Picking up solder with wick

[cyberfish]

Do you have trouble picking up solder with wick? I know I do.

After endless cursing, I decided to try something new today - adding some flux to the wick.

It worked very well.

I was doing some TQFP soldering and ended up with a huge blob of solder all over 1 of the sides. Tried to pick it up with just the wick for 20 minutes. No success.

The wick with flux picked ALL the solder up in about half a second. The pins became unsoldered!

Just thought I would share this.

[Psi]

Yeah, its a good tip for people who've not used solder wick before.

You normally have to wet the solder wick with some solder before you start.
Just like you sometimes need to apply solder to the pin of a component to be able to unsolder it.

The reason is because you need to get an object hot to be able to solder/unsolder it and a piece of metal has to many microscopic pits/groves to make good thermal contact with another object. Putting some solder on it fills in all the pits/groves and vastly improves the thermal contact. This allows the object you're soldering to get nice and hot even with most of the heat bleeding away. The flux in the solder also helps a lot by cleaning the metal.

You can also use a big chisel tip on your iron when using solder wick, that helps get the heat to where you need it.

[thakidd]

No wonder why I have always had trouble with wick. Tried this and worked like a champ. Now I can finally put the vacuum pump to rest. Good riddance too as I have used it to the extent of the solder melting the plastic innards.

[mikeselectricstuff]

There is a huge difference between different brands - Chemtronics Soder-Wick is by far the best I've used - size 4 is about right - smaller stuff saturates too quickly - if you need a fine point just cut it at an angle.
Place the wick on the joint and the iron on the wick- solder likes to travel towards the heat.
The flux in the Chemtronics stuff works well, but some extra flux never hurts.

[joelby]

I bought some cheap wick from eBay and it didn't wick at all, though I haven't tried adding flux. I picked one up from Jaycar, labelled with the same brand, and it worked fine. Beware dodgy counterfeits!

[cyberfish]

I did some more researching online, and it seems like the biggest factor is age of the wick, because of oxidation.

I guess adding flux just takes out the oxidation.

For me, I only use wick for SMD. For through hole I use vacuum pump. I prefer the pump, but they cannot be used on SMD. Takes out the pad/bends pins etc.

I bought some cheap wick from eBay and it didn't wick at all, though I haven't tried adding flux. I picked one up from Jaycar, labelled with the same brand, and it worked fine. Beware dodgy counterfeits!

May not be counterfeit. Could have just sat on the shelf for longer.

[DJPhil]

I've had good luck with both Chemtronics and Techspray #4. Neither really requires flux, but it always helps. I picked up some MG Chemicals RA flux some time ago (#835-100ml) and it can be used to make just about anything work, even the cheap brands. It's messy stuff, but dispensed properly it'll last forever. I've been using it heavily for six months and I've gone through maybe 5% of it.

[JohnS_AZ]

Same here. I bought a bunch of wick off of eBay and it won't work at all. When I added flux it works great. These were name-brand rolls from a quality manufacturer so I have no doubt that it's an age issue.

[JohnS_AZ]

BTW ... for applying liquid flux, I feel that having one of these (or something like it) is absolutely essential!

http://www.hobbymasters.com/a-weststainlessneedle-pointapplicatorbottle.aspx

[osmosis321]

Ever since I was trained in soldering/desoldering techniques back in the day, I've always preferred to have fluxes within easy reach when I'm working on a board.  I don't even think about it anymore, in fact it never occurred to me NOT to flux my wick.

"flux my wick"...  that's what she said.

I use wick and pump, depending on the solder amount to remove.  Typically I'll pump off the bulk of it and use the wick for the fine cleaning.  Good wick has a high affinity to solder, and any hot solder will seek it out, preferring the wick over whatever it was on originally.  Works like a charm.

[crusader66]

Chemtronics makes several widths of solder wick with a rosin coating on the wick.  The type I use for most smd can be purchased from digikey.  Chemtronics # 50-1-25, Digikey number add a -ND.  This stuff works pretty good. 

The varying sizes of wick are for the pin width of the device you are attempting to desolder.  A wick that is 3/16" wide will not work as well as using a wick that is only 1/16" wide for most SOIC type ic's (even when you are laying it across multiple pins) or discretes between 0603 - 2512.  Most people just have that standard, thick, solder wick laying around from the through hole days.  My experience is that this doesn't work well with smd (but fluxing the crap out of it will help).

Hope this helps someone.