desolder braid or suction pump

depends on a lot of factors. Are these plated PTH or SMD IC's? Are you trying to recover the IC's and scrap the board, or vice versa?

Rule#1: If you don't want to save the (leaded) chip, cut the legs first and remove them one-by-one. If SMD, I'd still be trying to minimise board damage by cutting leads if at all possible.

My Rule#2: Desolder braid is largely ineffective on PTH unless the hole is laaaarge. I would (do) use a desoldering sucker.

Just my 2c worth.

trying

and

damage by

is

I have a board. I have 2 suspect chips. I have spares

They are normal IC's

it is an old vic 20

I want to remove and maybe re-use if ok.

If I put sockets on the board, can I put the ex soldered chip in the socket ? I mean, can I clean the legs enough to do this ?

thanks

The legs of the ICs are usually tinned from the factory anyway, so the basic answer is yes. When you've got as much solder off as you can, finish off by scraping with a blunt curved scalpel blade. Use good quality turned pin sockets rather than leaf contact types.

As others have said, a lot depends on the type of board as to whether a desolder pump or braid is better. If using braid, it is essential to use good quality, that is not old. And before the usual suspects start saying you can roll your own, yes you can, but it's a lot more convenient to just buy new. Whichever method you use, you should first flood the original joints with new solder, and let each one bubble a couple of seconds.

You will struggle with either a hand desolder pump or braid, when you get to any pins connected to the power and ground planes. My advice would be to try both removal methods first, but once only. If you struggle to release any pins, I would not pursue it further, as board damage is sure to result. In that case, just cut the IC pins and remove them one at a time. There is a board that I work on regularly that has some ordinary DIL ICs which fail. I have a proper professional desoldering station that I use on them, and even that struggles sometimes. If it doesn't get the IC out first time, I just cut it out. Takes more time, but guarantees that the board will stay OK.

Arfa

Mostly the sucker beats the braid by a long way. But there are a few folk that prefer braid.

In that case its likely a multilayer board. Trouble with those is that sucking the solder out makes it impossible to melt what little's left. You may be better off not removing the solder at all, but melting and removing each pin, after cutting it from the IC. Then just use the sucker to clear the holes.

Yes, but... you'll not get a flat smooth surface, so it may be difficult to get it into the socket, and very difficult to get it out again, but yes its poss, if you dont cook the IC or cut its legs off. With multilayer boards theres a good probability you'll end up doing one or both of those.

NT

Used braid for many years but it depends on your skill factor.

-- #1 Offishul Ruiner of Usenet, March 2007 #1 Usenet Asshole, March 2007 #1 Bartlo Pset, March 13-24 2007 #10 Most hated Usenetizen of all time Pierre Salinger Memorial Hook, Line & Sinker, June 2004 COOSN-266-06-25794

It depends. I have both on hand, usually I try the bulb first, it's attached to a desoldering iron, very useful tool so long as you keep a new tip on it. I haven't had much luck with the standalone bulbs.

If the braid is old, dip it in liquid flux. Makes a huge difference.

I've had a solder sucker for twent years, and found that does work the best. On the other hand, at some point I did buy some desoldering braid, and when that runs out I would get some more to have around.

I also bought a cheap desoldering iron, from Radio Shack, in the late eighties. It has the advantage that it's easier to use than an iron and a solder sucker. It was about ten dollars at the time, so I felt it was worth having around. But, the tip wasn't plated, so it didn't take long before it corroded and the unit wasn't particularly useful. The tip was removeable, but they didn't carry replacement sat the time. They later did, but I'd gotten out of the habit. I think except for the tip issue, the desoldering iron seemed the best choice.

But again, some braid and a sucker are not really expensive, so one might want to keep both around.

Michael

Make sure it is ROSIN flux. Mild RMA is even better.

Both.

Graham

In article , snipped-for-privacy@spam.com (known to some as Dave) scribed...

Thru-hole or surface mount?

Are you trying to salvage chips for later re-use, or repair something?

For thru-hole, I prefer a good power desoldering unit. I'm using the Pace ST-115 at both home and work. Excellent unit.

For surface-mount, there are a number of rework stations available, none of which are particularly cheap. At the low end, you have the convection-heating (hot air) units, such as Hakko and Madell. At the higher end, you're still doing convection, but the units are better built (A.P.E., Pace, etc.)

At the top of the line for surface mount are the infrared rework stations. I've never seen one sell for less than in the high four-figure area, and new ones have price tags that rival luxury cars or small homes.

Now, with all that said: I do also use desolder braid. However, its main use with me is cleaning off surface-mount pads, or component holes, prior to replacing said component.

Happy hunting.

thankyou for all your help.

i dont want to spend much, so I shall struggle on....

On Sun, 15 Apr 2007 15:16:39 GMT, "Dave" put finger to keyboard and composed:

I use a DS017 Soldapullt:

- Franc Zabkar

I never did have much luck with those things, the solder always seems to solidify by the time I get a good seal. That mechanism with a heated metal tip would probably work well.

"Dave" wrote in news:rlrUh.24133$aB1.15834 @fe3.news.blueyonder.co.uk:

Be sure and get some 63/37 solder. It is eutectic solder (the solder melts and freezes at a single temperature, the lowest possible for the elements involved.

Many use 60/40 or even 50/50 solder. These both pass through a 'plastic' stage when melting and when freezing. Any disturbance of the joint during the plastic stage results in a 'cold solder joint'. Crystals of the higher melting element form.

Note, now many countries require 'no lead' or 'low lead' solders. These tend to melt at much higher temperatures. For each pair (or trio) of elements, there is a ratio that gives a eutectic mixture.

In any case, when desoldering, adding some 63/37 solder to the joint. It will help you 'disolve' the original, higher melting solder, and remove it.

There are some controlled temperature irons combined with a vacuum pump into a desoldering station. They are not cheap but are a good investment if you are doing a lot of board repair.

There are conductive ink 'pens' to allow repair of circuit board traces.

For a more professional look, there are stick on solder pads and traces. Some of the board repair kits even include fiberglass making materials to repair the board itself and solder resist to repair the solder mask, along with dyes to color these so that the board looks 'as good as new' when you finish with it.

Google for 'eutectic solder', 'desoldering station' and for 'pcb repair kit'