transfer from the iron.
I also keep a cheap unregulated temperature iron for difficult to remove parts. I find that it is particularly useful for removing parts on large groundplanes, or multi layer PCBs (as on a computer motherboard for instance).
If these capacitors have bent over tags, you may need to remove the solder with braid, then heat and straighten the tag using an iron and a small pointed tool. Then add more solder and pull the leads out, then clean up with the solder sucker

[Enzo]

I'm with Robert here. Heat one leg of the cap until the solder melts, using a regular iron. Rock the cap body away from that leg however far the slack will let you. Then heat the other leg and push the cap sideways to rock that leg out as far as it will let you. Each step will get you more slack. Back and forth a couple times and your cap is free.

THEN worry about cleaning the hole.

Even with all my fancy desoldering stations, I don't always rely on sucking all the solder away to get large parts out

[Conrad Hoffman]

I'm with Dangus- anything smaller than the full size "Soldapullit" he recommends is useless. I have about 4 of the shorter units from them, RS and others, and they're all inadequate. We have commercial desoldering stations at work and the DS-017 is just as effective, albeit slower to use. I'm not a big fan of wick, having burned myself on it too many times, but for some things it can't be beat. Definitely add flux and solder and be sure your iron tip has a lot of thermal mass, i.e., is big enough for the job.

CH

[johnferrier]

A guy I worked with used to cut a notch into the side of the solder sucker tip, so that the iron can be on the part, at the same time.

[Glowbug]

Originally Posted by Enzo

I'm with Robert here. Heat one leg of the cap until the solder melts, using a regular iron. Rock the cap body away from that leg however far the slack will let you. Then heat the other leg and push the cap sideways to rock that leg out as far as it will let you. Each step will get you more slack. Back and forth a couple times and your cap is free.

THEN worry about cleaning the hole.

Even with all my fancy desoldering stations, I don't always rely on sucking all the solder away to get large parts out

This is pretty much what I had to do, came out perfectly.

Does anyone have experience with a desoldering gun, like a Hakko 808? I hear good things about Pace stations, but also that they can be a little maintenance-intensive, and I'm not sure I want to make that kind of investment unless I know I'm going to be using it a lot (which I probably won't).

[Enzo]

I have used basic Pace desoldering stations the last 25 years and am very happy. Yes, I do keep bags of tips in stock.

[indianajo]

I have the RS WP 45 desoldering tool, it's hollow tip won't transfer heat fast enough to do anything bigger than a TO-92 transistor or DIP IC. For big old electrolytics, that suck a ton of heat into the can, I use a 120W Sears pistol gun. I'm cheap,to suck solder I use scrap wire of about the size I am trying to remove (16 or 14 ga on big electrolytics) dipped in Oatey #5 Solder paste (zinc cloride) from the hardware store, to suck the solder off. I cut the shiny bit of wire off with cutters, strip some more, dip in flux, and keeps sucking until solder is gone. This is cheaper than desoldering braid and much more available in a non-electronic town like this. For heavy work like FP cans using a solder sucker tool risks melting the plastic tip off. The Oatey flux is said by others to be an acid flux, so I wash the area down with a damp paper towel when I am finished. As a previous person said, on a FP type or Aerovox can with ground tabs you will have to suck the solder off and also twist the can tab while hot to get out of the socket or chassis. A lot of times the can tab breaks. When I put the can back on, usually a WP25 iron with chisel tip has enough heat for the wires(not pointed), the Sears gun is put away. Sometimes I have to use the big gun on the can tabs to chassis. I have a WP80 iron which should be big enough, but it doesn't really get hot enough to melt SN-PB solder at all hardly.

[TicksNLeeches]

Pretty much what the others have already said. Your first mistake is the use of the wrong tool and your second, the wrong technique.

Big power caps have big power and ground traces, or even worse in this case, planes, and they're all excellent heatsinks. A weak iron will just slowly heat up the cap and the board, not good for either of them.

You'll almost never get a cap out by cleaning the joint first. They tend to be a tight fit and with the heatsink properties, as the joint clears and you lose thermal transfer from the lack of solder/contact area, it cools what's left and leaves too much in the joint to enable the removal of it. If you try breaking it, you very likely will. You'll have an impossible time reflowing the joint then as well without additional solder.

First step is to reflow the joint and add fresh, leaded solder. If it's lead free solder in the joint it'll turn cloudy with the mix, but that's fine, it will lower the melting point anyway.

I tend to use braid to clean it as much as possible, then wash it with fresh leaded solder, and maybe repeat once or twice so that it flows easily, then lace the solder to it for good heat transfer while I wiggle it out one leg at a time. Keep adding solder to ensure good thermal transfer, as what's there will get sucked through the via by the leads as they pull out.

If you try using braid to clean the joint fully with cap in place it's just adding another heatsink so you really need a hot iron.

I Wouldn't bother with the guns, they're pieces of junk, never reliably heat the tip, and you can get a pencil or butane iron for the same price that's hot enough for the job.

Of course when you use the wiggle technique, since it can start off very slow, it often doesn't hurt to trim the leads a little before you start, and bend them straight.

For smaller caps with a tight lead pitch let the surface tension of the solder bridge the leads, heat both simultaneously while alternating via to via to ensure good heat transfer directly and wiggle it right out in under three seconds with minimal strain.

Extra tip, when doing one leg at a time, hold the cap tilted while you remove the iron and let the joint solidify, don't worry if your finger burns, this is normal. Otherwise you may be going nowhere fast as the cap will resettle in the second it takes for it to solidify.

[40 watt]

In a pinch, and from the run what you brung department, I just strip some insulation off cheap stranded copper wire, 18 gauge or so. Twist the strands together tight, form a nice u-hook at the end, dip into solder paste, put some solder flux paste on the soldered joint, and place the fluxed wire right up against the soldered joint and apply a hot solder iron tip onto the copper stranded wire. It should fill the wire with the solder in no time. I make a 3" double ended one, leaving the insulation on in the middle so it's easy to hold without feeling heat on your fingers. Works great! Cleans the joint really nice and helps preserve the solder pads on removal of the component. Tilting the soldering iron down to put more surface area of the heated iron helps too. a 45 degree angle works well.

[davada]

Originally Posted by dangus

You want one of these:
Edsyn DS017
Anything less is a waste of money. And many things that cost much more don't perform much better.

I find braid is most useful for cleaning up, like when replacing surface-mount things. Braid varies in effectiveness, too. Maybe the flux deteriorates with age, or off-brands just aren't as good.

Just be sure to clean out the pump before use or you can get a big pile of powdered solder all over your work.