Desoldering/modding amp advice

[jball85]

If you were to mod a pcb tube amp, what would you use for desoldering in way that won't ruin the pcb pads? Is there an inexpensive, yet decent desoldering air station? Other suggestions....

[miter53]

Desoldering braid. Get a good brand, like Chemtronics. I've found the cheap ones don't work as well.

[jkokura]

I actually don't recommend braid unless you're fine with wrecking things. Braid will work, but I find it requires so much heat that it's rare that it actually does what you're looking for without making things look awful or stop working.

I still think the best approach is a combination of whatever tools you like to use. If you have a desoldering sucker, that's the best place to start. A station would be highly recommended, but I've never seen a decent one for a good price except the Radio Shack special.

Jacob

[rullywowr]

I actually don't recommend braid unless you're fine with wrecking things. Braid will work, but I find it requires so much heat that it's rare that it actually does what you're looking for without making things look awful or stop working.

I have to respectfully disagree.  Soldering braid works very nicely and is not just for "wrecking pcbs."  A helpful hint when using braid is that you should apply flux (like with a flux pen) directly to the braid before using it.  When used in conjunction with flux, it wicks up the solder quickly and without fuss.  If you are wrecking PCBs, you haven't applied enough flux or you are not using enough heat - therefore baking the board for a while and you will get lifted traces etc. Get in, get out quickly is the key (less than 2-3 seconds).  I have a pretty expensive desoldering station (which I love) and still find myself using braid from time to time in tight areas around 720F-740F where my desoldering pencil won't go.

For a manual spring-loaded solder sucker, the "Soldapullt" brand is the one to get.  They are typically yellow and blue in color and are the premium version of all the cheap copies out there. 

[miter53]

Maybe it's my dumb luck, but braid has worked pretty well for me. I managed to remove a 16 pin socket on a Zero Point DD that I soldered in one pin off with no pcb damage.

[Bret608]

I have caused damage with braid too, but have gotten better with it recently. If I get some solder onto the tip of my iron and then quickly get contact with the braid and pad, it works pretty well. I still like my pump better. Good luck to you! I just ordered some parts to mod my Blues Jr. so will be trying this myself soon.

[GeorgeFormanGrill]

A helpful hint when using braid is that you should apply flux (like with a flux pen) directly to the braid before using it.  When used in conjunction with flux, it wicks up the solder quickly and without fuss.  If you are wrecking PCBs, you haven't applied enough flux or you are not using enough heat - therefore baking the board for a while and you will get lifted traces etc.

Is there a specific brand of flux pen you recommend?

[rullywowr]

Is there a specific brand of flux pen you recommend?

Kester makes a variety of flux pens, and if you haven't used one yet you will love it.  Essentially, you paint the flux on like you are using a felt tip marker.  I use it on all my PCBs, just about anytime I am soldering anything.  Just "write" the flux all over the pads you are about to solder up.  This makes the solder flow so much easier.  The main thing is to get a flux pen which is compatible with your solder that you use (they have same flux type).  For example, if you are using a rosin flux solder, you should use a flux pen which is of the rosin type.

A few months ago, I switched to Kester "no-clean" solder in .031" diameter so I use a Kester #951 flux pen (to be compatible).  The "no-clean" stuff is a treat to work with as it doesn't leave behind a sticky residue like the rosin flux does.  It requires a bit more heat but I am pleased with how it works.  I put my older rosin flux pen and old spool of rosin-based solder away for a rainy day.   Flux pens are about $4-$5 each and will last at least a year.

You can search the web or Mouser etc for "Kester flux pen" and find them easily.

[jball85]

I'll try one of those flux pens. I use braid for pedals, but Im not confident enough to use it on my Marshall which is going under my knife for the third time, and some of these soldering joints came cold from the factory. I was hoping someone would tell me to buy a chinese solder vacuum because they were the best thing since man invented the wheel or antiseptics.

[wgc]

There are a few key things to using braids

1. Flux, as mentioned already, though the good stuff already contains a lot

2.  Counterintuitive, but add some solder to the braid to help heat transfer and get things going. It's kind of like tinning your tip and/or siphoning.

3. The right amount of heat is important. It's tempting to crank things up but especially on cheap single sided pcbs you can burn the glue holding the pad to the fr4 and it will lift. If your heat is too low, you can solder the braid to the pad and pull too hard, and you guessed it, lift a pad.

4.  Slide the braid along as you go, it will help the braid do its job. Not too fast...

5.  Don't leave more than 1/4" of used braid on the end. The iron just has to work harder.

6.  Practice, practice, practice.

[alanp]

If the braid has solder on it, it can also tin pads you drag it across as well

[jball85]

Cranked the heat up to near max on the Weller, and the solder braid worked beautifully. Thank ya, thank ya. 

[rullywowr]

Cranked the heat up to near max on the Weller, and the solder braid worked beautifully. Thank ya, thank ya. 

Werks like a chaaaaarm!  Nicely done.