2 Soldering/Desoldering questions

[tenser75]

1. how to desolder multiple legs (3 or more) components?
I want to salvage elements from old prototypes: 3pdt switches, trannies, pcb mounted jacks, etc... which are very difficult to desolder... what's the best technique?

2. I'm trying to solder a ground wire to the back of a pot (metal, no plastic) but it seems the tin doesn't stick... is this a matter of power/ heat? i tried at 800F with my Weller WDS50... no luck

[Ben Lyman]

1. Do you own a solder sucker?
2. quality solder might help, SBE has great solder, what kind are you using?

[Ice-9]

I use a solder sucker/plunger to remove as much of the solder as possible, the component might still be connected but with an iron you can then release each pin and with a little wiggle the component comes out. It is something that takes a bit of practice to get right without killing stuff.

Getting solder to take to the back of a pot usually require a little sanding of the metal to expose a surface the solder will take too. I use a little sanding wheel in my dremel to do this.

[Derringer]

https://www.amazon.com/LyonsBlue-Desoldering-Vacuum-Solder-Removal/dp/B003FHYL7I/ref=sr_1_12?s=hi&ie=UTF8&qid=1478371547&sr=1-12&keywords=solder+sucker

got one of these a while ago to do some amp repair ... love it and use the hell out of it

[pervyinthepark123]

In the past I used a solder rework station such as at here.
Cheap ones are kinda expensive, but the one I no longer have access to was only about 50/60 bucks, rework tool and solder iron with a huge power supply, could get really @#$%in hot but also very not hot, fast heat up and dial out display. Its an older model though.

[thermionix]

For #2, what kind of pot?  There are different metals and platings out there, and some don't like to take solder.  Sometimes sanding first will make it take.

[Hatredman]

1. how to desolder multiple legs (3 or more) components?
I want to salvage elements from old prototypes: 3pdt switches, trannies, pcb mounted jacks, etc... which are very difficult to desolder... what's the best technique?

2. I'm trying to solder a ground wire to the back of a pot (metal, no plastic) but it seems the tin doesn't stick... is this a matter of power/ heat? i tried at 800F with my Weller WDS50... no luck

Used this for years:

https://goo.gl/images/wcjZUO

This is a .sig.

[bloxstompboxes]

Sokder wick like hatredman posted is excellent for single and multiple pin parts. However it runs out quick. When I had a job, we had hot air guns and suckers that worked awesomely for things V850 ICs or 100 something pin header connections. I find at home that the solder sucker like Derringer posted when used first for most of the solder, and the solder wick for what's left over work fine for my simpler projects.

[Ben Lyman]

Ya, I got a solder sucker like derringer posted, indispensable tool.
When I'm making a pedal I always say to myself, "It's not complete until I've used my solder sucker at least once!"
Hopefully someday I will not need it so much! 

[tenser75]

1. yes i have a sucker, but i have never used it (duh) it must in some drawer..., I will give it another try tomorrow!

2. sanding is a great suggestion... duh again!

THANKS eveybody

[ShOrEbReAk]

I am a total noob and thought oh look eBay has cheap solder wick! Let's just say I had to buy some real stuff for it to work.

I put the iron across the three pins on the back and they pop out but hey might be beginners luck.

Also have a sucker but not sure how to use it properly, but that's what YouTube is for hahaha seen it done but doing it are different thing.

Troy

[Phoenix]

On soldering to the backs of pots, yes, some brands do not use a solderable plating, or at least have some sort of oily coating to prevent corrosion, in this case it's usually necessary to sand or otherwise abrade the surface, but it's usually preferable to avoid this if possible, as we don't know what the composition of the substrate is, and theoretically the plating should accept solder.

The best trick is FLUX, and lots of it. Electrical solder has flux core, but extra flux can really make a huge difference. You can get it in paste, rosin, liquid and other forms. One of the most convenient (but most expensive comparatively) is the flux pen. These have a felt tip much like a sharpie that when depressed deposits flux. Flux helps to deoxidize and clean the joint before the solder wets the surface.

Depending on the type of flux, it may or may not need to be cleaned after making the joint to prevent corrosion. Activated flux (RA flux) needs to be cleaned, medium (RMA) may or may not, non activated (R) should not need cleaning. Refer to the data sheet for specifics. There are various other types of flux, such as no-clean and water soluble. Ethanol/methanol/isopropyl alcohol cleans all types well, as does water for the water soluble type. There are specialist flux cleaners but they're generally significantly more expensive, it's up to you whether they are worth the extra cost.

[bool]

The best trick is FLUX, and lots of it.

This.
And wood toothpicks + handheld solderpumps. (like the swedish-made one that Austin Powers had).

[Phoenix]

1. how to desolder multiple legs (3 or more) components?
I want to salvage elements from old prototypes: 3pdt switches, trannies, pcb mounted jacks, etc... which are very difficult to desolder... what's the best technique?

The advice you've already gotten is good, ie solder sucker, solder braid: but the cheap stuff is no good, if you can find it, buy Goot, it's almost universally regarded as the best. Also, solder braid comes pre-loaded with flux (that's why it soaks up solder so readily), but that flux can dry out with time. If your solder braid isn't working that well, add some... you guessed it: FLUX!

For things like TO92 transistors with three legs, you can often bridge the three pads with your tip and some extra solder. Counterintuitively, you often want to ADD solder when desoldering, if you're trying to salvage the part that is. Fresh solder flows better and can help to add thermal mass and keep everything flowing longer. When you're done then you can use a solder sucker/braid to clean the holes/pads if you need.

You can also play the wiggle game, heating as many pads as you can and slowly levering the part up one direction, then the other, ad nauseam until the part finally comes free. Be careful to avoid overheating the pads though as if you apply heat for too long the traces can delaminate or through-hole plating can be damaged. You may need to get something only part way out before allowing it to cool for a while, then continuing to avoid damaging things. Hemostats (basically ratcheting tweezers/pliers) can be useful as heatsinks to avoid damaging things.

There are also vacuum desoldering irons, which are specialist pieces of equipment, but some reasonable ones can be had relatively inexpensively these days eBay example. These make quick work of desoldering.
Don't bother with the cheaper manual ones like this, they're junk and will clog immediately.

2. I'm trying to solder a ground wire to the back of a pot (metal, no plastic) but it seems the tin doesn't stick... is this a matter of power/ heat? i tried at 800F with my Weller WDS50... no luck

That temperature is part of your problem, that is FAR too hot. At those temperatures you'll be burning off the flux before it can do its job. 600F should be your baseline temp, and you should never need to go above 660F.
I believe the WDS50 is an 50W iron, so it should have more than enough power and thermal mass. Seriously, try some extra flux, it'll make all the difference.

[blackieNYC]

beware of the "no-clean" solder wick, it's terrible.
with a transistor, or a 4 pin bridge rectifier, you can pool the solder across some legs as stated or maybe even hop around with the tip while pulling on it gently, to get the part out.
Then you can desolder, which is a lot easier when it's just a pad-n-puddle with the component leg removed.
Dumb questions I have to ask: Do you need to solder the back of the pot?  no metal box I take it. Are you sure you have leaded solder?  Have to ask. Since we are making priceless heirlooms that our offspring will hand down for generations, it's not totally environmentally irresponsible to use lead.

[tubegeek]

(like the swedish-made one that Austin Powers had).

What if that's not his bag?

[tenser75]

beware of the "no-clean" solder wick, it's terrible.
with a transistor, or a 4 pin bridge rectifier, you can pool the solder across some legs as stated or maybe even hop around with the tip while pulling on it gently, to get the part out.
Then you can desolder, which is a lot easier when it's just a pad-n-puddle with the component leg removed.
Dumb questions I have to ask: Do you need to solder the back of the pot?  no metal box I take it. Are you sure you have leaded solder?  Have to ask. Since we are making priceless heirlooms that our offspring will hand down for generations, it's not totally environmentally irresponsible to use lead.

i'm using a good quality non-lead solder don't remember the brand but i paid it like $40